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Nikiforova AB, Baburina YL, Borisova MP, Surin AK, Kharechkina ES, Krestinina OV, Suvorina MY, Kruglova SA, Kruglov AG. Mitochondrial F-ATP Synthase Co-Migrating Proteins and Ca 2+-Dependent Formation of Large Channels. Cells 2023; 12:2414. [PMID: 37830628 PMCID: PMC10572550 DOI: 10.3390/cells12192414] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/18/2023] [Accepted: 10/02/2023] [Indexed: 10/14/2023] Open
Abstract
Monomers, dimers, and individual FOF1-ATP synthase subunits are, presumably, involved in the formation of the mitochondrial permeability transition pore (PTP), whose molecular structure, however, is still unknown. We hypothesized that, during the Ca2+-dependent assembly of a PTP complex, the F-ATP synthase (subunits) recruits mitochondrial proteins that do not interact or weakly interact with the F-ATP synthase under normal conditions. Therefore, we examined whether the PTP opening in mitochondria before the separation of supercomplexes via BN-PAGE will increase the channel stability and channel-forming capacity of isolated F-ATP synthase dimers and monomers in planar lipid membranes. Additionally, we studied the specific activity and the protein composition of F-ATP synthase dimers and monomers from rat liver and heart mitochondria before and after PTP opening. Against our expectations, preliminary PTP opening dramatically suppressed the high-conductance channel activity of F-ATP synthase dimers and monomers and decreased their specific "in-gel" activity. The decline in the channel-forming activity correlated with the reduced levels of as few as two proteins in the bands: methylmalonate-semialdehyde dehydrogenase and prohibitin 2. These results indicate that proteins co-migrating with the F-ATP synthase may be important players in PTP formation and stabilization.
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Affiliation(s)
- Anna B. Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
| | - Yulia L. Baburina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
| | - Marina P. Borisova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
| | - Alexey K. Surin
- Branch of the Shemyakin—Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Prospekt Nauki 6, 142290 Pushchino, Russia;
- State Research Centre for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Russia;
| | - Ekaterina S. Kharechkina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
| | - Olga V. Krestinina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
| | - Maria Y. Suvorina
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Russia;
| | - Svetlana A. Kruglova
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya 2, 142290 Pushchino, Russia;
| | - Alexey G. Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, 142290 Pushchino, Russia; (A.B.N.); (Y.L.B.); (M.P.B.); (E.S.K.); (O.V.K.)
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2
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Kharechkina ES, Nikiforova AB, Kruglov AG. Regulation of Mitochondrial Permeability Transition Pore Opening by Monovalent Cations in Liver Mitochondria. Int J Mol Sci 2023; 24:ijms24119237. [PMID: 37298189 DOI: 10.3390/ijms24119237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
The opening of the permeability transition pore (PTP) in mitochondria is a key event in the initiation of cell death in various pathologic states, including ischemia/reperfusion. The activation of K+ transport into mitochondria protects cells from ischemia/reperfusion. However, the role of K+ transport in PTP regulation is unclear. Here, we studied the role of K+ and other monovalent cations in the regulation of the PTP opening in an in vitro model. The registration of the PTP opening, membrane potential, Ca2+-retention capacity, matrix pH, and K+ transport was performed using standard spectral and electrode techniques. We found that the presence of all cations tested in the medium (K+, Na+, choline+, and Li+) strongly stimulated the PTP opening compared with sucrose. Several possible reasons for this were examined: the effect of ionic strength, the influx of cations through selective and non-selective channels and exchangers, the suppression of Ca2+/H+ exchange, and the influx of anions. The data obtained indicate that the mechanism of PTP stimulation by cations includes the suppression of K+/H+ exchange and acidification of the matrix, which facilitates the influx of phosphate. Thus, the K+/H+ exchanger and the phosphate carrier together with selective K+ channels compose a PTP regulatory triad, which might operate in vivo.
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Affiliation(s)
- Ekaterina S Kharechkina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
| | - Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
| | - Alexey G Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
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3
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NAD(H) Regulates the Permeability Transition Pore in Mitochondria through an External Site. Int J Mol Sci 2021; 22:ijms22168560. [PMID: 34445270 PMCID: PMC8395297 DOI: 10.3390/ijms22168560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/28/2021] [Accepted: 08/05/2021] [Indexed: 11/17/2022] Open
Abstract
The opening of the permeability transition pore (mPTP) in mitochondria initiates cell death in numerous diseases. The regulation of mPTP by NAD(H) in the mitochondrial matrix is well established; however, the role of extramitochondrial (cytosolic) NAD(H) is still unclear. We studied the effect of added NADH and NAD+ on: (1) the Ca2+-retention capacity (CRC) of isolated rat liver, heart, and brain mitochondria; (2) the Ca2+-dependent mitochondrial swelling in media whose particles can (KCl) or cannot (sucrose) be extruded from the matrix by mitochondrial carriers; (3) the Ca2+-dependent mitochondrial depolarization and the release of entrapped calcein from mitochondria of permeabilized hepatocytes; and (4) the Ca2+-dependent mitochondrial depolarization and subsequent repolarization. NADH and NAD+ increased the CRC of liver, heart, and brain mitochondria 1.5-2.5 times, insignificantly affecting the rate of Ca2+-uptake and the free Ca2+ concentration in the medium. NAD(H) suppressed the Ca2+-dependent mitochondrial swelling both in KCl- and sucrose-based media but did not induce the contraction and repolarization of swollen mitochondria. By contrast, EGTA caused mitochondrial repolarization in both media and the contraction in KCl-based medium only. NAD(H) delayed the Ca2+-dependent depolarization and the release of calcein from individual mitochondria in hepatocytes. These data unambiguously demonstrate the existence of an external NAD(H)-dependent site of mPTP regulation.
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Kruglov AG, Kharechkina ES, Nikiforova AB, Odinokova IV, Kruglova SA. Dynamics of the permeability transition pore size in isolated mitochondria and mitoplasts. FASEB J 2021; 35:e21764. [PMID: 34245631 DOI: 10.1096/fj.202100596r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/28/2021] [Accepted: 06/14/2021] [Indexed: 11/11/2022]
Abstract
The size of the permeability transition pore (PTP) is accepted to be ≤1.5 kDa. However, different authors reported values from 650 to 4000 Da. The present study is focused on the variability of the average PTP size in and between mitochondrial samples, its reasons and relations with PTP dynamics. Measurement of PTP size by the standard method revealed its 500 Da-range variability between mitochondrial samples. Sequential measurements in the same sample showed that the PTP size tends to grow with time and Ca2+ concentration. Selective damage to the mitochondrial outer membrane (MOM) reduced the apparent PTP size by ~200-300 Da. Hypotonic and hypertonic osmotic shock and partial removal of the MOM with the preservation of the mitochondrial inner membrane intactness decreased the apparent PTP size by ~50%. We developed an approach to continuous monitoring of the PTP size that revealed the existence of stable PTP states with different pore sizes (~700, 900-1000, ~1350, 1700-1800, and 2100-2200 Da) and transitions between them. The transitions were accelerated by elevating the Ca2+ concentration, temperature, and osmotic pressure, which demonstrates an increased capability of PTP to accommodate to large molecules (plasticity). Cyclosporin A inhibited the transitions between states. The analysis of PTP size dynamics in osmotically shocked mitochondria and mitoplasts confirmed the importance of the MOM for the stabilization of PTP structure. Thus, this approach provides a new tool for PTP studies and the opportunity to reconcile data on the PTP size and mitochondrial megachannel conductance.
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Affiliation(s)
- Alexey G Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Ekaterina S Kharechkina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Irina V Odinokova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Svetlana A Kruglova
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia
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5
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Hamilton S, Terentyeva R, Martin B, Perger F, Li J, Stepanov A, Bonilla IM, Knollmann BC, Radwański PB, Györke S, Belevych AE, Terentyev D. Increased RyR2 activity is exacerbated by calcium leak-induced mitochondrial ROS. Basic Res Cardiol 2020; 115:38. [PMID: 32444920 PMCID: PMC7244455 DOI: 10.1007/s00395-020-0797-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/07/2020] [Indexed: 11/29/2022]
Abstract
Cardiac disease is associated with deleterious emission of mitochondrial reactive oxygen species (mito-ROS), as well as enhanced oxidation and activity of the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor (RyR2). The transfer of Ca2+ from the SR via RyR2 to mitochondria is thought to play a key role in matching increased metabolic demand during stress. In this study, we investigated whether augmented RyR2 activity results in self-imposed exacerbation of SR Ca2+ leak, via altered SR-mitochondrial Ca2+ transfer and elevated mito-ROS emission. Fluorescent indicators and spatially restricted genetic ROS probes revealed that both pharmacologically and genetically enhanced RyR2 activity, in ventricular myocytes from rats and catecholaminergic polymorphic ventricular tachycardia (CPVT) mice, respectively, resulted in increased ROS emission under β-adrenergic stimulation. Expression of mitochondrial Ca2+ probe mtRCamp1h revealed diminished net mitochondrial [Ca2+] with enhanced SR Ca2+ leak, accompanied by depolarization of the mitochondrial matrix. While this may serve as a protective mechanism to prevent mitochondrial Ca2+ overload, protection is not complete and enhanced mito-ROS emission resulted in oxidation of RyR2, further amplifying proarrhythmic SR Ca2+ release. Importantly, the effects of augmented RyR2 activity could be attenuated by mitochondrial ROS scavenging, and experiments with dominant-negative paralogs of the mitochondrial Ca2+ uniporter (MCU) supported the hypothesis that SR-mitochondria Ca2+ transfer is essential for the increase in mito-ROS. We conclude that in a process whereby leak begets leak, augmented RyR2 activity modulates mitochondrial Ca2+ handling, promoting mito-ROS emission and driving further channel activity in a proarrhythmic feedback cycle in the diseased heart.
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Affiliation(s)
- Shanna Hamilton
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Radmila Terentyeva
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Benjamin Martin
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Fruzsina Perger
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jiaoni Li
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Andrei Stepanov
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Laboratory of Cell Pathology, Institute RAS, Saint Petersburg, Russia
| | - Ingrid M Bonilla
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN, 37232, USA
| | - Przemyslaw B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Sandor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Andriy E Belevych
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Dmitry Terentyev
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA. .,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.
