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Mendoza A, Patel P, Robichaux D, Ramirez D, Karch J. Inhibition of the mPTP and Lipid Peroxidation Is Additively Protective Against I/R Injury. Circ Res 2024; 134:1292-1305. [PMID: 38618716 PMCID: PMC11081482 DOI: 10.1161/circresaha.123.323882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/16/2024]
Abstract
BACKGROUND During myocardial ischemia/reperfusion (I/R) injury, high levels of matrix Ca2+ and reactive oxygen species (ROS) induce the opening of the mitochondrial permeability transition pore (mPTP), which causes mitochondrial dysfunction and ultimately necrotic death. However, the mechanisms of how these triggers individually or cooperatively open the pore have yet to be determined. METHODS Here, we use a combination of isolated mitochondrial assays and in vivo I/R surgery in mice. We challenged isolated liver and heart mitochondria with Ca2+, ROS, and Fe2+ to induce mitochondrial swelling. Using inhibitors of the mPTP (cyclosporine A or ADP) lipid peroxidation (ferrostatin-1, MitoQ), we determined how the triggers elicit mitochondrial damage. Additionally, we used the combination of inhibitors during I/R injury in mice to determine if dual inhibition of these pathways is additivity protective. RESULTS In the absence of Ca2+, we determined that ROS fails to trigger mPTP opening. Instead, high levels of ROS induce mitochondrial dysfunction and rupture independently of the mPTP through lipid peroxidation. As expected, Ca2+ in the absence of ROS induces mPTP-dependent mitochondrial swelling. Subtoxic levels of ROS and Ca2+ synergize to induce mPTP opening. Furthermore, this synergistic form of Ca2+- and ROS-induced mPTP opening persists in the absence of CypD (cyclophilin D), suggesting the existence of a CypD-independent mechanism for ROS sensitization of the mPTP. These ex vivo findings suggest that mitochondrial dysfunction may be achieved by multiple means during I/R injury. We determined that dual inhibition of the mPTP and lipid peroxidation is significantly more protective against I/R injury than individually targeting either pathway alone. CONCLUSIONS In the present study, we have investigated the relationship between Ca2+ and ROS, and how they individually or synergistically induce mitochondrial swelling. Our findings suggest that Ca2+ mediates mitochondrial damage through the opening of the mPTP, although ROS mediates its damaging effects through lipid peroxidation. However, subtoxic levels both Ca2+ and ROS can induce mPTP-mediated mitochondrial damage. Targeting both of these triggers to preserve mitochondria viability unveils a highly effective therapeutic approach for mitigating I/R injury.
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Affiliation(s)
- Arielys Mendoza
- Department of Integrative Physiology (A.M., P.P., D.R., D.R., J.K.), Baylor College of Medicine, Houston TX
| | - Pooja Patel
- Department of Integrative Physiology (A.M., P.P., D.R., D.R., J.K.), Baylor College of Medicine, Houston TX
| | - Dexter Robichaux
- Department of Integrative Physiology (A.M., P.P., D.R., D.R., J.K.), Baylor College of Medicine, Houston TX
| | - Daniel Ramirez
- Department of Integrative Physiology (A.M., P.P., D.R., D.R., J.K.), Baylor College of Medicine, Houston TX
| | - Jason Karch
- Department of Integrative Physiology (A.M., P.P., D.R., D.R., J.K.), Baylor College of Medicine, Houston TX
- the Cardiovascular Research Institute (J.K.), Baylor College of Medicine, Houston TX
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2
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Role of respiratory uncoupling in drug-induced mitochondrial permeability transition. Toxicol Appl Pharmacol 2021; 427:115659. [PMID: 34332991 DOI: 10.1016/j.taap.2021.115659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 12/30/2022]
Abstract
Mitochondrial injury contributes to severe drug-induced liver injury. Particularly, mitochondrial permeability transition (MPT) is thought to be relevant to cytolytic hepatitis. However, the mechanism of drug-induced MPT is unclear and prediction of MPT is not adequately evaluated in the preclinical stage. In a previous study, we found that troglitazone, a drug withdrawn due to liver injury, induced MPT via mild depolarization probably resulting from uncoupling. Herein, we investigated whether other drugs that induce MPT share similar properties as troglitazone, using isolated mitochondria from rat liver. Of the 22 test drugs examined, six drugs, including troglitazone, induced MPT and showed an uncoupling effect. Additionally, receiver operating characteristic analysis was conducted to predict the MPT potential from the respiratory control ratio, an indicator of uncoupling intensity. Results showed that 2.5 was the best threshold that exhibited high sensitivity (1.00) and high specificity (0.81), indicating that uncoupling was correlated with MPT potential. Activation of calcium-independent phospholipase A2 appeared to be involved in uncoupling-induced MPT. Furthermore, a strong relationship between MPT intensity and the uncoupling effect among similar compounds was confirmed. These results may help in predicting MPT potential using cultured cells and modifying the chemical structures of the drugs to reduce MPT risk.
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3
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The Role of Human LRRK2 in Acute Methylmercury Toxicity in Caenorhabditis elegans. Neurochem Res 2021; 46:2991-3002. [PMID: 34272628 DOI: 10.1007/s11064-021-03394-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
Methylmercury (MeHg) exposure and its harmful effects on the developing brain continue to be a global environmental health concern. Decline in mitochondrial function is central to the toxic effects of MeHg and pathogenesis of mitochondria-related diseases including Parkinson's disease (PD). LRRK2 (Leucine-rich repeat kinase 2) mutation is one of the most common genetic risk factors for PD. In this study, we utilize an acute toxicity model of MeHg exposure in the model organism Caenorhabditis elegans (C. elegans) to compare lifespan, developmental progression, mitochondrial membrane potential and reactive oxygen species (ROS) between the wild-type N2 strain, wild-type LRRK2 transgenic strain (WLZ1), and mutant LRRK2(G2019S) transgenic strain (WLZ3). Additionally, the expression levels of skn-1 and gst-4 were investigated. Our results show that acute MeHg exposure (5 and 10 µM) caused a significant developmental delay in the N2 and WLZ3 worms. Notably, the worms expressing wild-type LRRK2 were resistant to 5 µM MeHg- induced developmental retardation. ROS levels in response to MeHg exposure were increased in the N2 worms, but not in the WLZ1 or WLZ3 worms. The mitochondrial membrane potential was decreased in the N2 worms but increased in the WLZ1 and WLZ3 worms following MeHg exposure. Furthermore, MeHg exposure increased the expression of skn-1 in N2, but not in WLZ1 worms. Although skn-1 expression was increased in the WLZ3 worms following MeHg exposure, gst-4 expression was not induced. Both skn-1 and gst-4 had higher basal expression levels in LRRK2s transgenic than wild-type N2 worms. Knocking down of skn-1 with feeding RNAi had a significant developmental effect in WLZ1 worms; however, the effect was not found in WLZ3 worms. These results suggest that mitochondrial dysfunction and a defect in the SKN-1 signaling in the LRRK2 G2019S worms contribute to the severe developmental delay, establishing a modulatory role of LRRK2 mutation in MeHg-induced acute toxicity.
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Cheng YS, Linetsky M, Li H, Ayyash N, Gardella A, Salomon RG. 4-Hydroxy-7-oxo-5-heptenoic acid lactone can induce mitochondrial dysfunction in retinal pigmented epithelial cells. Free Radic Biol Med 2020; 160:719-733. [PMID: 32920040 PMCID: PMC7704664 DOI: 10.1016/j.freeradbiomed.2020.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/25/2020] [Accepted: 09/04/2020] [Indexed: 11/30/2022]
Abstract
Oxidation of docosahexaenoate (DHA)-containing phospholipids in the cell plasma membrane leads to release of the α,β-unsaturated aldehyde 4-hydroxy-7-oxo-5-heptenoic acid (HOHA) lactone which is capable of inducing retinal pigmented epithelial (RPE) cell dysfunction. Previously, HOHA lactone was shown to induce apoptosis and angiogenesis, and to activate the alternative complement pathway. RPE cells metabolize HOHA lactone through enzymatic conjugation with glutathione (GSH). Competing with this process is the adduction of HOHA lactone to protein lysyl residues generating 2-(ω-carboxyethyl)pyrrole (CEP) derivatives that have pathological relevance to age-related macular degeneration (AMD). We now find that HOHA lactone induces mitochondrial dysfunction. It decreases ATP levels, mitochondrial membrane potentials, enzymatic activities of mitochondrial complexes, depletes GSH and induces oxidative stress in RPE cells. The present study confirmed that pyridoxamine and other primary amines, which have been shown to scavenge γ-ketoaldehydes formed by carbohydrate or lipid peroxidation, are ineffective for scavenging the α,β-unsaturated aldehydes. Histidyl hydrazide (HH), that has both hydrazide and imidazole nucleophile functionalities, is an effective scavenger of HOHA lactone and it protects ARPE-19 cells against HOHA lactone-induced cytotoxicity. The HH α-amino group is not essential for this electrophile trapping activity. The Nα-acyl L-histidyl hydrazide derivatives with 2- to 7-carbon acyl groups with increasing lipophilicities are capable of maintaining the effectiveness of HH in protecting ARPE-19 cells against HOHA lactone toxicity, which potentially has therapeutic utility for treatment of age related eye diseases.
