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Chinopoulos C. Complex I activity in hypoxia: implications for oncometabolism. Biochem Soc Trans 2024; 52:529-538. [PMID: 38526218 PMCID: PMC11088919 DOI: 10.1042/bst20230189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/06/2024] [Accepted: 03/14/2024] [Indexed: 03/26/2024]
Abstract
Certain cancer cells within solid tumors experience hypoxia, rendering them incapable of oxidative phosphorylation (OXPHOS). Despite this oxygen deficiency, these cells exhibit biochemical pathway activity that relies on NAD+. This mini-review scrutinizes the persistent, residual Complex I activity that oxidizes NADH in the absence of oxygen as the electron acceptor. The resulting NAD+ assumes a pivotal role in fueling the α-ketoglutarate dehydrogenase complex, a critical component in the oxidative decarboxylation branch of glutaminolysis - a hallmark oncometabolic pathway. The proposition is that through glutamine catabolism, high-energy phosphate intermediates are produced via substrate-level phosphorylation in the mitochondrial matrix substantiated by succinyl-CoA ligase, partially compensating for an OXPHOS deficiency. These insights provide a rationale for exploring Complex I inhibitors in cancer treatment, even when OXPHOS functionality is already compromised.
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2
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Ravasz D, Bui D, Nazarian S, Pallag G, Karnok N, Roberts J, Marzullo BP, Tennant DA, Greenwood B, Kitayev A, Hill C, Komlódi T, Doerrier C, Cunatova K, Fernandez-Vizarra E, Gnaiger E, Kiebish MA, Raska A, Kolev K, Czumbel B, Narain NR, Seyfried TN, Chinopoulos C. Residual Complex I activity and amphidirectional Complex II operation support glutamate catabolism through mtSLP in anoxia. Sci Rep 2024; 14:1729. [PMID: 38242919 PMCID: PMC10798963 DOI: 10.1038/s41598-024-51365-4] [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: 05/05/2023] [Accepted: 01/04/2024] [Indexed: 01/21/2024] Open
Abstract
Anoxia halts oxidative phosphorylation (OXPHOS) causing an accumulation of reduced compounds in the mitochondrial matrix which impedes dehydrogenases. By simultaneously measuring oxygen concentration, NADH autofluorescence, mitochondrial membrane potential and ubiquinone reduction extent in isolated mitochondria in real-time, we demonstrate that Complex I utilized endogenous quinones to oxidize NADH under acute anoxia. 13C metabolic tracing or untargeted analysis of metabolites extracted during anoxia in the presence or absence of site-specific inhibitors of the electron transfer system showed that NAD+ regenerated by Complex I is reduced by the 2-oxoglutarate dehydrogenase Complex yielding succinyl-CoA supporting mitochondrial substrate-level phosphorylation (mtSLP), releasing succinate. Complex II operated amphidirectionally during the anoxic event, providing quinones to Complex I and reducing fumarate to succinate. Our results highlight the importance of quinone provision to Complex I oxidizing NADH maintaining glutamate catabolism and mtSLP in the absence of OXPHOS.
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Affiliation(s)
- Dora Ravasz
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - David Bui
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Sara Nazarian
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Gergely Pallag
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Noemi Karnok
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Jennie Roberts
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Bryan P Marzullo
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | | | | | | | - Timea Komlódi
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
- Oroboros Instruments, Innsbruck, Austria
| | | | - Kristyna Cunatova
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
| | | | | | | | - Alexandra Raska
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Krasimir Kolev
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Bence Czumbel
- Department of Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | | | - Thomas N Seyfried
- Biology Department, Boston College, Chestnut Hill, Boston, MA, 02467, USA
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Mishukov A, Mndlyan E, Berezhnov AV, Kobyakova M, Lomovskaya Y, Holmuhamedov E, Odinokova I. TR-57 Treatment of SUM159 Cells Induces Mitochondrial Dysfunction without Affecting Membrane Potential. Int J Mol Sci 2024; 25:1193. [PMID: 38256264 PMCID: PMC10816083 DOI: 10.3390/ijms25021193] [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: 12/04/2023] [Revised: 01/08/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024] Open
Abstract
Recent works identified ClpXP, mitochondrial caseinolytic protease, as the only target of imipridones, a new class of antitumor agents. Our study of the mechanism of imipridone derivative TR-57 action in SUM159 human breast cancer cells demonstrated mitochondrial fragmentation, degradation of mitochondrial mtDNA and mitochondrial dysfunction due to inhibition of Complex I and Complex II activity. Complete inhibition of oxidative phosphorylation accompanied 90, 94, 88 and 87% decreases in the content of Complex I, II, III and IV proteins, respectively. The content of the FOF1-ATPase subunits decreased sharply by approximately 35% after 24 h and remained unchanged up to 72 h of incubation with TR-57. At the same time, a disappearance of the ATPIF1, the natural inhibitor of mitochondrial FOF1-ATPase, was observed after 24 h exposure to TR-57. ATPase inhibitor oligomycin did not affect the mitochondrial membrane potential in intact SUM159, whereas it caused a 65% decrease in TR-57-treated cells. SUM159 cells incubated with TR57 up to 72 h retained the level of proteins facilitating the ATP transfer across the mitochondrial membranes: VDAC1 expression was not affected, while expression of ANT-1/2 and APC2 increased by 20% and 40%, respectively. Thus, our results suggest that although TR-57 treatment leads to complete inhibition of respiratory chain activity of SUM159 cells, hydrolysis of cytoplasmic ATP by reversal activity of FOF1-ATPase supports mitochondrial polarization.
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Affiliation(s)
- Artem Mishukov
- Center of Theoretical Problems of Physico-Chemical Pharmacology, Russian Academy of Sciences, 109029 Moscow, Russia;
| | - Ekaterina Mndlyan
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.); (M.K.); (Y.L.); (E.H.)
| | - Alexey V. Berezhnov
- Institute of Cell Biophysics, Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia;
| | - Margarita Kobyakova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.); (M.K.); (Y.L.); (E.H.)
| | - Yana Lomovskaya
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.); (M.K.); (Y.L.); (E.H.)
| | - Ekhson Holmuhamedov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.); (M.K.); (Y.L.); (E.H.)
| | - Irina Odinokova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.); (M.K.); (Y.L.); (E.H.)
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4
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Taleva G, Husová M, Panicucci B, Hierro-Yap C, Pineda E, Biran M, Moos M, Šimek P, Butter F, Bringaud F, Zíková A. Mitochondrion of the Trypanosoma brucei long slender bloodstream form is capable of ATP production by substrate-level phosphorylation. PLoS Pathog 2023; 19:e1011699. [PMID: 37819951 PMCID: PMC10593219 DOI: 10.1371/journal.ppat.1011699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/23/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
The long slender bloodstream form Trypanosoma brucei maintains its essential mitochondrial membrane potential (ΔΨm) through the proton-pumping activity of the FoF1-ATP synthase operating in the reverse mode. The ATP that drives this hydrolytic reaction has long been thought to be generated by glycolysis and imported from the cytosol via an ATP/ADP carrier (AAC). Indeed, we demonstrate that AAC is the only carrier that can import ATP into the mitochondrial matrix to power the hydrolytic activity of the FoF1-ATP synthase. However, contrary to expectations, the deletion of AAC has no effect on parasite growth, virulence or levels of ΔΨm. This suggests that ATP is produced by substrate-level phosphorylation pathways in the mitochondrion. Therefore, we knocked out the succinyl-CoA synthetase (SCS) gene, a key mitochondrial enzyme that produces ATP through substrate-level phosphorylation in this parasite. Its absence resulted in changes to the metabolic landscape of the parasite, lowered virulence, and reduced mitochondrial ATP content. Strikingly, these SCS mutant parasites become more dependent on AAC as demonstrated by a 25-fold increase in their sensitivity to the AAC inhibitor, carboxyatractyloside. Since the parasites were able to adapt to the loss of SCS in culture, we also analyzed the more immediate phenotypes that manifest when SCS expression is rapidly suppressed by RNAi. Importantly, when performed under nutrient-limited conditions mimicking various host environments, SCS depletion strongly affected parasite growth and levels of ΔΨm. In totality, the data establish that the long slender bloodstream form mitochondrion is capable of generating ATP via substrate-level phosphorylation pathways.
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Affiliation(s)
- Gergana Taleva
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech republic
| | - Michaela Husová
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech republic
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech republic
| | - Carolina Hierro-Yap
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech republic
| | - Erika Pineda
- Univ. Bordeaux, CNRS, Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, Bordeaux, France
| | - Marc Biran
- Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques (CRMSB), Bordeaux, France
| | - Martin Moos
- Institute of Entomology, Biology Centre CAS, Ceske Budejovice, Czech republic
| | - Petr Šimek
- Institute of Entomology, Biology Centre CAS, Ceske Budejovice, Czech republic
| | - Falk Butter
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Greifswald, Germany
| | - Frédéric Bringaud
- Univ. Bordeaux, CNRS, Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), Université de Bordeaux, Bordeaux, France
| | - Alena Zíková
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech republic
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5
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Murphy E, Liu JC. Mitochondrial calcium and reactive oxygen species in cardiovascular disease. Cardiovasc Res 2023; 119:1105-1116. [PMID: 35986915 PMCID: PMC10411964 DOI: 10.1093/cvr/cvac134] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/26/2022] [Accepted: 06/02/2022] [Indexed: 08/11/2023] Open
Abstract
Cardiomyocytes are one of the most mitochondria-rich cell types in the body, with ∼30-40% of the cell volume being composed of mitochondria. Mitochondria are well established as the primary site of adenosine triphosphate (ATP) generation in a beating cardiomyocyte, generating up to 90% of its ATP. Mitochondria have many functions in the cell, which could contribute to susceptibility to and development of cardiovascular disease (CVD). Mitochondria are key players in cell metabolism, ATP production, reactive oxygen species (ROS) production, and cell death. Mitochondrial calcium (Ca2+) plays a critical role in many of these pathways, and thus the dynamics of mitochondrial Ca2+ are important in regulating mitochondrial processes. Alterations in these varied and in many cases interrelated functions play an important role in CVD. This review will focus on the interrelationship of mitochondrial energetics, Ca2+, and ROS and their roles in CVD. Recent insights into the regulation and dysregulation of these pathways have led to some novel therapeutic approaches.
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Affiliation(s)
- Elizabeth Murphy
- NHLBI, NIH, Bethesda, MD and Department of Integrative Biology and Physiology, University of Minnesota, 2231 6th St. SE, Minneapolis, MN 55455, USA
| | - Julia C Liu
- NHLBI, NIH, Bethesda, MD and Department of Integrative Biology and Physiology, University of Minnesota, 2231 6th St. SE, Minneapolis, MN 55455, USA
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6
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Preservation of mitochondrial membrane potential is necessary for lifespan extension from dietary restriction. GeroScience 2023:10.1007/s11357-023-00766-w. [PMID: 36877298 PMCID: PMC10400507 DOI: 10.1007/s11357-023-00766-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/01/2023] [Indexed: 03/07/2023] Open
Abstract
Dietary restriction (DR) increases lifespan in many organisms, but its underlying mechanisms are not fully understood. Mitochondria play a central role in metabolic regulation and are known to undergo changes in structure and function in response to DR. Mitochondrial membrane potential (Δψm) is the driving force for ATP production and mitochondrial outputs that integrate many cellular signals. One such signal regulated by Δψm is nutrient-status sensing. Here, we tested the hypothesis that DR promotes longevity through preserved Δψm during adulthood. Using the nematode Caenorhabditis elegans, we find that Δψm declines with age relatively early in the lifespan, and this decline is attenuated by DR. Pharmacologic depletion of Δψm blocked the longevity and health benefits of DR. Genetic perturbation of Δψm and mitochondrial ATP availability similarly prevented lifespan extension from DR. Taken together, this study provides further evidence that appropriate regulation of Δψm is a critical factor for health and longevity in response to DR.