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6
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Wacquier B, Combettes L, Dupont G. Dual dynamics of mitochondrial permeability transition pore opening. Sci Rep 2020; 10:3924. [PMID: 32127570 PMCID: PMC7054270 DOI: 10.1038/s41598-020-60177-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/06/2020] [Indexed: 11/09/2022] Open
Abstract
Mitochondria play an essential role in bioenergetics and cellular Ca\documentclass[12pt]{minimal}
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\begin{document}$${}^{2+}$$\end{document}2+ handling. The mitochondrial permeability transition pore (mPTP) is a non-specific channel located in the inner mitochondrial membrane. Long-lasting openings of the pore allow the rapid passage of ions and large molecules, which can result in cell death. The mPTP also exhibits transient, low conductance openings that contribute to Ca\documentclass[12pt]{minimal}
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\begin{document}$${}^{2+}$$\end{document}2+ homeostasis. Although many regulators of the pore have been identified, none of them uniquely governs the passage between the two operating modes, which thus probably relies on a still unidentified network of interactions. By developing a core computational model for mPTP opening under the control of mitochondrial voltage and Ca\documentclass[12pt]{minimal}
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\begin{document}$${}^{2+}$$\end{document}2+, we uncovered the existence of a positive feedback loop leading to bistability. The characteristics of the two stable steady-states correspond to those of the two opening states. When inserted in a full model of Ca\documentclass[12pt]{minimal}
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\begin{document}$${}^{2+}$$\end{document}2+ handling by mitochondria, our description of the pore reproduces observations in mitochondrial suspensions. Moreover, the model predicted the occurrence of hysteresis in the switching between the two modes, upon addition and removal of free Ca\documentclass[12pt]{minimal}
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\begin{document}$${}^{2+}$$\end{document}2+ in the extra-mitochondrial medium. Stochastic simulations then confirmed that the pore can undergo transient openings resembling those observed in intact cells.
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Affiliation(s)
- Benjamin Wacquier
- Unit of Theoretical Chronobiology, Faculté des Sciences, Université Libre de Bruxelles (ULB) CP231, B1050, Brussels, Belgium
| | | | - Geneviève Dupont
- Unit of Theoretical Chronobiology, Faculté des Sciences, Université Libre de Bruxelles (ULB) CP231, B1050, Brussels, Belgium.
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7
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Huang L, Reis C, Boling WW, Zhang JH. Stem Cell Therapy in Brain Ischemia: The Role of Mitochondrial Transfer. Stem Cells Dev 2020; 29:555-561. [PMID: 31964239 DOI: 10.1089/scd.2019.0237] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial dysfunction is an important pathological process in the setting of ischemic brain injury. Stem cell-mediated mitochondrial transfer provides an efficient intercellular process to supply additional mitochondria in the ischemic brain tissues. In this review, we summarize the mitochondrial pathology associated with brain ischemia, mechanisms of stem cell-mediated mitochondrial transfer, and in vitro/in vivo experimental findings of mitochondrial transfer from stem cells to ischemic vascular endothelial cells/neurons as potential therapeutic strategy in the management of ischemic brain injury.
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Affiliation(s)
- Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, California, USA
| | - Cesar Reis
- Occupational Medicine, Southern California Kaiser Permanente, Riverside, California, USA.,Department of Preventive Medicine, Loma Linda University, Loma Linda, California, USA
| | - Warren W Boling
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, California, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, California, USA
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8
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Zhao XY, Lu MH, Yuan DJ, Xu DE, Yao PP, Ji WL, Chen H, Liu WL, Yan CX, Xia YY, Li S, Tao J, Ma QH. Mitochondrial Dysfunction in Neural Injury. Front Neurosci 2019; 13:30. [PMID: 30778282 PMCID: PMC6369908 DOI: 10.3389/fnins.2019.00030] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/14/2019] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are the double membrane organelles providing most of the energy for cells. In addition, mitochondria also play essential roles in various cellular biological processes such as calcium signaling, apoptosis, ROS generation, cell growth, and cell cycle. Mitochondrial dysfunction is observed in various neurological disorders which harbor acute and chronic neural injury such as neurodegenerative diseases and ischemia, hypoxia-induced brain injury. In this review, we describe how mitochondrial dysfunction contributes to the pathogenesis of neurological disorders which manifest chronic or acute neural injury.
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Affiliation(s)
- Xiu-Yun Zhao
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Mei-Hong Lu
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - De-Juan Yuan
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Physiology, Liaoning Provincial Key Laboratory of Cerebral Diseases, Dalian Medical University, Dalian, China
| | - De-En Xu
- Wuxi No. 2 People’s Hospital, Wuxi, China
| | - Pei-Pei Yao
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Wen-Li Ji
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Hong Chen
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Wen-Long Liu
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Chen-Xiao Yan
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Yi-Yuan Xia
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Shao Li
- Department of Physiology, Liaoning Provincial Key Laboratory of Cerebral Diseases, Dalian Medical University, Dalian, China
| | - Jin Tao
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
- Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou, China
| | - Quan-Hong Ma
- Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, China
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9
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Hamilton S, Terentyeva R, Kim TY, Bronk P, Clements RT, O-Uchi J, Csordás G, Choi BR, Terentyev D. Pharmacological Modulation of Mitochondrial Ca 2+ Content Regulates Sarcoplasmic Reticulum Ca 2+ Release via Oxidation of the Ryanodine Receptor by Mitochondria-Derived Reactive Oxygen Species. Front Physiol 2018; 9:1831. [PMID: 30622478 PMCID: PMC6308295 DOI: 10.3389/fphys.2018.01831] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/06/2018] [Indexed: 01/09/2023] Open
Abstract
In a physiological setting, mitochondria increase oxidative phosphorylation during periods of stress to meet increased metabolic demand. This in part is mediated via enhanced mitochondrial Ca2+ uptake, an important regulator of cellular ATP homeostasis. In a pathophysiological setting pharmacological modulation of mitochondrial Ca2+ uptake or retention has been suggested as a therapeutic strategy to improve metabolic homeostasis or attenuate Ca2+-dependent arrhythmias in cardiac disease states. To explore the consequences of mitochondrial Ca2+ accumulation, we tested the effects of kaempferol, an activator of mitochondrial Ca2+ uniporter (MCU), CGP-37157, an inhibitor of mitochondrial Na+/Ca2+ exchanger, and MCU inhibitor Ru360 in rat ventricular myocytes (VMs) from control rats and rats with hypertrophy induced by thoracic aortic banding (TAB). In periodically paced VMs under β-adrenergic stimulation, treatment with kaempferol (10 μmol/L) or CGP-37157 (1 μmol/L) enhanced mitochondrial Ca2+ accumulation monitored by mitochondrial-targeted Ca2+ biosensor mtRCamp1h. Experiments with mitochondrial membrane potential-sensitive dye TMRM revealed this was accompanied by depolarization of the mitochondrial matrix. Using redox-sensitive OMM-HyPer and ERroGFP_iE biosensors, we found treatment with kaempferol or CGP-37157 increased the levels of reactive oxygen species (ROS) in mitochondria and the sarcoplasmic reticulum (SR), respectively. Confocal Ca2+ imaging showed that accelerated Ca2+ accumulation reduced Ca2+ transient amplitude and promoted generation of spontaneous Ca2+ waves in VMs paced under ISO, suggestive of abnormally high activity of the SR Ca2+ release channel ryanodine receptor (RyR). Western blot analyses showed increased RyR oxidation after treatment with kaempferol or CGP-37157 vs. controls. Furthermore, in freshly isolated TAB VMs, confocal Ca2+ imaging demonstrated that enhancement of mitochondrial Ca2+ accumulation further perturbed global Ca2+ handling, increasing the number of cells exhibiting spontaneous Ca2+ waves, shortening RyR refractoriness and decreasing SR Ca2+ content. In ex vivo optically mapped TAB hearts, kaempferol exacerbated proarrhythmic phenotype. On the contrary, incubation of cells with MCU inhibitor Ru360 (2 μmol/L, 30 min) normalized RyR oxidation state, improved intracellular Ca2+ homeostasis and reduced triggered activity in ex vivo TAB hearts. These findings suggest facilitation of mitochondrial Ca2+ uptake in cardiac disease can exacerbate proarrhythmic disturbances in Ca2+ homeostasis via ROS and enhanced activity of oxidized RyRs, while strategies to reduce mitochondrial Ca2+ accumulation can be protective.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Radmila Terentyeva
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Tae Yun Kim
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Peter Bronk
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Richard T. Clements
- Department of Surgery, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, RI, United States
| | - Jin O-Uchi
- Lillehei Heart Institute University of Minnesota, Cancer and Cardiovascular Research Building, Minneapolis, MN, United States
| | - György Csordás
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Bum-Rak Choi
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
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10
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Zorov DB, Juhaszova M, Sollott SJ. Mitochondrial reactive oxygen species (ROS) and ROS-induced ROS release. Physiol Rev 2014; 94:909-50. [PMID: 24987008 DOI: 10.1152/physrev.00026.2013] [Citation(s) in RCA: 3318] [Impact Index Per Article: 331.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca(2+), etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca(2+)). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo.
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Affiliation(s)
- Dmitry B Zorov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Magdalena Juhaszova
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Steven J Sollott
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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11
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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Rauckhorst AJ, Broekemeier KM, Pfeiffer DR. Regulation of the Ca(2+)-independent phospholipase A2 in liver mitochondria by changes in the energetic state. J Lipid Res 2014; 55:826-36. [PMID: 24586040 DOI: 10.1194/jlr.m043307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of electron transport chain redox status on activity of the mitochondrial Ca(2+)-independent phospholipase A2 (iPLA2) has been examined. When oxidizing NAD-linked substrates, the enzyme is not active unless deenergization occurs. Uncoupler, rotenone, antimycin A, and cyanide are equally effective at upregulating the enzyme, while oligomycin is ineffective. Thenoyltrifluoroacetone causes deenergization and activates the enzyme, but only if succinate is the respiratory substrate. These findings show that the mitochondrial iPLA2 responds to the energetic state overall, rather than to the redox status of individual electron transport chain complexes. With NAD-linked substrates, and using rotenone to deenergize, iPLA2 activation can be reversed by adding succinate to reestablish a membrane potential. For this purpose, ascorbate plus N,N,N'N'-tetramethyl-phenylenediamine can be used instead of succinate and is equally effective. With succinate as substrate, the membrane potential can be reduced in a graded and stable fashion by adding increasing concentrations of malonate, which is a competitive inhibitor of succinate utilization. A partial and stable activation of the iPLA2 accompanies partial deenergization. These findings suggest that in addition to the several functions that have been proposed, the mitochondrial iPLA2 may help to coordinate local capillary blood flow with changing energy demands.