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Affiliation(s)
- Yu-Shiuan Cheng
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Mikhail Linetsky
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Haoting Li
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Naji Ayyash
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Anthony Gardella
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Robert G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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5
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Zhu N, Guo X, Pang S, Chang Y, Liu X, Shi Z, Feng S. Mitochondria-Immobilized Unimolecular Fluorescent Probe for Multiplexing Imaging of Living Cancer Cells. Anal Chem 2020; 92:11103-11110. [DOI: 10.1021/acs.analchem.0c01046] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Nansong Zhu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Xiaolei Guo
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Shirui Pang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yulei Chang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
| | - Xiaomin Liu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Zhan Shi
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
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6
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Carraro M, Carrer A, Urbani A, Bernardi P. Molecular nature and regulation of the mitochondrial permeability transition pore(s), drug target(s) in cardioprotection. J Mol Cell Cardiol 2020; 144:76-86. [DOI: 10.1016/j.yjmcc.2020.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/28/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022]
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7
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Bround MJ, Bers DM, Molkentin JD. A 20/20 view of ANT function in mitochondrial biology and necrotic cell death. J Mol Cell Cardiol 2020; 144:A3-A13. [PMID: 32454061 DOI: 10.1016/j.yjmcc.2020.05.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/16/2020] [Accepted: 05/20/2020] [Indexed: 12/25/2022]
Abstract
The adenosine nucleotide translocase (ANT) family of proteins are inner mitochondrial membrane proteins involved in energy homeostasis and cell death. The primary function of ANT proteins is to exchange cytosolic ADP with matrix ATP, facilitating the export of newly synthesized ATP to the cell while providing new ADP substrate to the mitochondria. As such, the ANT proteins are central to maintaining energy homeostasis in all eukaryotic cells. Evidence also suggests that the ANTs constitute a pore-forming component of the mitochondrial permeability transition pore (MPTP), a structure that forms in the inner mitochondrial membrane that is thought to underlie regulated necrotic cell death. Additionally, emerging studies suggest that ANT proteins are also critical for mitochondrial uncoupling and for promoting mitophagy. Thus, the ANTs are multifunctional proteins that are poised to participate in several aspects of mitochondrial biology and the greater regulation of cell death, which will be discussed here.
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Affiliation(s)
- Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA; Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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8
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Griffiths KK, Wang A, Wang L, Tracey M, Kleiner G, Quinzii CM, Sun L, Yang G, Perez-Zoghbi JF, Licznerski P, Yang M, Jonas EA, Levy RJ. Inefficient thermogenic mitochondrial respiration due to futile proton leak in a mouse model of fragile X syndrome. FASEB J 2020; 34:7404-7426. [PMID: 32307754 DOI: 10.1096/fj.202000283rr] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS) is the leading known inherited intellectual disability and the most common genetic cause of autism. The full mutation results in transcriptional silencing of the Fmr1 gene and loss of fragile X mental retardation protein (FMRP) expression. Defects in neuroenergetic capacity are known to cause a variety of neurodevelopmental disorders. Thus, we explored the integrity of forebrain mitochondria in Fmr1 knockout mice during the peak of synaptogenesis. We found inefficient thermogenic respiration due to futile proton leak in Fmr1 KO mitochondria caused by coenzyme Q (CoQ) deficiency and an open cyclosporine-sensitive channel. Repletion of mitochondrial CoQ within the Fmr1 KO forebrain closed the channel, blocked the pathological proton leak, restored rates of protein synthesis during synaptogenesis, and normalized the key phenotypic features later in life. The findings demonstrate that FMRP deficiency results in inefficient oxidative phosphorylation during the neurodevelopment and suggest that dysfunctional mitochondria may contribute to the FXS phenotype.
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Affiliation(s)
- Keren K Griffiths
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Aili Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Lifei Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Matthew Tracey
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Giulio Kleiner
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Catarina M Quinzii
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Linlin Sun
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Guang Yang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Jose F Perez-Zoghbi
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Pawel Licznerski
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Mu Yang
- Institute of Genomic Medicine and Psychiatry, Columbia University Medical Center, New York, NY, USA
| | - Elizabeth A Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Richard J Levy
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
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9
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Boczek T, Radzik T, Ferenc B, Zylinska L. The Puzzling Role of Neuron-Specific PMCA Isoforms in the Aging Process. Int J Mol Sci 2019; 20:ijms20246338. [PMID: 31888192 PMCID: PMC6941135 DOI: 10.3390/ijms20246338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 01/02/2023] Open
Abstract
The aging process is a physiological phenomenon associated with progressive changes in metabolism, genes expression, and cellular resistance to stress. In neurons, one of the hallmarks of senescence is a disturbance of calcium homeostasis that may have far-reaching detrimental consequences on neuronal physiology and function. Among several proteins involved in calcium handling, plasma membrane Ca2+-ATPase (PMCA) is the most sensitive calcium detector controlling calcium homeostasis. PMCA exists in four main isoforms and PMCA2 and PMCA3 are highly expressed in the brain. The overall effects of impaired calcium extrusion due to age-dependent decline of PMCA function seem to accumulate with age, increasing the susceptibility to neurotoxic insults. To analyze the PMCA role in neuronal cells, we have developed stable transfected differentiated PC12 lines with down-regulated PMCA2 or PMCA3 isoforms to mimic age-related changes. The resting Ca2+ increased in both PMCA-deficient lines affecting the expression of several Ca2+-associated proteins, i.e., sarco/endoplasmic Ca2+-ATPase (SERCA), calmodulin, calcineurin, GAP43, CCR5, IP3Rs, and certain types of voltage-gated Ca2+ channels (VGCCs). Functional studies also demonstrated profound changes in intracellular pH regulation and mitochondrial metabolism. Moreover, modification of PMCAs membrane composition triggered some adaptive processes to counterbalance calcium overload, but the reduction of PMCA2 appeared to be more detrimental to the cells than PMCA3.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Tomasz Radzik
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Correspondence: ; Tel.: +48-42-272-5680
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10
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Tan VP, Smith JM, Tu M, Yu JD, Ding EY, Miyamoto S. Dissociation of mitochondrial HK-II elicits mitophagy and confers cardioprotection against ischemia. Cell Death Dis 2019; 10:730. [PMID: 31570704 PMCID: PMC6768853 DOI: 10.1038/s41419-019-1965-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/11/2019] [Accepted: 09/09/2019] [Indexed: 12/23/2022]
Abstract
Preservation of mitochondrial integrity is critical for maintaining cellular homeostasis. Mitophagy is a mitochondria-specific type of autophagy which eliminates damaged mitochondria thereby contributing to mitochondrial quality control. Depolarization of the mitochondrial membrane potential is an established mechanism for inducing mitophagy, mediated through PINK1 stabilization and Parkin recruitment to mitochondria. Hexokinase-II (HK-II) which catalyzes the first step in glucose metabolism, also functions as a signaling molecule to regulate cell survival, and a significant fraction of cellular HK-II is associated with mitochondria (mitoHK-II). We demonstrate here that pharmacological interventions and adenoviral expression of a mitoHK-II dissociating peptide which reduce mitoHK-II levels lead to robust increases in mitochondrial Parkin and ubiquitination of mitochondrial proteins in cardiomyocytes and in a human glioblastoma cell line 1321N1, independent of mitochondrial membrane depolarization or PINK1 accumulation. MitoHK-II dissociation-induced mitophagy was demonstrated using Mito-Keima in cardiomyocytes and in 1321N1 cells. Subjecting cardiomyocytes or the in vivo heart to ischemia leads to modest dissociation of mitoHK-II. This response is potentiated by expression of the mitoHK-II dissociating peptide, which increases Parkin recruitment to mitochondria and, importantly, provides cardioprotection against ischemic stress. These results suggest that mitoHK-II dissociation is a physiologically relevant cellular event that is induced by ischemic stress, the enhancement of which protects against ischemic damage. The mechanism which underlies the effects of mitoHK-II dissociation can be attributed to the ability of Bcl2-associated athanogene 5 (BAG5), an inhibitor of Parkin, to localize to mitochondria and form a molecular complex with HK-II. Overexpression of BAG5 attenuates while knockdown of BAG5 sensitizes the effect of mitoHK-II dissociation on mitophagy. We suggest that HK-II, a glycolytic molecule, can function as a sensor for metabolic derangements at mitochondria to trigger mitophagy, and modulating the intracellular localization of HK-II could be a novel way of regulating mitophagy to prevent cell death induced by ischemic stress.
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Affiliation(s)
- Valerie P Tan
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA
| | - Jeffrey M Smith
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA
| | - Michelle Tu
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA
| | - Justin D Yu
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA
| | - Eric Y Ding
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA
| | - Shigeki Miyamoto
- Department of Pharmacology, University of California, San Diego, 9500 Gilman drive, La Jolla, CA, 92093-0636, USA.
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11
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D'Acunzo P, Strappazzon F, Caruana I, Meneghetti G, Di Rita A, Simula L, Weber G, Del Bufalo F, Dalla Valle L, Campello S, Locatelli F, Cecconi F. Reversible induction of mitophagy by an optogenetic bimodular system. Nat Commun 2019; 10:1533. [PMID: 30948710 PMCID: PMC6449392 DOI: 10.1038/s41467-019-09487-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 03/12/2019] [Indexed: 11/13/2022] Open
Abstract
Autophagy-mediated degradation of mitochondria (mitophagy) is a key process in cellular quality control. Although mitophagy impairment is involved in several patho-physiological conditions, valuable methods to induce mitophagy with low toxicity in vivo are still lacking. Herein, we describe a new optogenetic tool to stimulate mitophagy, based on light-dependent recruitment of pro-autophagy protein AMBRA1 to mitochondrial surface. Upon illumination, AMBRA1-RFP-sspB is efficiently relocated from the cytosol to mitochondria, where it reversibly mediates mito-aggresome formation and reduction of mitochondrial mass. Finally, as a proof of concept of the biomedical relevance of this method, we induced mitophagy in an in vitro model of neurotoxicity, fully preventing cell death, as well as in human T lymphocytes and in zebrafish in vivo. Given the unique features of this tool, we think it may turn out to be very useful for a wide range of both therapeutic and research applications. Autophagic degradation of mitochondria (mitophagy) is a key quality control mechanism in cellular homeostasis, and its misregulation is involved in neurodegenerative diseases. Here the authors develop an optogenetic system for reversible induction of mitophagy and validate its use in cell culture and zebrafish embryos.
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Affiliation(s)
- Pasquale D'Acunzo
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy
| | - Flavie Strappazzon
- IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143, Rome, Italy.,Department of Biology, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Ignazio Caruana
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy
| | - Giacomo Meneghetti
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35131, Padova, Italy
| | - Anthea Di Rita
- IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143, Rome, Italy.,Department of Biology, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Luca Simula
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy.,Department of Biology, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Gerrit Weber
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy
| | - Francesca Del Bufalo
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy
| | - Luisa Dalla Valle
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35131, Padova, Italy
| | - Silvia Campello
- IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143, Rome, Italy.,Department of Biology, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Franco Locatelli
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy.,Department of Gynecology/Obstetrics and Pediatrics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Francesco Cecconi
- Department of Paediatric Haematology, Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Piazza Sant'Onofrio 4, 00165, Rome, Italy. .,Department of Biology, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy. .,Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Strandboulevarden 49, DK-2100, Copenhagen, Denmark.