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7
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Kumar S, Choudhary N, Faruq M, Kumar A, Saran RK, Indercanti PK, Singh V, Sait H, Jaitley S, Valis M, Kuca K, Polipalli SK, Kumar M, Singh T, Suravajhala P, Sharma R, Kapoor S. Anastrozole-mediated modulation of mitochondrial activity by inhibition of mitochondrial permeability transition pore opening: an initial perspective. J Biomol Struct Dyn 2023; 41:14063-14079. [PMID: 36815262 DOI: 10.1080/07391102.2023.2176927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/31/2023] [Indexed: 02/24/2023]
Abstract
The mitochondrial permeability transition pore (mtPTP) plays a vital role in altering the structure and function of mitochondria. Cyclophilin D (CypD) is a mitochondrial protein that regulates mtPTP function and a known drug target for therapeutic studies involving mitochondria. While the effect of aromatase inhibition on the mtPTP has been studied previously, the effect of anastrozole on the mtPTP has not been completely elucidated. The role of anastrozole in modulating the mtPTP was evaluated by docking, molecular dynamics and network-guided studies using human CypD data. The peripheral blood mononuclear cells (PBMCs) of patients with mitochondrial disorders and healthy controls were treated with anastrozole and evaluated for mitochondrial permeability transition pore (mtPTP) function and apoptosis using a flow cytometer. Spectrophotometry was employed for estimating total ATP levels. The anastrozole-CypD complex is more stable than cyclosporin A (CsA)-CypD. Anastrozole performed better than cyclosporine in inhibiting mtPTP. Additional effects included inducing mitochondrial membrane depolarization and a reduction in mitochondrial swelling and superoxide generation, intrinsic caspase-3 activity and cellular apoptosis, along with an increase in ATP levels. Anastrozole may serve as a potential therapeutic agent for mitochondrial disorders and ameliorate the clinical phenotype by regulating the activity of mtPTP. However, further studies are required to substantiate our preliminary findings.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Somesh Kumar
- Pediatrics Genetics & Research Laboratory, Department of Pediatrics, Maulana Azad Medical College & Associated LN Hospital, Delhi, India
| | - Neha Choudhary
- Centre for Computational Biology and Bioinformatics, Central University of Himachal Pradesh, Dharamsala, India
| | - Mohammed Faruq
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research (CSIR), Delhi, India
| | - Arun Kumar
- Department of Emergency Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, India
- Department of Zoology, Kirori Mal College, University of Delhi, Delhi, India
| | - Ravindra K Saran
- Department of Pathology, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research, Delhi, India
| | | | - Vikram Singh
- Centre for Computational Biology and Bioinformatics, Central University of Himachal Pradesh, Dharamsala, India
| | - Haseena Sait
- Pediatrics Genetics & Research Laboratory, Department of Pediatrics, Maulana Azad Medical College & Associated LN Hospital, Delhi, India
| | - Sunita Jaitley
- Department of Biomedical Sciences, Acharya Narendra Dev College, University of Delhi, Delhi, India
| | - Martin Valis
- Department of Neurology of the Medical Faculty of Charles University and University Hospital in Hradec Králové, Hradec Králové, Czech Republic
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Králové, Hradec Králové, Czech Republic
| | - Sunil K Polipalli
- Pediatrics Genetics & Research Laboratory, Department of Pediatrics, Maulana Azad Medical College & Associated LN Hospital, Delhi, India
| | - Manoj Kumar
- Department of Emergency Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, India
- Department of Microbiology, World College of Medical Science and Research, Jhajjar, Haryana, India
| | - Tejveer Singh
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | | | - Rohit Sharma
- Department of Rasa Shastra and Bhaishajya Kalpana, Faculty of Ayurveda, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Seema Kapoor
- Pediatrics Genetics & Research Laboratory, Department of Pediatrics, Maulana Azad Medical College & Associated LN Hospital, Delhi, India
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Wang Y, Wang Y, Yue G, Zhao Y. Energy metabolism disturbance in migraine: From a mitochondrial point of view. Front Physiol 2023; 14:1133528. [PMID: 37123270 PMCID: PMC10133718 DOI: 10.3389/fphys.2023.1133528] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/20/2023] [Indexed: 05/02/2023] Open
Abstract
Migraine is a serious central nervous system disease with a high incidence rate. Its pathogenesis is very complex, which brings great difficulties for clinical treatment. Recently, many studies have revealed that mitochondrial dysfunction may play a key role in migraine, which affects the hyperosmotic of Ca2+, the excessive production of free radicals, the decrease of mitochondrial membrane potential, the imbalance of mPTP opening and closing, and the decrease of oxidative phosphorylation level, which leads to neuronal energy exhaustion and apoptosis, and finally lessens the pain threshold and migraine attack. This article mainly introduces cortical spreading depression, a pathogenesis of migraine, and then damages the related function of mitochondria, which leads to migraine. Oxidative phosphorylation and the tricarboxylic acid cycle are the main ways to provide energy for the body. 95 percent of the energy needed for cell survival is provided by the mitochondrial respiratory chain. At the same time, hypoxia can lead to cell death and migraine. The pathological opening of the mitochondrial permeability transition pore can promote the interaction between pro-apoptotic protein and mitochondrial, destroy the structure of mPTP, and further lead to cell death. The increase of mPTP permeability can promote the accumulation of reactive oxygen species, which leads to a series of changes in the expression of proteins related to energy metabolism. Both Nitric oxide and Calcitonin gene-related peptide are closely related to the attack of migraine. Recent studies have shown that changes in their contents can also affect the energy metabolism of the body, so this paper reviews the above mechanisms and discusses the mechanism of brain energy metabolism of migraine, to provide new strategies for the prevention and treatment of migraine and promote the development of individualized and accurate treatment of migraine.
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Affiliation(s)
- Yicheng Wang
- Department of Neurology, The Third Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Yongli Wang
- Department of Neurology, Xiamen Hospital of Traditional Chinese Medicine, Xiamen, China
| | - Guangxin Yue
- Institute of Basic Theory for Chinese Medicine, Chinese Academy of Chinese Medical Sciences, Beijing, China
| | - Yonglie Zhao
- Department of Neurology, The Third Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
- *Correspondence: Yonglie Zhao,
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9
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Kinetic Mathematical Modeling of Oxidative Phosphorylation in Cardiomyocyte Mitochondria. Cells 2022; 11:cells11244020. [PMID: 36552784 PMCID: PMC9777548 DOI: 10.3390/cells11244020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022] Open
Abstract
Oxidative phosphorylation (OXPHOS) is an oxygen-dependent process that consumes catabolized nutrients to produce adenosine triphosphate (ATP) to drive energy-dependent biological processes such as excitation-contraction coupling in cardiomyocytes. In addition to in vivo and in vitro experiments, in silico models are valuable for investigating the underlying mechanisms of OXPHOS and predicting its consequences in both physiological and pathological conditions. Here, we compare several prominent kinetic models of OXPHOS in cardiomyocytes. We examine how their mathematical expressions were derived, how their parameters were obtained, the conditions of their experimental counterparts, and the predictions they generated. We aim to explore the general landscape of energy production mechanisms in cardiomyocytes for future in silico models.
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10
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Horváth G, Sváb G, Komlódi T, Ravasz D, Kacsó G, Doczi J, Chinopoulos C, Ambrus A, Tretter L. Reverse and Forward Electron Flow-Induced H2O2 Formation Is Decreased in α-Ketoglutarate Dehydrogenase (α-KGDH) Subunit (E2 or E3) Heterozygote Knock Out Animals. Antioxidants (Basel) 2022; 11:antiox11081487. [PMID: 36009207 PMCID: PMC9404749 DOI: 10.3390/antiox11081487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 12/04/2022] Open
Abstract
α-ketoglutarate dehydrogenase complex (KGDHc), or 2-oxoglutarate dehydrogenase complex (OGDHc) is a rate-limiting enzyme in the tricarboxylic acid cycle, that has been identified in neurodegenerative diseases such as in Alzheimer’s disease. The aim of the present study was to establish the role of the KGDHc and its subunits in the bioenergetics and reactive oxygen species (ROS) homeostasis of brain mitochondria. To study the bioenergetic profile of KGDHc, genetically modified mouse strains were used having a heterozygous knock out (KO) either in the dihydrolipoyl succinyltransferase (DLST+/−) or in the dihydrolipoyl dehydrogenase (DLD+/−) subunit. Mitochondrial oxygen consumption, hydrogen peroxide (H2O2) production, and expression of antioxidant enzymes were measured in isolated mouse brain mitochondria. Here, we demonstrate that the ADP-stimulated respiration of mitochondria was partially arrested in the transgenic animals when utilizing α-ketoglutarate (α-KG or 2-OG) as a fuel substrate. Succinate and α-glycerophosphate (α-GP), however, did not show this effect. The H2O2 production in mitochondria energized with α-KG was decreased after inhibiting the adenine nucleotide translocase and Complex I (CI) in the transgenic strains compared to the controls. Similarly, the reverse electron transfer (RET)-evoked H2O2 formation supported by succinate or α-GP were inhibited in mitochondria isolated from the transgenic animals. The decrease of RET-evoked ROS production by DLST+/− or DLD+/− KO-s puts the emphasis of the KGDHc in the pathomechanism of ischemia-reperfusion evoked oxidative stress. Supporting this notion, expression of the antioxidant enzyme glutathione peroxidase was also decreased in the KGDHc transgenic animals suggesting the attenuation of ROS-producing characteristics of KGDHc. These findings confirm the contribution of the KGDHc to the mitochondrial ROS production and in the pathomechanism of ischemia-reperfusion injury.
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11
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Proline Oxidation Supports Mitochondrial ATP Production When Complex I Is Inhibited. Int J Mol Sci 2022; 23:ijms23095111. [PMID: 35563503 PMCID: PMC9106064 DOI: 10.3390/ijms23095111] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 02/01/2023] Open
Abstract
The oxidation of proline to pyrroline-5-carboxylate (P5C) leads to the transfer of electrons to ubiquinone in mitochondria that express proline dehydrogenase (ProDH). This electron transfer supports Complexes CIII and CIV, thus generating the protonmotive force. Further catabolism of P5C forms glutamate, which fuels the citric acid cycle that yields the reducing equivalents that sustain oxidative phosphorylation. However, P5C and glutamate catabolism depend on CI activity due to NAD+ requirements. NextGen-O2k (Oroboros Instruments) was used to measure proline oxidation in isolated mitochondria of various mouse tissues. Simultaneous measurements of oxygen consumption, membrane potential, NADH, and the ubiquinone redox state were correlated to ProDH activity and F1FO-ATPase directionality. Proline catabolism generated a sufficiently high membrane potential that was able to maintain the F1FO-ATPase operation in the forward mode. This was observed in CI-inhibited mouse liver and kidney mitochondria that exhibited high levels of proline oxidation and ProDH activity. This action was not observed under anoxia or when either CIII or CIV were inhibited. The duroquinone fueling of CIII and CIV partially reproduced the effects of proline. Excess glutamate, however, could not reproduce the proline effect, suggesting that processes upstream of the glutamate conversion from proline were involved. The ProDH inhibitors tetrahydro-2-furoic acid and, to a lesser extent, S-5-oxo-2-tetrahydrofurancarboxylic acid abolished all proline effects. The data show that ProDH-directed proline catabolism could generate sufficient CIII and CIV proton pumping, thus supporting ATP production by the F1FO-ATPase even under CI inhibition.
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12
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Zíková A. Mitochondrial adaptations throughout the Trypanosoma brucei life cycle. J Eukaryot Microbiol 2022; 69:e12911. [PMID: 35325490 DOI: 10.1111/jeu.12911] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/18/2022] [Accepted: 03/18/2022] [Indexed: 12/01/2022]
Abstract
The unicellular parasite Trypanosoma brucei has a digenetic life cycle that alternates between a mammalian host and an insect vector. During programmed development, this extracellular parasite encounters strikingly different environments that determine its energy metabolism. Functioning as a bioenergetic, biosynthetic, and signaling center, the single mitochondrion of T. brucei is drastically remodeled to support the dynamic cellular demands of the parasite. This manuscript will provide an up-to-date overview of how the distinct T. brucei developmental stages differ in their mitochondrial metabolic and bioenergetic pathways, with a focus on the electron transport chain, proline oxidation, TCA cycle, acetate production, and ATP generation. Although mitochondrial metabolic rewiring has always been simply viewed as a consequence of the differentiation process, the possibility that certain mitochondrial activities reinforce parasite differentiation will be explored.
