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Szabo I, Szewczyk A. Mitochondrial Ion Channels. Annu Rev Biophys 2023; 52:229-254. [PMID: 37159294 DOI: 10.1146/annurev-biophys-092622-094853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Mitochondria are involved in multiple cellular tasks, such as ATP synthesis, metabolism, metabolite and ion transport, regulation of apoptosis, inflammation, signaling, and inheritance of mitochondrial DNA. The majority of the correct functioning of mitochondria is based on the large electrochemical proton gradient, whose component, the inner mitochondrial membrane potential, is strictly controlled by ion transport through mitochondrial membranes. Consequently, mitochondrial function is critically dependent on ion homeostasis, the disturbance of which leads to abnormal cell functions. Therefore, the discovery of mitochondrial ion channels influencing ion permeability through the membrane has defined a new dimension of the function of ion channels in different cell types, mainly linked to the important tasks that mitochondrial ion channels perform in cell life and death. This review summarizes studies on animal mitochondrial ion channels with special focus on their biophysical properties, molecular identity, and regulation. Additionally, the potential of mitochondrial ion channels as therapeutic targets for several diseases is briefly discussed.
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Affiliation(s)
- Ildiko Szabo
- Department of Biology, University of Padova, Italy;
| | - Adam Szewczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland;
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2
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Boyenle ID, Oyedele AK, Ogunlana AT, Adeyemo AF, Oyelere FS, Akinola OB, Adelusi TI, Ehigie LO, Ehigie AF. Targeting the mitochondrial permeability transition pore for drug discovery: Challenges and opportunities. Mitochondrion 2022; 63:57-71. [PMID: 35077882 DOI: 10.1016/j.mito.2022.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/22/2021] [Accepted: 01/17/2022] [Indexed: 12/29/2022]
Abstract
Several drug targets have been amenable to drug discovery pursuit not until the characterization of the mitochondrial permeability transition pore (MPTP), a pore with an undefined molecular identity that forms on the inner mitochondrial membrane upon mitochondrial permeability transition (MPT) under the influence of calcium overload and oxidative stress. The opening of the pore which is presumed to cause cell death in certain human diseases also has implications under physiological parlance. Different models for this pore have been postulated following its first identification in the last six decades. The mitochondrial community has witnessed many protein candidates such as; voltage-dependent anion channel (VDAC), adenine nucleotide translocase (ANT), Mitochondrial phosphate carrier (PiC), Spastic Paralegin (SPG7), disordered proteins, and F1Fo ATPase. However, genetic studies have cast out most of these candidates with only F1Fo ATPase currently under intense argument. Cyclophilin D (CyPD) remains the widely accepted positive regulator of the MPTP known to date, but no drug candidate has emerged as its inhibitor, raising concern issues for therapeutics. Thus, in this review, we discuss various models of MPTP reported with the hope of stimulating further research in this field. We went beyond the classical description of the MPTP to ascribe a 'two-edged sword property' to the pore for therapeutic function in human disease because its inhibition and activation have pharmacological relevance. We suggested putative proteins upstream to CyPD that can regulate its activity and prevent cell deaths in neurodegenerative disease and ischemia-reperfusion injury.