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12
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Sato T, Segawa M, Sekine S, Ito K. Mild depolarization is involved in troglitazone-induced liver mitochondrial membrane permeability transition via mitochondrial iPLA 2 activation. J Toxicol Sci 2019; 44:811-820. [DOI: 10.2131/jts.44.811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Tomoyuki Sato
- The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University
| | - Masahiro Segawa
- The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University
| | - Shuichi Sekine
- The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University
| | - Kousei Ito
- The Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University
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13
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Kasimova MA, Lindahl E, Delemotte L. Determining the molecular basis of voltage sensitivity in membrane proteins. J Gen Physiol 2018; 150:1444-1458. [PMID: 30150239 PMCID: PMC6168238 DOI: 10.1085/jgp.201812086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/07/2018] [Indexed: 12/31/2022] Open
Abstract
The identification of voltage-sensing elements in membrane proteins is challenging due to the diversity of voltage-sensing mechanisms. Kasimova et al. present a computational approach to predict the elements involved in voltage sensing, which they validate using voltage-gated ion channels. Voltage-sensitive membrane proteins are united by their ability to transform changes in membrane potential into mechanical work. They are responsible for a spectrum of physiological processes in living organisms, including electrical signaling and cell-cycle progression. Although the mechanism of voltage-sensing has been well characterized for some membrane proteins, including voltage-gated ion channels, even the location of the voltage-sensing elements remains unknown for others. Moreover, the detection of these elements by using experimental techniques is challenging because of the diversity of membrane proteins. Here, we provide a computational approach to predict voltage-sensing elements in any membrane protein, independent of its structure or function. It relies on an estimation of the propensity of a protein to respond to changes in membrane potential. We first show that this property correlates well with voltage sensitivity by applying our approach to a set of voltage-sensitive and voltage-insensitive membrane proteins. We further show that it correctly identifies authentic voltage-sensitive residues in the voltage-sensor domain of voltage-gated ion channels. Finally, we investigate six membrane proteins for which the voltage-sensing elements have not yet been characterized and identify residues and ions that might be involved in the response to voltage. The suggested approach is fast and simple and enables a characterization of voltage sensitivity that goes beyond mere identification of charges. We anticipate that its application before mutagenesis experiments will significantly reduce the number of potential voltage-sensitive elements to be tested.
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Affiliation(s)
- Marina A Kasimova
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Erik Lindahl
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden.,Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Lucie Delemotte
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
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14
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Briston T, Hicks AR. Mitochondrial dysfunction and neurodegenerative proteinopathies: mechanisms and prospects for therapeutic intervention. Biochem Soc Trans 2018; 46:829-842. [PMID: 29986938 PMCID: PMC6103456 DOI: 10.1042/bst20180025] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/10/2018] [Accepted: 05/21/2018] [Indexed: 12/22/2022]
Abstract
Neurodegenerative proteinopathies are a group of pathologically similar, progressive disorders of the nervous system, characterised by structural alterations within and toxic misfolding of susceptible proteins. Oligomerisation of Aβ, tau, α-synuclein and TDP-43 leads to a toxin gain- or loss-of-function contributing to the phenotype observed in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and frontotemporal dementia. Misfolded proteins can adversely affect mitochondria, and post-mitotic neurones are especially sensitive to metabolic dysfunction. Misfolded proteins impair mitochondrial dynamics (morphology and trafficking), preventing functional mitochondria reaching the synapse, the primary site of ATP utilisation. Furthermore, a direct association of misfolded proteins with mitochondria may precipitate or augment dysfunctional oxidative phosphorylation and mitochondrial quality control, causing redox dyshomeostasis observed in disease. As such, a significant interest lies in understanding mechanisms of mitochondrial toxicity in neurodegenerative disorders and in dissecting these mechanisms with a view of maintaining mitochondrial homeostasis in disease. Recent advances in understanding mitochondrially controlled cell death pathways and elucidating the mitochondrial permeability pore bioarchitecture are beginning to present new avenues to target neurodegeneration. Novel mitochondrial roles of deubiquitinating enzymes are coming to light and present an opportunity for a new class of proteins to target therapeutically with the aim of promoting mitophagy and the ubiquitin-proteasome system. The brain is enormously metabolically active, placing a large emphasis on maintaining ATP supply. Therefore, identifying mechanisms to sustain mitochondrial function may represent a common intervention point across all proteinopathies.
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Affiliation(s)
- Thomas Briston
- Neurology Innovation Centre, Hatfield Research Laboratories, Eisai Ltd, Hatfield, U.K.
| | - Amy R Hicks
- Neurology Innovation Centre, Hatfield Research Laboratories, Eisai Ltd, Hatfield, U.K
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15
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Panel M, Ghaleh B, Morin D. Mitochondria and aging: A role for the mitochondrial transition pore? Aging Cell 2018; 17:e12793. [PMID: 29888494 PMCID: PMC6052406 DOI: 10.1111/acel.12793] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2018] [Indexed: 12/15/2022] Open
Abstract
The cellular mechanisms responsible for aging are poorly understood. Aging is considered as a degenerative process induced by the accumulation of cellular lesions leading progressively to organ dysfunction and death. The free radical theory of aging has long been considered the most relevant to explain the mechanisms of aging. As the mitochondrion is an important source of reactive oxygen species (ROS), this organelle is regarded as a key intracellular player in this process and a large amount of data supports the role of mitochondrial ROS production during aging. Thus, mitochondrial ROS, oxidative damage, aging, and aging-dependent diseases are strongly connected. However, other features of mitochondrial physiology and dysfunction have been recently implicated in the development of the aging process. Here, we examine the potential role of the mitochondrial permeability transition pore (mPTP) in normal aging and in aging-associated diseases.
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Affiliation(s)
- Mathieu Panel
- INSERM U955, équipe 3; Créteil France
- Université Paris-Est, UMR_S955, DHU A-TVB, UPEC; Créteil France
| | - Bijan Ghaleh
- INSERM U955, équipe 3; Créteil France
- Université Paris-Est, UMR_S955, DHU A-TVB, UPEC; Créteil France
| | - Didier Morin
- INSERM U955, équipe 3; Créteil France
- Université Paris-Est, UMR_S955, DHU A-TVB, UPEC; Créteil France
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16
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Vygodina TV, Mukhaleva E, Azarkina NV, Konstantinov AA. Cytochrome c oxidase inhibition by calcium at physiological ionic composition of the medium: Implications for physiological significance of the effect. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:982-990. [DOI: 10.1016/j.bbabio.2017.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
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17
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Mitochondrial permeability transition pore: sensitivity to opening and mechanistic dependence on substrate availability. Sci Rep 2017; 7:10492. [PMID: 28874733 PMCID: PMC5585167 DOI: 10.1038/s41598-017-10673-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 08/11/2017] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial Ca2+ uptake has a key role in cellular Ca2+ homeostasis. Excessive matrix Ca2+ concentrations, especially when coincident with oxidative stress, precipitate opening of an inner mitochondrial membrane, high-conductance channel: the mitochondrial permeability transition pore (mPTP). mPTP opening has been implicated as a final cell death pathway in numerous diseases and therefore understanding conditions dictating mPTP opening is crucial for developing targeted therapies. Here, we have investigated the impact of mitochondrial metabolic state on the probability and consequences of mPTP opening. Isolated mitochondria were energised using NADH- or FADH2-linked substrates. The functional consequences of Ca2+-induced mPTP opening were assessed by Ca2+ retention capacity, using fluorescence-based analysis, and simultaneous measurements of mitochondrial Ca2+ handling, membrane potential, respiratory rate and production of reactive oxygen species (ROS). Succinate-induced, membrane potential-dependent reverse electron transfer sensitised mitochondria to mPTP opening. mPTP-induced depolarisation under succinate subsequently inhibited reverse electron transfer. Complex I-driven respiration was reduced after mPTP opening but sustained in the presence of complex II-linked substrates, consistent with inhibition of complex I-supported respiration by leakage of matrix NADH. Additionally, ROS generated at complex III did not sensitise mitochondria to mPTP opening. Thus, cellular metabolic fluxes and metabolic environment dictate mitochondrial functional response to Ca2+ overload.
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18
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Bellum S, Bawa B, Thuett KA, Stoica G, Abbott LC. Changes in Biochemical Processes in Cerebellar Granule Cells of Mice Exposed To Methylmercury. Int J Toxicol 2017; 26:261-9. [PMID: 17564908 DOI: 10.1080/10915810701369758] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
At postnatal day 34, male and female C57BL/6J mice were exposed orally once a day to a total of five doses totaling 1.0 or 5.0 mg/kg of methylmercuric chloride or sterile deionized water in moistened rodent chow. Eleven days after the last dose cerebellar granule cells were acutely isolated to measure reactive oxygen species (ROS) levels and mitochondrial membrane potential using CM-H2DCFDA and TMRM dyes, respectively. For visualizing intracellular calcium ion distribution using transmission electron microscopy, mice were perfused 11 days after the last dose of methylmercury (MeHg) using the oxalate-pyroantimonate method. Cytosolic and mitochondrial protein fractions from acutely isolated granule cells were analyzed for cytochrome c content using Western blot analysis. Histochemistry (Fluoro-Jade dye) and immunohistochemistry (activated caspase 3) was performed on frozen serial cerebellar sections to label granule cell death and activation of caspase 3, respectively. Granule cells isolated from MeHg-treated mice showed elevated ROS levels and decreased mitochondrial membrane potential when compared to granule cells from control mice. Electron photomicrographs of MeHg-treated granule cells showed altered intracellular calcium ion homeostasis ([Ca2+]i) when compared to control granule cells. However, in spite of these subcellular changes and moderate relocalization of cytochrome c into the cytosol, the concentrations of MeHg used in this study did not produce significant neuronal cell death/apoptosis at the time point examined, as evidenced by Fluoro-Jade and activated caspase 3 immunostaining, respectively. These results demonstrate that short-term in vivo exposure to total doses of 1.0 and 5.0 mg/kg MeHg through the most common exposure route (oral) can result in significant subcellular changes that are not accompanied by overt neuronal cell death.