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Affiliation(s)
- Alena Zíková
- Biology Centre CAS, Institute of Parasitology, University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic
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13
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Can the Mitochondrial Metabolic Theory Explain Better the Origin and Management of Cancer than Can the Somatic Mutation Theory? Metabolites 2021; 11:metabo11090572. [PMID: 34564387 PMCID: PMC8467939 DOI: 10.3390/metabo11090572] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/24/2022] Open
Abstract
A theory that can best explain the facts of a phenomenon is more likely to advance knowledge than a theory that is less able to explain the facts. Cancer is generally considered a genetic disease based on the somatic mutation theory (SMT) where mutations in proto-oncogenes and tumor suppressor genes cause dysregulated cell growth. Evidence is reviewed showing that the mitochondrial metabolic theory (MMT) can better account for the hallmarks of cancer than can the SMT. Proliferating cancer cells cannot survive or grow without carbons and nitrogen for the synthesis of metabolites and ATP (Adenosine Triphosphate). Glucose carbons are essential for metabolite synthesis through the glycolysis and pentose phosphate pathways while glutamine nitrogen and carbons are essential for the synthesis of nitrogen-containing metabolites and ATP through the glutaminolysis pathway. Glutamine-dependent mitochondrial substrate level phosphorylation becomes essential for ATP synthesis in cancer cells that over-express the glycolytic pyruvate kinase M2 isoform (PKM2), that have deficient OxPhos, and that can grow in either hypoxia (0.1% oxygen) or in cyanide. The simultaneous targeting of glucose and glutamine, while elevating levels of non-fermentable ketone bodies, offers a simple and parsimonious therapeutic strategy for managing most cancers.
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14
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Rigotto G, Zentilin L, Pozzan T, Basso E. Effects of Mild Excitotoxic Stimulus on Mitochondria Ca 2+ Handling in Hippocampal Cultures of a Mouse Model of Alzheimer's Disease. Cells 2021; 10:cells10082046. [PMID: 34440815 PMCID: PMC8394681 DOI: 10.3390/cells10082046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 01/19/2023] Open
Abstract
In Alzheimer’s disease (AD), the molecular mechanisms involved in the neurodegeneration are still incompletely defined, though this aspect is crucial for a better understanding of the malady and for devising effective therapies. Mitochondrial dysfunctions and altered Ca2+ signaling have long been implicated in AD, though it is debated whether these events occur early in the course of the pathology, or whether they develop at late stages of the disease and represent consequences of different alterations. Mitochondria are central to many aspects of cellular metabolism providing energy, lipids, reactive oxygen species, signaling molecules for cellular quality control, and actively shaping intracellular Ca2+ signaling, modulating the intensity and duration of the signal itself. Abnormalities in the ability of mitochondria to take up and subsequently release Ca2+ could lead to changes in the metabolism of the organelle, and of the cell as a whole, that eventually result in cell death. We sought to investigate the role of mitochondria and Ca2+ signaling in a model of Familial Alzheimer’s disease and found early alterations in mitochondria physiology under stressful condition, namely, reduced maximal respiration, decreased ability to sustain membrane potential, and a slower return to basal matrix Ca2+ levels after a mild excitotoxic stimulus. Treatment with an inhibitor of the permeability transition pore attenuated some of these mitochondrial disfunctions and may represent a promising tool to ameliorate mitochondria and cellular functioning in AD and prevent or slow down cell loss in the disease.
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Affiliation(s)
- Giulia Rigotto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (G.R.); (T.P.)
| | - Lorena Zentilin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy;
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (G.R.); (T.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
- Venetian Institute of Molecular Medicine (VIMM), 35131 Padua, Italy
| | - Emy Basso
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (G.R.); (T.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
- Correspondence:
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15
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Abstract
PURPOSE OF REVIEW To present a method enabling in vivo quantification of tissue membrane potential (ΔΨT), a proxy of mitochondrial membrane potential (ΔΨm), to review the origin and role of ΔΨm, and to highlight potential applications of myocardial ΔΨT imaging. RECENT FINDINGS Radiolabelled lipophilic cations have been used for decades to measure ΔΨm in vitro. Using similar compounds labeled with positron emitters and appropriate compartment modeling, this technique now allows in vivo quantification of ΔΨT with positron emission tomography. Studies have confirmed the feasibility of measuring myocardial ΔΨT in both animals and humans. In addition, ΔΨT showed very low variability among healthy subjects, suggesting that this method could allow detection of relatively small pathological changes. In vivo assessment of myocardial ΔΨT provides a new tool to study the pathophysiology of cardiovascular diseases and has the potential to serve as a new biomarker to assess disease stage, prognosis, and response to therapy.
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16
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Auger C, Vinaik R, Appanna VD, Jeschke MG. Beyond mitochondria: Alternative energy-producing pathways from all strata of life. Metabolism 2021; 118:154733. [PMID: 33631145 PMCID: PMC8052308 DOI: 10.1016/j.metabol.2021.154733] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/09/2021] [Accepted: 02/13/2021] [Indexed: 12/12/2022]
Abstract
It is well-established that mitochondria are the powerhouses of the cell, producing adenosine triphosphate (ATP), the universal energy currency. However, the most significant strengths of the electron transport chain (ETC), its intricacy and efficiency, are also its greatest downfalls. A reliance on metal complexes (FeS clusters, hemes), lipid moities such as cardiolipin, and cofactors including alpha-lipoic acid and quinones render oxidative phosphorylation vulnerable to environmental toxins, intracellular reactive oxygen species (ROS) and fluctuations in diet. To that effect, it is of interest to note that temporal disruptions in ETC activity in most organisms are rarely fatal, and often a redundant number of failsafes are in place to permit continued ATP production when needed. Here, we highlight the metabolic reconfigurations discovered in organisms ranging from parasitic Entamoeba to bacteria such as pseudomonads and then complex eukaryotic systems that allow these species to adapt to and occasionally thrive in harsh environments. The overarching aim of this review is to demonstrate the plasticity of metabolic networks and recognize that in times of duress, life finds a way.
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Affiliation(s)
- Christopher Auger
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada
| | - Roohi Vinaik
- University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | | | - Marc G Jeschke
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada; University of Toronto, Toronto, Ontario M5S 1A1, Canada.
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17
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Hierro-Yap C, Šubrtová K, Gahura O, Panicucci B, Dewar C, Chinopoulos C, Schnaufer A, Zíková A. Bioenergetic consequences of F oF 1-ATP synthase/ATPase deficiency in two life cycle stages of Trypanosoma brucei. J Biol Chem 2021; 296:100357. [PMID: 33539923 PMCID: PMC7949148 DOI: 10.1016/j.jbc.2021.100357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/23/2020] [Accepted: 01/28/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial ATP synthase is a reversible nanomotor synthesizing or hydrolyzing ATP depending on the potential across the membrane in which it is embedded. In the unicellular parasite Trypanosoma brucei, the direction of the complex depends on the life cycle stage of this digenetic parasite: in the midgut of the tsetse fly vector (procyclic form), the FoF1–ATP synthase generates ATP by oxidative phosphorylation, whereas in the mammalian bloodstream form, this complex hydrolyzes ATP and maintains mitochondrial membrane potential (ΔΨm). The trypanosome FoF1–ATP synthase contains numerous lineage-specific subunits whose roles remain unknown. Here, we seek to elucidate the function of the lineage-specific protein Tb1, the largest membrane-bound subunit. In procyclic form cells, Tb1 silencing resulted in a decrease of FoF1–ATP synthase monomers and dimers, rerouting of mitochondrial electron transfer to the alternative oxidase, reduced growth rate and cellular ATP levels, and elevated ΔΨm and total cellular reactive oxygen species levels. In bloodstream form parasites, RNAi silencing of Tb1 by ∼90% resulted in decreased FoF1–ATPase monomers and dimers, but it had no apparent effect on growth. The same findings were obtained by silencing of the oligomycin sensitivity-conferring protein, a conserved subunit in T. brucei FoF1–ATP synthase. However, as expected, nearly complete Tb1 or oligomycin sensitivity-conferring protein suppression was lethal because of the inability to sustain ΔΨm. The diminishment of FoF1–ATPase complexes was further accompanied by a decreased ADP/ATP ratio and reduced oxygen consumption via the alternative oxidase. Our data illuminate the often diametrically opposed bioenergetic consequences of FoF1–ATP synthase loss in insect versus mammalian forms of the parasite.
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Affiliation(s)
- Carolina Hierro-Yap
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Karolína Šubrtová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Caroline Dewar
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | | | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.
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18
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Pepperberg DR. Amyloid-β-Dependent Inactivation of the Mitochondrial Electron Transport Chain at Low Transmembrane Potential: An Ameliorating Process in Hypoxia-Associated Neurodegenerative Disease? J Alzheimers Dis 2020; 72:663-675. [PMID: 31640091 DOI: 10.3233/jad-190476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cerebral hypoperfusion-induced hypoxia, a condition that impairs oxygen utilization and thus ATP production by mitochondrial oxidative phosphorylation (oxphos), is thought to contribute to neural degeneration in Alzheimer's disease. However, hypoxia upregulates the generation of amyloid-β (Aβ), a group of peptides known to impair/inhibit the electron transport chain (ETC) of reactions that support oxphos in the inner mitochondrial membrane (IMM). This is a hypothesis paper that reconciles the hypoxia-induced upregulation of Aβ with Aβ's ETC-inhibiting action and, specifically, posits an oxphos-enhancing effect of this inhibition under conditions of newly developing or otherwise mild hypoxia. This effect is typically transient; that is, under conditions of prolonged or severe hypoxia, the oxphos-enhancing activity is overwhelmed by Aβ's well-known toxic actions on mitochondria and other cellular components. The hypothesis is motivated by evidence that the IMM transmembrane potential Ψm, an important determinant of ETC activity, exhibits heterogeneity, i.e., a range of values, among a given local population of mitochondria. It specifically proposes that during oxygen limitation, Aβ selectively inactivates ETC complexes in mitochondria that exhibit relatively low absolute values of Ψm, thereby suppressing oxygen binding and consumption by complex IV of the ETC in these mitochondria. This effect of Aβ on low-Ψm mitochondria is hypothesized to spare hypoxia-limited oxygen for oxphos-enabling utilization by the ETC of the remaining active, higher-Ψm local mitochondria, and thereby to increase overall ATP generated collectively by the local mitochondrial population, i.e., to ameliorate hypoxia-induced oxphos reduction. The protective action of Aβ hypothesized here may slow the early development of hypoxia-associated cellular deterioration/loss in Alzheimer's disease and perhaps other neurodegenerative diseases.
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Affiliation(s)
- David R Pepperberg
- Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
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19
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Hotka M, Cagalinec M, Hilber K, Hool L, Boehm S, Kubista H. L-type Ca 2+ channel-mediated Ca 2+ influx adjusts neuronal mitochondrial function to physiological and pathophysiological conditions. Sci Signal 2020; 13:eaaw6923. [PMID: 32047116 PMCID: PMC7116774 DOI: 10.1126/scisignal.aaw6923] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
L-type voltage-gated Ca2+ channels (LTCCs) are implicated in neurodegenerative processes and cell death. Accordingly, LTCC antagonists have been proposed to be neuroprotective, although this view is disputed, because intentional LTCC activation can also have beneficial effects. LTCC-mediated Ca2+ influx influences mitochondrial function, which plays a crucial role in the regulation of cell viability. Hence, we investigated the effect of modulating LTCC-mediated Ca2+ influx on mitochondrial function in cultured hippocampal neurons. To activate LTCCs, neuronal activity was stimulated by increasing extracellular K+ or by application of the GABAA receptor antagonist bicuculline. The activity of LTCCs was altered by application of an agonistic (Bay K8644) or an antagonistic (isradipine) dihydropyridine. Our results demonstrated that activation of LTCC-mediated Ca2+ influx affected mitochondrial function in a bimodal manner. At moderate stimulation strength, ATP synthase activity was enhanced, an effect that involved Ca2+-induced Ca2+ release from intracellular stores. In contrast, high LTCC-mediated Ca2+ loads led to a switch in ATP synthase activity to reverse-mode operation. This effect, which required nitric oxide, helped to prevent mitochondrial depolarization and sustained increases in mitochondrial Ca2+ Our findings indicate a complex role of LTCC-mediated Ca2+ influx in the tuning and maintenance of mitochondrial function. Therefore, the use of LTCC inhibitors to protect neurons from neurodegeneration should be reconsidered carefully.
