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Guven C, Taskin E, Aydın Ö, Kaya ST, Sevgiler Y. Diazoxide attenuates DOX-induced cardiotoxicity in cultured rat myocytes. Biotech Histochem 2024; 99:113-124. [PMID: 38439686 DOI: 10.1080/10520295.2024.2324368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024] Open
Abstract
Doxorubicin (DOX)-induced cardiotoxicity is a well known clinical problem, and many investigations have been made of its possible amelioration. We have investigated whether diazoxide (DIA), an agonist at mitochondrial ATP-sensitive potassium channels (mitoKATP), could reverse DOX-induced apoptotic myocardial cell loss, in cultured rat cardiomyocytes. The role of certain proteins in this pathway was also studied. The rat cardiomyocyte cell line (H9c2) was treated with DOX, and also co-treated with DOX and DIA, for 24 h. Distribution of actin filaments, mitochondrial membrane potential, superoxide dismutase (SOD) activity, total oxidant and antioxidant status (TOS and TAS, respectively), and some protein expressions, were assessed. DOX significantly decreased SOD activity, increased ERK1/2 protein levels, and depolarised the mitochondrial membrane, while DIA co-treatment inhibited such changes. DIA co-treatment ameliorated DOX-induced cytoskeletal changes via F-actin distribution and mitoKATP structure. Co-treatment also decreased ERK1/2 and cytochrome c protein levels. Cardiomyocyte loss due to oxidative stress-mediated apoptosis is a key event in DOX-induced cytotoxicity. DIA had protective effects on DOX-induced cardiotoxicity, via mitoKATP integrity, especially with elevated SUR2A levels; but also by a cascade including SOD/AMPK/ERK1/2. Therefore, DIA may be considered a candidate agent for protecting cardiomyocytes against DOX chemotherapy.
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Affiliation(s)
- Celal Guven
- Department of Biophysics, Faculty of Medicine, Adıyaman University, Adıyaman, Turkey
| | - Eylem Taskin
- Department of Physiology, Faculty of Medicine, Adıyaman University, Adıyaman, Turkey
| | - Özgül Aydın
- Department of Biology, Institute of Natural and Applied Sciences, Adıyaman University, Adıyaman, Turkey
| | - Salih Tunç Kaya
- Department of Biology, Faculty of Science and Letters, Düzce University, Düzce, Turkey
| | - Yusuf Sevgiler
- Department of Biology, Faculty of Science and Letters, Adıyaman University, Adıyaman, Turkey
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2
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Kharechkina ES, Nikiforova AB, Kruglov AG. Regulation of Mitochondrial Permeability Transition Pore Opening by Monovalent Cations in Liver Mitochondria. Int J Mol Sci 2023; 24:ijms24119237. [PMID: 37298189 DOI: 10.3390/ijms24119237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
The opening of the permeability transition pore (PTP) in mitochondria is a key event in the initiation of cell death in various pathologic states, including ischemia/reperfusion. The activation of K+ transport into mitochondria protects cells from ischemia/reperfusion. However, the role of K+ transport in PTP regulation is unclear. Here, we studied the role of K+ and other monovalent cations in the regulation of the PTP opening in an in vitro model. The registration of the PTP opening, membrane potential, Ca2+-retention capacity, matrix pH, and K+ transport was performed using standard spectral and electrode techniques. We found that the presence of all cations tested in the medium (K+, Na+, choline+, and Li+) strongly stimulated the PTP opening compared with sucrose. Several possible reasons for this were examined: the effect of ionic strength, the influx of cations through selective and non-selective channels and exchangers, the suppression of Ca2+/H+ exchange, and the influx of anions. The data obtained indicate that the mechanism of PTP stimulation by cations includes the suppression of K+/H+ exchange and acidification of the matrix, which facilitates the influx of phosphate. Thus, the K+/H+ exchanger and the phosphate carrier together with selective K+ channels compose a PTP regulatory triad, which might operate in vivo.