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Affiliation(s)
- Sairam Bellum
- Department of Safety Assessment, Merck Research Laboratories, West Point, Pennsylvania, USA
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19
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Fahanik-Babaei J, Shayanfar F, Khodaee N, Saghiri R, Eliassi A. Electro-pharmacological profiles of two brain mitoplast anion channels: Inferences from single channel recording. EXCLI JOURNAL 2017; 16:531-545. [PMID: 28694756 PMCID: PMC5491910 DOI: 10.17179/excli2016-808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/21/2017] [Indexed: 11/29/2022]
Abstract
We have characterized the conduction and blocking properties of two different chloride channels from brain mitochondrial inner membranes after incorporation into planar lipid bilayers. Our experiments revealed the existence of channels with a mean conductance of 158 ± 7 and 301 ± 8 pS in asymmetrical 200 mM cis/50 mM trans KCl solutions. We determined that the channels were ten times more permeable for Cl− than for K+, calculated from the reversal potential using the Goldman-Hodgkin-Katz equation. The channels were bell-shaped voltage dependent, with maximum open probability 0.9 at ± 20 mV. Two mitochondrial chloride channels were blocked after the addition of 10 µM DIDS. In addition, 158 pS chloride channel was blocked by 300 nM NPPB, acidic pH and 2.5 mM ATP, whereas the 301 pS chloride channel was blocked by 600 µM NPPB but not by acidic pH or ATP. Gating and conducting behaviors of these channels were unaffected by Ca2+. These results demonstrate that the 158 pS anion channel present in brain mitochondrial inner membrane, is probably identical to IMAC and 301 pS Cl channel displays different properties than those classically described for mitochondrial anion channels.
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Affiliation(s)
- Javad Fahanik-Babaei
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzad Shayanfar
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Naser Khodaee
- Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Faculty of Paramedical Sciences, AJA University of Medical Sciences, Tehran, Iran
| | - Reza Saghiri
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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20
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Ca 2+ ionophores are not suitable for inducing mPTP opening in murine isolated adult cardiac myocytes. Sci Rep 2017; 7:4283. [PMID: 28655872 PMCID: PMC5487341 DOI: 10.1038/s41598-017-04618-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/17/2017] [Indexed: 11/08/2022] Open
Abstract
Opening of the mitochondrial permeability transition pore (mPTP) plays a major role in cell death during cardiac ischaemia-reperfusion. Adult isolated rodent cardiomyocytes are valuable cells to study the effect of drugs targeting mPTP. This study investigated whether the use of Ca2+ ionophores (A23187, ionomycin and ETH129) represent a reliable model to study inhibition of mPTP opening in cardiomyocytes. We monitored mPTP opening using the calcein/cobalt fluorescence technique in adult rat and wild type or cyclophilin D (CypD) knock-out mice cardiomyocytes. Cells were either treated with Ca2+ ionophores or subjected to hypoxia followed by reoxygenation. The ionophores induced mPTP-dependent swelling in isolated mitochondria. A23187, but not ionomycin, induced a decrease in calcein fluorescence. This loss could not be inhibited by CypD deletion and was explained by a direct interaction between A23187 and cobalt. ETH129 caused calcein loss, mitochondrial depolarization and cell death but CypD deletion did not alleviate these effects. In the hypoxia-reoxygenation model, CypD deletion delayed both mPTP opening and cell death occurring at the time of reoxygenation. Thus, Ca2+ ionophores are not suitable to induce CypD-dependent mPTP opening in adult murine cardiomyocytes. Hypoxia-reoxygenation conditions appear therefore as the most reliable model to investigate mPTP opening in these cells.
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21
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Kozlov AV, Lancaster JR, Meszaros AT, Weidinger A. Mitochondria-meditated pathways of organ failure upon inflammation. Redox Biol 2017; 13:170-181. [PMID: 28578275 PMCID: PMC5458092 DOI: 10.1016/j.redox.2017.05.017] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 02/06/2023] Open
Abstract
Liver failure induced by systemic inflammatory response (SIRS) is often associated with mitochondrial dysfunction but the mechanism linking SIRS and mitochondria-mediated liver failure is still a matter of discussion. Current hypotheses suggest that causative events could be a drop in ATP synthesis, opening of mitochondrial permeability transition pore, specific changes in mitochondrial morphology, impaired Ca2+ uptake, generation of mitochondrial reactive oxygen species (mtROS), turnover of mitochondria and imbalance in electron supply to the respiratory chain. The aim of this review is to critically analyze existing hypotheses, in order to highlight the most promising research lines helping to prevent liver failure induced by SIRS. Evaluation of the literature shows that there is no consistent support that impaired Ca++ metabolism, electron transport chain function and ultrastructure of mitochondria substantially contribute to liver failure. Moreover, our analysis suggests that the drop in ATP levels has protective rather than a deleterious character. Recent data suggest that the most critical mitochondrial event occurring upon SIRS is the release of mtROS in cytoplasm, which can activate two specific intracellular signaling cascades. The first is the mtROS-mediated activation of NADPH-oxidase in liver macrophages and endothelial cells; the second is the acceleration of the expression of inflammatory genes in hepatocytes. The signaling action of mtROS is strictly controlled in mitochondria at three points, (i) at the site of ROS generation at complex I, (ii) the site of mtROS release in cytoplasm via permeability transition pore, and (iii) interaction with specific kinases in cytoplasm. The systems controlling mtROS-signaling include pro- and anti-inflammatory mediators, nitric oxide, Ca2+ and NADPH-oxidase. Analysis of the literature suggests that further research should be focused on the impact of mtROS on organ failure induced by inflammation and simultaneously providing a new theoretical basis for a targeted therapy of overwhelmed inflammatory response. Relationship between mitochondrial dysfunction and high lethality upon sepsis. Criteria to define critical for lethality mitochondrial dysfunction. ATP, calcium, mitochondrial ultrastructure and apoptosis, upon inflammation. Regulation of inflammatory processes by mitochondrial ROS.
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Affiliation(s)
- Andrey V Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Donaueschingen Str. 13, 1200 Vienna, Austria.
| | - Jack R Lancaster
- University of Pittsburgh, Departments of Pharmacology & Chemical Biology, Surgery, and Medicine, 1341A Thomas E. Starzl Biomedical Science Tower, PA 15261, United States
| | - Andras T Meszaros
- University of Szeged, Institute of Surgical Research, 6720 Szeged, Hungary
| | - Adelheid Weidinger
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Donaueschingen Str. 13, 1200 Vienna, Austria
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22
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Gordan R, Fefelova N, Gwathmey JK, Xie LH. Involvement of mitochondrial permeability transition pore (mPTP) in cardiac arrhythmias: Evidence from cyclophilin D knockout mice. Cell Calcium 2016; 60:363-372. [PMID: 27616659 PMCID: PMC5127715 DOI: 10.1016/j.ceca.2016.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 02/04/2023]
Abstract
In the present study, we have used a genetic mouse model that lacks cyclophilin D (CypD KO) to assess the cardioprotective effect of mitochondrial permeability transition pore (mPTP) inhibition on Ca2+ waves and Ca2+ alternans at the single cell level, and cardiac arrhythmias in whole-heart preparations. The protonophore carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) caused mitochondrial membrane potential depolarization to the same extent in cardiomyocytes from both WT and CypD KO mice, however, cardiomyocytes from CypD KO mice exhibited significantly less mPTP opening than cardiomyocytes from WT mice (p<0.05). Consistent with these results, FCCP caused significant increases in CaW rate in WT cardiomyocytes (p<0.05) but not in CypD KO cardiomyocytes. Furthermore, the incidence of Ca2+ alternans after treatment with FCCP and programmed stimulation was significantly higher in WT cardiomyocytes (11 of 13), than in WT cardiomyocytes treated with CsA (2 of 8; p<0.05) or CypD KO cardiomyocytes (2 of 10; p<0.01). (Pseudo-)Lead II ECGs were recorded from ex vivo hearts. We observed ST-T-wave alternans (a precursor of lethal arrhythmias) in 5 of 7 WT hearts. ST-T-wave alternans was not seen in CypD KO hearts (n=5) and in only 1 of 6 WT hearts treated with CsA. Consistent with these results, WT hearts exhibited a significantly higher average arrhythmia score than CypD KO (p<0.01) hearts subjected to FCCP treatment or chemical ischemia-reperfusion (p<0.01). In conclusion, CypD deficiency- induced mPTP inhibition attenuates CaWs and Ca2+ alternans during mitochondrial depolarization, and thereby protects against arrhythmogenesis in the heart.
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Affiliation(s)
- Richard Gordan
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ 07103, USA
| | - Nadezhda Fefelova
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ 07103, USA
| | - Judith K Gwathmey
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ 07103, USA
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ 07103, USA.
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23
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Briston T, Lewis S, Koglin M, Mistry K, Shen Y, Hartopp N, Katsumata R, Fukumoto H, Duchen MR, Szabadkai G, Staddon JM, Roberts M, Powney B. Identification of ER-000444793, a Cyclophilin D-independent inhibitor of mitochondrial permeability transition, using a high-throughput screen in cryopreserved mitochondria. Sci Rep 2016; 6:37798. [PMID: 27886240 PMCID: PMC5122887 DOI: 10.1038/srep37798] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 11/02/2016] [Indexed: 12/19/2022] Open
Abstract
Growing evidence suggests persistent mitochondrial permeability transition pore (mPTP) opening is a key pathophysiological event in cell death underlying a variety of diseases. While it has long been clear the mPTP is a druggable target, current agents are limited by off-target effects and low therapeutic efficacy. Therefore identification and development of novel inhibitors is necessary. To rapidly screen large compound libraries for novel mPTP modulators, a method was exploited to cryopreserve large batches of functionally active mitochondria from cells and tissues. The cryopreserved mitochondria maintained respiratory coupling and ATP synthesis, Ca2+ uptake and transmembrane potential. A high-throughput screen (HTS), using an assay of Ca2+-induced mitochondrial swelling in the cryopreserved mitochondria identified ER-000444793, a potent inhibitor of mPTP opening. Further evaluation using assays of Ca2+-induced membrane depolarisation and Ca2+ retention capacity also indicated that ER-000444793 acted as an inhibitor of the mPTP. ER-000444793 neither affected cyclophilin D (CypD) enzymatic activity, nor displaced of CsA from CypD protein, suggesting a mechanism independent of CypD inhibition. Here we identified a novel, CypD-independent inhibitor of the mPTP. The screening approach and compound described provides a workflow and additional tool to aid the search for novel mPTP modulators and to help understand its molecular nature.