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Affiliation(s)
- Adam J Rauckhorst
- Departments of Molecular and Cellular Biochemistry Ohio State University, Columbus, OH 43210
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13
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Dedkova EN, Blatter LA. Calcium signaling in cardiac mitochondria. J Mol Cell Cardiol 2013; 58:125-33. [PMID: 23306007 DOI: 10.1016/j.yjmcc.2012.12.021] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/01/2012] [Accepted: 12/28/2012] [Indexed: 01/02/2023]
Abstract
Mitochondrial Ca signaling contributes to the regulation of cellular energy metabolism, and mitochondria participate in cardiac excitation-contraction coupling (ECC) through their ability to store Ca, shape the cytosolic Ca signals and generate ATP required for contraction. The mitochondrial inner membrane is equipped with an elaborate system of channels and transporters for Ca uptake and extrusion that allows for the decoding of cytosolic Ca signals, and the storage of Ca in the mitochondrial matrix compartment. Controversy, however remains whether the fast cytosolic Ca transients underlying ECC in the beating heart are transmitted rapidly into the matrix compartment or slowly integrated by the mitochondrial Ca transport machinery. This review summarizes established and novel findings on cardiac mitochondrial Ca transport and buffering, and discusses the evidence either supporting or arguing against the idea that Ca can be taken up rapidly by mitochondria during ECC.
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Affiliation(s)
- Elena N Dedkova
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL 60612, USA
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14
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von Stockum S, Basso E, Petronilli V, Sabatelli P, Forte MA, Bernardi P. Properties of Ca(2+) transport in mitochondria of Drosophila melanogaster. J Biol Chem 2011; 286:41163-41170. [PMID: 21984833 DOI: 10.1074/jbc.m111.268375] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied the pathways for Ca(2+) transport in mitochondria of the fruit fly Drosophila melanogaster. We demonstrate the presence of ruthenium red (RR)-sensitive Ca(2+) uptake, of RR-insensitive Ca(2+) release, and of Na(+)-stimulated Ca(2+) release in energized mitochondria, which match well characterized Ca(2+) transport pathways of mammalian mitochondria. Following larger matrix Ca(2+) loading Drosophila mitochondria underwent spontaneous RR-insensitive Ca(2+) release, an event that in mammals is due to opening of the permeability transition pore (PTP). Like the PTP of mammals, Drosophila Ca(2+)-induced Ca(2+) release could be triggered by uncoupler, diamide, and N-ethylmaleimide, indicating the existence of regulatory voltage- and redox-sensitive sites and was inhibited by tetracaine. Unlike PTP-mediated Ca(2+) release in mammals, however, it was (i) insensitive to cyclosporin A, ubiquinone 0, and ADP; (ii) inhibited by P(i), as is the PTP of yeast mitochondria; and (iii) not accompanied by matrix swelling and cytochrome c release even in KCl-based medium. We conclude that Drosophila mitochondria possess a selective Ca(2+) release channel with features intermediate between the PTP of yeast and mammals.
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Affiliation(s)
- Sophia von Stockum
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Emy Basso
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Valeria Petronilli
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Patrizia Sabatelli
- Institute of Molecular Genetics at the Istituto Ortopedico Rizzoli, I-40126 Bologna, Italy
| | - Michael A Forte
- Vollum Institute, Oregon Health & Sciences University, Portland, Oregon 97239
| | - Paolo Bernardi
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy.
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15
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Dedkova EN, Blatter LA. Measuring mitochondrial function in intact cardiac myocytes. J Mol Cell Cardiol 2011; 52:48-61. [PMID: 21964191 DOI: 10.1016/j.yjmcc.2011.08.030] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/30/2011] [Accepted: 08/09/2011] [Indexed: 12/01/2022]
Abstract
Mitochondria are involved in cellular functions that go beyond the traditional role of these organelles as the power plants of the cell. Mitochondria have been implicated in several human diseases, including cardiac dysfunction, and play a role in the aging process. Many aspects of our knowledge of mitochondria stem from studies performed on the isolated organelle. Their relative inaccessibility imposes experimental difficulties to study mitochondria in their natural environment-the cytosol of intact cells-and has hampered a comprehensive understanding of the plethora of mitochondrial functions. Here we review currently available methods to study mitochondrial function in intact cardiomyocytes. These methods primarily use different flavors of fluorescent dyes and genetically encoded fluorescent proteins in conjunction with high-resolution imaging techniques. We review methods to study mitochondrial morphology, mitochondrial membrane potential, Ca(2+) and Na(+) signaling, mitochondrial pH regulation, redox state and ROS production, NO signaling, oxygen consumption, ATP generation and the activity of the mitochondrial permeability transition pore. Where appropriate we complement this review on intact myocytes with seminal studies that were performed on isolated mitochondria, permeabilized cells, and in whole hearts.
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Affiliation(s)
- Elena N Dedkova
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL 60612, USA
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16
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Park JS, Pasupulati R, Feldkamp T, Roeser NF, Weinberg JM. Cyclophilin D and the mitochondrial permeability transition in kidney proximal tubules after hypoxic and ischemic injury. Am J Physiol Renal Physiol 2011; 301:F134-50. [PMID: 21490135 PMCID: PMC3129895 DOI: 10.1152/ajprenal.00033.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 04/08/2011] [Indexed: 01/08/2023] Open
Abstract
Mitochondrial matrix cyclophilin D (CyPD) is known to promote development of the mitochondrial permeability transition (MPT). Kidney proximal tubule cells are especially prone to deleterious effects of mitochondrial damage because of their dependence on oxidative mitochondrial metabolism for ATP production. To clarify the role of CyPD and the MPT in proximal tubule injury during ischemia-reperfusion (I/R) and hypoxia-reoxygenation (H/R), we assessed freshly isolated tubules and in vivo injury in wild-type (WT) and Ppif(-/-) CyPD-null mice. Isolated mouse tubules developed a sustained, nonesterified fatty acid-mediated energetic deficit after H/R in vitro that could be substantially reversed by delipidated albumin and supplemental citric acid cycle substrates but was not modified by the absence of CyPD. Susceptibility of WT and Ppif(-/-) tubules to the MPT was increased by H/R but was less in normoxic and H/R Ppif(-/-) than WT tubules. Correction of the energetic deficit that developed during H/R strongly increased resistance to the MPT. Ppif(-/-) mice were resistant to I/R injury in vivo spanning a wide range of severity. The data clarify involvement of the MPT in oxygen deprivation-induced tubule cell injury by showing that the MPT does not contribute to the initial bioenergetic deficit produced by H/R but the deficit predisposes to subsequent development of the MPT, which contributes pathogenically to kidney I/R injury in vivo.
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Affiliation(s)
- Jeong Soon Park
- Nephrology Division, Dept. of Internal Medicine, Rm. 1560, MSRB II, University of Michigan Medical Center, Ann Arbor, MI 48109-0676, USA
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Lidocaine depolarizes the mitochondrial membrane potential by intracellular alkalization in rat dorsal root ganglion neurons. J Anesth 2011; 25:229-39. [PMID: 21212988 DOI: 10.1007/s00540-010-1079-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE The mitochondrial membrane potential (ΔΨm) is an important factor for apoptosis, and it is produced by the proton electrochemical gradient (ΔµH(+)). Therefore, the intracellular proton concentration (pH(in)) is an important factor for modifying the ΔΨm. However, the effects of lidocaine on pH(in) are unclear. To investigate mitochondrial responses to lidocaine, therefore, we simultaneously measured pH(in) with ΔΨm, flavin adenine dinucleotide (FAD), and reduced form of nicotinamide adenine dinucleotide (NADH) fluorescence, and calculated the FAD/NADH ratio (redox ratio), the superoxide production in mitochondria. METHODS Morphological change and early apoptosis were observed by annexin-V FITC staining under fluorescent microscope. The ratiometric fluorescent probe JC-1 and HPTS were used for the simultaneous measurements of ΔΨm with pH(in) in rat dorsal root ganglion (DRG) neurons. FAD and NADH autofluorescence were simultaneously measured, and the FAD/NADH fluorescence ratio (redox ratio) was calculated. The superoxide was measured by mitosox-red fluorescent probe for mitochondrial superoxide. Lidocaine was evaluated at 1, 5, and 10 mM. RESULTS Morphological change and early apoptosis were observed after 10 mM lidocaine administration. Lidocaine depolarized ΔΨm with increased pH(in) in a dose-dependent manner. In low-pH saline (pH 6), in the presence of both the weak acids (acetate and propionate), lidocaine failed to depolarize ΔΨm and increase pH(in). On the other hand, lidocaine decreased the redox ratio in the cell and increased the levels of superoxide in a dose-dependent manner. CONCLUSION These results demonstrated that lidocaine depolarizes ΔΨm by intracellular alkalization. These results may indicate one of the mechanisms responsible for lidocaine-induced neurotoxicity.
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18
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Onizuka S, Tamura R, Hosokawa N, Kawasaki Y, Tsuneyoshi I. Local anesthetics depolarize mitochondrial membrane potential by intracellular alkalization in rat dorsal root ganglion neurons. Anesth Analg 2010; 111:775-83. [PMID: 20686005 DOI: 10.1213/ane.0b013e3181e9f03b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Although it has been reported that local anesthetics, especially lidocaine, are cytotoxic, the mechanism is unclear. Depolarization of the mitochondrial membrane potential (DeltaPsim), one of the markers of mitochondrial failure, is regulated by the proton electrochemical gradient (Delta H(+)). Therefore, intracellular pH ([pH]in) and mitochondrial pH ([pH]m) are important factors for modifying DeltaPsim. However, the effects of local anesthetics on [pH]in and [pH]m are unclear. To investigate mitochondrial responses to local anesthetics, we simultaneously measured [pH]m and [pH]in, along with DeltaPsim. METHODS The ratiometric fluorescent probe JC-1 and HPTS were used for the simultaneous measurements of DeltaPsim with [pH]in in rat dorsal root ganglion neurons. A carboxy-SNARF-1 fluorescent probe was used to measure [pH]m. Lidocaine, mepivacaine, bupivacaine, procaine, QX-314, a charged form of lidocaine, and ammonium chloride (NH(4)Cl) were evaluated. RESULTS DeltaPsim was depolarized and [pH]in was increased by lidocaine, mepivacaine, bupivacaine, and procaine in a dose-dependent manner. Significantly, a relationship between DeltaPsim and [pH]in was observed for lidocaine, mepivacaine, bupivacaine, procaine, and NH(4)Cl perfusion. In contrast, QX-314 did not change DeltaPsim or [pH]in. In low-pH saline (pH6) and in the presence of a weak acid, lidocaine failed to increase [pH]in or depolarize DeltaPsim. The [pH]m was also increased by lidocaine, mepivacaine, bupivacaine, procaine, and NH(4)Cl. CONCLUSION These results demonstrate that uncharged (base) forms of local anesthetics induce DeltaPsim depolarization. One of the causes is intracellular and mitochondrial alkalization.