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Affiliation(s)
- Ekaterina S Kharechkina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
| | - Anna B Nikiforova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
| | - Alexey G Kruglov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya 3, Pushchino, 142290 Moscow, Russia
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3
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Kleinbongard P, Lieder H, Skyschally A, Heusch G. Diazoxide is a powerful cardioprotectant but is not feasible in a realistic infarct scenario. Front Cardiovasc Med 2023; 10:1173462. [PMID: 37153458 PMCID: PMC10154575 DOI: 10.3389/fcvm.2023.1173462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 03/31/2023] [Indexed: 05/09/2023] Open
Abstract
Introduction Diazoxide is a powerful cardioprotective agent that activates mitochondrial ATP-dependent K-channels and stimulates mitochondrial respiration. Diazoxide reduced infarct size in isolated rodent heart preparations and upon pretreatment in juvenile pigs with coronary occlusion/reperfusion. We aimed to study the use of diazoxide in a more realistic adult pig model of reperfused acute myocardial infarction when diazoxide was administered just before reperfusion. Methods and results In a first approach, we pretreated anaesthetised adult Göttingen minipigs with 7 mg kg-1 diazoxide (n = 5) or placebo (n = 5) intravenously over 10 min and subjected them to 60 min coronary occlusion and 180 min reperfusion; blood pressure was maintained by use of an aortic snare. The primary endpoint was infarct size (triphenyl tetrazolium chloride staining) as a fraction of area at risk; no-reflow area (thioflavin-S staining) was the secondary endpoint. In a second approach, diazoxide (n = 5) was given from 50 to 60 min coronary occlusion, and blood pressure was not maintained. There was a significant reduction in infarct size (22% ± 11% of area at risk with diazoxide pretreatment vs. 47% ± 11% with placebo) and area of no-reflow (14% ± 14% of infarct size with diazoxide pretreatment vs. 46% ± 20% with placebo). With diazoxide from 50 to 60 min coronary occlusion, however, there was marked hypotension, and infarct size (44% ± 7%) and area of no-reflow were not reduced (35% ± 25%). Conclusions Cardioprotection by diazoxide pretreatment was confirmed in adult pigs with reperfused acute myocardial infarction but is not feasible when diazoxide is administered in a more realistic scenario before reperfusion and causes hypotension.
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Wrzosek A, Gałecka S, Żochowska M, Olszewska A, Kulawiak B. Alternative Targets for Modulators of Mitochondrial Potassium Channels. Molecules 2022; 27:299. [PMID: 35011530 PMCID: PMC8746388 DOI: 10.3390/molecules27010299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.
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Affiliation(s)
- Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Shur Gałecka
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Monika Żochowska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Anna Olszewska
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211 Gdansk, Poland;
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
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5
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Goyal A, Agrawal N, Jain A, Gupta JK, Garabadu D. Role of caveolin-eNOS platform and mitochondrial ATP-sensitive potassium channel in abrogated cardioprotective effect of ischemic preconditioning in postmenopausal women. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e20081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
| | | | - Ankit Jain
- Dr. Hari Singh Gour Central University, India
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6
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Karagiannis A, Gallopin T, Lacroix A, Plaisier F, Piquet J, Geoffroy H, Hepp R, Naudé J, Le Gac B, Egger R, Lambolez B, Li D, Rossier J, Staiger JF, Imamura H, Seino S, Roeper J, Cauli B. Lactate is an energy substrate for rodent cortical neurons and enhances their firing activity. eLife 2021; 10:e71424. [PMID: 34766906 PMCID: PMC8651295 DOI: 10.7554/elife.71424] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Glucose is the mandatory fuel for the brain, yet the relative contribution of glucose and lactate for neuronal energy metabolism is unclear. We found that increased lactate, but not glucose concentration, enhances the spiking activity of neurons of the cerebral cortex. Enhanced spiking was dependent on ATP-sensitive potassium (KATP) channels formed with KCNJ11 and ABCC8 subunits, which we show are functionally expressed in most neocortical neuronal types. We also demonstrate the ability of cortical neurons to take-up and metabolize lactate. We further reveal that ATP is produced by cortical neurons largely via oxidative phosphorylation and only modestly by glycolysis. Our data demonstrate that in active neurons, lactate is preferred to glucose as an energy substrate, and that lactate metabolism shapes neuronal activity in the neocortex through KATP channels. Our results highlight the importance of metabolic crosstalk between neurons and astrocytes for brain function.