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Affiliation(s)
- Ibrahim Damilare Boyenle
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria; Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Abdulquddus Kehinde Oyedele
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Abdeen Tunde Ogunlana
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Aishat Folashade Adeyemo
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | | | - Olateju Balikis Akinola
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Temitope Isaac Adelusi
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Leonard Ona Ehigie
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Adeola Folasade Ehigie
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
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Methods of Measuring Mitochondrial Potassium Channels: A Critical Assessment. Int J Mol Sci 2022; 23:ijms23031210. [PMID: 35163132 PMCID: PMC8835872 DOI: 10.3390/ijms23031210] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/22/2022] Open
Abstract
In this paper, the techniques used to study the function of mitochondrial potassium channels are critically reviewed. The majority of these techniques have been known for many years as a result of research on plasma membrane ion channels. Hence, in this review, we focus on the critical evaluation of techniques used in the studies of mitochondrial potassium channels, describing their advantages and limitations. Functional analysis of mitochondrial potassium channels in comparison to that of plasmalemmal channels presents additional experimental challenges. The reliability of functional studies of mitochondrial potassium channels is often affected by the need to isolate mitochondria and by functional properties of mitochondria such as respiration, metabolic activity, swelling capacity, or high electrical potential. Three types of techniques are critically evaluated: electrophysiological techniques, potassium flux measurements, and biochemical techniques related to potassium flux measurements. Finally, new possible approaches to the study of the function of mitochondrial potassium channels are presented. We hope that this review will assist researchers in selecting reliable methods for studying, e.g., the effects of drugs on mitochondrial potassium channel function. Additionally, this review should aid in the critical evaluation of the results reported in various articles on mitochondrial potassium channels.
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Kruglov AG, Kharechkina ES, Nikiforova AB, Odinokova IV, Kruglova SA. Dynamics of the permeability transition pore size in isolated mitochondria and mitoplasts. FASEB J 2021; 35:e21764. [PMID: 34245631 DOI: 10.1096/fj.202100596r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/28/2021] [Accepted: 06/14/2021] [Indexed: 11/11/2022]
Abstract
The size of the permeability transition pore (PTP) is accepted to be ≤1.5 kDa. However, different authors reported values from 650 to 4000 Da. The present study is focused on the variability of the average PTP size in and between mitochondrial samples, its reasons and relations with PTP dynamics. Measurement of PTP size by the standard method revealed its 500 Da-range variability between mitochondrial samples. Sequential measurements in the same sample showed that the PTP size tends to grow with time and Ca2+ concentration. Selective damage to the mitochondrial outer membrane (MOM) reduced the apparent PTP size by ~200-300 Da. Hypotonic and hypertonic osmotic shock and partial removal of the MOM with the preservation of the mitochondrial inner membrane intactness decreased the apparent PTP size by ~50%. We developed an approach to continuous monitoring of the PTP size that revealed the existence of stable PTP states with different pore sizes (~700, 900-1000, ~1350, 1700-1800, and 2100-2200 Da) and transitions between them. The transitions were accelerated by elevating the Ca2+ concentration, temperature, and osmotic pressure, which demonstrates an increased capability of PTP to accommodate to large molecules (plasticity). Cyclosporin A inhibited the transitions between states. The analysis of PTP size dynamics in osmotically shocked mitochondria and mitoplasts confirmed the importance of the MOM for the stabilization of PTP structure. Thus, this approach provides a new tool for PTP studies and the opportunity to reconcile data on the PTP size and mitochondrial megachannel conductance.
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Affiliation(s)
- Alexey G Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Ekaterina S Kharechkina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Irina V Odinokova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Svetlana A Kruglova