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Affiliation(s)
- Shin Onizuka
- Department of Anesthesiology and Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki 889-1692, Japan
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19
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Zhu J, Rebecchi MJ, Tan M, Glass PSA, Brink PR, Liu L. Age-associated differences in activation of Akt/GSK-3beta signaling pathways and inhibition of mitochondrial permeability transition pore opening in the rat heart. J Gerontol A Biol Sci Med Sci 2010; 65:611-9. [PMID: 20427381 DOI: 10.1093/gerona/glq035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pretreatment with isoflurane decreased myocardial infarction size in young rats (3-5 months) but not in old rats (20-24 months). To understand the mechanisms underlying the failure to protect the old myocardium, differences in phosphorylation of Akt/GSK-3beta and age-associated differences in mitochondrial permeability transition pore (mPTP) opening in the aging heart in vivo were measured. Isoflurane significantly increased Akt and GSK-3beta phosphorylation in the young groups. In contrast, levels of p-Akt and p-GSK-3beta were highly elevated in the old sham control groups. Isoflurane preconditioning significantly reduced the fall in NAD(+) levels induced by ischemia/reperfusion injury in the young animals, reflecting the inhibition of mPTP opening. In the old animals, however, isoflurane failed to prevent the fall in NAD(+) levels induced by ischemia/reperfusion injury. Lack of isoflurane-induced cardioprotective effects, seen in the old animals, can be explained by age-related differences in Akt/GSK-3beta signaling pathway and the inability to reduce mPTP opening following ischemia/reperfusion injury.
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Affiliation(s)
- Jiang Zhu
- Department of Anesthesiology, Stony Brook University School of Medicine, HSC L4 060, Stony Brook, NY 11794, USA
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20
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Daiber A. Redox signaling (cross-talk) from and to mitochondria involves mitochondrial pores and reactive oxygen species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:897-906. [PMID: 20122895 DOI: 10.1016/j.bbabio.2010.01.032] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 01/15/2010] [Accepted: 01/26/2010] [Indexed: 12/13/2022]
Abstract
This review highlights the important role of redox signaling between mitochondria and NADPH oxidases. Besides the definition and general importance of redox signaling, the cross-talk between mitochondrial and Nox-derived reactive oxygen species (ROS) is discussed on the basis of 4 different examples. In the first model, angiotensin-II is discussed as a trigger for NADPH oxidase activation with subsequent ROS-dependent opening of mitochondrial ATP-sensitive potassium channels leading to depolarization of mitochondrial membrane potential followed by mitochondrial ROS formation and respiratory dysfunction. This concept was supported by observations that ethidium bromide-induced mitochondrial damage suppressed angiotensin-II-dependent increase in Nox1 and oxidative stress. In another example hypoxia was used as a stimulator of mitochondrial ROS formation and by using pharmacological and genetic inhibitors, a role of mitochondrial ROS for the induction of NADPH oxidase via PKCvarepsilon was demonstrated. The third model was based on cell death by serum withdrawal that promotes the production of ROS in human 293T cells by stimulating both the mitochondria and Nox1. By superior molecular biological methods the authors showed that mitochondria were responsible for the fast onset of ROS formation followed by a slower but long-lasting oxidative stress condition based on the activation of an NADPH oxidase (Nox1) in response to the fast mitochondrial ROS formation. Finally, a cross-talk between mitochondria and NADPH oxidases (Nox2) was shown in nitroglycerin-induced tolerance involving the mitochondrial permeability transition pore and ATP-sensitive potassium channels. The use of these redox signaling pathways as pharmacological targets is briefly discussed.
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Affiliation(s)
- Andreas Daiber
- Universitätsmedizin der Johannes Gutenberg-Universität Mainz, II. Med. Klinik u. Poliklinik-Labor für Molekulare Kardiologie, Obere Zahlbacher Str. 63, 55101 Mainz, Germany.
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21
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Feldkamp T, Park JS, Pasupulati R, Amora D, Roeser NF, Venkatachalam MA, Weinberg JM. Regulation of the mitochondrial permeability transition in kidney proximal tubules and its alteration during hypoxia-reoxygenation. Am J Physiol Renal Physiol 2009; 297:F1632-46. [PMID: 19741014 PMCID: PMC2801335 DOI: 10.1152/ajprenal.00422.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 09/03/2009] [Indexed: 12/30/2022] Open
Abstract
Development of the mitochondrial permeability transition (MPT) can importantly contribute to lethal cell injury from both necrosis and apoptosis, but its role varies considerably with both the type of cell and type of injury, and it can be strongly opposed by the normally abundant endogenous metabolites ADP and Mg(2+). To better characterize the MPT in kidney proximal tubule cells and assess its contribution to injury to them, we have refined and validated approaches to follow the process in whole kidney proximal tubules and studied its regulation in normoxic tubules and after hypoxia-reoxygenation (H/R). Physiological levels of ADP and Mg(2+) greatly decreased sensitivity to the MPT. Inhibition of cyclophilin D by cyclosporine A (CsA) effectively opposed the MPT only in the presence of ADP and/or Mg(2+). Nonesterified fatty acids (NEFA) had a large role in the decreased resistance to the MPT seen after H/R irrespective of the available substrate or the presence of ADP, Mg(2+), or CsA, but removal of NEFA was less effective at restoring normal resistance to the MPT in the presence of electron transport complex I-dependent substrates than with succinate. The data indicate that the NEFA accumulation that occurs during both hypoxia in vitro and ischemic acute kidney injury in vivo is a critical sensitizing factor for the MPT that overcomes the antagonistic effect of endogenous metabolites and cyclophilin D inhibition, particularly in the presence of complex I-dependent substrates, which predominate in vivo.
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Affiliation(s)
- Thorsten Feldkamp
- Nephrology Division, Dept. of Internal Medicine, Univ. of Michigan Medical Center, Ann Arbor, MI 48109-0676, USA
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22
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Differential effects of non-steroidal anti-inflammatory drugs on mitochondrial dysfunction during oxidative stress. Arch Biochem Biophys 2009; 490:1-8. [DOI: 10.1016/j.abb.2009.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Stowe DF, Camara AKS. Mitochondrial reactive oxygen species production in excitable cells: modulators of mitochondrial and cell function. Antioxid Redox Signal 2009; 11:1373-414. [PMID: 19187004 PMCID: PMC2842133 DOI: 10.1089/ars.2008.2331] [Citation(s) in RCA: 341] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 12/14/2022]
Abstract
The mitochondrion is a major source of reactive oxygen species (ROS). Superoxide (O(2)(*-)) is generated under specific bioenergetic conditions at several sites within the electron-transport system; most is converted to H(2)O(2) inside and outside the mitochondrial matrix by superoxide dismutases. H(2)O(2) is a major chemical messenger that, in low amounts and with its products, physiologically modulates cell function. The redox state and ROS scavengers largely control the emission (generation scavenging) of O(2)(*-). Cell ischemia, hypoxia, or toxins can result in excess O(2)(*-) production when the redox state is altered and the ROS scavenger systems are overwhelmed. Too much H(2)O(2) can combine with Fe(2+) complexes to form reactive ferryl species (e.g., Fe(IV) = O(*)). In the presence of nitric oxide (NO(*)), O(2)(*-) forms the reactant peroxynitrite (ONOO(-)), and ONOOH-induced nitrosylation of proteins, DNA, and lipids can modify their structure and function. An initial increase in ROS can cause an even greater increase in ROS and allow excess mitochondrial Ca(2+) entry, both of which are factors that induce cell apoptosis and necrosis. Approaches to reduce excess O(2)(*-) emission include selectively boosting the antioxidant capacity, uncoupling of oxidative phosphorylation to reduce generation of O(2)(*-) by inducing proton leak, and reversibly inhibiting electron transport. Mitochondrial cation channels and exchangers function to maintain matrix homeostasis and likely play a role in modulating mitochondrial function, in part by regulating O(2)(*-) generation. Cell-signaling pathways induced physiologically by ROS include effects on thiol groups and disulfide linkages to modify posttranslationally protein structure to activate/inactivate specific kinase/phosphatase pathways. Hypoxia-inducible factors that stimulate a cascade of gene transcription may be mediated physiologically by ROS. Our knowledge of the role played by ROS and their scavenging systems in modulation of cell function and cell death has grown exponentially over the past few years, but we are still limited in how to apply this knowledge to develop its full therapeutic potential.
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Affiliation(s)
- David F Stowe
- Anesthesiology Research Laboratories, Department of Anesthesiology, The Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Yao Y, Li L, Li L, Gao C, Shi C. Sevoflurane Postconditioning Protects Chronically-Infarcted Rat Hearts against Ischemia-Reperfusion Injury by Activation of Pro-survival Kinases and Inhibition of Mitochondrial Permeability Transition Pore Opening upon Reperfusion. Biol Pharm Bull 2009; 32:1854-61. [DOI: 10.1248/bpb.32.1854] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yuntai Yao
- Department of Anesthesiology, Fuwai Cardiovascular Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College
| | - Lihuan Li
- Department of Anesthesiology, Fuwai Cardiovascular Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College
| | - Libing Li
- Department of Cardiovascular Surgery and Cardiovascular Institute, General Hospital of the People's Liberation Army
| | - Changqing Gao
- Department of Cardiovascular Surgery and Cardiovascular Institute, General Hospital of the People's Liberation Army
| | - Chunxia Shi
- Department of Anesthesiology, Fuwai Cardiovascular Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College
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25
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Koshkin V, Dai FF, Robson-Doucette CA, Chan CB, Wheeler MB. Limited Mitochondrial Permeabilization Is an Early Manifestation of Palmitate-induced Lipotoxicity in Pancreatic β-Cells. J Biol Chem 2008; 283:7936-48. [DOI: 10.1074/jbc.m705652200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Eliseev RA, Filippov G, Velos J, VanWinkle B, Goldman A, Rosier RN, Gunter TE. Role of cyclophilin D in the resistance of brain mitochondria to the permeability transition. Neurobiol Aging 2007; 28:1532-42. [PMID: 16876914 DOI: 10.1016/j.neurobiolaging.2006.06.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 05/12/2006] [Accepted: 06/23/2006] [Indexed: 11/26/2022]
Abstract
The mitochondrial permeability transition (MPT) is involved in both necrosis and apoptosis. Cyclophilin D (CypD) is an important component of the MPT. Brain mitochondria are more resistant to the MPT when compared to heart or liver mitochondria. We found that this increased resistance correlates with low expression of CypD in brain when compared to heart or liver. In newborn rats, sensitivity of brain mitochondria to the MPT and CypD expression are significantly higher than in mature animals. In an in vitro model of neuronal development, mitochondria in differentiated neuronal-like cells exert a higher calcium threshold toward MPT induction and express significantly less CypD when compared to undifferentiated precursor cells. Gain and loss of function experiments confirm the role of CypD in sensitivity to the MPT. Together our data indicate that the increased calcium threshold of brain mitochondria to the MPT correlates with low expression of CypD in brain; and that neuronal cells lose CypD during differentiation and become less sensitive to the MPT induction. This may be a protection mechanism that raises the threshold of brain tissue against injuries.