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Affiliation(s)
- Anastassios Karagiannis
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Thierry Gallopin
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Alexandre Lacroix
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Fabrice Plaisier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Juliette Piquet
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Hélène Geoffroy
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Régine Hepp
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jérémie Naudé
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Benjamin Le Gac
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Richard Egger
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bertrand Lambolez
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Dongdong Li
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jean Rossier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Göttingen, Georg-August- University GöttingenGoettingenGermany
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of MedicineHyogoJapan
| | - Jochen Roeper
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bruno Cauli
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
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7
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Abstract
Mitochondria have been recognized as key organelles in cardiac physiology and are potential targets for clinical interventions to improve cardiac function. Mitochondrial dysfunction has been accepted as a major contributor to the development of heart failure. The main function of mitochondria is to meet the high energy demands of the heart by oxidative metabolism. Ionic homeostasis in mitochondria directly regulates oxidative metabolism, and any disruption in ionic homeostasis causes mitochondrial dysfunction and eventually contractile failure. The mitochondrial ionic homeostasis is closely coupled with inner mitochondrial membrane potential. To regulate and maintain ionic homeostasis, mitochondrial membranes are equipped with ion transporting proteins. Ion transport mechanisms involving several different ion channels and transporters are highly efficient and dynamic, thus helping to maintain the ionic homeostasis of ions as well as their salts present in the mitochondrial matrix. In recent years, several novel proteins have been identified on the mitochondrial membranes and these proteins are actively being pursued in research for roles in the organ as well as organelle physiology. In this article, the role of mitochondrial ion channels in cardiac function is reviewed. In recent times, the major focus of the mitochondrial ion channel field is to establish molecular identities as well as assigning specific functions to them. Given the diversity of mitochondrial ion channels and their unique roles in cardiac function, they present novel and viable therapeutic targets for cardiac diseases.
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Affiliation(s)
- Harpreet Singh
- Department of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio
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8
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Kravenska Y, Checchetto V, Szabo I. Routes for Potassium Ions across Mitochondrial Membranes: A Biophysical Point of View with Special Focus on the ATP-Sensitive K + Channel. Biomolecules 2021; 11:1172. [PMID: 34439838 PMCID: PMC8393992 DOI: 10.3390/biom11081172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 12/18/2022] Open
Abstract
Potassium ions can cross both the outer and inner mitochondrial membranes by means of multiple routes. A few potassium-permeable ion channels exist in the outer membrane, while in the inner membrane, a multitude of different potassium-selective and potassium-permeable channels mediate K+ uptake into energized mitochondria. In contrast, potassium is exported from the matrix thanks to an H+/K+ exchanger whose molecular identity is still debated. Among the K+ channels of the inner mitochondrial membrane, the most widely studied is the ATP-dependent potassium channel, whose pharmacological activation protects cells against ischemic damage and neuronal injury. In this review, we briefly summarize and compare the different hypotheses regarding the molecular identity of this patho-physiologically relevant channel, taking into account the electrophysiological characteristics of the proposed components. In addition, we discuss the characteristics of the other channels sharing localization to both the plasma membrane and mitochondria.
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Affiliation(s)
| | | | - Ildiko Szabo
- Department of Biology, University of Padova, 35131 Padova, Italy; (Y.K.); (V.C.)