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia
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Kukes VG, Parfenova OK, Romanov BK, Prokofiev AB, Parfenova EV, Sidorov NG, Gazdanova AA, Pavlova LI, Zozina VI, Andreev AD, Aleksandrova TV, Chernova SV, Ramenskaya GV. The Mechanism of Action of Ethoxidol on Oxidative Stress Indices in Heart Failure and Hypotension. Sovrem Tekhnologii Med 2020; 12:67-72. [PMID: 34513055 PMCID: PMC8353682 DOI: 10.17691/stm2020.12.2.08] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Indexed: 11/14/2022] Open
Abstract
The aim of the investigation was to study the effect of 2-ethyl-6-methyl-3-hydroxypyridine malate (Ethoxidol) on the concentration of oxidative stress metabolites in patients with chronic heart failure (CHF) and hypertension. Materials and Methods 126 patients with FC I-III CHF have been examined. In addition to their individual therapy these patients received intravenous infusions of Ethoxidol. Blood content of 2,3-diphosphoglycerate (2,3-DPG), oxygen tension (рО2), pH, concentration of total peroxides, lactate, and aldosterone were identified. 2,3-DPG levels (g/L erythrocytes) in whole blood samples were determined by an enzyme assay using the reagent kit (Rosh, Germany), values of рО2, рСО2, рН, lactate in the venous blood were measured using gas analyzer Stat Profil pHOx Ultra (Nova Biomedical, USA). Indices of oxidative stress, i.e. the concentration of plasma total peroxides, were investigated by ELISA using OxyStat kit (Biomedica, Austria). Peripheral venous blood samples were collected from all patients before and 6 days after the daily intravenous Ethoxidol infusion. Results In patients with FC I, II, III CHF, on day 7 after intravenous Ethoxidol infusion at a dose of 100 mg/day, statistically significant growth (p=0.0002) of PaO2 level by 15.7, 17.4, and 22.8%, respectively, was noted. In patients with FC I, II, III CHF in the group receiving standard therapy, statistically significant (p=0.002) reduction of 2,3-DPG level by 2.7, 2.4, and 4.0%, respectively, was registered. On day 7 after the infusion of Ethoxidol at a dose of 100 mg/day, its decrease by 5.7, 10.5, and 26.2%, respectively (p<0.0001), was also observed. Conclusion The increased concentrations of active oxygen forms have been established to negatively affect various bodily functions and adversely influence the pathophysiology of numerous diseases. Application of antioxidants, including Ethoxidol presented by us in this article, may become a clue to the development of preventive measures for many serious diseases.
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Affiliation(s)
- V G Kukes
- Academician of the Russian Academy of Sciences, Professor, Department of Clinical Pharmacology and Propedeutics of Internal Diseases, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia; Head of the Scientific Direction "Pharmacology", Scientific Centre for Expert Evaluation of Medicinal Products of the Ministry of Health of the Russian Federation, 8, Bld. 2, Petrovsky Boulevard, Moscow, 127051, Russia
| | - O K Parfenova
- Student, A.P. Nelyubin Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - B K Romanov
- Deputy Director General on Scientific Work, Scientific Centre for Expert Evaluation of Medicinal Products of the Ministry of Health of the Russian Federation, 8, Bld. 2, Petrovsky Boulevard, Moscow, 127051, Russia
| | - A B Prokofiev
- Professor, Department of Clinical Pharmacology and Propedeutics of Internal Diseases, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia; Director of the Clinical Pharmacology Center, Scientific Centre for Expert Evaluation of Medicinal Products of the Ministry of Health of the Russian Federation, 8, Bld. 2, Petrovsky Boulevard, Moscow, 127051, Russia
| | - E V Parfenova
- Professor, Corresponding Member of the Russian Academy of Sciences, Deputy Director General, National Medical Research Center of Cardiology of the Ministry of Health of the Russian Federation, 15A 3 Cherepkovskaya St., Moscow, 121552, Russia; Director of the Institute of Experimental Cardiology, National Medical Research Center of Cardiology of the Ministry of Health of the Russian Federation, 15A 3 Cherepkovskaya St., Moscow, 121552, Russia
| | - N G Sidorov
- Student, A.P. Nelyubin Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - A A Gazdanova
- Associate Professor, Department of Clinical Pharmacology and Propedeutics of Internal Diseases, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - L I Pavlova
- Associate Professor, Department of Clinical Pharmacology and Propedeutics of Internal Diseases, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - V I Zozina