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Affiliation(s)
- Roman A Eliseev
- Musculoskeletal Research Center, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States. roman
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Racay P. Effect of magnesium on calcium-induced depolarisation of mitochondrial transmembrane potential. Cell Biol Int 2007; 32:136-45. [PMID: 17933560 DOI: 10.1016/j.cellbi.2007.08.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 06/28/2007] [Accepted: 08/27/2007] [Indexed: 10/22/2022]
Abstract
An effect of magnesium on calcium-induced depolarisation of mitochondrial transmembrane potential (DeltaPsi(m)) was investigated. Depending on the presence of Mg(2+), addition of Ca(2+) to suspension of isolated rat heart mitochondria induced either reversible depolarisation or irreversible collapse of succinate-driven DeltaPsi(m). Irreversible collapse of DeltaPsi(m), observed in the absence of Mg(2+), was insensitive to Ca(2+) chelation, inhibition of Ca(2+) uptake and increased efflux of Ca(2+) from mitochondrial matrix. Based on these data, opening of mPTP in a high-conductance mode is considered to be a major cause of the Ca(2+)-induced irreversible collapse of DeltaPsi(m) in the absence of Mg(2+). Involvement of mPTP in the process of Ca(2+)-induced collapse of DeltaPsi(m) was further supported by protective effect of both CsA and ADP. Reversible collapse of DeltaPsi(m), observed in the presence of Mg(2+), was sensitive to EGTA, ADP; and inhibition of Ca(2+) uptake and increased efflux of Ca(2+) from mitochondrial matrix. This may represent selective induction of a low-conductance permeability pathway. Presented results indicate important role of Mg(2+) in the process of Ca(2+)-induced depolarisation of DeltaPsi(m) mainly through discrimination between low- and high-conductance modes of mPTP. Minor effect of Mg(2+) on Ca(2+)-induced depolarisation of DeltaPsi(m) was observed at the level of stimulation of DeltaPsi(m) generation and inhibition of mitochondrial Ca(2+) uptake.
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Affiliation(s)
- Peter Racay
- Institute of Biochemistry, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.
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Shalbuyeva N, Brustovetsky T, Bolshakov A, Brustovetsky N. Calcium-dependent spontaneously reversible remodeling of brain mitochondria. J Biol Chem 2006; 281:37547-58. [PMID: 17056496 DOI: 10.1074/jbc.m607263200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An exposure of cultured hippocampal neurons expressing mitochondrially targeted enhanced yellow fluorescent protein to excitotoxic glutamate resulted in reversible mitochondrial remodeling that in many instances could be interpreted as swelling. Remodeling was not evident if glutamate receptors were blocked with MK801, if Ca(2+) was omitted or substituted for Sr(2+) in the bath solution, if neurons were treated with carbonylcyanide p-trifluoromethoxyphenylhydrazone to depolarize mitochondria, or if neurons were pretreated with cyclosporin A or N-methyl-4-isoleucine-cyclosporin (NIM811) to inhibit the mitochondrial permeability transition. In the experiments with isolated brain synaptic or nonsynaptic mitochondria, Ca(2+) triggered transient, spontaneously reversible cyclosporin A-sensitive swelling closely resembling remodeling of organelles in cultured neurons. The swelling was accompanied by the release of cytochrome c, Smac/DIABLO, Omi/HtrA2, and AIF but not endonuclease G. Depolarization with carbonylcyanide p-trifluoromethoxyphenylhydrazone or inhibition of the Ca(2+) uniporter with Ru360 prevented rapid onset of the swelling. Sr(2+) depolarized mitochondria but failed to induce swelling. Neither inhibitors of the large conductance Ca(2+)-activated K(+) channel (charybdotoxin, iberiotoxin, quinine, and Ba(2+)) nor inhibitors of the mitochondrial ATP-sensitive K(+) channel (5-hydroxydecanoate and glibenclamide) suppressed swelling. Quinine, dicyclohexylcarbodiimide, and Mg(2+), inhibitors of the mitochondrial K(+)/H(+) exchanger, as well as external alkalization inhibited a recovery phase of the reversible swelling. In contrast to brain mitochondria, liver and heart mitochondria challenged with Ca(2+) experienced sustained swelling without spontaneous recovery. The proposed model suggests an involvement of the Ca(2+)-dependent transient K(+) influx into the matrix causing mitochondrial swelling followed by activation of the K(+)/H(+) exchanger leading to spontaneous mitochondrial contraction both in situ and in vitro.
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Affiliation(s)
- Natalia Shalbuyeva
- Department of Pharmacology and Toxicology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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29
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Zungu M, Felix R, Essop MF. Wy-14,643 and fenofibrate inhibit mitochondrial respiration in isolated rat cardiac mitochondria. Mitochondrion 2006; 6:315-22. [PMID: 17046337 DOI: 10.1016/j.mito.2006.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 08/30/2006] [Accepted: 09/01/2006] [Indexed: 10/24/2022]
Abstract
We investigated the direct effects of two selective PPARalpha ligands, fenofibrate and Wy-14,643, on mitochondrial respiratory function using isolated rat cardiac mitochondria. Isolated left ventricular mitochondria were incubated with increasing concentrations of fenofibrate or Wy-14,643 (10, 100, and 500 microM) and mitochondrial respiration determined using: malate/glutamate (complex I), succinate (complex II) and palmitoyl-l-carnitine as oxidative substrates. Our data show that acute exposure to Wy-14,643 and fenofibrate differentially perturb cardiac mitochondrial respiration i.e., fenofibrate more potently inhibited mitochondrial respiration and bioenergetic capacity compared to Wy-14,643. Moreover, we found that both agents increased uncoupling of mitochondrial oxidative phosphorylation.
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Affiliation(s)
- Makhosazane Zungu
- Hatter Heart Research Institute, Department of Medicine, University of Cape Town Faculty of Health Sciences, Cape Town, South Africa
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30
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Nadtochiy S, Tompkins A, Brookes P. Different mechanisms of mitochondrial proton leak in ischaemia/reperfusion injury and preconditioning: implications for pathology and cardioprotection. Biochem J 2006; 395:611-8. [PMID: 16436046 PMCID: PMC1462692 DOI: 10.1042/bj20051927] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mechanisms of mitochondrial proton (H+) leak under various pathophysiological conditions are poorly understood. In the present study it was hypothesized that different mechanisms underlie H+ leak in cardiac IR (ischaemia/reperfusion) injury and IPC (ischaemic preconditioning). Potential H(+) leak mechanisms examined were UCPs (uncoupling proteins), allosteric activation of the ANT (adenine nucleotide translocase) by AMP, or the PT (permeability transition) pore. Mitochondria isolated from perfused rat hearts that were subjected to IPC exhibited a greater H+ leak than did controls (202+/-27%, P<0.005), and this increased leakage was completely abolished by the UCP inhibitor, GDP, or the ANT inhibitor, CAT (carboxyattractyloside). Mitochondria from hearts subjected to IR injury exhibited a much greater amount of H+ leak than did controls (411+/-28%, P<0.001). The increased leakage after IR was weakly inhibited by GDP, but was inhibited, >50%, by carboxyattractyloside. In addition, it was inhibited by cardioprotective treatment strategies including pre-IR perfusion with the PT pore inhibitors cyclosporin A or sanglifehrin A, the adenylate kinase inhibitor, AP5A (diadenosine pentaphosphate), or IPC. Together these data suggest that the small increase in H+ leak in IPC is mediated by UCPs, while the large increase in H+ leak in IR is mediated by the ANT. Furthermore, under all conditions studied, in situ myocardial O2 efficiency was correlated with isolated mitochondrial H+ leak (r2=0.71). In conclusion, these data suggest that the modulation of H+ leak may have important implications for the outcome of IR injury.
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Affiliation(s)
- Sergiy M. Nadtochiy
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY 14642, U.S.A
| | - Andrew J. Tompkins
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY 14642, U.S.A
| | - Paul S. Brookes
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY 14642, U.S.A
- To whom correspondence should be addressed (email )
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31
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Gadd ME, Broekemeier KM, Crouser ED, Kumar J, Graff G, Pfeiffer DR. Mitochondrial iPLA2 Activity Modulates the Release of Cytochrome c from Mitochondria and Influences the Permeability Transition. J Biol Chem 2006; 281:6931-9. [PMID: 16407316 DOI: 10.1074/jbc.m510845200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial Ca(2+)-independent phospholipase A(2) is activated during energy-dependent Ca(2+) accumulation under conditions where there is a sustained depression of the membrane potential. This activation is not dependent on induction of the mitochondrial permeability transition. Bromoenol lactone, which inhibits the phospholipase, is effective as an inhibitor of the transition, and this action can be overcome by low levels of exogenous free fatty acids. Apparently, activation of the Ca(2+)-independent phospholipase is a factor in the mechanisms by which depolarization and Ca(2+) accumulation promote opening of the permeability transition pore. Sustained activity of the Ca(2+)-independent phospholipase A(2) promotes rupture of the outer mitochondrial membrane and spontaneous release of cytochrome c on a time scale similar to that of apoptosis occurring in cells. However, more swelling of the matrix space must occur to provoke release of a given cytochrome c fraction when the enzyme is active, compared with when it is inhibited. Through its effects on the permeability transition and release of intermembrane space proteins, the mitochondrial Ca(2+)-independent phospholipase A(2) may be an important factor governing cell death caused by necrosis or apoptosis.