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Affiliation(s)
- Matej Hotka
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
| | - Michal Cagalinec
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovakia
- Laboratory of Mitochondrial Dynamics, Department of Pharmacology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, University of Tartu, Ravila 19, 50 411 Tartu, Estonia
| | - Karlheinz Hilber
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Livia Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA 6009, Australia
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia
| | - Stefan Boehm
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Helmut Kubista
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
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20
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Depaoli MR, Karsten F, Madreiter-Sokolowski CT, Klec C, Gottschalk B, Bischof H, Eroglu E, Waldeck-Weiermair M, Simmen T, Graier WF, Malli R. Real-Time Imaging of Mitochondrial ATP Dynamics Reveals the Metabolic Setting of Single Cells. Cell Rep 2019; 25:501-512.e3. [PMID: 30304688 PMCID: PMC6456002 DOI: 10.1016/j.celrep.2018.09.027] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/07/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022] Open
Abstract
Reprogramming of metabolic pathways determines cell functions and fate. In our work, we have used organelle-targeted ATP biosensors to evaluate cellular metabolic settings with high resolution in real time. Our data indicate that mitochondria dynamically supply ATP for glucose phosphorylation in a variety of cancer cell types. This hexokinase-dependent process seems to be reversed upon the removal of glucose or other hexose sugars. Our data further verify that mitochondria in cancer cells have increased ATP consumption. Similar subcellular ATP fluxes occurred in young mouse embryonic fibroblasts (MEFs). However, pancreatic beta cells, senescent MEFs, and MEFs lacking mitofusin 2 displayed completely different mitochondrial ATP dynamics, indicative of increased oxidative phosphorylation. Our findings add perspective to the variability of the cellular bioenergetics and demonstrate that live cell imaging of mitochondrial ATP dynamics is a powerful tool to evaluate metabolic flexibility and heterogeneity at a single-cell level.
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Affiliation(s)
- Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Felix Karsten
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Corina T Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Christiane Klec
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; Division of Oncology, Research Unit for Long Non-coding RNAs and Genome Editing in Cancer, Medical University of Graz, Stiftingtalstraße 24, 8010 Graz, Austria
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Emrah Eroglu
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Thomas Simmen
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria.
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21
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Chinopoulos C. Quantification of mitochondrial DNA from peripheral tissues: Limitations in predicting the severity of neurometabolic disorders and proposal of a novel diagnostic test. Mol Aspects Med 2019; 71:100834. [PMID: 31740079 DOI: 10.1016/j.mam.2019.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 11/25/2022]
Abstract
Neurometabolic disorders stem from errors in metabolic processes yielding a neurological phenotype. A subset of those disorders encompasses mitochondrial abnormalities partially due to mitochondrial DNA (mtDNA) depletion. mtDNA depletion can be attributed to inheritance, spontaneous mutations or acquired from drug-related toxicities. In the armamentarium of diagnostic procedures, mtDNA quantification is a standard for disease classification. However, alterations in mtDNA obtained from peripheral tissues such as skin fibroblasts and blood cells do not often reflect the severity of the affected organ, in this case, the brain. The purpose of this review is to highlight the pitfalls of quantitating mtDNA from peripheral -and not limited to-tissues for diagnosing patients suffering from a variety of mtDNA depletion syndromes exhibiting neurologic abnormalities. In lieu, a qualitative test of mitochondrial substrate-level phosphorylation -even from peripheral tissues-reflecting the ability of mitochondria to rely on glutaminolysis in the presence of respiratory chain defects is proposed as a novel diagnostic assessment of mitochondrial functionality.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto St. 37-47, Budapest, 1094, Hungary.
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22
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Chinopoulos C, Seyfried TN. Mitochondrial Substrate-Level Phosphorylation as Energy Source for Glioblastoma: Review and Hypothesis. ASN Neuro 2019; 10:1759091418818261. [PMID: 30909720 PMCID: PMC6311572 DOI: 10.1177/1759091418818261] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and malignant of the primary adult brain cancers. Ultrastructural and biochemical evidence shows that GBM cells exhibit mitochondrial abnormalities incompatible with energy production through oxidative phosphorylation (OxPhos). Under such conditions, the mitochondrial F0-F1 ATP synthase operates in reverse at the expense of ATP hydrolysis to maintain a moderate membrane potential. Moreover, expression of the dimeric M2 isoform of pyruvate kinase in GBM results in diminished ATP output, precluding a significant ATP production from glycolysis. If ATP synthesis through both glycolysis and OxPhos was impeded, then where would GBM cells obtain high-energy phosphates for growth and invasion? Literature is reviewed suggesting that the succinate-CoA ligase reaction in the tricarboxylic acid cycle can substantiate sufficient ATP through mitochondrial substrate-level phosphorylation (mSLP) to maintain GBM growth when OxPhos is impaired. Production of high-energy phosphates would be supported by glutaminolysis—a hallmark of GBM metabolism—through the sequential conversion of glutamine → glutamate → alpha-ketoglutarate → succinyl CoA → succinate. Equally important, provision of ATP through mSLP would maintain the adenine nucleotide translocase in forward mode, thus preventing the reverse-operating F0-F1 ATP synthase from depleting cytosolic ATP reserves. Because glucose and glutamine are the primary fuels driving the rapid growth of GBM and most tumors for that matter, simultaneous restriction of these two substrates or inhibition of mSLP should diminish cancer viability, growth, and invasion.
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23
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Bui D, Ravasz D, Chinopoulos C. The Effect of 2-Ketobutyrate on Mitochondrial Substrate-Level Phosphorylation. Neurochem Res 2019; 44:2301-2306. [PMID: 30810978 PMCID: PMC6776489 DOI: 10.1007/s11064-019-02759-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 01/31/2023]
Abstract
The reaction catalyzed by succinate-CoA ligase in the mitochondrial matrix yields a high-energy phosphate when operating towards hydrolysis of the thioester bond of succinyl-CoA, known as mitochondrial substrate-level phosphorylation (mSLP). The catabolism of several metabolites converge to succinyl-CoA but through different biochemical pathways. Among them, threonine, serine and methionine catabolize to succinyl-CoA through the common intermediate, 2-ketobutyrate. During the course of this pathway 2-ketobutyrate will become succinyl-CoA through propionyl-CoA catabolism, obligatorily passing through an ATP-consuming step substantiated by propionyl-CoA carboxylase. Here, by recording the directionality of the adenine nucleotide translocase while measuring membrane potential we tested the hypothesis that catabolism of 2-ketobutyrate negates mSLP due to the ATP-consuming propionyl-CoA carboxylase step in rotenone-treated, isolated mouse liver and brain mitochondria. 2-Ketobutyrate produced a less negative membrane potential compared to NADH or FADH2-linked substrates, which was sensitive to inhibition by rotenone, atpenin and arsenate, implying the involvement of complex I, complex II and a dehydrogenase-most likely branched chain keto-acid dehydrogenase, respectively. Co-addition of 2-ketobutyrate with NADH- or FADH2-linked substrates yielded no greater membrane potential than in the presence of substrates alone. However, in the presence of NADH-linked substrates, 2-ketobutyrate prevented mSLP in a dose-dependent manner. Our results imply that despite that 2-ketobutyrate leads to succinyl-CoA formation, obligatory metabolism through propionyl-CoA carboxylase associated with ATP expenditure abolishes mSLP. The provision of metabolites converging to 2-ketobutyrate may be a useful way for manipulating mSLP without using pharmacological or genetic tools.
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Affiliation(s)
- David Bui
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary
| | - Dora Ravasz
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary.
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24
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Chinopoulos C. Succinate in ischemia: Where does it come from? Int J Biochem Cell Biol 2019; 115:105580. [PMID: 31394174 DOI: 10.1016/j.biocel.2019.105580] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 12/20/2022]
Abstract
During tissue ischemia succinate accumulates. Herein, literature spanning the past nine decades is reviewed leaning towards the far greater role of Krebs cycle's canonical activity yielding succinate through α-ketoglutarate -> succinyl-CoA -> succinate even in hypoxia, as opposed to reversal of succinate dehydrogenase. Furthermore, the concepts of i) a diode-like property of succinate dehydrogenase rendering it difficult to reverse, and ii) the absence of mammalian mitochondrial quinones exhibiting redox potentials in the [-60, -80] mV range needed for fumarate reduction, are discussed. Finally, it is emphasized that a "fumarate reductase" enzyme entity reducing fumarate to succinate found in some bacteria and lower eukaryotes remains to be discovered in mammalian mitochondria.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary.
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25
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Jaña F, Bustos G, Rivas J, Cruz P, Urra F, Basualto-Alarcón C, Sagredo E, Ríos M, Lovy A, Dong Z, Cerda O, Madesh M, Cárdenas C. Complex I and II are required for normal mitochondrial Ca 2+ homeostasis. Mitochondrion 2019; 49:73-82. [PMID: 31310854 DOI: 10.1016/j.mito.2019.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 04/01/2019] [Accepted: 07/12/2019] [Indexed: 01/03/2023]
Abstract
Cytosolic calcium (cCa2+) entry into mitochondria is facilitated by the mitochondrial membrane potential (ΔΨm), an electrochemical gradient generated by the electron transport chain (ETC). Is has been assumed that as long as mutations that affect the ETC do not affect the ΔΨm, the mitochondrial Ca2+ (mCa2+) homeostasis remains normal. We show that knockdown of NDUFAF3 and SDHB reduce ETC activity altering mCa2+ efflux and influx rates while ΔΨm remains intact. Shifting the equilibrium toward lower [Ca2+]m accumulation renders cells resistant to death. Our findings reveal an unexpected relationship between complex I and II with the mCa2+ homeostasis independent of ΔΨm.
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Affiliation(s)
- Fabian Jaña
- Departamento de Ciencias de la Salud, Universidad de Aysén, Coyhaique, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Galdo Bustos
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - José Rivas
- Departamento de Ciencias de la Salud, Universidad de Aysén, Coyhaique, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Pablo Cruz
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Felix Urra
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Molecular and Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Carla Basualto-Alarcón
- Departamento de Ciencias de la Salud, Universidad de Aysén, Coyhaique, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Anatomy and Legal Medicine Department, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Eduardo Sagredo
- Centro de Investigación y Tratamiento del Cáncer, Facultad de Medicina, Universidad de Chile, Chile
| | - Melany Ríos
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Alenka Lovy
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile; Center for Neuroscience Research, Tufts University School of Medicine, Boston, MA, USA
| | - Zhiwei Dong
- Department of Medicine, Center for Precision Medicine, University of Texas Health San Antonio, TX, USA
| | - Oscar Cerda
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile; Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Santiago, Chile.; The Wound Repair, Treatment and Health (WoRTH), Chile
| | - Muniswamy Madesh
- Department of Medicine, Center for Precision Medicine, University of Texas Health San Antonio, TX, USA.
| | - César Cárdenas
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA, USA; Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States.
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Šileikytė J, Forte M. The Mitochondrial Permeability Transition in Mitochondrial Disorders. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:3403075. [PMID: 31191798 PMCID: PMC6525910 DOI: 10.1155/2019/3403075] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/15/2019] [Accepted: 04/01/2019] [Indexed: 12/22/2022]
Abstract
Mitochondrial permeability transition pore (PTP), a (patho)physiological phenomenon discovered over 40 years ago, is still not completely understood. PTP activation results in a formation of a nonspecific channel within the inner mitochondrial membrane with an exclusion size of 1.5 kDa. PTP openings can be transient and are thought to serve a physiological role to allow quick Ca2+ release and/or metabolite exchange between mitochondrial matrix and cytosol or long-lasting openings that are associated with pathological conditions. While matrix Ca2+ and oxidative stress are crucial in its activation, the consequence of prolonged PTP opening is dissipation of the inner mitochondrial membrane potential, cessation of ATP synthesis, bioenergetic crisis, and cell death-a primary characteristic of mitochondrial disorders. PTP involvement in mitochondrial and cellular demise in a variety of disease paradigms has been long appreciated, yet the exact molecular entity of the PTP and the development of potent and specific PTP inhibitors remain areas of active investigation. In this review, we will (i) summarize recent advances made in elucidating the molecular nature of the PTP focusing on evidence pointing to mitochondrial FoF1-ATP synthase, (ii) summarize studies aimed at discovering novel PTP inhibitors, and (iii) review data supporting compromised PTP activity in specific mitochondrial diseases.