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9
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Morisaki Y, Nakagawa I, Ogawa Y, Yokoyama S, Furuta T, Saito Y, Nakase H. Ischemic Postconditioning Reduces NMDA Receptor Currents Through the Opening of the Mitochondrial Permeability Transition Pore and K ATP Channel in Mouse Neurons. Cell Mol Neurobiol 2020; 42:1079-1089. [PMID: 33159622 DOI: 10.1007/s10571-020-00996-y] [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: 07/25/2020] [Accepted: 11/03/2020] [Indexed: 11/29/2022]
Abstract
Ischemic postconditioning (PostC) is known to reduce cerebral ischemia/reperfusion (I/R) injury; however, whether the opening of mitochondrial ATP-dependent potassium (mito-KATP) channels and mitochondrial permeability transition pore (mPTP) cause the depolarization of the mitochondrial membrane that remains unknown. We examined the involvement of the mito-KATP channel and the mPTP in the PostC mechanism. Ischemic PostC consisted of three cycles of 15 s reperfusion and 15 s re-ischemia, and was started 30 s after the 7.5 min ischemic load. We recorded N-methyl-D-aspartate receptors (NMDAR)-mediated currents and measured cytosolic Ca2+ concentrations, and mitochondrial membrane potentials in mouse hippocampal pyramidal neurons. Both ischemic PostC and the application of a mito-KATP channel opener, diazoxide, reduced NMDAR-mediated currents, and suppressed cytosolic Ca2+ elevations during the early reperfusion period. An mPTP blocker, cyclosporine A, abolished the reducing effect of PostC on NMDAR currents. Furthermore, both ischemic PostC and the application of diazoxide potentiated the depolarization of the mitochondrial membrane potential. These results indicate that ischemic PostC suppresses Ca2+ influx into the cytoplasm by reducing NMDAR-mediated currents through mPTP opening. The present study suggests that depolarization of the mitochondrial membrane potential by opening of the mito-KATP channel is essential to the mechanism of PostC in neuroprotection against anoxic injury.
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Affiliation(s)
- Yudai Morisaki
- Department of Neurosurgery, Nara Medical University, Shijocho 840, Kashihara, Japan
| | - Ichiro Nakagawa
- Department of Neurosurgery, Nara Medical University, Shijocho 840, Kashihara, Japan.
| | - Yoichi Ogawa
- Department of Neurophysiology, Nara Medical University, Shijocho 840, Kashihara, Japan
| | - Shohei Yokoyama
- Department of Neurosurgery, Nara Medical University, Shijocho 840, Kashihara, Japan
| | - Takanori Furuta
- Department of Neurosurgery, Nara Medical University, Shijocho 840, Kashihara, Japan
| | - Yasuhiko Saito
- Department of Neurophysiology, Nara Medical University, Shijocho 840, Kashihara, Japan
| | - Hiroyuki Nakase
- Department of Neurosurgery, Nara Medical University, Shijocho 840, Kashihara, Japan
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10
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Wrzosek A, Augustynek B, Żochowska M, Szewczyk A. Mitochondrial Potassium Channels as Druggable Targets. Biomolecules 2020; 10:E1200. [PMID: 32824877 PMCID: PMC7466137 DOI: 10.3390/biom10081200] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/03/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial potassium channels have been described as important factors in cell pro-life and death phenomena. The activation of mitochondrial potassium channels, such as ATP-regulated or calcium-activated large conductance potassium channels, may have cytoprotective effects in cardiac or neuronal tissue. It has also been shown that inhibition of the mitochondrial Kv1.3 channel may lead to cancer cell death. Hence, in this paper, we examine the concept of the druggability of mitochondrial potassium channels. To what extent are mitochondrial potassium channels an important, novel, and promising drug target in various organs and tissues? The druggability of mitochondrial potassium channels will be discussed within the context of channel molecular identity, the specificity of potassium channel openers and inhibitors, and the unique regulatory properties of mitochondrial potassium channels. Future prospects of the druggability concept of mitochondrial potassium channels will be evaluated in this paper.
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Affiliation(s)
| | | | | | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (B.A.); (M.Ż.)
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11
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Signaling pathways targeting mitochondrial potassium channels. Int J Biochem Cell Biol 2020; 125:105792. [PMID: 32574707 DOI: 10.1016/j.biocel.2020.105792] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe key signaling pathways regulating potassium channels present in the inner mitochondrial membrane. The signaling cascades covered here include phosphorylation, redox reactions, modulation by calcium ions and nucleotides. The following types of potassium channels have been identified in the inner mitochondrial membrane of various tissues: ATP-sensitive, Ca2+-activated, voltage-gated and two-pore domain potassium channels. The direct roles of these channels involve regulation of mitochondrial respiration, membrane potential and synthesis of reactive oxygen species (ROS). Changes in channel activity lead to diverse pro-life and pro-death responses in different cell types. Hence, characterizing the signaling pathways regulating mitochondrial potassium channels will facilitate understanding the physiological role of these proteins. Additionally, we describe in this paper certain regulatory mechanisms, which are unique to mitochondrial potassium channels.