- PhD Student, Department of Clinical Pharmacology and Propedeutics of Internal Diseases, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - A D Andreev
- Student, Medical Faculty, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - T V Aleksandrova
- Senior Analyst, Scientific Centre for Expert Evaluation of Medicinal Products of the Ministry of Health of the Russian Federation, 8, Bld. 2, Petrovsky Boulevard, Moscow, 127051, Russia
| | - S V Chernova
- Associate Professor, Department of Pharmaceutical and Toxicological Chemistry named after A.P. Arzamastsev, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
| | - G V Ramenskaya
- Director, A.P. Nelyubin Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia; Head of the Department of Pharmaceutical and Toxicological Chemistry named after A.P. Arzamastsev, I.M. Sechenov First Moscow State Medical University (Sechenov University), 8/2 Malaya Trubetskaya St., Moscow, 119991, Russia
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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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7
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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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Gouriou Y, Demaurex N, Bijlenga P, De Marchi U. Mitochondrial calcium handling during ischemia-induced cell death in neurons. Biochimie 2011; 93:2060-7. [PMID: 21846486 DOI: 10.1016/j.biochi.2011.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/03/2011] [Indexed: 12/18/2022]
Abstract
Mitochondria sense and shape cytosolic Ca(2+) signals by taking up and subsequently releasing Ca(2+) ions during physiological and pathological Ca(2+) elevations. Sustained elevations in the mitochondrial matrix Ca(2+) concentration are increasingly recognized as a defining feature of the intracellular cascade of lethal events that occur in neurons during cerebral ischemia. Here, we review the recently identified transport proteins that mediate the fluxes of Ca(2+) across mitochondria and discuss the implication of the permeability transition pore in decoding the abnormally sustained mitochondrial Ca(2+) elevations that occur during cerebral ischemia.
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Affiliation(s)
- Yves Gouriou
- Department of Cell Physiology and Metabolism, University of Geneva, rue Michel-Servet 1, Genève, Switzerland
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Benzoquinone ansamycin 17AAG binds to mitochondrial voltage-dependent anion channel and inhibits cell invasion. Proc Natl Acad Sci U S A 2011; 108:4105-10. [PMID: 21368131 DOI: 10.1073/pnas.1015181108] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Geldanamycin and its derivative 17AAG [17-(Allylamino)-17-demethoxygeldanamycin, telatinib] bind selectively to the Hsp90 chaperone protein and inhibit its function. We discovered that these drugs associate with mitochondria, specifically to the mitochondrial membrane voltage-dependent anion channel (VDAC) via a hydrophobic interaction that is independent of HSP90. In vitro, 17AAG functions as a Ca(2+) mitochondrial regulator similar to benzoquinone-ubiquinones like Ub0. All of these compounds increase intracellular Ca(2+) and diminish the plasma membrane cationic current, inhibiting urokinase activity and cell invasion. In contrast, the HSP90 inhibitor radicicol, lacking a bezoquinone moiety, has no measurable effect on cationic current and is less effective in influencing intercellular Ca(2+) concentration. We conclude that some of the effects of 17-AAG and other ansamycins are due to their effects on VDAC and that this may play a role in their clinical activity.
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Zoratti M, De Marchi U, Biasutto L, Szabò I. Electrophysiology clarifies the megariddles of the mitochondrial permeability transition pore. FEBS Lett 2010; 584:1997-2004. [PMID: 20080089 DOI: 10.1016/j.febslet.2010.01.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/08/2010] [Accepted: 01/08/2010] [Indexed: 12/18/2022]
Abstract
After a brief review of the early history of mitochondrial electrophysiology, the contribution of this approach to the study of the mitochondrial permeability transition (MPT) is recapitulated. It has for example provided evidence for a dimeric nature of the MPT pore, allowed the distinction between two levels of control of its activity, and underscored the relevance of redox events for the phenomenon. Single-channel recording provides a means to finally solve the riddle of the biochemical entity underlying it by comparing the characteristics of the pore with those of channels formed by candidate molecules or complexes. The possibility that this entity may be the protein import machinery of the inner mitochondrial membrane is emphasized.