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Affiliation(s)
- Justina Šileikytė
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Michael Forte
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
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Wei-LaPierre L, Dirksen RT. Isolating a reverse-mode ATP synthase-dependent mechanism of mitoflash activation. J Gen Physiol 2019; 151:708-713. [PMID: 31010808 PMCID: PMC6571996 DOI: 10.1085/jgp.201912358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Wei-LaPierre and Dirksen discuss new work investigating the molecular events underlying mitoflash biogenesis.
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Affiliation(s)
- Lan Wei-LaPierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY
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Frenguelli BG. The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury. Neurochem Res 2019; 44:661-675. [PMID: 28836168 PMCID: PMC6420432 DOI: 10.1007/s11064-017-2386-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 12/24/2022]
Abstract
Brain slices have been the workhorse for many neuroscience labs since the pioneering work of Henry McIlwain in the 1950s. Their utility is undisputed and their acceptance as appropriate models for the central nervous system is widespread, if not universal. However, the skeleton in the closet is that ATP levels in brain slices are lower than those found in vivo, which may have important implications for cellular physiology and plasticity. Far from this being a disadvantage, the ATP-impoverished slice can serve as a useful and experimentally-tractable surrogate for the injured brain, which experiences similar depletion of cellular ATP. We have shown that the restoration of cellular ATP in brain slices to in vivo values is possible with a simple combination of D-ribose and adenine (RibAde), two substrates for ATP synthesis. Restoration of ATP in slices to physiological levels has implications for synaptic transmission and plasticity, whilst in the injured brain in vivo RibAde shows encouraging positive results. Given that ribose, adenine, and a third compound, allopurinol, are all separately in use in man, their combined application after acute brain injury, in accelerating ATP synthesis and increasing the reservoir of the neuroprotective metabolite, adenosine, may help reduce the morbidity associated with stroke and traumatic brain injury.
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29
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Haumann J, Camara AKS, Gadicherla AK, Navarro CD, Boelens AD, Blomeyer CA, Dash RK, Boswell MR, Kwok WM, Stowe DF. Slow Ca 2+ Efflux by Ca 2+/H + Exchange in Cardiac Mitochondria Is Modulated by Ca 2+ Re-uptake via MCU, Extra-Mitochondrial pH, and H + Pumping by F OF 1-ATPase. Front Physiol 2019; 9:1914. [PMID: 30804812 PMCID: PMC6378946 DOI: 10.3389/fphys.2018.01914] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 12/18/2018] [Indexed: 02/04/2023] Open
Abstract
Mitochondrial (m) Ca2+ influx is largely dependent on membrane potential (ΔΨm), whereas mCa2+ efflux occurs primarily via Ca2+ ion exchangers. We probed the kinetics of Ca2+/H+ exchange (CHEm) in guinea pig cardiac muscle mitochondria. We tested if net mCa2+ flux is altered during a matrix inward H+ leak that is dependent on matrix H+ pumping by ATPm hydrolysis at complex V (FOF1-ATPase). We measured [Ca2+]m, extra-mitochondrial (e) [Ca2+]e, ΔΨm, pHm, pHe, NADH, respiration, ADP/ATP ratios, and total [ATP]m in the presence or absence of protonophore dinitrophenol (DNP), mitochondrial uniporter (MCU) blocker Ru360, and complex V blocker oligomycin (OMN). We proposed that net slow influx/efflux of Ca2+ after adding DNP and CaCl2 is dependent on whether the ΔpHm gradient is/is not maintained by reciprocal outward H+ pumping by complex V. We found that adding CaCl2 enhanced DNP-induced increases in respiration and decreases in ΔΨm while [ATP]m decreased, ΔpHm gradient was maintained, and [Ca2+]m continued to increase slowly, indicating net mCa2+ influx via MCU. In contrast, with complex V blocked by OMN, adding DNP and CaCl2 caused larger declines in ΔΨm as well as a slow fall in pHm to near pHe while [Ca2+]m continued to decrease slowly, indicating net mCa2+ efflux in exchange for H+ influx (CHEm) until the ΔpHm gradient was abolished. The kinetics of slow mCa2+ efflux with slow H+ influx via CHEm was also observed at pHe 6.9 vs. 7.6 by the slow fall in pHm until ΔpHm was abolished; if Ca2+ reuptake via the MCU was also blocked, mCa2+ efflux via CHEm became more evident. Of the two components of the proton electrochemical gradient, our results indicate that CHEm activity is driven largely by the ΔpHm chemical gradient with H+ leak, while mCa2+ entry via MCU depends largely on the charge gradient ΔΨm. A fall in ΔΨm with excess mCa2+ loading can occur during cardiac cell stress. Cardiac cell injury due to mCa2+ overload may be reduced by temporarily inhibiting FOF1-ATPase from pumping H+ due to ΔΨm depolarization. This action would prevent additional slow mCa2+ loading via MCU and permit activation of CHEm to mediate efflux of mCa2+. HIGHLIGHTSWe examined how slow mitochondrial (m) Ca2+ efflux via Ca2+/H+ exchange (CHEm) is triggered by matrix acidity after a rapid increase in [Ca2+]m by adding CaCl2 in the presence of dinitrophenol (DNP) to permit H+ influx, and oligomycin (OMN) to block H+ pumping via FOF1-ATP synthase/ase (complex V). Declines in ΔΨm and pHm after DNP and added CaCl2 were larger when complex V was blocked. [Ca2+]m slowly increased despite a fall in ΔΨm but maintained pHm when H+ pumping by complex V was permitted. [Ca2+]m slowly decreased and external [Ca2+]e increased with declines in both ΔΨm and pHm when complex V was blocked. ATPm hydrolysis supports a falling pHm and redox state and promotes a slow increase in [Ca2+]m. After rapid Ca2+ influx due to a bolus of CaCl2, slow mCa2+ efflux by CHEm occurs directly if pHe is low.
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Affiliation(s)
- Johan Haumann
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ashish K Gadicherla
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christopher D Navarro
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Age D Boelens
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States
| | - Michael R Boswell
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States.,Research Service, Veterans Affairs Medical Center, Milwaukee, WI, United States
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30
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High glycolytic activity of tumor cells leads to underestimation of electron transport system capacity when mitochondrial ATP synthase is inhibited. Sci Rep 2018; 8:17383. [PMID: 30478338 PMCID: PMC6255871 DOI: 10.1038/s41598-018-35679-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023] Open
Abstract
This study sought to elucidate how oligomycin, an ATP synthase blocker, leads to underestimation of maximal oxygen consumption rate (maxOCR) and spare respiratory capacity (SRC) in tumor cells. T98G and U-87MG glioma cells were titrated with the protonophore CCCP to induce maxOCR. The presence of oligomycin (0.3-3.0 µg/mL) led to underestimation of maxOCR and a consequent decrease in SRC values of between 25% and 40% in medium containing 5.5 or 11 mM glucose. The inhibitory effect of oligomycin on CCCP-induced maxOCR did not occur when glutamine was the metabolic substrate or when the glycolytic inhibitor 2-deoxyglucose was present. ATP levels were reduced and ADP/ATP ratios increased in cells treated with CCCP, but these changes were minimized when oligomycin was used to inhibit reverse activity of ATP synthase. Exposing digitonin-permeabilized cells to exogenous ATP, but not ADP, resulted in partial inhibition of CCCP-induced maxOCR. We conclude that underestimation of maxOCR and SRC in tumor cells when ATP synthase is inhibited is associated with high glycolytic activity and that the glycolytic ATP yield may have an inhibitory effect on the metabolism of respiratory substrates and cytochrome c oxidase activity. Under CCCP-induced maxOCR, oligomycin preserves intracellular ATP by inhibiting ATP synthase reverse activity.
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31
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Zorova LD, Popkov VA, Plotnikov EY, Silachev DN, Pevzner IB, Jankauskas SS, Babenko VA, Zorov SD, Balakireva AV, Juhaszova M, Sollott SJ, Zorov DB. Mitochondrial membrane potential. Anal Biochem 2018; 552:50-59. [PMID: 28711444 PMCID: PMC5792320 DOI: 10.1016/j.ab.2017.07.009] [Citation(s) in RCA: 1048] [Impact Index Per Article: 174.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 01/13/2023]
Abstract
The mitochondrial membrane potential (ΔΨm) generated by proton pumps (Complexes I, III and IV) is an essential component in the process of energy storage during oxidative phosphorylation. Together with the proton gradient (ΔpH), ΔΨm forms the transmembrane potential of hydrogen ions which is harnessed to make ATP. The levels of ΔΨm and ATP in the cell are kept relatively stable although there are limited fluctuations of both these factors that can occur reflecting normal physiological activity. However, sustained changes in both factors may be deleterious. A long-lasting drop or rise of ΔΨm vs normal levels may induce unwanted loss of cell viability and be a cause of various pathologies. Among other factors, ΔΨm plays a key role in mitochondrial homeostasis through selective elimination of dysfunctional mitochondria. It is also a driving force for transport of ions (other than H+) and proteins which are necessary for healthy mitochondrial functioning. We propose additional potential mechanisms for which ΔΨm is essential for maintenance of cellular health and viability and provide recommendations how to accurately measure ΔΨm in a cell and discuss potential sources of artifacts.
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Affiliation(s)
- Ljubava D Zorova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; International Laser Center, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Vasily A Popkov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Egor Y Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Denis N Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Irina B Pevzner
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Stanislovas S Jankauskas
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Valentina A Babenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Savva D Zorov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Anastasia V Balakireva
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russian Federation
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Dmitry B Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
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32
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Ravasz D, Kacso G, Fodor V, Horvath K, Adam-Vizi V, Chinopoulos C. Reduction of 2-methoxy-1,4-naphtoquinone by mitochondrially-localized Nqo1 yielding NAD + supports substrate-level phosphorylation during respiratory inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:909-924. [PMID: 29746824 DOI: 10.1016/j.bbabio.2018.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/26/2018] [Accepted: 05/03/2018] [Indexed: 01/07/2023]
Abstract
Provision of NAD+ for oxidative decarboxylation of alpha-ketoglutarate to succinyl-CoA by the ketoglutarate dehydrogenase complex (KGDHC) is critical for maintained operation of succinyl-CoA ligase yielding high-energy phosphates, a process known as mitochondrial substrate-level phosphorylation (mSLP). We have shown previously that when NADH oxidation by complex I is inhibited by rotenone or anoxia, mitochondrial diaphorases yield NAD+, provided that suitable quinones are present (Kiss G et al., FASEB J 2014, 28:1682). This allows for KGDHC reaction to proceed and as an extension of this, mSLP. NAD(P)H quinone oxidoreductase 1 (NQO1) is an enzyme exhibiting diaphorase activity. Here, by using Nqo1-/- and WT littermate mice we show that in rotenone-treated, isolated liver mitochondria 2-methoxy-1,4-naphtoquinone (MNQ) is preferentially reduced by matrix Nqo1 yielding NAD+ to KGDHC, supporting mSLP. This process was sensitive to inhibition by specific diaphorase inhibitors. Reduction of idebenone and its analogues MRQ-20 and MRQ-56, menadione, mitoquinone and duroquinone were unaffected by genetic disruption of the Nqo1 gene. The results allow for the conclusions that i) MNQ is a Nqo1-preferred substrate, and ii) in the presence of suitable quinones, mitochondrially-localized diaphorases other than Nqo1 support NADH oxidation when complex I is inhibited. Our work confirms that complex I bypass can occur by quinones reduced by intramitochondrial diaphorases oxidizing NADH, ultimately supporting mSLP. Finally, it may help to elucidate structure-activity relationships of redox-active quinones with diaphorase enzymes.
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Affiliation(s)
- Dora Ravasz
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Gergely Kacso
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Viktoria Fodor
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Kata Horvath
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary.