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Affiliation(s)
- Martha E Gadd
- Department of Molecular and Cellular Biochemistry, Ohio State University, 1645 Neil Avenue, Columbus, OH 43210, USA
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32
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Du Y, Ko KM. Effects of emodin treatment on mitochondrial ATP generation capacity and antioxidant components as well as susceptibility to ischemia-reperfusion injury in rat hearts: single versus multiple doses and gender difference. Life Sci 2006; 77:2770-82. [PMID: 15964600 DOI: 10.1016/j.lfs.2005.03.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Accepted: 03/15/2005] [Indexed: 11/25/2022]
Abstract
Effects of emodin (EMD) treatment on mitochondrial ATP generation capacity and antioxidant components as well as susceptibility to ischemia-reperfusion (I-R) injury were examined in male and female rat hearts. Isolated-perfused hearts prepared from female rats were less susceptible to I-R injury than those of male rats. I-R caused significant decreases in ATP generation capacity and reduced glutathione (GSH) and alpha-tocopherol (alpha-TOC) levels as well as glutathione reductase, Se-glutathione peroxidase and Mn-superoxide dismutase (SOD) activities. The lower susceptibility of female hearts to myocardial I-R injury was associated with higher levels of GSH and alpha-TOC as well as activity of SOD than those of male hearts. EMD treatment at 3 daily doses (0.6 or 1.2 mmol/kg) could enhance myocardial mitochondrial ATP generation capacity and antioxidant components in both male and female rat hearts, but it only significantly protected against I-R injury in female hearts. Treatment with a single dose of EMD invariably enhanced mitochondrial antioxidant components and protected against I-R injury in both male and female hearts. The gender-dependent effect of EMD treatment at multiple doses may be related to the differential antioxidant response in the myocardium and/or induction of drug metabolizing enzymes in the liver.
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Affiliation(s)
- Ying Du
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
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Tian X, Ma X, Qiao D, Ma A, Yan F, Huang X. mCICR is required for As2O3-induced permeability transition pore opening and cytochrome c release from mitochondria. Mol Cell Biochem 2005; 277:33-42. [PMID: 16132712 DOI: 10.1007/s11010-005-4818-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Accepted: 04/01/2005] [Indexed: 01/21/2023]
Abstract
The permeability transition pore (PTP) is central for apoptosis by acting as a good candidate pathway for the release of Cyt. c and apoptosis induction factors (AIF). Arsenite induces apoptosis via a direct effect on PTP. To characterize the exact mechanism for arsenite induces PTP opening, the effect of Ca2+ on As2O3-induced PTP opening, the relationship between As2O3-induced PTP opening and Cyt. c release from mitochondria and calcium-induced calcium release from mitochondria (mCICR), and the effects of As2O3 on Ca2+-induced PTP opening were studied. The results showed As2O3 induces Cyt. c release by triggering PTP opening. Ca2+ is necessary for As2O3-induced PTP opening. As2O3-induced PTP opening and Cyt. c release depends on mCICR. As2O3 promotes PTP opening by lowering Ca2+-threshold. These results indicated As2O3 induce Cyt. c release from mitochondria by lowering Ca2+-threshold for PTP and triggering mCICR-dependent PTP opening. Suggesting that it is possible to control apoptosis by altering Ca2+ threshold and mCICR to modulate PTP opening and Cyt. c release.
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Affiliation(s)
- Xuemei Tian
- Deparment of Histology and Embryology, Southern Medical University, Guangzhou, Guangdong, 510515, China
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Xie YX, Bezard E, Zhao BL. Investigating the receptor-independent neuroprotective mechanisms of nicotine in mitochondria. J Biol Chem 2005; 280:32405-12. [PMID: 15985439 DOI: 10.1074/jbc.m504664200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although nicotine has been associated with a decreased risk of developing Parkinson disease, the underlying mechanisms are still unclear. By using isolated brain mitochondria, we found that nicotine inhibited N-methyl-4-phenylpyridine (MPP(+)) and calcium-induced mitochondria high amplitude swelling and cytochrome c release from intact mitochondria. Intra-mitochondria redox state was also maintained by nicotine, which could be attributed to an attenuation of mitochondria permeability transition. Further investigation revealed that nicotine did not prevent MPP(+)- or calcium-induced mitochondria membrane potential loss, but instead decreased the electron leak at the site of respiratory chain complex I. In the presence of mecamylamine hydrochloride, a nonselective nicotinic acetylcholine receptor inhibitor, nicotine significantly postponed mitochondria swelling and cytochrome c release induced by a mixture of neurotoxins (MPP(+) and 6-hydroxydopamine) in SH-SY5Y cells, suggesting that there is a receptor-independent nicotine-mediated neuroprotective effect of nicotine. These results show that interaction of nicotine with mitochondria respiratory chain together with its antioxidant effects should be considered in the neuroprotective effects of nicotine.
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Affiliation(s)
- Yu-Xiang Xie
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Academia Sinica, Beijing, China
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35
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Feldkamp T, Kribben A, Weinberg JM. F1FO-ATPase activity and ATP dependence of mitochondrial energization in proximal tubules after hypoxia/reoxygenation. J Am Soc Nephrol 2005; 16:1742-51. [PMID: 15843467 DOI: 10.1681/asn.2005010053] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Isolated kidney proximal tubules subjected to hypoxia/reoxygenation (H/R) have incomplete recovery of mitochondrial membrane potential (DeltaPsi(m)) that can be improved, but not normalized, by ATP in permeabilized cells as measured by safranin O uptake. In these studies, the mechanisms for the decreased DeltaPsi(m) in the tubules after H/R are further investigated and impairment of the function of the mitochondrial F(1)F(O)-ATPase is assessed. Normoxic control tubules had a small ATP-dependent component to DeltaPsi(m), but it required low micromolar levels of ATP, not the millimolar levels needed to support DeltaPsi(m) in tubules de-energized with rotenone or after H/R. Micromolar levels of ATP did not improve DeltaPsi(m) after either mild or severe H/R injury. The dependence of DeltaPsi(m) on millimolar levels of ATP after H/R decreased over time during reoxygenation. ATP hydrolysis by the oligomycin-sensitive, mitochondrial F(1)F(O)-ATPase was well preserved after H/R as long as Mg(2+) was available, indicating that function of both the F(1)F(O)-ATPase and of the adenine nucleotide translocase, which delivers nucleotides to it, are largely intact. However, ATP hydrolysis by the ATPase did not restore DeltaPsi(m) as much as expected from the rate of ATP utilization. These findings, taken together with the observation that substrate-supported generation of DeltaPsi(m) is impaired despite intact electron transport, make it likely that uncoupling plays a major role in the mitochondrial dysfunction in proximal tubules during H/R.
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Affiliation(s)
- Thorsten Feldkamp
- Division of Nephrology, Department of Internal Medicine, Veterans Affairs Ann Arbor Healthcare System and University of Michigan, Ann Arbor, MI, USA
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36
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Zoratti M, Szabò I, De Marchi U. Mitochondrial permeability transitions: how many doors to the house? BIOCHIMICA ET BIOPHYSICA ACTA 2005; 1706:40-52. [PMID: 15620364 DOI: 10.1016/j.bbabio.2004.10.006] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 12/18/2022]
Abstract
The inner mitochondrial membrane is famously impermeable to solutes not provided with a specific carrier. When this impermeability is lost, either in a developmental context or under stress, the consequences for the cell can be far-reaching. Permeabilization of isolated mitochondria, studied since the early days of the field, is often discussed as if it were a biochemically well-defined phenomenon, occurring by a unique mechanism. On the contrary, evidence has been accumulating that it may be the common outcome of several distinct processes, involving different proteins or protein complexes, depending on circumstances. A clear definition of this putative variety is a prerequisite for an understanding of mitochondrial permeabilization within cells, of its roles in the life of organisms, and of the possibilities for pharmacological intervention.
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Affiliation(s)
- Mario Zoratti
- CNR Institute of Neuroscience, Biomembranes Section, Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
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Gerencser AA, Adam-Vizi V. Mitochondrial Ca2+ dynamics reveals limited intramitochondrial Ca2+ diffusion. Biophys J 2005; 88:698-714. [PMID: 15501949 PMCID: PMC1305047 DOI: 10.1529/biophysj.104.050062] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 10/13/2004] [Indexed: 11/18/2022] Open
Abstract
To reveal heterogeneity of mitochondrial function on the single-mitochondrion level we have studied the spatiotemporal dynamics of the mitochondrial Ca2+ signaling and the mitochondrial membrane potential using wide-field fluorescence imaging and digital image processing techniques. Here we demonstrate first-time discrete sites--intramitochondrial hotspots--of Ca2+ uptake after Ca2+ release from intracellular stores, and spreading of Ca2+ rise within the mitochondria. The phenomenon was characterized by comparison of observations in intact cells stimulated by ATP and in plasma membrane permeabilized or in ionophore-treated cells exposed to elevated buffer [Ca2+]. The findings indicate that Ca2+ diffuses laterally within the mitochondria, and that the diffusion is limited for shorter segments of the mitochondrial network. These observations were supported by mathematical simulation of buffered diffusion. The mitochondrial membrane potential was investigated using the potentiometric dye TMRM. Irradiation-induced fluctuations (flickering) of TMRM fluorescence showed synchronicity over large regions of the mitochondrial network, indicating that certain parts of this network form electrical syncytia. The spatial extension of these syncytia was decreased by 2-aminoethoxydiphenyl borate (2-APB) or by propranolol (blockers of nonclassical mitochondrial permeabilities). Our data suggest that mitochondria form syncytia of electrical conductance whereas the passage of Ca2+ is restricted to the individual organelle.