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De Marchi U, Biasutto L, Garbisa S, Toninello A, Zoratti M. Quercetin can act either as an inhibitor or an inducer of the mitochondrial permeability transition pore: A demonstration of the ambivalent redox character of polyphenols. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1425-32. [PMID: 19523917 DOI: 10.1016/j.bbabio.2009.06.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 05/29/2009] [Accepted: 06/01/2009] [Indexed: 01/08/2023]
Abstract
The Ca(2+)- and oxidative stress-induced mitochondrial permeability transition (MPT) plays an important role in phenomena ranging from tissue damage upon infarction to muscle wasting in some forms of dystrophy. The process is due to the activation of a large pore in the inner mitochondrial membrane. Anti-oxidants are considered a preventive and remedial tool, and mitochondria-targeted redox-active compounds have been developed. Plant polyphenols are generally considered as anti-oxidants, and thus candidates to the role of mitochondria-protecting agents. In patch-clamp experiments, easily oxidizable polyphenols induced closure of the MPT channel. In swelling experiments with suspensions of mitochondria, high (20-50 microM) concentrations of quercetin, the most efficient inhibitor, promoted instead the onset of the MPT. Chelators of Fe(2+/3+) and Cu(+/2+) ions counteracted this effect. Fluorescent indicators of superoxide production confirmed that quercetin potentiates O(2)(*-) generation by isolated mitochondria and cultured cells. Since this was not affected by chelating Fe and Cu ions, the MPT-inducing effect can be ascribed to a "secondary", metal ion-catalyzed production of ROS. These results are a direct demonstration of the ambivalent redox character of polyphenols. Their mode of action in vivo cannot be taken for granted, but needs to be experimentally verified.
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Affiliation(s)
- Umberto De Marchi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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12
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De Marchi U, Szabò I, Cereghetti GM, Hoxha P, Craigen WJ, Zoratti M. A maxi-chloride channel in the inner membrane of mammalian mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1438-48. [DOI: 10.1016/j.bbabio.2008.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 08/01/2008] [Accepted: 08/12/2008] [Indexed: 01/09/2023]
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13
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Neuzil J, Tomasetti M, Zhao Y, Dong LF, Birringer M, Wang XF, Low P, Wu K, Salvatore BA, Ralph SJ. Vitamin E analogs, a novel group of "mitocans," as anticancer agents: the importance of being redox-silent. Mol Pharmacol 2007; 71:1185-99. [PMID: 17220355 DOI: 10.1124/mol.106.030122] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The search for a selective and efficient anticancer agent for treating all neoplastic disease has yet to deliver a universally suitable compound(s). The majority of established anticancer drugs either are nonselective or lose their efficacy because of the constant mutational changes of malignant cells. Until recently, a largely neglected target for potential anticancer agents was the mitochondrion, showing a considerable promise for future clinical applications. Vitamin E (VE) analogs, epitomized by alpha-tocopheryl succinate, belong to the group of "mitocans" (mitochondrially targeted anticancer drugs). They are selective for malignant cells, cause destabilization of their mitochondria, and suppress cancer in preclinical models. This review focuses on our current understanding of VE analogs in the context of their proapoptotic/anticancer efficacy and suggests that their effect on mitochondria may be amplified by modulation of alternative pathways operating in parallel. We show here that the analogs of VE that cause apoptosis (which translates into their anticancer efficacy) generally do not possess antioxidant (redox) activity and are prototypical of the mitocan group of anticancer compounds. Therefore, by analogy to Oscar Wilde's play The Importance of Being Earnest, we use the motto in the title "the importance of being redox-silent" to emphasize an essentially novel paradigm for cancer therapy, in which redox-silence is a prerequisite property for most of the anticancer activities described in this communication.
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Affiliation(s)
- Jiri Neuzil
- Apoptosis Research Group, Heart Foundation Research Centre, School of Medical Science, Griffith University Gold Coast Campus, Southport, Queensland, Australia.