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33
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Sgarbi G, Barbato S, Costanzini A, Solaini G, Baracca A. The role of the ATPase inhibitor factor 1 (IF 1) in cancer cells adaptation to hypoxia and anoxia. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:99-109. [PMID: 29097244 DOI: 10.1016/j.bbabio.2017.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/19/2017] [Accepted: 10/27/2017] [Indexed: 12/23/2022]
Abstract
The physiological role of the mitochondrial ATP synthase complex is to generate ATP through oxidative phosphorylation. Indeed, the enzyme can reverse its activity and hydrolyze ATP under ischemic conditions, as shown in isolated mitochondria and in mammalian heart and liver. However, what occurs when cancer cells experience hypoxia or anoxia has not been well explored. In the present study, we investigated the bioenergetics of cancer cells under hypoxic/anoxic conditions with particular emphasis on ATP synthase, and the conditions driving it to work in reverse. In this context, we further examined the role exerted by its endogenous inhibitor factor, IF1, that it is overexpressed in cancer cells. Metabolic and bioenergetic analysis of cancer cells exposed to severe hypoxia (down to 0.1% O2) unexpectedly showed that Δψm is preserved independently of the presence of IF1 and that ATP synthase still phosphorylates ADP though at a much lower rate than in normoxia. However, when we induced an anoxia-mimicking condition by collapsing ΔμΗ+ with the FCCP uncoupler, the IF1-silenced clones only reversed the ATP synthase activity hydrolyzing ATP in order to reconstitute the electrochemical proton gradient. Notably, in cancer cells IF1 overexpression fully prevents ATP synthase hydrolytic activity activation under uncoupling conditions. Therefore, our results suggest that IF1 overexpression promotes cancer cells survival under temporary anoxic conditions by preserving cellular ATP despite mitochondria dysfunction.
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Affiliation(s)
- G Sgarbi
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - S Barbato
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - A Costanzini
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy
| | - G Solaini
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy.
| | - A Baracca
- Department of Biomedical and Neuromotor Sciences, Laboratory of Biochemistry and Mitochondrial Pathophysiology, University of Bologna, via Irnerio, 48, 40126 Bologna, Italy.
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34
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Schirris TJJ, Jansen J, Mihajlovic M, van den Heuvel LP, Masereeuw R, Russel FGM. Mild intracellular acidification by dexamethasone attenuates mitochondrial dysfunction in a human inflammatory proximal tubule epithelial cell model. Sci Rep 2017; 7:10623. [PMID: 28878224 PMCID: PMC5587643 DOI: 10.1038/s41598-017-10483-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/10/2017] [Indexed: 01/12/2023] Open
Abstract
Septic acute kidney injury (AKI) associates with poor survival rates and often requires renal replacement therapy. Glucocorticoids may pose renal protective effects in sepsis via stimulation of mitochondrial function. Therefore, we studied the mitochondrial effects of dexamethasone in an experimental inflammatory proximal tubule epithelial cell model. Treatment of human proximal tubule epithelial cells with lipopolysaccharide (LPS) closely resembles pathophysiological processes during endotoxaemia, and led to increased cytokine excretion rates and cellular reactive oxygen species levels, combined with a reduced mitochondrial membrane potential and respiratory capacity. These effects were attenuated by dexamethasone. Dexamethasone specifically increased the expression and activity of mitochondrial complex V (CV), which could not be explained by an increase in mitochondrial mass. Finally, we demonstrated that dexamethasone acidified the intracellular milieu and consequently reversed LPS-induced alkalisation, leading to restoration of the mitochondrial function. This acidification also provides an explanation for the increase in CV expression, which is expected to compensate for the inhibitory effect of the acidified environment on this complex. Besides the mechanistic insights into the beneficial effects of dexamethasone during renal cellular inflammation, our work also supports a key role for mitochondria in this process and, hence, provides novel therapeutic avenues for the treatment of AKI.
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Affiliation(s)
- T J J Schirris
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, 6500 HB, Nijmegen, The Netherlands.,Center for Systems Biology and Bioenergetics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
| | - J Jansen
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, 6500 HB, Nijmegen, The Netherlands.,Department of Physiology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.,Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3584 CG, Utrecht, The Netherlands
| | - M Mihajlovic
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, 6500 HB, Nijmegen, The Netherlands.,Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3584 CG, Utrecht, The Netherlands
| | - L P van den Heuvel
- Department of Pediatrics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.,Department of Pediatric Nephrology & Growth and Regeneration, Catholic University Leuven, 3000, Leuven, Belgium
| | - R Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 3584 CG, Utrecht, The Netherlands.
| | - F G M Russel
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, 6500 HB, Nijmegen, The Netherlands. .,Center for Systems Biology and Bioenergetics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.
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35
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Komlódi T, Tretter L. Methylene blue stimulates substrate-level phosphorylation catalysed by succinyl-CoA ligase in the citric acid cycle. Neuropharmacology 2017; 123:287-298. [PMID: 28495375 DOI: 10.1016/j.neuropharm.2017.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/05/2017] [Accepted: 05/07/2017] [Indexed: 10/19/2022]
Abstract
Methylene blue (MB), a potential neuroprotective agent, is efficient in various neurodegenerative disease models. Beneficial effects of MB have been attributed to improvements in mitochondrial functions. Substrate-level phosphorylation (SLP) results in the production of ATP independent from the ATP synthase (ATP-ase). In energetically compromised mitochondria, ATP produced by SLP can prevent the reversal of the adenine nucleotide translocase and thus the hydrolysis of glycolytic ATP. The aim of the present study was to investigate the effect of MB on mitochondrial SLP catalysed by succinyl-CoA ligase. Measurements were carried out on isolated guinea pig cortical mitochondria respiring on α-ketoglutarate, glutamate, malate or succinate. The mitochondrial functions and parameters like ATP synthesis, oxygen consumption, membrane potential, and NAD(P)H level were followed online, in parallel with the redox state of MB. SLP-mediated ATP synthesis was measured in the presence of inhibitors for ATP-ase and adenylate kinase. In the presence of the ATP-ase inhibitor oligomycin MB stimulated respiration with all of the respiratory substrates. However, the rate of ATP synthesis increased only with substrates α-ketoglutarate and glutamate (forming succinyl-CoA). MB efficiently stimulated SLP and restored the membrane potential in mitochondria also with the combined inhibition of Complex I and ATP synthase. ATP formed by SLP alleviated the energetic insufficiency generated by the lack of oxidative phosphorylation. Thus, the MB-mediated stimulation of SLP might be important in maintaining the energetic competence of mitochondria and in preventing the mitochondrial hydrolysis of glycolytic ATP. The mitochondrial effects of MB are explained by the ability to accept electrons from reducing equivalents and transfer them to cytochrome c bypassing the respiratory Complexes I and III.
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Affiliation(s)
- T Komlódi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto St., Budapest, 1094, Hungary
| | - L Tretter
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto St., Budapest, 1094, Hungary.
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Zhdanov AV, Andreev DE, Baranov PV, Papkovsky DB. Low energy costs of F1Fo ATP synthase reversal in colon carcinoma cells deficient in mitochondrial complex IV. Free Radic Biol Med 2017; 106:184-195. [PMID: 28189850 DOI: 10.1016/j.freeradbiomed.2017.02.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 10/20/2022]
Abstract
Mitochondrial polarisation is paramount for a variety of cellular functions. Under ischemia, mitochondrial membrane potential (ΔΨm) and proton gradient (ΔpH) are maintained via a reversal of mitochondrial F1Fo ATP synthase (mATPase), which can rapidly deplete ATP and drive cells into energy crisis. We found that under normal conditions in cells with disassembled cytochrome c oxidase complex (COX-deficient HCT116), mATPase maintains ΔΨm at levels only 15-20% lower than in WT cells, and for this utilises relatively little ATP. For a small energy expenditure, mATPase enables mitochondrial ΔpH, protein import, Ca2+ turnover, and supports free radical detoxication machinery enlarged to protect the cells from oxidative damage. Whereas in COX-deficient cells the main source of ATP is glycolysis, the ΔΨm is still maintained upon inhibition of the adenine nucleotide translocators with bongkrekic acid and carboxyatractyloside, indicating that the role of ANTs is redundant, and matrix substrate level phosphorylation alone or in cooperation with ATP-Mg/Pi carriers can continuously support the mATPase activity. Intriguingly, we found that mitochondrial complex III is active, and it contributes not only to free radical production, but also to ΔΨm maintenance and energy budget of COX-deficient cells. Overall, this study demonstrates that F1Fo ATP synthase can support general mitochondrial and cellular functions, working in extremely efficient 'energy saving' reverse mode and flexibly recruiting free radical detoxication and ATP producing / transporting pathways.
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Affiliation(s)
- Alexander V Zhdanov
- School of Biochemistry & Cell Biology, University College Cork, Cork, Ireland.
| | - Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Pavel V Baranov
- School of Biochemistry & Cell Biology, University College Cork, Cork, Ireland
| | - Dmitri B Papkovsky
- School of Biochemistry & Cell Biology, University College Cork, Cork, Ireland
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Ravasz D, Kacso G, Fodor V, Horvath K, Adam-Vizi V, Chinopoulos C. Catabolism of GABA, succinic semialdehyde or gamma-hydroxybutyrate through the GABA shunt impair mitochondrial substrate-level phosphorylation. Neurochem Int 2017; 109:41-53. [PMID: 28300620 DOI: 10.1016/j.neuint.2017.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 10/20/2022]
Abstract
GABA is catabolized in the mitochondrial matrix through the GABA shunt, encompassing transamination to succinic semialdehyde followed by oxidation to succinate by the concerted actions of GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH), respectively. Gamma-hydroxybutyrate (GHB) is a neurotransmitter and a psychoactive drug that could enter the citric acid cycle through transhydrogenation with α-ketoglutarate to succinic semialdehyde and d-hydroxyglutarate, a reaction catalyzed by hydroxyacid-oxoacid transhydrogenase (HOT). Here, we tested the hypothesis that the elevation in matrix succinate concentration caused by exogenous addition of GABA, succinic semialdehyde or GHB shifts the equilibrium of the reversible reaction catalyzed by succinate-CoA ligase towards ATP (or GTP) hydrolysis, effectively negating substrate-level phosphorylation (SLP). Mitochondrial SLP was addressed by interrogating the directionality of the adenine nucleotide translocase during anoxia in isolated mouse brain and liver mitochondria. GABA eliminated SLP, and this was rescued by the GABA-T inhibitors vigabatrin and aminooxyacetic acid. Succinic semialdehyde was an extremely efficient substrate energizing mitochondria during normoxia but mimicked GABA in abolishing SLP in anoxia, in a manner refractory to vigabatrin and aminooxyacetic acid. GHB could moderately energize liver but not brain mitochondria consistent with the scarcity of HOT expression in the latter. In line with these results, GHB abolished SLP in liver but not brain mitochondria during anoxia and this was unaffected by either vigabatrin or aminooxyacetic acid. It is concluded that when mitochondria catabolize GABA or succinic semialdehyde or GHB through the GABA shunt, their ability to perform SLP is impaired.
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Affiliation(s)
- Dora Ravasz
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Gergely Kacso
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Viktoria Fodor
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Kata Horvath
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Laboratory for Neurobiochemistry, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; MTA-SE Lendület Neurobiochemistry Research Group, Hungary.