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Affiliation(s)
- Thomas Briston
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Sian Lewis
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Mumta Koglin
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Kavita Mistry
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Yongchun Shen
- Next Generation Systems CFU, Eisai Inc., Andover, MA, USA
| | - Naomi Hartopp
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | | | - Hironori Fukumoto
- NGM-PCU, Eisai Co. Ltd., Tsukuba Research Laboratories, Tsukuba, Japan
| | - Michael R. Duchen
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, University College London, London, UK
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - James M. Staddon
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Malcolm Roberts
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
| | - Ben Powney
- UCL Collaboration Research Group, NGM-PCU, Eisai Ltd., Hatfield, UK
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24
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Doczi J, Torocsik B, Echaniz-Laguna A, Mousson de Camaret B, Starkov A, Starkova N, Gál A, Molnár MJ, Kawamata H, Manfredi G, Adam-Vizi V, Chinopoulos C. Alterations in voltage-sensing of the mitochondrial permeability transition pore in ANT1-deficient cells. Sci Rep 2016; 6:26700. [PMID: 27221760 PMCID: PMC4879635 DOI: 10.1038/srep26700] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 05/09/2016] [Indexed: 01/03/2023] Open
Abstract
The probability of mitochondrial permeability transition (mPT) pore opening is inversely related to the magnitude of the proton electrochemical gradient. The module conferring sensitivity of the pore to this gradient has not been identified. We investigated mPT’s voltage-sensing properties elicited by calcimycin or H2O2 in human fibroblasts exhibiting partial or complete lack of ANT1 and in C2C12 myotubes with knocked-down ANT1 expression. mPT onset was assessed by measuring in situ mitochondrial volume using the ‘thinness ratio’ and the ‘cobalt-calcein’ technique. De-energization hastened calcimycin-induced swelling in control and partially-expressing ANT1 fibroblasts, but not in cells lacking ANT1, despite greater losses of mitochondrial membrane potential. Matrix Ca2+ levels measured by X-rhod-1 or mitochondrially-targeted ratiometric biosensor 4mtD3cpv, or ADP-ATP exchange rates did not differ among cell types. ANT1-null fibroblasts were also resistant to H2O2-induced mitochondrial swelling. Permeabilized C2C12 myotubes with knocked-down ANT1 exhibited higher calcium uptake capacity and voltage-thresholds of mPT opening inferred from cytochrome c release, but intact cells showed no differences in calcimycin-induced onset of mPT, irrespective of energization and ANT1 expression, albeit the number of cells undergoing mPT increased less significantly upon chemically-induced hypoxia than control cells. We conclude that ANT1 confers sensitivity of the pore to the electrochemical gradient.
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Affiliation(s)
- Judit Doczi
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary.,MTA-SE Lendület Neurobiochemistry Research Group, Budapest, Hungary
| | - Beata Torocsik
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary
| | - Andoni Echaniz-Laguna
- Département de Neurologie, Hôpitaux Universitaires, Hôpital de Hautepierre, 67098 Strasbourg cedex, France
| | - Bénédicte Mousson de Camaret
- Service des Maladies Héréditaires du Métabolisme, Centre de Biologie et de Pathologie Est, CHU Lyon, 69677 Bron cedex, France
| | - Anatoly Starkov
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Natalia Starkova
- Icahn School of Medicine at Mount Sinai, Department of Hematology and Medical Oncology, New York, NY 10029, USA
| | - Aniko Gál
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary
| | - Mária J Molnár
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary.,MTA-SE Lendület Neurobiochemistry Research Group, Budapest, Hungary
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25
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Bernardi P, Rasola A, Forte M, Lippe G. The Mitochondrial Permeability Transition Pore: Channel Formation by F-ATP Synthase, Integration in Signal Transduction, and Role in Pathophysiology. Physiol Rev 2015; 95:1111-55. [PMID: 26269524 DOI: 10.1152/physrev.00001.2015] [Citation(s) in RCA: 420] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mitochondrial permeability transition (PT) is a permeability increase of the inner mitochondrial membrane mediated by a channel, the permeability transition pore (PTP). After a brief historical introduction, we cover the key regulatory features of the PTP and provide a critical assessment of putative protein components that have been tested by genetic analysis. The discovery that under conditions of oxidative stress the F-ATP synthases of mammals, yeast, and Drosophila can be turned into Ca(2+)-dependent channels, whose electrophysiological properties match those of the corresponding PTPs, opens new perspectives to the field. We discuss structural and functional features of F-ATP synthases that may provide clues to its transition from an energy-conserving into an energy-dissipating device as well as recent advances on signal transduction to the PTP and on its role in cellular pathophysiology.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Michael Forte
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Giovanna Lippe
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
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26
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Antonenkov VD, Isomursu A, Mennerich D, Vapola MH, Weiher H, Kietzmann T, Hiltunen JK. The Human Mitochondrial DNA Depletion Syndrome Gene MPV17 Encodes a Non-selective Channel That Modulates Membrane Potential. J Biol Chem 2015; 290:13840-61. [PMID: 25861990 DOI: 10.1074/jbc.m114.608083] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Indexed: 12/17/2022] Open
Abstract
The human MPV17-related mitochondrial DNA depletion syndrome is an inherited autosomal recessive disease caused by mutations in the inner mitochondrial membrane protein MPV17. Although more than 30 MPV17 gene mutations were shown to be associated with mitochondrial DNA depletion syndrome, the function of MPV17 is still unknown. Mice deficient in Mpv17 show signs of premature aging. In the present study, we used electrophysiological measurements with recombinant MPV17 to reveal that this protein forms a non-selective channel with a pore diameter of 1.8 nm and located the channel's selectivity filter. The channel was weakly cation-selective and showed several subconductance states. Voltage-dependent gating of the channel was regulated by redox conditions and pH and was affected also in mutants mimicking a phosphorylated state. Likewise, the mitochondrial membrane potential (Δψm) and the cellular production of reactive oxygen species were higher in embryonic fibroblasts from Mpv17(-/-) mice. However, despite the elevated Δψm, the Mpv17-deficient mitochondria showed signs of accelerated fission. Together, these observations uncover the role of MPV17 as a Δψm-modulating channel that apparently contributes to mitochondrial homeostasis under different conditions.
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Affiliation(s)
- Vasily D Antonenkov
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
| | - Antti Isomursu
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
| | - Daniela Mennerich
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
| | - Miia H Vapola
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
| | - Hans Weiher
- the Heinrich Pette Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Thomas Kietzmann
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
| | - J Kalervo Hiltunen
- From the Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland and
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27
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Bonora M, Wieckowski MR, Chinopoulos C, Kepp O, Kroemer G, Galluzzi L, Pinton P. Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition. Oncogene 2015; 34:1475-86. [PMID: 24727893 DOI: 10.1038/onc.2014.96] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 12/14/2022]
Abstract
The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.
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Affiliation(s)
- M Bonora
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
| | - M R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - C Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - O Kepp
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - G Kroemer
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France [4] Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - L Galluzzi
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - P Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
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28
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Ca(2+)-dependent nonspecific permeability of the inner membrane of liver mitochondria in the guinea fowl (Numida meleagris). J Bioenerg Biomembr 2015; 47:235-42. [PMID: 25690874 DOI: 10.1007/s10863-015-9606-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 02/10/2015] [Indexed: 10/24/2022]
Abstract
This comparative study presents the results of the induction of Ca(2+)-dependent nonspecific permeability of the inner membrane (pore opening) of rat and guinea fowl liver mitochondria by mechanisms that are both sensitive and insensitive to cyclosporin A (CsA). It was established that energized rat and guinea fowl liver mitochondria incubated with 1 mM of inorganic phosphate (Pi) are capable of swelling upon addition of at least 125 and 875 nmol of CaCl2 per 1 mg protein, respectively. Under these conditions, the Ca(2+) release from the mitochondria of these animals and a drop in Δψ are observed. All of these processes are inhibited by 1 μM of CsA. FCCP, causing organelle de-energization, induces pore opening in rat and guinea fowl liver mitochondria upon addition of 45 и 625 nmol of CaCl2 per 1 mg protein, respectively. These results suggest the existence of a CsA-sensitive mechanism for the induction of Ca(2+)-dependent pores in guinea fowl liver mitochondria, which has been reported in rat liver mitochondria. However, guinea fowl liver mitochondria have a significantly greater resistance to Ca(2+) as a pore inducer compared to rat liver mitochondria. It was found that the addition of α,ω-hexadecanedioic acid (HDA) to rat and guinea fowl liver mitochondria incubated with CsA and loaded with Ca(2+) causes organelle swelling and Ca(2+) release from the matrix. It is assumed that in contrast to the CsA-sensitive pore, the CsA-insensitive pore induced by HDA in the inner membrane of guinea fowl liver mitochondria, as well as in rat liver mitochondria, is lipid in nature.