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12
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Akopova O, Kolchinskaya L, Nosar V, Mankovska I, Sagach V. Diazoxide affects mitochondrial bioenergetics by the opening of mKATP channel on submicromolar scale. BMC Mol Cell Biol 2020; 21:31. [PMID: 32306897 PMCID: PMC7168813 DOI: 10.1186/s12860-020-00275-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 04/07/2020] [Indexed: 12/21/2022] Open
Abstract
Background Cytoprotection afforded by mitochondrial ATP-sensitive K+-channel (mKATP-channel) opener diazoxide (DZ) largely depends on the activation of potassium cycle with eventual modulation of mitochondrial functions and ROS production. However, generally these effects were studied in the presence of Mg∙ATP known to block K+ transport. Thus, the purpose of our work was the estimation of DZ effects on K+ transport, K+ cycle and ROS production in rat liver mitochondria in the absence of Mg∙ATP. Results Without Mg·ATP, full activation of native mKATP-channel, accompanied by the increase in ATP-insensitive K+ uptake, activation of K+-cycle and respiratory uncoupling, was reached at ≤0.5 μM of DZ,. Higher diazoxide concentrations augmented ATP-insensitive K+ uptake, but not mKATP-channel activity. mKATP-channel was blocked by Mg·ATP, reactivated by DZ, and repeatedly blocked by mKATP-channel blockers glibenclamide and 5-hydroxydecanoate, whereas ATP-insensitive potassium transport was blocked by Mg2+ and was not restored by DZ. High sensitivity of potassium transport to DZ in native mitochondria resulted in suppression of mitochondrial ROS production caused by the activation of K+-cycle on sub-micromolar scale. Based on the oxygen consumption study, the share of mKATP-channel in respiratory uncoupling by DZ was found. Conclusions The study of mKATP-channel activation by diazoxide in the absence of MgATP discloses novel, not described earlier, aspects of mKATP-channel interaction with this drug. High sensitivity of mKATP-channel to DZ results in the modulation of mitochondrial functions and ROS production by DZ on sub-micromolar concentration scale. Our experiments led us to the hypothesis that under the conditions marked by ATP deficiency affinity of mKATP-channel to DZ can increase, which might contribute to the high effectiveness of this drug in cardio- and neuroprotection.
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Affiliation(s)
- Olga Akopova
- Circulation department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, Kiev, 01601, Ukraine.
| | - Liudmila Kolchinskaya
- Circulation department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, Kiev, 01601, Ukraine
| | - Valentina Nosar
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Iryna Mankovska
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Vadim Sagach
- Circulation department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, Kiev, 01601, Ukraine
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13
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Yokoyama S, Nakagawa I, Ogawa Y, Morisaki Y, Motoyama Y, Park YS, Saito Y, Nakase H. Ischemic postconditioning prevents surge of presynaptic glutamate release by activating mitochondrial ATP-dependent potassium channels in the mouse hippocampus. PLoS One 2019; 14:e0215104. [PMID: 30978206 PMCID: PMC6461229 DOI: 10.1371/journal.pone.0215104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/26/2019] [Indexed: 01/09/2023] Open
Abstract
A mild ischemic load applied after a lethal ischemic insult reduces the subsequent ischemia–reperfusion injury, and is called ischemic postconditioning (PostC). We studied the effect of ischemic PostC on synaptic glutamate release using a whole-cell patch-clamp technique. We recorded spontaneous excitatory post-synaptic currents (sEPSCs) from CA1 pyramidal cells in mouse hippocampal slices. The ischemic load was perfusion of artificial cerebrospinal fluid (ACSF) equilibrated with mixed gas (95% N2 and 5% CO2). The ischemic load was applied for 7.5 min, followed by ischemic PostC 30 s later, consisting of three cycles of 15 s of reperfusion and 15 s of re-ischemia. We found that a surging increase in sEPSCs frequency occurred during the immediate-early reperfusion period after the ischemic insult. We found a significant positive correlation between cumulative sEPSCs and the number of dead CA1 neurons (r = 0.70; p = 0.02). Ischemic PostC significantly suppressed this surge of sEPSCs. The mitochondrial KATP (mito-KATP) channel opener, diazoxide, also suppressed the surge of sEPSCs when applied for 15 min immediately after the ischemic load. The mito-KATP channel blocker, 5-hydroxydecanoate (5-HD), significantly attenuated the suppressive effect of both ischemic PostC and diazoxide application on the surge of sEPSCs. These results suggest that the opening of mito-KATP channels is involved in the suppressive effect of ischemic PostC on synaptic glutamate release and protection against neuronal death. We hypothesize that activation of mito-KATP channels prevents mitochondrial malfunction and breaks mutual facilitatory coupling between glutamate release and Ca2+ entry at presynaptic sites.