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Félix L, Oliveira M, Videira R, Maciel E, Alves ND, Nunes FM, Alves A, Almeida JM, Domingues MRM, Peixoto FP. Carvedilol exacerbate gentamicin-induced kidney mitochondrial alterations in adult rat. ACTA ACUST UNITED AC 2017; 69:83-92. [DOI: 10.1016/j.etp.2016.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/05/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
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Kosic M, Arsikin-Csordas K, Paunovic V, Firestone RA, Ristic B, Mircic A, Petricevic S, Bosnjak M, Zogovic N, Mandic M, Bumbasirevic V, Trajkovic V, Harhaji-Trajkovic L. Synergistic Anticancer Action of Lysosomal Membrane Permeabilization and Glycolysis Inhibition. J Biol Chem 2016; 291:22936-22948. [PMID: 27587392 DOI: 10.1074/jbc.m116.752113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Indexed: 12/21/2022] Open
Abstract
We investigated the in vitro and in vivo anticancer effect of combining lysosomal membrane permeabilization (LMP)-inducing agent N-dodecylimidazole (NDI) with glycolytic inhibitor 2-deoxy-d-glucose (2DG). NDI-triggered LMP and 2DG-mediated glycolysis block synergized in inducing rapid ATP depletion, mitochondrial damage, and reactive oxygen species production, eventually leading to necrotic death of U251 glioma cells but not primary astrocytes. NDI/2DG-induced death of glioma cells was partly prevented by lysosomal cathepsin inhibitor E64 and antioxidant α-tocopherol, suggesting the involvement of LMP and oxidative stress in the observed cytotoxicity. LMP-inducing agent chloroquine also displayed a synergistic anticancer effect with 2DG, whereas glucose deprivation or glycolytic inhibitors iodoacetate and sodium fluoride synergistically cooperated with NDI, thus further indicating that the anticancer effect of NDI/2DG combination was indeed due to LMP and glycolysis block. The two agents synergistically induced ATP depletion, mitochondrial depolarization, oxidative stress, and necrotic death also in B16 mouse melanoma cells. Moreover, the combined oral administration of NDI and 2DG reduced in vivo melanoma growth in C57BL/6 mice by inducing necrotic death of tumor cells, without causing liver, spleen, or kidney toxicity. Based on these results, we propose that NDI-triggered LMP causes initial mitochondrial damage that is further increased by 2DG due to the lack of glycolytic ATP required to maintain mitochondrial health. This leads to a positive feedback cycle of mitochondrial dysfunction, ATP loss, and reactive oxygen species production, culminating in necrotic cell death. Therefore, the combination of LMP-inducing agents and glycolysis inhibitors seems worthy of further exploration as an anticancer strategy.
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Affiliation(s)
- Milica Kosic
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Katarina Arsikin-Csordas
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Verica Paunovic
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Raymond A Firestone
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Biljana Ristic
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Aleksandar Mircic
- the Institute of Histology and Embryology, School of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia
| | - Sasa Petricevic
- the Institute of Biomedical Research, Galenika a.d., Pasterova 2, 11000 Belgrade, Serbia, and
| | - Mihajlo Bosnjak
- the Institute of Histology and Embryology, School of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia
| | - Nevena Zogovic
- the Institute for Biological Research, University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia
| | - Milos Mandic
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia
| | - Vladimir Bumbasirevic
- the Institute of Histology and Embryology, School of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia
| | - Vladimir Trajkovic
- From the Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia,
| | - Ljubica Harhaji-Trajkovic
- the Institute for Biological Research, University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia
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Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochem J 2016; 473:3463-3485. [PMID: 27496549 PMCID: PMC5126846 DOI: 10.1042/bcj20160594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/05/2016] [Indexed: 12/14/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer enzyme composed of Suclg1 α-subunit and a substrate-specific Sucla2 or Suclg2 β-subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation (SLP) were not different between wild-type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of SUCL was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or SLP, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression, which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with SUCL. These results as well as the availability of the transgenic mouse colonies will be of value in understanding SUCL deficiency.
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Doczi J, Torocsik B, Echaniz-Laguna A, Mousson de Camaret B, Starkov A, Starkova N, Gál A, Molnár MJ, Kawamata H, Manfredi G, Adam-Vizi V, Chinopoulos C. Alterations in voltage-sensing of the mitochondrial permeability transition pore in ANT1-deficient cells. Sci Rep 2016; 6:26700. [PMID: 27221760 PMCID: PMC4879635 DOI: 10.1038/srep26700] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 05/09/2016] [Indexed: 01/03/2023] Open
Abstract
The probability of mitochondrial permeability transition (mPT) pore opening is inversely related to the magnitude of the proton electrochemical gradient. The module conferring sensitivity of the pore to this gradient has not been identified. We investigated mPT’s voltage-sensing properties elicited by calcimycin or H2O2 in human fibroblasts exhibiting partial or complete lack of ANT1 and in C2C12 myotubes with knocked-down ANT1 expression. mPT onset was assessed by measuring in situ mitochondrial volume using the ‘thinness ratio’ and the ‘cobalt-calcein’ technique. De-energization hastened calcimycin-induced swelling in control and partially-expressing ANT1 fibroblasts, but not in cells lacking ANT1, despite greater losses of mitochondrial membrane potential. Matrix Ca2+ levels measured by X-rhod-1 or mitochondrially-targeted ratiometric biosensor 4mtD3cpv, or ADP-ATP exchange rates did not differ among cell types. ANT1-null fibroblasts were also resistant to H2O2-induced mitochondrial swelling. Permeabilized C2C12 myotubes with knocked-down ANT1 exhibited higher calcium uptake capacity and voltage-thresholds of mPT opening inferred from cytochrome c release, but intact cells showed no differences in calcimycin-induced onset of mPT, irrespective of energization and ANT1 expression, albeit the number of cells undergoing mPT increased less significantly upon chemically-induced hypoxia than control cells. We conclude that ANT1 confers sensitivity of the pore to the electrochemical gradient.
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Affiliation(s)
- Judit Doczi
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary.,MTA-SE Lendület Neurobiochemistry Research Group, Budapest, Hungary
| | - Beata Torocsik
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary
| | - Andoni Echaniz-Laguna
- Département de Neurologie, Hôpitaux Universitaires, Hôpital de Hautepierre, 67098 Strasbourg cedex, France
| | - Bénédicte Mousson de Camaret
- Service des Maladies Héréditaires du Métabolisme, Centre de Biologie et de Pathologie Est, CHU Lyon, 69677 Bron cedex, France
| | - Anatoly Starkov
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Natalia Starkova
- Icahn School of Medicine at Mount Sinai, Department of Hematology and Medical Oncology, New York, NY 10029, USA
| | - Aniko Gál
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary
| | - Mária J Molnár
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary.,MTA-SE Lendület Neurobiochemistry Research Group, Budapest, Hungary
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Succinate, an intermediate in metabolism, signal transduction, ROS, hypoxia, and tumorigenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1086-1101. [PMID: 26971832 DOI: 10.1016/j.bbabio.2016.03.012] [Citation(s) in RCA: 315] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/31/2022]
Abstract
Succinate is an important metabolite at the cross-road of several metabolic pathways, also involved in the formation and elimination of reactive oxygen species. However, it is becoming increasingly apparent that its realm extends to epigenetics, tumorigenesis, signal transduction, endo- and paracrine modulation and inflammation. Here we review the pathways encompassing succinate as a metabolite or a signal and how these may interact in normal and pathological conditions.(1).
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43
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Ruas JS, Siqueira-Santos ES, Amigo I, Rodrigues-Silva E, Kowaltowski AJ, Castilho RF. Underestimation of the Maximal Capacity of the Mitochondrial Electron Transport System in Oligomycin-Treated Cells. PLoS One 2016; 11:e0150967. [PMID: 26950698 PMCID: PMC4780810 DOI: 10.1371/journal.pone.0150967] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/22/2016] [Indexed: 12/21/2022] Open
Abstract
The maximal capacity of the mitochondrial electron transport system (ETS) in intact cells is frequently estimated by promoting protonophore-induced maximal oxygen consumption preceded by inhibition of oxidative phosphorylation by oligomycin. In the present study, human glioma (T98G and U-87MG) and prostate cancer (PC-3) cells were titrated with different concentrations of the protonophore CCCP to induce maximal oxygen consumption rate (OCR) within respirometers in a conventional growth medium. The results demonstrate that the presence of oligomycin or its A-isomer leads to underestimation of maximal ETS capacity. In the presence of oligomycin, the spare respiratory capacity (SRC), i.e., the difference between the maximal and basal cellular OCR, was underestimated by 25 to 45%. The inhibitory effect of oligomycin on SRC was more pronounced in T98G cells and was observed in both suspended and attached cells. Underestimation of SRC also occurred when oxidative phosphorylation was fully inhibited by the ATP synthase inhibitor citreoviridin. Further experiments indicated that oligomycin cannot be replaced by the adenine nucleotide translocase inhibitors bongkrekic acid or carboxyatractyloside because, although these compounds have effects in permeabilized cells, they do not inhibit oxidative phosphorylation in intact cells. We replaced CCCP by FCCP, another potent protonophore and similar results were observed. Lower maximal OCR and SRC values were obtained with the weaker protonophore 2,4-dinitrophenol, and these parameters were not affected by the presence of oligomycin. In permeabilized cells or isolated brain mitochondria incubated with respiratory substrates, only a minor inhibitory effect of oligomycin on CCCP-induced maximal OCR was observed. We conclude that unless a previously validated protocol is employed, maximal ETS capacity in intact cells should be estimated without oligomycin. The inhibitory effect of an ATP synthase blocker on potent protonophore-induced maximal OCR may be associated with impaired metabolism of mitochondrial respiratory substrates.
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Affiliation(s)
- Juliana S. Ruas
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Edilene S. Siqueira-Santos
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ignacio Amigo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Erika Rodrigues-Silva
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Alicia J. Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Roger F. Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
- * E-mail:
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Short-Term Differentiation of Glioblastoma Stem Cells Induces Hypoxia Tolerance. Neurochem Res 2016; 41:1545-58. [PMID: 26915110 PMCID: PMC4893075 DOI: 10.1007/s11064-016-1868-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 01/28/2023]
Abstract
Glioblastoma is the most common and malignant brain cancer. In spite of surgical removal, radiation and chemotherapy, this cancer recurs within short time and median survival after diagnosis is less than a year. Glioblastoma stem cells (GSCs) left in the brain after surgery is thought to explain the inevitable recurrence of the tumor. Although hypoxia is a prime factor contributing to treatment resistance in many cancers, its effect on GSC has been little studied. Especially how differentiation influences the tolerance to acute hypoxia in GSCs is not well explored. We cultured GSCs from three patient biopsies and exposed these and their differentiated (1- and 4-weeks) progeny to acute hypoxia while monitoring intracellular calcium and mitochondrial membrane potential (ΔΨm). Undifferentiated GSCs were not hypoxia tolerant, showing both calcium overload and mitochondrial depolarization. One week differentiated cells were the most tolerant to hypoxia, preserving intracellular calcium stability and ΔΨm during 15 min of acute hypoxia. After 4 weeks of differentiation, mitochondrial mass was significantly reduced. In these cells calcium homeostasis was maintained during hypoxia, although the mitochondria were depolarized, suggesting a reduced mitochondrial dependency. Basal metabolic rate increased by differentiation, however, low oxygen consumption and high ΔΨm in undifferentiated GSCs did not provide hypoxia tolerance. The results suggest that undifferentiated GSCs are oxygen dependent, and that limited differentiation induces relative hypoxia tolerance. Hypoxia tolerance may be a factor involved in high-grade malignancy. This warrants a careful approach to differentiation as a glioblastoma treatment strategy.
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Matic I, Cocco S, Ferraina C, Martin-Jimenez R, Florenzano F, Crosby J, Lupi R, Amadoro G, Russell C, Pignataro G, Annunziato L, Abramov AY, Campanella M. Neuroprotective coordination of cell mitophagy by the ATPase Inhibitory Factor 1. Pharmacol Res 2016; 103:56-68. [PMID: 26484591 DOI: 10.1016/j.phrs.2015.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 01/03/2023]
Abstract
The mitochondrial ATPase Inhibitory Factor 1 (hereafter referred to as IF1) blocks the reversal of the F1Fo-ATPsynthase to prevent detrimental consumption of cellular ATP and associated demise. Herein, we infer further its molecular physiology by assessing its protective function in neurons during conditions of challenged homeostatic respiration. By adopting in vitro and in vivo protocols of hypoxia/ischemia and re-oxygenation, we show that a shift in the IF1:F1Fo-ATPsynthase expression ratio occurs in neurons. This increased IF1 level is essential to induce accumulation of the PTEN-induced putative kinase 1 (PINK-1) and recruitment of the mitophagic ubiquitin ligase PARK-2 to promote autophagic "control" of the mitochondrial population. In IF1 overexpressing neurons ATP depletion is reduced during hypoxia/ischemia and the mitochondrial membrane potential (ΔYm) resilient to re-oxygenation as well as resistant to electrogenic, Ca(2+) dependent depolarization. These data suggest that in mammalian neurons mitochondria adapt to respiratory stress by upregulating IF1, which exerts a protective role by coordinating pro-survival cell mitophagy and bioenergetics resilience.