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29
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Testai L, Rapposelli S, Martelli A, Breschi M, Calderone V. Mitochondrial Potassium Channels as Pharmacological Target for Cardioprotective Drugs. Med Res Rev 2014; 35:520-53. [DOI: 10.1002/med.21332] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- L. Testai
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - S. Rapposelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - A. Martelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - M.C. Breschi
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - V. Calderone
- Department of Pharmacy; University of Pisa; Pisa Italy
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30
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Remote cardioprotection by transfer of coronary effluent from ischemic preconditioned rabbit heart preserves mitochondrial integrity and function via adenosine receptor activation. Cardiovasc Drugs Ther 2014; 28:7-17. [PMID: 24018748 DOI: 10.1007/s10557-013-6489-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Coronary effluent from an isolated perfused heart undergoing ischemic preconditioning can be transferred to precondition another naïve isolated heart. We investigated the effects of this effluent on mitochondrial integrity and function following a global infarct model of ischemia/reperfusion and the role of adenosine in this model of remote preconditioning. METHODS AND RESULTS Coronary effluent from isolated perfused rabbit hearts was collected prior to (control effluent) and during three cycles of 5-min ischemia and 10-min reperfusion (IPC effluent). Adenosine concentration was significantly increased in IPC effluent (2.6 ± 1.1 μM) versus control effluent (0.21 ± 0.06 μM, P < 0.01). Infarct size (% necrotic LV mass) after 30-min global ischemia and 90-min reperfusion was significantly reduced in hearts preconditioned with IPC effluent (IPC(eff), 23 ± 7 %) and control effluent supplemented with 2.5 μM exogenous adenosine (C(eff)+ 2.5 μM ADO, 25 ± 10 %) when compared to control effluent perfused hearts (C(eff), 41 ± 8 %, P < 0.05). Compared to C(eff) mitochondria, IPC(eff) mitochondria had preserved complex I/State3 and complex IV/State 3 respiration and outer membrane integrity, and reduced cytochrome c release. In contrast, C(eff) + 2.5 μM ADO mitochondria had improved state 2 respiration and coupling to oxidative phosphorylation, reduced reactive oxygen species production and preserved outer membrane integrity. Administration of adenosine receptor blocker 8-(p-sulfophenyl)theophylline abolished the infarct limiting effect (46 ± 7 %) and the mitochondrial integrity and function preservation of IPC effluent. CONCLUSION Remote cardioprotection by IPC effluent preserves mitochondrial integrity and function in an adenosine receptor dependent mechanism, and although infarct size reduction can be mimicked by adenosine, IPC effluent contains additional factor(s) contributing to modulation of the mitochondrial response to ischemia/reperfusion injury.
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31
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Impaired mitochondrial homeostasis and neurodegeneration: towards new therapeutic targets? J Bioenerg Biomembr 2014; 47:89-99. [PMID: 25216534 PMCID: PMC4323516 DOI: 10.1007/s10863-014-9576-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/25/2014] [Indexed: 12/12/2022]
Abstract
The sustained integrity of the mitochondrial population of a cell is critical for maintained cell health, and disruption of that integrity is linked strongly to human disease, especially to the neurodegenerative diseases. These are appalling diseases causing untold levels of suffering for which treatment is woefully inadequate. Understanding the mechanisms that disturb mitochondrial homeostasis may therefore prove key to identification of potential new therapeutic pathways. Mechanisms causing mitochondrial dysfunction include the acute catastrophic loss of function caused by opening of the mitochondrial permeability transition pore (mPTP), which collapses bioenergetic function and initiates cell death. This is best characterised in ischaemic reperfusion injury, although it may also contribute to a number of other diseases. More insidious disturbances of mitochondrial homeostasis may result from impaired balance in the pathways that promote mitochondrial repair (biogenesis) and pathways that remove dysfunctional mitochondria (mitophagy). Impaired coordination between these processes is emerging as a key feature of a number of neurodegenerative and neuromuscular disorders. Here we review pathways that may prove to be valuable potential therapeutic targets, focussing on the molecular mechanisms that govern the coordination of these processes and their involvement in neurodegenerative diseases.
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32
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Halestrap AP, Richardson AP. The mitochondrial permeability transition: a current perspective on its identity and role in ischaemia/reperfusion injury. J Mol Cell Cardiol 2014; 78:129-41. [PMID: 25179911 DOI: 10.1016/j.yjmcc.2014.08.018] [Citation(s) in RCA: 310] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 08/21/2014] [Accepted: 08/24/2014] [Indexed: 12/29/2022]
Abstract
The mitochondrial permeability transition pore (MPTP) is a non-specific pore that opens in the inner mitochondrial membrane (IMM) when matrix [Ca(2+)] is high, especially when accompanied by oxidative stress, high [Pi] and adenine nucleotide depletion. Such conditions occur during ischaemia and subsequent reperfusion, when MPTP opening is known to occur and cause irreversible damage to the heart. Matrix cyclophilin D facilitates MPTP opening and is the target of its inhibition by cyclosporin A that is cardioprotective. Less certainty exists over the composition of the pore itself, with structural and/or regulatory roles proposed for the adenine nucleotide translocase, the phosphate carrier and the FoF1 ATP synthase. Here we critically review the supporting data for the role of each and suggest that they may interact with each other through their bound cardiolipin to form the ATP synthasome. We propose that under conditions favouring MPTP opening, calcium-triggered conformational changes in these proteins may perturb the interface between them generating the pore. Proteins associated with the outer mitochondrial membrane (OMM), such as members of the Bcl-2 family and hexokinase (HK), whilst not directly involved in pore formation, may regulate MPTP opening through interactions between OMM and IMM proteins at "contact sites". Recent evidence suggests that cardioprotective protocols such as preconditioning inhibit MPTP opening at reperfusion by preventing the loss of mitochondrial bound HK2 that stabilises these contact sites. Contact site breakage both sensitises the MPTP to [Ca(2+)] and facilitates cytochrome c loss from the intermembrane space leading to greater ROS production and further MPTP opening. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Affiliation(s)
- Andrew P Halestrap
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
| | - Andrew P Richardson
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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33
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Yamamoto T, Ito M, Kageyama K, Kuwahara K, Yamashita K, Takiguchi Y, Kitamura S, Terada H, Shinohara Y. Mastoparan peptide causes mitochondrial permeability transition not by interacting with specific membrane proteins but by interacting with the phospholipid phase. FEBS J 2014; 281:3933-44. [DOI: 10.1111/febs.12930] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/24/2014] [Accepted: 07/14/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Takenori Yamamoto
- Institute for Genome Research; University of Tokushima; Japan
- Faculty of Pharmaceutical Sciences; University of Tokushima; Japan
| | - Mika Ito
- Institute for Genome Research; University of Tokushima; Japan
- Faculty of Pharmaceutical Sciences; University of Tokushima; Japan
| | - Keita Kageyama
- Institute for Genome Research; University of Tokushima; Japan
- Faculty of Pharmaceutical Sciences; University of Tokushima; Japan
| | - Kana Kuwahara
- Institute for Genome Research; University of Tokushima; Japan
- Faculty of Pharmaceutical Sciences; University of Tokushima; Japan
| | | | | | | | - Hiroshi Terada
- Faculty of Pharmaceutical Sciences; Niigata University of Pharmacy and Applied Life Sciences; Japan
| | - Yasuo Shinohara
- Institute for Genome Research; University of Tokushima; Japan
- Faculty of Pharmaceutical Sciences; University of Tokushima; Japan
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34
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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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35
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Hilgemann DW, Fine M, Linder ME, Jennings BC, Lin MJ. Massive endocytosis triggered by surface membrane palmitoylation under mitochondrial control in BHK fibroblasts. eLife 2013; 2:e01293. [PMID: 24282236 PMCID: PMC3839538 DOI: 10.7554/elife.01293] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Large Ca transients cause massive endocytosis (MEND) in BHK fibroblasts by nonclassical mechanisms. We present evidence that MEND depends on mitochondrial permeability transition pore (PTP) openings, followed by coenzyme A (CoA) release, acyl CoA synthesis, and membrane protein palmitoylation. MEND is blocked by inhibiting mitochondrial Ca uptake or PTP openings, depleting fatty acids, blocking acyl CoA synthesis, metabolizing CoA, or inhibiting palmitoylation. It is triggered by depolarizing mitochondria or promoting PTP openings. After mitochondrial MEND blockade, MEND is restored by cytoplasmic acyl CoA or CoA. MEND is blocked by siRNA knockdown of the plasmalemmal acyl transferase, DHHC5. When acyl CoA is abundant, transient H2O2 oxidative stress or PKC activation initiates MEND, but the immediate presence of H2O2 prevents MEND. The PTP inhibitor, NIM811, significantly increases plasmalemma in normally growing cells. Thus, the MEND pathway may contribute to constitutive as well as pathological plasmalemma turnover in dependence on mitochondrial stress signaling. DOI: http://dx.doi.org/10.7554/eLife.01293.001.
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Affiliation(s)
- Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States
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36
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Monteiro JP, Silva AM, Jurado AS, Oliveira PJ. Rapeseed oil-rich diet alters in vitro menadione and nimesulide hepatic mitochondrial toxicity. Food Chem Toxicol 2013; 60:479-87. [DOI: 10.1016/j.fct.2013.07.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 07/25/2013] [Accepted: 07/27/2013] [Indexed: 11/16/2022]
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Panov A, Orynbayeva Z. Bioenergetic and antiapoptotic properties of mitochondria from cultured human prostate cancer cell lines PC-3, DU145 and LNCaP. PLoS One 2013; 8:e72078. [PMID: 23951286 PMCID: PMC3738524 DOI: 10.1371/journal.pone.0072078] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/05/2013] [Indexed: 12/03/2022] Open
Abstract
The purpose of this work was to reveal the metabolic features of mitochondria that might be essential for inhibition of apoptotic potential in prostate cancer cells. We studied mitochondria isolated from normal prostate epithelial cells (PrEC), metastatic prostate cancer cell lines LNCaP, PC-3, DU145; and non-prostate cancer cells - human fibrosarcoma HT1080 cells; and normal human lymphoblastoid cells. PrEC cells contained 2 to 4 times less mitochondria per gram of cells than the three PC cell lines. Respiratory activities of PrEC cell mitochondria were 5-20-fold lower than PC mitochondria, depending on substrates and the metabolic state, due to lower content and lower activity of the respiratory enzyme complexes. Mitochondria from the three metastatic prostate cancer cell lines revealed several features that are distinctive only to these cells: low affinity of Complex I for NADH, 20-30 mV higher electrical membrane potential (ΔΨ). Unprotected with cyclosporine A (CsA) the PC-3 mitochondria required 4 times more Ca2+ to open the permeability transition pore (mPTP) when compared with the PrEC mitochondria, and they did not undergo swelling even in the presence of alamethicin, a large pore forming antibiotic. In the presence of CsA, the PC-3 mitochondria did not open spontaneously the mPTP. We conclude that the low apoptotic potential of the metastatic PC cells may arise from inhibition of the Ca2+-dependent permeability transition due to a very high ΔΨ and higher capacity to sequester Ca2+. We suggest that due to the high ΔΨ, mitochondrial metabolism of the metastatic prostate cancer cells is predominantly based on utilization of glutamate and glutamine, which may promote development of cachexia.
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Affiliation(s)
- Alexander Panov
- Institute of Molecular Biology and Biophysics, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk, Russia.