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Affiliation(s)
- Shohei Yokoyama
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
| | - Ichiro Nakagawa
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
- * E-mail:
| | - Yoichi Ogawa
- Department of Neurophysiology, Nara Medical University, Kashihara, Japan
| | - Yudai Morisaki
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
| | - Yasushi Motoyama
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
| | - Young Su Park
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
| | - Yasuhiko Saito
- Department of Neurophysiology, Nara Medical University, Kashihara, Japan
| | - Hiroyuki Nakase
- Department of Neurosurgery, Nara Medical University, Kashihara, Japan
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14
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TLR2-Dependent Reversible Oxidation of Connexin 43 at Cys260 Modifies Electrical Coupling After Experimental Myocardial Ischemia/Reperfusion. J Cardiovasc Transl Res 2019; 12:478-487. [DOI: 10.1007/s12265-019-09887-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/27/2019] [Indexed: 12/27/2022]
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15
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Ale-Agha N, Goy C, Jakobs P, Spyridopoulos I, Gonnissen S, Dyballa-Rukes N, Aufenvenne K, von Ameln F, Zurek M, Spannbrucker T, Eckermann O, Jakob S, Gorressen S, Abrams M, Grandoch M, Fischer JW, Köhrer K, Deenen R, Unfried K, Altschmied J, Haendeler J. CDKN1B/p27 is localized in mitochondria and improves respiration-dependent processes in the cardiovascular system-New mode of action for caffeine. PLoS Biol 2018; 16:e2004408. [PMID: 29927970 PMCID: PMC6013014 DOI: 10.1371/journal.pbio.2004408] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Abstract
We show that the cyclin-dependent kinase inhibitor 1B (CDKN1B)/p27, previously known as a cell cycle inhibitor, is also localized within mitochondria. The migratory capacity of endothelial cells, which need intact mitochondria, is completely dependent on mitochondrial p27. Mitochondrial p27 improves mitochondrial membrane potential, increases adenosine triphosphate (ATP) content, and is required for the promigratory effect of caffeine. Domain mapping of p27 revealed that the N-terminus and C-terminus are required for those improvements. Further analysis of those regions revealed that the translocation of p27 into the mitochondria and its promigratory activity depend on serine 10 and threonine 187. In addition, mitochondrial p27 protects cardiomyocytes against apoptosis. Moreover, mitochondrial p27 is necessary and sufficient for cardiac myofibroblast differentiation. In addition, p27 deficiency and aging decrease respiration in heart mitochondria. Caffeine does not increase respiration in p27-deficient animals, whereas aged mice display improvement after 10 days of caffeine in drinking water. Moreover, caffeine induces transcriptome changes in a p27-dependent manner, affecting mostly genes relevant for mitochondrial processes. Caffeine also reduces infarct size after myocardial infarction in prediabetic mice and increases mitochondrial p27. Our data characterize mitochondrial p27 as a common denominator that improves mitochondria-dependent processes and define an increase in mitochondrial p27 as a new mode of action of caffeine.