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Abstract
Decylubiquinone treatment in vitro has demonstrated a potent inhibitor effect on reactive oxidative species production. However, the effectin vivo has not been demonstrated yet. Thus, rats SHRSP male were divided in two groups: treated and controls (n=6, each). The treated group received 10 mg/Kg(-)/body weight of decylubiquinone diluted in coconut oil by oral gavage during four weeks. Control rats just received the vehicle. Body weight, diuresis, food and water intake, systolic blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, blood glucose levels and malondialdehyde were determined. There were a significant (p<0.05) reduction on systolic blood pressure, plasma malondialdehyde, total cholesterol and LDL-cholesterol in the treated group. Additionally, HDL-cholesterol also increased significantly. However, body weight, diuresis, food and water intake, blood glucose levels and triglycerides did not alter after treatment. Thus, decylubiquinone can be a new antihypertensive, hypolipidemic and antioxidant agent on the prevention and treatment of diseases linked to oxidative stress.
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Affiliation(s)
- Leonardo Borges Murad
- Laboratory of Nutritional Investigation and Degenerative-Chronic Diseases, Federal University of Rio de Janeiro State (UNIRIO), Rio de Janeiro (City), Brazil
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15
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De Marchi U, Basso E, Szabò I, Zoratti M. Electrophysiological characterization of the Cyclophilin D-deleted mitochondrial permeability transition pore. Mol Membr Biol 2006; 23:521-30. [PMID: 17127624 DOI: 10.1080/09687860600907644] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mitochondria isolated from engineered mice lacking Cyclophilin D (CypD), a component of the Permeability Transition Pore (PTP) complex, can still undergo a Ca2+ -dependent but Cyclosporin A-insensitive permeabilization of the inner membrane. Higher Ca2+ concentrations are required than for wild-type controls. The characteristics of the pore formed in this system were not known, and it has been proposed that they might differ substantially from those of the normal PTP. To test this hypothesis, we have characterized the PTP of isogenic wild-type and CypD- mouse liver mitochondria in patch clamp experiments, which allow biophysical characterization. The pores observed in the two cases, very similar to those of rat liver mitochondria, are indistinguishable according to a number of criteria. The only clear difference is in their sensitivity to Cyclosporin A. CypD is thus shown to be an auxiliary, modulatory component of the "standard" PTP, which forms and has essentially the same properties even in its absence. The observations suggest that Ca2+, CypD, and presumably other inducers and inhibitors act at the level of an activation or assembly process. Activation is separate and upstream of the gating observable on a short or medium-term time scale. Once the pore is activated, its molecular dynamics and biophysical properties may thus be predicted not to depend on the details of the induction process.
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Affiliation(s)
- Umberto De Marchi
- Department of Experimental Biomedical Sciences, University of Padova, Padova, Italy
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16
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Jacotot E, Deniaud A, Borgne-Sanchez A, Touat Z, Briand JP, Le Bras M, Brenner C. Therapeutic peptides: Targeting the mitochondrion to modulate apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1312-23. [PMID: 16928356 DOI: 10.1016/j.bbabio.2006.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/29/2006] [Accepted: 07/11/2006] [Indexed: 10/24/2022]
Abstract
For many years, medical drug discovery has extensively exploited peptides as lead compounds. Currently, novel structures of therapeutic peptides are derived from active pre-existing peptides or from high-throughput screening, and optimized following a rational drug design approach. Molecules of interest may prove their ability to influence the disease outcome in animal models and must respond to a set of criteria based on toxicity studies, ease of administration, the cost of their synthesis, and logistic for clinical use to validate it as a good candidate in a therapeutic perspective. This applies to the potential use of peptides to target one central intracellular organelle, the mitochondrion, to modulate (i.e. activate or prevent) apoptosis. Putative mitochondrial protein targets and the strategies already elaborated to correct the defects linked to these proteins (overexpression, inactivation, mutation..., etc.) are described, and recent advances that led or may lead to the conception of therapeutic peptides via a specific action on these mitochondrial targets in the future are discussed.