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38
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Bellum S, Thuett KA, Bawa B, Abbott LC. The effect of methylmercury exposure on behavior and cerebellar granule cell physiology in aged mice. J Appl Toxicol 2012; 33:959-69. [DOI: 10.1002/jat.2786] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 04/26/2012] [Accepted: 04/27/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Sairam Bellum
- Safety Assessment, Merck Research Laboratories; West Point; PA; 19486; USA
| | - Kerry A. Thuett
- ChemRisk; 101 2nd Street, Suite 700; San Francisco; CA; 94105; USA
| | - Bhupinder Bawa
- Department of Diagnostic Medicine/Pathology; Kansas State University, College of Veterinary Medicine; 101 Trotter Hall; Manhattan; KS; 66506-5601; USA
| | - Louise C. Abbott
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, 4458 TAMU; Texas A&M University; College Station; TX; 77843-4458; USA
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39
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Siyiannis VF, Protonotarios VE, Zechmann B, Chorianopoulou SN, Müller M, Hawkesford MJ, Bouranis DL. Comparative spatiotemporal analysis of root aerenchyma formation processes in maize due to sulphate, nitrate or phosphate deprivation. PROTOPLASMA 2012; 249:671-86. [PMID: 21870204 DOI: 10.1007/s00709-011-0309-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 07/28/2011] [Indexed: 05/07/2023]
Abstract
Nitrate (N), phosphate (P) or sulphate (S) deprivation causes aerenchyma formation in maize (Zea mays L.) nodal roots. The exact mechanisms that trigger the formation of aerenchyma under these circumstances are unclear. We have compared aerenchyma distribution across the nodal roots of first whorl (just emerging in 10-day-old seedlings), which were subject to S, N or P deprivation over a period of 10 days in connection with oxygen consumption, ATP concentration, cellulase and polygalacturonase activity in the whole root. The effect of deprivation on aerenchyma formation was examined using light and electron microscopy, along with in situ detection of calcium and of reactive oxygen species (ROS) by fluorescence microscopy. Aerenchyma was not found in the root base regardless of the deprivation. Programmed cell death (PCD) was observed near the root tip, either within the first two days (-N) or a few days later (-S, -P) of the treatment. Roots at day 6 under all three nutrient-deprived conditions showed signs of PCD 1 cm behind the cap, whereas only N-deprived root cells 0.5 cm behind the cap showed severe ultrastructural alterations, due to advanced PCD. The lower ATP concentration and the higher oxygen consumptions observed at day 2 in N-, P- and S-deprived roots compared to the control indicated that PCD may be triggered by perturbations in energy status of the root. The peaks of cellulase activity located between days 3 (-N) and 6 (-P), along with the respective alterations in polygalacturonase activity, indicated a coordination which preceded aerenchyma formation. ROS and calcium seemed to contribute to PCD initiation, with ROS possessing dual roles as signals and eliminators. All the examined parameters presented both common features and characteristic variations among the deprivations.
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Affiliation(s)
- Vassilis F Siyiannis
- Plant Physiology Laboratory, Plant Biology Department, Faculty of Agricultural Biotechnology, Agricultural University of Athens, 75 Iera Odos, 11855, Athens, Greece
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40
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Li K, Zhang W, Fang H, Xie W, Liu J, Zheng M, Wang X, Wang W, Tan W, Cheng H. Superoxide flashes reveal novel properties of mitochondrial reactive oxygen species excitability in cardiomyocytes. Biophys J 2012; 102:1011-21. [PMID: 22404923 DOI: 10.1016/j.bpj.2012.01.044] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 01/02/2012] [Accepted: 01/27/2012] [Indexed: 11/18/2022] Open
Abstract
Superoxide flash represents quantal and bursting production of mitochondrial reactive oxygen species (ROS) instigated by transient opening of the mitochondrial permeability transition pore (mPTP). Given their critical role in metabolism, ischemia-reperfusion injury, and apoptosis, characterization of flash properties would be valuable to further mechanistic and physiological studies of this newly discovered mitochondrial phenomenon. Here we developed the flash detector FlashSniper based on segmentation of two-dimensional feature maps extracted from time-lapse confocal image stacks, and on the theory for correcting optical distortion of flash-amplitude histograms. Through large-scale analysis of superoxide flashes in cardiomyocytes, we demonstrated uniform mitochondrial ROS excitability among subsarcolemmal and intermyofibrillar mitochondria, and exponential distribution of intervals between consecutive flash events. Flash ignition displayed three different patterns: an abrupt rise from quiescence (44%), a rise with an exponential foot (27%), or a rise occurring after a pedestal precursor (29%), closely resembling action-potential initiation in excitable cells. However, the optical blurring-corrected amplitudes of superoxide flashes were highly variable, as were their durations, indicating stochastic automaticity of single-mitochondrion ROS excitation. Simultaneous measurement of mitochondrial membrane potential revealed that graded, rather than all-or-none, depolarization mirrored the precursor and the primary peak of the flash. We propose that superoxide flash production is a regenerative process dominated by stochastic, autonomous recruitment of a limited number of units (e.g., mPTPs) in single mitochondria.
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Affiliation(s)
- Kaitao Li
- Institute of Molecular Medicine and State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Life Sciences, Peking University, Beijing, China
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41
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Chinopoulos C, Adam-Vizi V. Modulation of the mitochondrial permeability transition by cyclophilin D: moving closer to F(0)-F(1) ATP synthase? Mitochondrion 2012; 12:41-5. [PMID: 21586346 DOI: 10.1016/j.mito.2011.04.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 03/21/2011] [Accepted: 04/29/2011] [Indexed: 01/08/2023]
Abstract
Cyclophilin D was recently shown to mask an inhibitory site of the mitochondrial permeability transition pore (PTP) for phosphate, and to constitutively bind F(0)-F(1) ATP synthase resulting in the slowing of ATP synthesis and hydrolysis rates, thus regulating matrix adenine nucleotide levels. Here we review the striking similarities of the factors affecting the threshold for PTP induction, to those affecting binding of phosphate to formerly proposed sides on F(1)-ATPase affecting ATP hydrolytic activity, including critical arginine residues, matrix pH, [Mg(2+)], adenine nucleotides and proton motive force. Based on these similarities, we scrutinize the hypothesis that in depolarized mitochondria exhibiting reversal of F(0)-F(1) ATP synthase operation, the genetic ablation of cyclophilin D or its inhibition by cyclosporin A results in accelerated proton pumping by ATP hydrolysis, opposing a further decrease in membrane potential and promoting high matrix phosphate levels, both negatively affecting the probability of PTP opening.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
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Rabchevsky AG, Patel SP, Springer JE. Pharmacological interventions for spinal cord injury: where do we stand? How might we step forward? Pharmacol Ther 2011; 132:15-29. [PMID: 21605594 DOI: 10.1016/j.pharmthera.2011.05.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 04/28/2011] [Indexed: 12/15/2022]
Abstract
Despite numerous studies reporting some measures of efficacy in the animal literature, there are currently no effective therapies for the treatment of traumatic spinal cord injuries (SCI) in humans. The purpose of this review is to delineate key pathophysiological processes that contribute to neurological deficits after SCI, as well as to describe examples of pharmacological approaches that are currently being tested in clinical trials, or nearing clinical translation, for the therapeutic management of SCI. In particular, we will describe the mechanistic rationale to promote neuroprotection and/or functional recovery based on theoretical, yet targeted pathological events. Finally, we will consider the clinical relevancy for emerging evidence that pharmacologically targeting mitochondrial dysfunction following injury may hold the greatest potential for increasing tissue sparing and, consequently, the extent of functional recovery following traumatic SCI.
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Affiliation(s)
- Alexander G Rabchevsky
- Spinal Cord & Brain injury Research Center, Lexington, University of Kentucky, KY 40536-0509, USA.
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Chinopoulos C, Konràd C, Kiss G, Metelkin E, Töröcsik B, Zhang SF, Starkov AA. Modulation of F0F1-ATP synthase activity by cyclophilin D regulates matrix adenine nucleotide levels. FEBS J 2011; 278:1112-25. [PMID: 21281446 PMCID: PMC3062657 DOI: 10.1111/j.1742-4658.2011.08026.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyclophilin D was recently shown to bind to and decrease the activity of F(0)F(1)-ATP synthase in submitochondrial particles and permeabilized mitochondria [Giorgio V et al. (2009) J Biol Chem, 284, 33982-33988]. Cyclophilin D binding decreased both ATP synthesis and hydrolysis rates. In the present study, we reaffirm these findings by demonstrating that, in intact mouse liver mitochondria energized by ATP, the absence of cyclophilin D or the presence of cyclosporin A led to a decrease in the extent of uncoupler-induced depolarization. Accordingly, in substrate-energized mitochondria, an increase in F(0)F(1)-ATP synthase activity mediated by a relief of inhibition by cyclophilin D was evident in the form of slightly increased respiration rates during arsenolysis. However, the modulation of F(0)F(1)-ATP synthase by cyclophilin D did not increase the adenine nucleotide translocase (ANT)-mediated ATP efflux rate in energized mitochondria or the ATP influx rate in de-energized mitochondria. The lack of an effect of cyclophilin D on the ANT-mediated adenine nucleotide exchange rate was attributed to the ∼ 2.2-fold lower flux control coefficient of the F(0)F(1)-ATP synthase than that of ANT, as deduced from measurements of adenine nucleotide flux rates in intact mitochondria. These findings were further supported by a recent kinetic model of the mitochondrial phosphorylation system, suggesting that an ∼ 30% change in F(0)F(1)-ATP synthase activity in fully energized or fully de-energized mitochondria affects the ADP-ATP exchange rate mediated by the ANT in the range 1.38-1.7%. We conclude that, in mitochondria exhibiting intact inner membranes, the absence of cyclophilin D or the inhibition of its binding to F(0)F(1)-ATP synthase by cyclosporin A will affect only matrix adenine nucleotides levels.