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Affiliation(s)
- Niloofar Ale-Agha
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Christine Goy
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Philipp Jakobs
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Ioakim Spyridopoulos
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stefanie Gonnissen
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Nadine Dyballa-Rukes
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Karin Aufenvenne
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Florian von Ameln
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Mark Zurek
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Tim Spannbrucker
- Environmentally-induced Skin and Lung Aging, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Olaf Eckermann
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Sascha Jakob
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Simone Gorressen
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Marcel Abrams
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Maria Grandoch
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Jens W. Fischer
- Institute for Pharmacology and Clinical Pharmacology, Medical Faculty, HHU Duesseldorf, Duesseldorf, Germany
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), HHU, Duesseldorf, Germany
| | - René Deenen
- Biological and Medical Research Center (BMFZ), HHU, Duesseldorf, Germany
| | - Klaus Unfried
- Environmentally-induced Skin and Lung Aging, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Joachim Altschmied
- Core Unit Biosafety Level 2 Laboratory, IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
| | - Judith Haendeler
- Heisenberg-group—Environmentally-induced Cardiovascular Degeneration, Medical Faculty, HHU Duesseldorf and IUF-Leibniz Research Institute for Environmental Medicine, Duesseldorf, Germany
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16
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Stowe DF, Yang M, Heisner JS, Camara AK. Endogenous and Agonist-induced Opening of Mitochondrial Big Versus Small Ca2+-sensitive K+ Channels on Cardiac Cell and Mitochondrial Protection. J Cardiovasc Pharmacol 2017; 70:314-328. [PMID: 28777255 PMCID: PMC5726766 DOI: 10.1097/fjc.0000000000000524] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Both big (BKCa) and small (SKCa) conductance Ca-sensitive K channels are present in mammalian cardiac cell mitochondria (m). We used pharmacological agonists and antagonists of BKCa and SKCa channels to examine the importance of endogenous opening of these channels and the relative contribution of either or both of these channels to protect against contractile dysfunction and reduce infarct size after ischemia reperfusion (IR) injury through a mitochondrial protective mechanism. After global cardiac IR injury of ex vivo perfused Guinea pig hearts, we found the following: both agonists NS1619 (for BKCa) and DCEB (for SKCa) improved contractility; BKCa antagonist paxilline (PAX) alone or with SKCa antagonist NS8593 worsened contractility and enhanced infarct size; both antagonists PAX and NS8593 obliterated protection by their respective agonists; BKCa and SKCa antagonists did not block protection afforded by SKCa and BKCa agonists, respectively; and all protective effects by the agonists were blocked by scavenging superoxide anions (O2) with Mn(III) tetrakis (4-benzoic acid) porphyrin (TBAP). Contractile function was inversely associated with global infarct size. In in vivo rats, infusion of NS8593, PAX, or both antagonists enhanced regional infarct size while infusion of either NS1619 or DCEB reduced infarct size. In cardiac mitochondria isolated from ex vivo hearts after IR, combined SKCa and BKCa agonists improved respiratory control index and Ca retention capacity compared with IR alone, whereas the combined antagonists did not alter respiratory control index but worsened Ca retention capacity. Although the differential protective bioenergetics effects of endogenous or exogenous BKCa and SKCa channel opening remain unclear, each channel likely responds to different sensing Ca concentrations and voltage gradients over time during oxidative stress-induced injury to individually or together protect cardiac mitochondria and myocytes.