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Affiliation(s)
- Etienne Jacotot
- Theraptosis Research Laboratory, Theraptosis S A, Pasteur BioTop, 25-28 rue du Dr Roux, 75015, France
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17
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Campello S, De Marchi U, Szabò I, Tombola F, Martinou JC, Zoratti M. The properties of the mitochondrial megachannel in mitoplasts from human colon carcinoma cells are not influenced by Bax. FEBS Lett 2005; 579:3695-700. [PMID: 15963994 DOI: 10.1016/j.febslet.2005.05.055] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2005] [Revised: 05/25/2005] [Accepted: 05/25/2005] [Indexed: 01/13/2023]
Abstract
This paper explores the relationship between Bax and the mitochondrial permeability transition pore (PTP). Isolated human colon tumor (HCT116) Bax- mitochondria exposed to recombinant Bax exhibited a slow, cyclosporin A-sensitive swelling, but only at [Bax]>200 nM. The amount of Bax incorporated was much higher than that found in organelles isolated from HCT116 Bax+ staurosporine- or etoposide-treated apoptotic cells, casting doubts on the significance of the putative PT induction for apoptosis. Bax did not influence the electrophysiological properties of an approximately 1 nS channel ascribed to the Ca2+-dependent mitochondrial permeability transition pore. These observations indicate that the PTP is independent of Bax.
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Affiliation(s)
- Silvia Campello
- CNR Institute of Neuroscience, Biomembranes Section, Department of Biomedical Sciences, University of Padova, Viale Giuseppe Colombo 3, 35121 Padova, Italy
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18
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Baker SK, Tarnopolsky MA. Targeting cellular energy production in neurological disorders. Expert Opin Investig Drugs 2005; 12:1655-79. [PMID: 14519086 DOI: 10.1517/13543784.12.10.1655] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The concepts of energy dysregulation and oxidative stress and their complicated interdependence have rapidly evolved to assume primary importance in understanding the pathophysiology of numerous neurological disorders. Therefore, neuroprotective strategies addressing specific bioenergetic defects hold particular promise in the treatment of these conditions (i.e., amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease, Friedreich's ataxia, mitochondrial cytopathies and other neuromuscular diseases), all of which, to some extent, share 'the final common pathway' leading to cell death through either necrosis or apoptosis. Compounds such as creatine monohydrate and coenzyme Q(10) offer substantial neuroprotection against ischaemia, trauma, oxidative damage and neurotoxins. Miscellaneous agents, including alpha-lipoic acid, beta-OH-beta-methylbutyrate, riboflavin and nicotinamide, have also been shown to improve various metabolic parameters in brain and/or muscle. This review will highlight the biological function of each of the above mentioned compounds followed by a discussion of their utility in animal models and human neurological disease. The balance of this work will be comprised of discussions on the therapeutic applications of creatine and coenzyme Q(10).
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Affiliation(s)
- Steven K Baker
- Neurology and Rehabilitation, Room 4U4, Department of Medicine, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
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19
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Zoratti M, Szabò I, De Marchi U. Mitochondrial permeability transitions: how many doors to the house? BIOCHIMICA ET BIOPHYSICA ACTA 2005; 1706:40-52. [PMID: 15620364 DOI: 10.1016/j.bbabio.2004.10.006] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 12/18/2022]
Abstract
The inner mitochondrial membrane is famously impermeable to solutes not provided with a specific carrier. When this impermeability is lost, either in a developmental context or under stress, the consequences for the cell can be far-reaching. Permeabilization of isolated mitochondria, studied since the early days of the field, is often discussed as if it were a biochemically well-defined phenomenon, occurring by a unique mechanism. On the contrary, evidence has been accumulating that it may be the common outcome of several distinct processes, involving different proteins or protein complexes, depending on circumstances. A clear definition of this putative variety is a prerequisite for an understanding of mitochondrial permeabilization within cells, of its roles in the life of organisms, and of the possibilities for pharmacological intervention.