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Affiliation(s)
- Christos Chinopoulos
- Weill Medical College Cornell University, New York, NY, 10021, USA
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Csaba Konràd
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Gergely Kiss
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | | | - Beata Töröcsik
- Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Steven F. Zhang
- Weill Medical College Cornell University, New York, NY, 10021, USA
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Doczi J, Turiák L, Vajda S, Mándi M, Töröcsik B, Gerencser AA, Kiss G, Konràd C, Adam-Vizi V, Chinopoulos C. Complex contribution of cyclophilin D to Ca2+-induced permeability transition in brain mitochondria, with relation to the bioenergetic state. J Biol Chem 2011; 286:6345-53. [PMID: 21173147 PMCID: PMC3057831 DOI: 10.1074/jbc.m110.196600] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/14/2010] [Indexed: 11/06/2022] Open
Abstract
Cyclophilin D (cypD)-deficient mice exhibit resistance to focal cerebral ischemia and to necrotic but not apoptotic stimuli. To address this disparity, we investigated isolated brain and in situ neuronal and astrocytic mitochondria from cypD-deficient and wild-type mice. Isolated mitochondria were challenged by high Ca(2+), and the effects of substrates and respiratory chain inhibitors were evaluated on permeability transition pore opening by light scatter. In situ neuronal and astrocytic mitochondria were visualized by mito-DsRed2 targeting and challenged by calcimycin, and the effects of glucose, NaCN, and an uncoupler were evaluated by measuring mitochondrial volume. In isolated mitochondria, Ca(2+) caused a large cypD-dependent change in light scatter in the absence of substrates that was insensitive to Ruthenium red or Ru360. Uniporter inhibitors only partially affected the entry of free Ca(2+) in the matrix. Inhibition of complex III/IV negated the effect of substrates, but inhibition of complex I was protective. Mitochondria within neurons and astrocytes exhibited cypD-independent swelling that was dramatically hastened when NaCN and 2-deoxyglucose were present in a glucose-free medium during calcimycin treatment. In the presence of an uncoupler, cypD-deficient astrocytic mitochondria performed better than wild-type mitochondria, whereas the opposite was observed in neurons. Neuronal mitochondria were examined further during glutamate-induced delayed Ca(2+) deregulation. CypD-knock-out mitochondria exhibited an absence or a delay in the onset of mitochondrial swelling after glutamate application. Apparently, some conditions involving deenergization render cypD an important modulator of PTP in the brain. These findings could explain why absence of cypD protects against necrotic (deenergized mitochondria), but not apoptotic (energized mitochondria) stimuli.
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Affiliation(s)
- Judit Doczi
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Lilla Turiák
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Szilvia Vajda
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Miklós Mándi
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Beata Töröcsik
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | | | - Gergely Kiss
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Csaba Konràd
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Vera Adam-Vizi
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
| | - Christos Chinopoulos
- From the Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary and
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Andriessen TMJC, Jacobs B, Vos PE. Clinical characteristics and pathophysiological mechanisms of focal and diffuse traumatic brain injury. J Cell Mol Med 2011; 14:2381-92. [PMID: 20738443 PMCID: PMC3823156 DOI: 10.1111/j.1582-4934.2010.01164.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Traumatic brain injury (TBI) is a frequent and clinically highly heterogeneous neurological disorder with large socioeconomic consequences. TBI severity classification, based on the hospital admission Glasgow Coma Scale (GCS) score, ranges from mild (GCS 13-15) and moderate (GCS 9-12) to severe (GCS ≤ 8). The GCS reflects the risk of dying from TBI, which is low after mild (∼1%), intermediate after moderate (up to 15%) and high (up to 40%) after severe TBI. Intracranial damage can be focal, such as epidural and subdural haematomas and parenchymal contusions, or diffuse, for example traumatic axonal injury and diffuse cerebral oedema, although this distinction is somewhat arbitrary. Study of the cellular and molecular post-traumatic processes is essential for the understanding of TBI pathophysiology but even more to find therapeutic targets for the development of neuroprotective drugs to be eventually used in human beings. To date, studies in vitro and in vivo, mainly in animals but also in human beings, are unravelling the pathological TBI mechanisms at high pace. Nevertheless, TBI pathophysiology is all but completely elucidated. Neuroprotective treatment studies in human beings have been disappointing thus far and have not resulted in commonly accepted drugs. This review presents an overview on the clinical aspects and the pathophysiology of focal and diffuse TBI, and it highlights several acknowledged important events that occur on molecular and cellular level after TBI.
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Hokari M, Kuroda S, Iwasaki Y. Pretreatment with the ciclosporin derivative NIM811 reduces delayed neuronal death in the hippocampus after transient forebrain ischaemia. J Pharm Pharmacol 2011; 62:485-90. [PMID: 20604838 DOI: 10.1211/jpp.62.04.0011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES There have been several previous studies showing that ciclosporin, a ligand for cyclophilin D (CypD), reduces mitochondrial permeability transition (mPT) and ameliorates delayed neuronal death. NIM811 is a non-immunosuppressive ciclosporin derivative that also inhibits mPT, but has significantly less cytotoxicity than ciclosporin. Actually, in animal experiments, several investigators have reported that NIM811 ameliorates central nervous system disorders, such as traumatic brain injury, transient focal cerebral ischaemia and spinal cord injury. Therefore, we evaluated whether the ciclosporin derivative, NIM811 reduces mPT and ameliorates delayed neuronal death in the hippocampal CA1 sectors in mice when subjected to transient forebrain ischaemia. METHODS Male C57BL/6 mice were treated with 50 mg/kg ciclosporin, 10, 50 or 100 mg/kg NIM811 or phosphate-buffered saline. At 30 min post-injection, all mice were subjected to 20 min bilateral common carotid artery occlusion (BCCAO). To estimate delayed neuronal death, the sections were prepared for HE staining and terminal deoxynucleotidyl transferase-mediated dUTP end-labelling (TUNEL) staining at 72 h after 20 min BCCAO. Furthermore, using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1) staining technique, we evaluated whether NIM811 (1, 10, 100 or 1000 microm) inhibited mPT in the neurons exposed to 100 microm glutamate. RESULTS Both delayed neuronal injury and apoptosis in the hippocampal CA1 sectors were significantly ameliorated at 72 h after transient forebrain ischaemia in the mice treated with 100 mg/kg NIM811 or 50 mg/kg ciclosporin. The treatments with 100 microm and 1,000 microm NIM811 significantly inhibited the reduction of mitochondrial membrane potential in the neurons exposed to 100 microm glutamate. CONCLUSIONS These findings strongly suggest that NIM811 inhibits mPT and ameliorates delayed neuronal death in mice subjected to transient forebrain ischaemia.
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Affiliation(s)
- Masaaki Hokari
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
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A pore way to die: the role of mitochondria in reperfusion injury and cardioprotection. Biochem Soc Trans 2010; 38:841-60. [DOI: 10.1042/bst0380841] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In addition to their normal physiological role in ATP production and metabolism, mitochondria exhibit a dark side mediated by the opening of a non-specific pore in the inner mitochondrial membrane. This mitochondrial permeability transition pore (MPTP) causes the mitochondria to breakdown rather than synthesize ATP and, if unrestrained, leads to necrotic cell death. The MPTP is opened in response to Ca2+ overload, especially when accompanied by oxidative stress, elevated phosphate concentration and adenine nucleotide depletion. These conditions are experienced by the heart and brain subjected to reperfusion after a period of ischaemia as may occur during treatment of a myocardial infarction or stroke and during heart surgery. In the present article, I review the properties, regulation and molecular composition of the MPTP. The evidence for the roles of CyP-D (cyclophilin D), the adenine nucleotide translocase and the phosphate carrier are summarized and other potential interactions with outer mitochondrial membrane proteins are discussed. I then review the evidence that MPTP opening mediates cardiac reperfusion injury and that MPTP inhibition is cardioprotective. Inhibition may involve direct pharmacological targeting of the MPTP, such as with cyclosporin A that binds to CyP-D, or indirect inhibition of MPTP opening such as with preconditioning protocols. These invoke complex signalling pathways to reduce oxidative stress and Ca2+ load. MPTP inhibition also protects against congestive heart failure in hypertensive animal models. Thus the MPTP is a very promising pharmacological target for clinical practice, especially once more specific drugs are developed.
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Bazil JN, Buzzard GT, Rundell AE. A bioenergetic model of the mitochondrial population undergoing permeability transition. J Theor Biol 2010; 265:672-90. [PMID: 20538008 DOI: 10.1016/j.jtbi.2010.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 05/11/2010] [Accepted: 06/01/2010] [Indexed: 11/30/2022]
Abstract
Mitochondrial permeability transition (MPT) is a highly regulated complex phenomenon that is a type of ischemia/reperfusion injury that can lead to cell death and ultimately organ dysfunction. A novel population transition and detailed permeability transition pore regulation model were integrated with an existing bioenergetics model to describe MPT induction under a variety of conditions. The framework of the MPT induction model includes the potential states of the mitochondria (aggregated, orthodox and post-transition), their transitions from one state to another as well as their interaction with the extra-mitochondrial environment. The model encodes the three basic necessary conditions for MPT: a high calcium load, alkaline matrix pH and circumstances which favor de-energization. The MPT induction model was able to reproduce the expected bioenergetic trends observed in a population of mitochondria subjected to conditions that favor MPT. The model was corroborated and used to predict that MPT in an acidic environment is mitigated by an increase in activity of the mitochondrial potassium/hydrogen exchanger. The model was also used to present the beneficial impact of reducing the duration mitochondria spend in the orthodox state on preserving the extra-mitochondrial ATP levels. The model serves as a tool for investigators to use to understand the MPT induction phenomenon, explore alternative hypotheses for PTP regulation, as well as identify endogenous pharmacological targets and evaluate potential therapeutics for MPT mitigation.
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Affiliation(s)
- Jason N Bazil
- Purdue University, Weldon School of Biomedical Engineering, 206 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
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Ron A, Fishelson N, Croitoru N, Shur I, Benayahu D, Shacham-Diamand Y. Examination of the induced potential gradients across inner and outer cellular interfaces in a realistic 3D cytoplasmic-embedded mitochondrion model. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2009.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Calderone V, Testai L, Martelli A, Rapposelli S, Digiacomo M, Balsamo A, Breschi MC. Anti-ischemic properties of a new spiro-cyclic benzopyran activator of the cardiac mito-KATP channel. Biochem Pharmacol 2010; 79:39-47. [DOI: 10.1016/j.bcp.2009.07.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 07/14/2009] [Accepted: 07/27/2009] [Indexed: 11/16/2022]
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