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Affiliation(s)
- Akos A Gerencser
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
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Ravid A, Koren R. The role of reactive oxygen species in the anticancer activity of vitamin D. Recent Results Cancer Res 2003; 164:357-67. [PMID: 12899535 DOI: 10.1007/978-3-642-55580-0_26] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Calcitriol, the hormonal form of vitamin D, enhances the anticancer activity of the immune cytokine tumor necrosis factor, interleukin 1 and interleukin 6 in human breast and renal cell carcinoma cells without affecting the cytotoxic action of interferon-alpha or killer lymphocytes. It also enhances cytotoxicity induced by the anticancer drug doxorubicin, by the redox cycling quinone menadione, and by the reactive oxygen species hydrogen peroxide. The synergistic interaction was accompanied by increased oxidative stress, as manifested by glutathione depletion and was abolished by exposure to the thiol antioxidant N-acetylcysteine. The hormone on its own brought about an increase in the cellular redox state as reflected in the ratio between oxidized and reduced glutathione and glyceraldehyde-3-phosphate dehydrogenase, and a reduction in the expression of the antioxidant enzyme Cu/Zn superoxide dismutase. These results support the notion that the interplay between active vitamin D derivatives and other anticancer agents such as immune cytokines and anticancer drugs plays a role in the in vivo anticancer activity of vitamin D and that reactive oxygen species are involved in the anticancer activity of vitamin D on its own and in its cross-talk with other anticancer modalities.
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Affiliation(s)
- Amiram Ravid
- Laboratory for Endocrine Immunology, Felsenstein Medical Research Center, Beilinson Campus, 49100 Petah Tikva, Israel.
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Correa F, García N, García G, Chávez E. Dehydroepiandrosterone as an inducer of mitochondrial permeability transition. J Steroid Biochem Mol Biol 2003; 87:279-84. [PMID: 14698209 DOI: 10.1016/j.jsbmb.2003.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This paper reports an investigation upon the effect of dehydroepiandrosterone (DHEA) on some mitochondrial membrane functions, such as electron transport, transmembrane electric gradient and calcium permeability. It was found that the hormone induced the efflux of accumulated matrix Ca(2+), inhibited Site I of the respiratory chain, as well as bringing about the collapse of the transmembrane potential, and mitochondrial swelling. Taking into account that cyclosporin A (CSA) inhibited Ca(2+) release and the collapse of the transmembrane potential, it is concluded that the hormone may induce the opening of a non-specific transmembrane pore. The mechanism of pore opening is ascribed to peroxidation of the membrane lipid bilayer. It should be mentioned that estrone, even at the concentration of 200 microM, failed to reproduce the behavior of dehydroepiandrosterone on mitochondrial functions.
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Affiliation(s)
- Francisco Correa
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Ignacio Chávez, Juan Badiano # 1, Tlalpan, Mexico, D.F. 014080, Mexico
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40
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Belyaeva EA, Korotkov SM. Mechanism of primary Cd2+-induced rat liver mitochondria dysfunction: discrete modes of Cd2+ action on calcium and thiol-dependent domains. Toxicol Appl Pharmacol 2003; 192:56-68. [PMID: 14554103 DOI: 10.1016/s0041-008x(03)00255-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We attempted to discern discrete sites of Cd2+ deleterious action on rat liver mitochondrial function. In particular, EGTA, ADP, and cyclosporin A (potent mitochondrial permeability transition antagonists) affected mainly Cd2+-induced changes in resting state respiration, eliminating its stimulation in KCl medium, while dithiothreitol (DTT, a dithiol reductant) produced its effect both on Cd2+ activation of the basal respiration and Cd2+ depression of uncoupler-stimulated respiration, evoking its restoration. Substantial differences in DTT influence on mitochondrial respiration at low and high [Cd2+] were revealed, namely, an enhanced mitochondrial permeabilization in the presence of saturated [DTT] at high [Cd2+] took place. Besides, DTT only partially reversed Cd2+-induced swelling in NH4NO3 medium when glutamate plus malate or succinate without rotenone was used. Contrarily, DTT produced complete reversal of the swelling of succinate-energized mitochondria when rotenone was present in the medium. In addition, in the presence of rotenone both Cd2+-produced activation of the resting state respiration in KCl medium and Cd2+-induced swelling in sucrose medium of succinate-energized mitochondria were more sensitive to cyclosporin A than the same Cd2+ effects obtained on mitochondria oxidizing succinate (without rotenone) or glutamate plus malate. We have concluded that Cd2+, producing primary mitochondrial dysfunction, acts both as a thiol and Me2+ binding site reagent. Suppositions about possible localization of separate sites of direct Cd2+ effects on mitochondrial function were made.
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Affiliation(s)
- Elena A Belyaeva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Thorez pr44, 194223, St. Petersburg, Russia.
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41
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Abstract
Mitochondria were simultaneously isolated from striatum and cortex of adult rats and compared in functional assays for their sensitivity to calcium activation of the permeability transition. Striatal mitochondria showed an increased dose-dependent sensitivity to Ca2+ compared with cortical mitochondria, as measured by mitochondrial depolarization, swelling, Ca2+ uptake, reactive oxygen species production, and respiration. Ratios of ATP to ADP were lower in striatal mitochondria exposed to calcium despite equal amounts of ADP and ATP under respiring and nonrespiring conditions. The Ca2+-induced changes were inhibited by cyclosporin A or ADP. These responses are consistent with Ca2+ activation of both low and high permeability pathways constituting the mitochondrial permeability transition. In addition to the striatal supersensitivity to induction of the permeability transition, cyclosporin A inhibition was less potent in striatal mitochondria. Immunoblots indicated that striatal mitochondria contained more cyclophilin D than cortical mitochondria. Thus striatal mitochondria may be selectively vulnerable to the permeability transition. Subsequent mitochondrial dysfunction could contribute to the initial toxicity of striatal neurons in Huntington's disease.
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42
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Korge P, Honda HM, Weiss JN. Effects of fatty acids in isolated mitochondria: implications for ischemic injury and cardioprotection. Am J Physiol Heart Circ Physiol 2003; 285:H259-69. [PMID: 12793979 DOI: 10.1152/ajpheart.01028.2002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fatty acids accumulate during myocardial ischemia and are implicated in ischemia-reperfusion injury and mitochondrial dysfunction. Because functional recovery after ischemia-reperfusion ultimately depends on the ability of the mitochondria to recover membrane potential (DeltaPsim), we studied the effects of fatty acids on DeltaPsim regulation, cytochrome c release, and Ca2+ handling in isolated mitochondria under conditions that mimicked aspects of ischemia-reperfusion. Long-chain but not short-chain free fatty acids caused a progressive and reversible (with BSA) increase in inner membrane leakiness (proton leak), which limited mitochondrial ability to support DeltaPsim. In comparison, long-chain activated fatty acids promoted 1). a slower depolarization that was not reversible with BSA, 2). cytochrome c loss that was unrelated to permeability transition pore opening, and 3). inhibition of the adenine nucleotide translocator. Together, these results impaired both mitochondrial ATP production and Ca2+ handling. Diazoxide, a selective opener of mitochondrial ATP-dependent potassium (KATP) channels, partially protected against these effects. These findings indicate that long-chain fatty acid accumulation during ischemia-reperfusion may predispose mitochondria to cytochrome c loss and irreversible injury and identify a novel cardioprotective action of diazoxide.
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Affiliation(s)
- Paavo Korge
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, California 90095-17690, USA.
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43
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Crouser ED, Gadd ME, Julian MW, Huff JE, Broekemeier KM, Robbins KA, Pfeiffer DR. Quantitation of cytochrome c release from rat liver mitochondria. Anal Biochem 2003; 317:67-75. [PMID: 12729602 DOI: 10.1016/s0003-2697(03)00044-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The apoptogenic protein cytochrome c can be quantitated by reverse-phase HPLC, but this method is not utilized by those who investigate mechanisms of cell death. Here, we extend the sensitivity of the method to exceed that available from immunogenic approaches and report specific procedures for applying the method to preparations of intact mitochondria, and to supernatants and pellets that arise from mitochondrial incubations. The detection limit corresponds to 0.6% of total cytochrome c found in 100 microg of rat liver mitochondrial protein, or to all of the cytochrome c that is expected in approximately 6000 hepatocytes. A single determination can be completed in 20 min, compared to a time scale of days for Western blotting methods, or hours for ELISA-based methods. The procedures are illustrated by experiments that determine the amount of cytochrome c released following the mitochondrial permeability transition as a function of medium ionic strength, and by long-term incubations of intact mitochondria in the presence and absence of an exogenous oxidizable substrate. Swelling and the release of adenylate kinase activity have been determined simultaneously to show how the data can be applied to evaluate the role of outer membrane disruption in mechanisms that release cytochrome c.
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Affiliation(s)
- Elliott D Crouser
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
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44
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La Piana G, Marzulli D, Consalvo MI, Lofrumento NE. Cytochrome c-induced cytosolic nicotinamide adenine dinucleotide oxidation, mitochondrial permeability transition, and apoptosis. Arch Biochem Biophys 2003; 410:201-11. [PMID: 12573279 DOI: 10.1016/s0003-9861(02)00687-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A catalytic amount of cytochrome c (cyto-c) added to the incubation medium of isolated mitochondria promotes the transfer of reducing equivalents from extramitochondrial nicotinamide adenine dinucleotide in its reduced state (NADH) to molecular oxygen inside the mitochondria, a process coupled to the generation of a membrane potential. This mimics in many aspects the early stages of those apoptotic pathways characterized by the persistence of mitochondrial membrane potential but with cyto-c already exported into the cytosol. In cyclosporin-sensitive and calcium-induced mitochondrial permeability transition (MPT) a release of cyto-c can also be observed. However, in MPT uncoupled respiration associated with mitochondrial swelling and preceded by the complete dissipation of the membrane potential which cannot be restored with ATP addition or any other source of energy is immediately activated. The results obtained and discussed with regard to intactness of mitochondrial preparations indicate that MPT could be an apoptotic event downstream but not upstream of cyto-c release linked to the energy-requiring processes. In the early stages of apoptosis cytosolic cyto-c participates in the activation of caspases and at the same time can promote the oxidation of cytosolic NADH, making more energy available for the correct execution of the cell death program. This hypothesis is not in contrast with available data in the literature showing that cyto-c is present in the cytosol of both control and apoptosis-induced cultured cell lines.
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Affiliation(s)
- Gianluigi La Piana
- Department of Biochemistry and Molecular Biology, University of Bari, via Orabona 4, 70126 Bari, Italy.