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Affiliation(s)
- Mario Zoratti
- CNR Institute of Neuroscience, Biomembranes Section, Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
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20
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Cesura AM, Pinard E, Schubenel R, Goetschy V, Friedlein A, Langen H, Polcic P, Forte MA, Bernardi P, Kemp JA. The voltage-dependent anion channel is the target for a new class of inhibitors of the mitochondrial permeability transition pore. J Biol Chem 2003; 278:49812-8. [PMID: 12952973 DOI: 10.1074/jbc.m304748200] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The relevance of the mitochondrial permeability transition pore (PTP) in Ca2+ homeostasis and cell death has gained wide attention. Yet, despite detailed functional characterization, the structure of this channel remains elusive. Here we report on a new class of inhibitors of the PTP and on the identification of their molecular target. The most potent among the compounds prepared, Ro 68-3400, inhibited PTP with a potency comparable to that of cyclosporin A. Since Ro 68-3400 has a reactive moiety capable of covalent modification of proteins, [3H]Ro 68-3400 was used as an affinity label for the identification of its protein target. In intact mitochondria isolated from rodent brain and liver and in SH-SY5Y human neuroblastoma cells, [3H]Ro 68-3400 predominantly labeled a protein of approximately 32 kDa. This protein was identified as the isoform 1 of the voltage-dependent anion channel (VDAC). Both functional and affinity labeling experiments indicated that VDAC might correspond to the site for the PTP inhibitor ubiquinone0, whereas other known PTP modulators acted at distinct sites. While Ro 68-3400 represents a new useful tool for the study of the structure and function of VDAC and the PTP, the results obtained provide direct evidence that VDAC1 is a component of this mitochondrial pore.
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Affiliation(s)
- Andrea M Cesura
- Pharmaceutical Division, Drug Discovery Department, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland.
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21
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Belyaeva EA, Korotkov SM. Mechanism of primary Cd2+-induced rat liver mitochondria dysfunction: discrete modes of Cd2+ action on calcium and thiol-dependent domains. Toxicol Appl Pharmacol 2003; 192:56-68. [PMID: 14554103 DOI: 10.1016/s0041-008x(03)00255-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We attempted to discern discrete sites of Cd2+ deleterious action on rat liver mitochondrial function. In particular, EGTA, ADP, and cyclosporin A (potent mitochondrial permeability transition antagonists) affected mainly Cd2+-induced changes in resting state respiration, eliminating its stimulation in KCl medium, while dithiothreitol (DTT, a dithiol reductant) produced its effect both on Cd2+ activation of the basal respiration and Cd2+ depression of uncoupler-stimulated respiration, evoking its restoration. Substantial differences in DTT influence on mitochondrial respiration at low and high [Cd2+] were revealed, namely, an enhanced mitochondrial permeabilization in the presence of saturated [DTT] at high [Cd2+] took place. Besides, DTT only partially reversed Cd2+-induced swelling in NH4NO3 medium when glutamate plus malate or succinate without rotenone was used. Contrarily, DTT produced complete reversal of the swelling of succinate-energized mitochondria when rotenone was present in the medium. In addition, in the presence of rotenone both Cd2+-produced activation of the resting state respiration in KCl medium and Cd2+-induced swelling in sucrose medium of succinate-energized mitochondria were more sensitive to cyclosporin A than the same Cd2+ effects obtained on mitochondria oxidizing succinate (without rotenone) or glutamate plus malate. We have concluded that Cd2+, producing primary mitochondrial dysfunction, acts both as a thiol and Me2+ binding site reagent. Suppositions about possible localization of separate sites of direct Cd2+ effects on mitochondrial function were made.
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Affiliation(s)
- Elena A Belyaeva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Thorez pr44, 194223, St. Petersburg, Russia.
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Abstract
Mitochondria are both morphologically and functionally diverse, and this variety is thought to have important biological ramifications. The development of methods to probe the properties of individual mitochondria is therefore of utmost importance. Recent advances have been made using in situ microscopy techniques and methods to investigate isolated mitochondria, including flow cytometry, capillary electrophoresis, patch-clamping and optical trapping. Such techniques have been used to study metabolism, mitochondrial calcium homeostasis, mitochondrial membrane potential, apoptosis, and other properties.
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Affiliation(s)
- Kathryn M Fuller
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
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