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Affiliation(s)
- Ivana Matic
- Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy
| | - Stefania Cocco
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Caterina Ferraina
- Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy; Regina Elena-National Cancer Institute, 00144 Rome, Italy
| | - Rebeca Martin-Jimenez
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | | | - James Crosby
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | - Ramona Lupi
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Giusy Amadoro
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Claire Russell
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II University of Naples, Italy; Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II University of Naples, Italy; Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Andrey Y Abramov
- Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom; UCL Consortium for Mitochondrial Research, Royal College Street, University of London, United Kingdom; Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy; Regina Elena-National Cancer Institute, 00144 Rome, Italy.
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46
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Németh B, Doczi J, Csete D, Kacso G, Ravasz D, Adams D, Kiss G, Nagy AM, Horvath G, Tretter L, Mócsai A, Csépányi-Kömi R, Iordanov I, Adam-Vizi V, Chinopoulos C. Abolition of mitochondrial substrate-level phosphorylation by itaconic acid produced by LPS-induced Irg1 expression in cells of murine macrophage lineage. FASEB J 2015; 30:286-300. [PMID: 26358042 DOI: 10.1096/fj.15-279398] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 08/31/2015] [Indexed: 01/28/2023]
Abstract
Itaconate is a nonamino organic acid exhibiting antimicrobial effects. It has been recently identified in cells of macrophage lineage as a product of an enzyme encoded by immunoresponsive gene 1 (Irg1), acting on the citric acid cycle intermediate cis-aconitate. In mitochondria, itaconate can be converted by succinate-coenzyme A (CoA) ligase to itaconyl-CoA at the expense of ATP (or GTP), and is also a weak competitive inhibitor of complex II. Here, we investigated specific bioenergetic effects of increased itaconate production mediated by LPS-induced stimulation of Irg1 in murine bone marrow-derived macrophages (BMDM) and RAW-264.7 cells. In rotenone-treated macrophage cells, stimulation by LPS led to impairment in substrate-level phosphorylation (SLP) of in situ mitochondria, deduced by a reversal in the directionality of the adenine nucleotide translocase operation. In RAW-264.7 cells, the LPS-induced impairment in SLP was reversed by short-interfering RNA(siRNA)-but not scrambled siRNA-treatment directed against Irg1. LPS dose-dependently inhibited oxygen consumption rates (61-91%) and elevated glycolysis rates (>21%) in BMDM but not RAW-264.7 cells, studied under various metabolic conditions. In isolated mouse liver mitochondria treated with rotenone, itaconate dose-dependently (0.5-2 mM) reversed the operation of adenine nucleotide translocase, implying impairment in SLP, an effect that was partially mimicked by malonate. However, malonate yielded greater ADP-induced depolarizations (3-19%) than itaconate. We postulate that itaconate abolishes SLP due to 1) a "CoA trap" in the form of itaconyl-CoA that negatively affects the upstream supply of succinyl-CoA from the α-ketoglutarate dehydrogenase complex; 2) depletion of ATP (or GTP), which are required for the thioesterification by succinate-CoA ligase; and 3) inhibition of complex II leading to a buildup of succinate which shifts succinate-CoA ligase equilibrium toward ATP (or GTP) utilization. Our results support the notion that Irg1-expressing cells of macrophage lineage lose the capacity of mitochondrial SLP for producing itaconate during mounting of an immune defense.
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Affiliation(s)
- Beáta Németh
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Judit Doczi
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dániel Csete
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gergely Kacso
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dora Ravasz
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Daniel Adams
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gergely Kiss
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Adam M Nagy
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gergo Horvath
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Laszlo Tretter
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Attila Mócsai
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Roland Csépányi-Kömi
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Iordan Iordanov
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Vera Adam-Vizi
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Christos Chinopoulos
- *Department of Medical Biochemistry and Department of Physiology, Semmelweis University, Budapest, Hungary; and Lendület Neurobiochemistry Research Group, Lendület Inflammation Physiology Research Group, Laboratory for Neurobiochemistry, and Lendület Ion Channel Research Group, Hungarian Academy of Sciences, Budapest, Hungary
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47
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Bonora M, Wieckowski MR, Chinopoulos C, Kepp O, Kroemer G, Galluzzi L, Pinton P. Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition. Oncogene 2015; 34:1475-86. [PMID: 24727893 DOI: 10.1038/onc.2014.96] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 12/14/2022]
Abstract
The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.
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Affiliation(s)
- M Bonora
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
| | - M R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - C Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - O Kepp
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - G Kroemer
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France [4] Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - L Galluzzi
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - P Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
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48
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Distelmaier F, Valsecchi F, Liemburg-Apers DC, Lebiedzinska M, Rodenburg RJ, Heil S, Keijer J, Fransen J, Imamura H, Danhauser K, Seibt A, Viollet B, Gellerich FN, Smeitink JAM, Wieckowski MR, Willems PHGM, Koopman WJH. Mitochondrial dysfunction in primary human fibroblasts triggers an adaptive cell survival program that requires AMPK-α. Biochim Biophys Acta Mol Basis Dis 2014; 1852:529-40. [PMID: 25536029 DOI: 10.1016/j.bbadis.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 12/11/2014] [Accepted: 12/15/2014] [Indexed: 01/06/2023]
Abstract
Dysfunction of complex I (CI) of the mitochondrial electron transport chain (ETC) features prominently in human pathology. Cell models of ETC dysfunction display adaptive survival responses that still are poorly understood but of relevance for therapy development. Here we comprehensively examined how primary human skin fibroblasts adapt to chronic CI inhibition. CI inhibition triggered transient and sustained changes in metabolism, redox homeostasis and mitochondrial (ultra)structure but no cell senescence/death. CI-inhibited cells consumed no oxygen and displayed minor mitochondrial depolarization, reverse-mode action of complex V, a slower proliferation rate and futile mitochondrial biogenesis. Adaptation was neither prevented by antioxidants nor associated with increased PGC1-α/SIRT1/mTOR levels. Survival of CI-inhibited cells was strictly glucose-dependent and accompanied by increased AMPK-α phosphorylation, which occurred without changes in ATP or cytosolic calcium levels. Conversely, cells devoid of AMPK-α died upon CI inhibition. Chronic CI inhibition did not increase mitochondrial superoxide levels or cellular lipid peroxidation and was paralleled by a specific increase in SOD2/GR, whereas SOD1/CAT/Gpx1/Gpx2/Gpx5 levels remained unchanged. Upon hormone stimulation, fully adapted cells displayed aberrant cytosolic and ER calcium handling due to hampered ATP fueling of ER calcium pumps. It is concluded that CI dysfunction triggers an adaptive program that depends on extracellular glucose and AMPK-α. This response avoids cell death by suppressing energy crisis, oxidative stress induction and substantial mitochondrial depolarization.
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Affiliation(s)
- Felix Distelmaier
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Federica Valsecchi
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Dania C Liemburg-Apers
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | | | - Richard J Rodenburg
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Sandra Heil
- Department of Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Jaap Keijer
- Department of Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Jack Fransen
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Hiromi Imamura
- The Hakubi Project, Kyoto University, 606-8501 Kyoto, Japan
| | - Katharina Danhauser
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Annette Seibt
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Benoit Viollet
- Institut Cochin, NSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Frank N Gellerich
- Department of Stereotactic Neurosurgery, Otto-von-Guericke-Universität, 39120 Magdeburg, Germany
| | - Jan A M Smeitink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | | | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands.
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49
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Localization of SUCLA2 and SUCLG2 subunits of succinyl CoA ligase within the cerebral cortex suggests the absence of matrix substrate-level phosphorylation in glial cells of the human brain. J Bioenerg Biomembr 2014; 47:33-41. [PMID: 25370487 DOI: 10.1007/s10863-014-9586-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/21/2014] [Indexed: 10/24/2022]
Abstract
We have recently shown that the ATP-forming SUCLA2 subunit of succinyl-CoA ligase, an enzyme of the citric acid cycle, is exclusively expressed in neurons of the human cerebral cortex; GFAP- and S100-positive astroglial cells did not exhibit immunohistoreactivity or in situ hybridization reactivity for either SUCLA2 or the GTP-forming SUCLG2. However, Western blotting of post mortem samples revealed a minor SUCLG2 immunoreactivity. In the present work we sought to identify the cell type(s) harboring SUCLG2 in paraformaldehyde-fixed, free-floating surgical human cortical tissue samples. Specificity of SUCLG2 antiserum was supported by co-localization with mitotracker orange staining of paraformaldehyde-fixed human fibroblast cultures, delineating the mitochondrial network. In human cortical tissue samples, microglia and oligodendroglia were identified by antibodies directed against Iba1 and myelin basic protein, respectively. Double immunofluorescence for SUCLG2 and Iba1 or myelin basic protein exhibited no co-staining; instead, SUCLG2 appeared to outline the cerebral microvasculature. In accordance to our previous work there was no co-localization of SUCLA2 immunoreactivity with either Iba1 or myelin basic protein. We conclude that SUCLG2 exist only in cells forming the vasculature or its contents in the human brain. The absence of SUCLA2 and SUCLG2 in human glia is in compliance with the presence of alternative pathways occurring in these cells, namely the GABA shunt and ketone body metabolism which do not require succinyl CoA ligase activity, and glutamate dehydrogenase 1, an enzyme exhibiting exquisite sensitivity to inhibition by GTP.
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Ivanes F, Faccenda D, Gatliff J, Ahmed AA, Cocco S, Cheng CHK, Allan E, Russell C, Duchen MR, Campanella M. The compound BTB06584 is an IF1 -dependent selective inhibitor of the mitochondrial F1 Fo-ATPase. Br J Pharmacol 2014; 171:4193-206. [PMID: 24641180 PMCID: PMC4241087 DOI: 10.1111/bph.12638] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 01/16/2014] [Accepted: 01/30/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Ischaemia compromises mitochondrial respiration. Consequently, the mitochondrial F1 Fo-ATPsynthase reverses and acts as a proton-pumping ATPase, so maintaining the mitochondrial membrane potential (ΔΨm ), while accelerating ATP depletion and cell death. Here we have looked for a molecule that can selectively inhibit this activity without affecting ATP synthesis, preserve ATP and delay ischaemic cell death. EXPERIMENTAL APPROACH We developed a chemoinformatic screen based on the structure of BMS199264, which is reported to selectively inhibit F1 Fo-ATPase activity and which is cardioprotective. Results suggested the molecule BTB06584 (hereafter referred to as BTB). Fluorescence microscopy was used to study its effects on ΔΨm and on the rate of ATP consumption following inhibition of respiration in several cell types. The effect of BTB on oxygen (O2 ) consumption was explored and protective potential determined using ischaemia/reperfusion assays. We also investigated a potential mechanism of action through its interaction with inhibitor protein of F1 subunit (IF1 ), the endogenous inhibitor of the F1 Fo-ATPase. KEY RESULTS BTB inhibited F1 Fo-ATPase activity with no effect on ΔΨm or O2 consumption. ATP consumption was decreased following inhibition of respiration, and ischaemic cell death was reduced. BTB efficiency was increased by IF1 overexpression and reduced by silencing the protein. In addition, BTB rescued defective haemoglobin synthesis in zebrafish pinotage (pnt) mutants in which expression of the Atpif1a gene is lost. CONCLUSIONS AND IMPLICATIONS BTB may represent a valuable tool to selectively inhibit mitochondrial F1 Fo-ATPase activity without compromising ATP synthesis and to limit ischaemia-induced injury caused by reversal of the mitochondrial F1 Fo-ATPsynthase.
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Affiliation(s)
- Fabrice Ivanes
- Department of Cell and Developmental Biology, University College LondonLondon, UK
| | - Danilo Faccenda
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Jemma Gatliff
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Ahmed A Ahmed
- Department of Cell and Developmental Biology, University College LondonLondon, UK
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Stefania Cocco
- European Brain Research Institute-Rita Levi-Montalcini FoundationRome, Italy
| | - Carol Ho Ka Cheng
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Emma Allan
- Department of Cell and Developmental Biology, University College LondonLondon, UK
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Claire Russell
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College LondonLondon, UK
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary CollegeLondon, UK
- European Brain Research Institute-Rita Levi-Montalcini FoundationRome, Italy
- Consortium for Mitochondrial Research, University College LondonLondon, UK
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