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45
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Abstract
The heart is capable of dramatically altering its overall energy flux with minimal changes in the concentrations of metabolites that are associated with energy metabolism. This cardiac energy metabolism homeostasis is discussed with regard to the potential cytosolic control network responsible for controlling the major energy conversion pathway, oxidative phosphorylation in mitochondria. Several models for this cytosolic control network have been proposed, but a cytosolic Ca(2+) dependent parallel activation scheme for metabolism and work is consistent with most of the experimental results. That model proposes that cytosolic Ca(2+) regulates both the utilization of ATP by the work producing ATPases as well as the mitochondrial production of ATP. Recent studies have provided evidence supporting this role of cytosolic Ca(2+). These data include the demonstration that mitochondrial [Ca(2+)] can track cytosolic [Ca(2+)] and that the compartmentation of cytosolic [Ca(2+)] can facilitate this process. On the metabolic side, Ca(2+) has been shown to rapidly activate several steps in oxidative phosphorylation, including F(1)F(0)-ATPase ATP production as well as several dehydrogenases, which results in a homeostasis of mitochondrial metabolites similar to that observed in the cytosol. Numerous problems with the Ca(2+) parallel activation hypothesis remain including the lack of specific mechanisms of mitochondrial Ca(2+) transport and regulation of F(1)F(0)-ATPase, the time dependence of Ca(2+) activation of cytosolic ATPases as well as oxidative phosphorylation, and the role of cytosolic compartmentation. In addition, the lack of cytosolic or mitochondrial [Ca(2+)] measurements under in vivo conditions is problematic. Several lines of investigation to address these issues are suggested. A model of the cardiac energy metabolism control network is proposed that includes a Ca(2+) parallel activation component together with more classical elements including metabolite feedback and cytosolic compartmentation.
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Affiliation(s)
- Robert S Balaban
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute/NIH, Building 10, Room B1 D161, Bethesda, MD 20892, USA.
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46
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Chen Y, Cai J, Murphy TJ, Jones DP. Overexpressed human mitochondrial thioredoxin confers resistance to oxidant-induced apoptosis in human osteosarcoma cells. J Biol Chem 2002; 277:33242-8. [PMID: 12032145 DOI: 10.1074/jbc.m202026200] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxidative damage to mitochondria is a central mechanism of apoptosis induced by many toxic chemicals. Thioredoxin family proteins share a conserved Cys-X-X-Cys motif at their active center and play important roles in control of cellular redox state and protection against oxidative damage. In addition to the well studied cytosolic and extracellular form (Trx1), rat and avian mitochondrial forms of thioredoxin (mtTrx) have been reported. In this study, we cloned the full-length human mtTrx cDNA and performed localization and functional studies in 143B human osteosarcoma cells. The coding sequence of human mtTrx consists of a region with homology to Trx1 as well as a putative mitochondrial localization signal (MLS) at its N terminus. In stably transfected cell lines, mtTrx had a mitochondrial localization as measured by subcellular fractionation studies and by confocal fluorescence microscopy. Deletion of the MLS rendered mtTrx to be solely expressed in the cytosolic fraction. On SDS-PAGE, transfected mtTrx had the same apparent molecular weight as the MLS truncated form, indicating that the leader sequence is cleaved during or after mitochondrial import. Treatment with the oxidant tert-butylhydroperoxide induced apoptosis in 143B cells. This oxidant-induced apoptosis was inhibited by overexpressing the full-length mtTrx in 143B cells. Thus, human mtTrx is a member of the thioredoxin family of proteins localized to mitochondria and may play important roles in protection against oxidant-induced apoptosis.
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Affiliation(s)
- Yan Chen
- Program of Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, Georgia 30322, USA
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47
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Wang E, Erdahl WL, Hamidinia SA, Chapman CJ, Taylor RW, Pfeiffer DR. Transport properties of the calcium ionophore ETH-129. Biophys J 2001; 81:3275-84. [PMID: 11720991 PMCID: PMC1301785 DOI: 10.1016/s0006-3495(01)75961-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The transport mechanism and specificities of ionophore ETH-29 have been investigated in a highly defined phospholipid vesicle system, with the goal of facilitating the application of this compound to biological problems. ETH-129 transports Ca(2+) via an electrogenic mechanism, in contrast to A23187 and ionomycin, which function in a charge neutral manner. The rate of transport is a function of membrane potential, increasing by 3.9-fold per 59 mV over a broad range of that parameter. Rate is independent of the transmembrane pH gradient and strongly stimulated by the uncoupler carbonyl cyanide m-chlorophenylhydrazone when no external potential has been applied. The effect of uncoupler reflects the collapse of an opposing potential arising during Ca(2+) transport, but also reflects the formation of a mixed complex between the uncoupler, ETH-129, and Ca(2+) that readily permeates the vesicle membrane. Oleate does not substitute for the uncoupler in either regard. ETH-129 transports polyvalent cations according to the selectivity sequence La(3+) > Ca(2+) > Zn(2+) approximately equal to Sr(2+) > Co(2+) approximately equal to Ni(2+) approximately equal to Mn(2+), with the magnitude of the selectivity coefficients reflecting the cation concentration range considered. There is little or no activity for the transport of Na(+), K(+), and Mg(2+). These properties suggest that ETH-129 will be useful for investigating the consequences of a mitochondrial Ca(2+) overload in mammalian cells, which is difficult to pursue through the application of electroneutral ionophores.
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Affiliation(s)
- E Wang
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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48
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Bradshaw PC, Jung DW, Pfeiffer DR. Free fatty acids activate a vigorous Ca(2+):2H(+) antiport activity in yeast mitochondria. J Biol Chem 2001; 276:40502-9. [PMID: 11457848 DOI: 10.1074/jbc.m105062200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The accumulation and retention of Ca(2+) by yeast mitochondria (Saccharomyces cerevisiae) mediated by ionophore ETH 129 occurs with a variable efficiency in different preparations. Ineffective Ca(2+) transport and a depressed membrane potential occur in parallel, are exacerbated in parallel by exogenous free fatty acids, and are corrected in parallel by the addition of bovine serum albumin. Bovine serum albumin is not required to develop a high membrane potential when either Ca(2+) or ETH 129 are absent, and when both are present membrane potential is restored by the addition of EGTA in a concentration-dependent manner. Respiration and swelling data indicate that the permeability transition pore does not open in yeast mitochondria that are treated with Ca(2+) and ETH 129, whereas fatty acid concentration studies and the inaction of carboxyatractyloside indicate that fatty acid-derived uncoupling does not underlie the other observations. It is concluded that yeast mitochondria contain a previously unrecognized Ca(2+):2H(+) antiporter that is highly active in the presence of free fatty acids and leads to a futile cycle of Ca(2+) accumulation and release when exogenous Ca(2+) and ETH 129 are available. It is also shown that isolated yeast mitochondria degrade their phospholipids at a relatively rapid rate. The activity responsible is also previously unrecognized. It is Ca(2+)-independent, little affected by the presence or absence of a respiratory substrate, and leads to the hydrolysis of ester linkages at both the sn-1 and sn-2 positions of the glycerophospholipids. The products of this activity, through their actions on the antiporter, explain the variable behavior of yeast mitochondria treated with Ca(2+) plus ETH 129.
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Affiliation(s)
- P C Bradshaw
- Department of Molecular and Cellular Biochemistry, Ohio State University Medical Center, Columbus, Ohio 43210, USA
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49
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Xu M, Wang Y, Ayub A, Ashraf M. Mitochondrial K(ATP) channel activation reduces anoxic injury by restoring mitochondrial membrane potential. Am J Physiol Heart Circ Physiol 2001; 281:H1295-303. [PMID: 11514300 DOI: 10.1152/ajpheart.2001.281.3.h1295] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial membrane potential (DeltaPsi(m)) is severely compromised in the myocardium after ischemia-reperfusion and triggers apoptotic events leading to cell demise. This study tests the hypothesis that mitochondrial ATP-sensitive K(+) (mitoK(ATP)) channel activation prevents the collapse of DeltaPsi(m) in myocytes during anoxia-reoxygenation (A-R) and is responsible for cell protection via inhibition of apoptosis. After 3-h anoxia and 2-h reoxygenation, the cultured myocytes underwent extensive damage, as evidenced by decreased cell viability, compromised membrane permeability, increased apoptosis, and decreased ATP concentration. Mitochondria in A-R myocytes were swollen and fuzzy as shown after staining with Mito Tracker Orange CMTMRos and in an electron microscope and exhibited a collapsed DeltaPsi(m), as monitored by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1). Cytochrome c was released from mitochondria into the cytosol as demonstrated by cytochrome c immunostaining. Activation of mitoK(ATP) channel with diazoxide (100 micromol/l) resulted in a significant protection against mitochondrial damage, ATP depletion, cytochrome c loss, and stabilized DeltaPsi(m). This protection was blocked by 5-hydroxydecanoate (500 micromol/l), a mitoK(ATP) channel-selective inhibitor, but not by HMR-1098 (30 micromol/l), a putative sarcolemmal K(ATP) channel-selective inhibitor. Dissipation of DeltaPsi(m) also leads to opening of mitochondrial permeability transition pore, which was prevented by cyclosporin A. The data support the hypothesis that A-R disrupts DeltaPsi(m) and induces apoptosis, which are prevented by the activation of the mitoK(ATP) channel. This further emphasizes the therapeutic significance of mitoK(ATP) channel agonists in the prevention of ischemia-reperfusion cell injury.
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Affiliation(s)
- M Xu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45267-0529, USA
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50
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Huang X, Zhai D, Huang Y. Dependence of permeability transition pore opening and cytochrome C release from mitochondria on mitochondria energetic status. Mol Cell Biochem 2001; 224:1-7. [PMID: 11693186 DOI: 10.1023/a:1011990300114] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The dependence of Ca2+-induced permeability transition pore (PTP) opening and cytochrome c (Cyt. c) release from mitochondria on mitochondria energetic status was investigated. Results of test the PTP opening and Cyt. c release of isolated rat liver mitochondria with different mitochondrial respiratory substrates, electron transport inhibitors and uncoupler by spectrophotometry and western blotting showed that, Cyt. c release from mitochondria by PTP opening. PTP opening and Cyt. c release showed more sensitive and responsive with FADH-linked succinate than with NADH-linked glutamate plus malate as substrate. Partial or full inhibition of electron flow with electron flow inhibitors resulted in partial or full inhibition of PTP opening and Cyt. c release, respectively. Partial recovery of electron flow with electron sponsors resulted in partial recovery of PTP opening and Cyt. c release. PTP opening and Cyt. c release were completely interrupted by uncoupler. These results indicated PTP opening and Cyt. c release are characterized by respiratory substrate selectivity, electron flow dependence and energy coupling reliance. Hence, PTP opening and Cyt. c release tightly depend on mitochondria energetic status. These findings suggested also that it is possible to regulate apoptosis by altering mitochondrial energetic status to alter PTP opening and Cyt. c release.
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Affiliation(s)
- X Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, China
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