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Affiliation(s)
- David F. Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
- Cardiovascular Center, The Medical College of Wisconsin, Milwaukee, WI, USA
- Research Service, Zablocki VA Medical Center, Milwaukee, WI, USA
| | - Meiying Yang
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - James S. Heisner
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Amadou K.S. Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Cardiovascular Center, The Medical College of Wisconsin, Milwaukee, WI, USA
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17
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Vishwakarma VK, Upadhyay PK, Gupta JK, Yadav HN. Pathophysiologic role of ischemia reperfusion injury: A review. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.jicc.2017.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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18
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Abstract
The pancreatic β-cell secretes insulin in response to elevated plasma glucose. This review applies an external bioenergetic critique to the central processes of glucose-stimulated insulin secretion, including glycolytic and mitochondrial metabolism, the cytosolic adenine nucleotide pool, and its interaction with plasma membrane ion channels. The control mechanisms responsible for the unique responsiveness of the cell to glucose availability are discussed from bioenergetic and metabolic control standpoints. The concept of coupling factor facilitation of secretion is critiqued, and an attempt is made to unravel the bioenergetic basis of the oscillatory mechanisms controlling secretion. The need to consider the physiological constraints operating in the intact cell is emphasized throughout. The aim is to provide a coherent pathway through an extensive, complex, and sometimes bewildering literature, particularly for those unfamiliar with the field.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Research on Aging, Novato, California; and Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmo, Sweden
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19
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Krishnathas R, Bonke E, Dröse S, Zickermann V, Nasiri HR. Identification of 4- N-[2-(4-phenoxyphenyl)ethyl]quinazoline-4,6-diamine as a novel, highly potent and specific inhibitor of mitochondrial complex I. MEDCHEMCOMM 2017; 8:657-661. [PMID: 30108783 DOI: 10.1039/c6md00655h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 02/17/2017] [Indexed: 12/21/2022]
Abstract
By probing the quinone substrate binding site of mitochondrial complex I with a focused set of quinazoline-based compounds, we identified substitution patterns as being critical for the observed inhibition. The structure activity relationship study also resulted in the discovery of the quinazoline 4-N-[2-(4-phenoxyphenyl)ethyl]quinazoline-4,6-diamine (EVP4593) as a highly potent inhibitor of the multisubunit membrane protein. EVP4593 specifically and effectively reduces the mitochondrial complex I-dependent respiration with no effect on the respiratory chain complexes II-IV. Similar to established Q-site inhibitors, EVP4593 elicits the release of reactive oxygen species at the flavin site of mitochondrial complex I. Recently, EVP4593 was nominated as a lead compound for the treatment of Huntingtons disease. Our results challenge the postulated primary mode-of-action of EVP4593 as an inhibitor of NF-κB pathway activation and/or store-operated calcium influx.
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Affiliation(s)
- Robin Krishnathas
- Johann Wolfgang Goethe-University Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Erik Bonke
- Department of Anaesthesiology , Intensive-Care Medicine and Pain Therapy , University Hospital Frankfurt , 60590 Frankfurt am Main , Germany
| | - Stefan Dröse
- Department of Anaesthesiology , Intensive-Care Medicine and Pain Therapy , University Hospital Frankfurt , 60590 Frankfurt am Main , Germany
| | - Volker Zickermann
- Structural Bioenergetics Group , Institute of Biochemistry II , Medical School , Goethe-University , 60438 Frankfurt am Main , Germany.,Cluster of Excellence Frankfurt "Macromolecular Complexes," , Goethe-University , 60438 Frankfurt am Main , Germany
| | - Hamid R Nasiri
- Johann Wolfgang Goethe-University Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
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20
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Bonke E, Siebels I, Zwicker K, Dröse S. Manganese ions enhance mitochondrial H 2O 2 emission from Krebs cycle oxidoreductases by inducing permeability transition. Free Radic Biol Med 2016; 99:43-53. [PMID: 27474449 DOI: 10.1016/j.freeradbiomed.2016.07.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/21/2016] [Accepted: 07/25/2016] [Indexed: 11/24/2022]
Abstract
Manganese-induced toxicity has been linked to mitochondrial dysfunction and an increased generation of reactive oxygen species (ROS). We could recently show in mechanistic studies that Mn2+ ions induce hydrogen peroxide (H2O2) production from the ubiquinone binding site of mitochondrial complex II (IIQ) and generally enhance H2O2 formation by accelerating the rate of superoxide dismutation. The present study with intact mitochondria reveals that manganese additionally enhances H2O2 emission by inducing mitochondrial permeability transition (mPT). In mitochondria fed by NADH-generating substrates, the combination of Mn2+ and different respiratory chain inhibitors led to a dynamically increasing H2O2emission which was sensitive to the mPT inhibitor cyclosporine A (CsA) as well as Ru-360, an inhibitor of the mitochondrial calcium uniporter (MCU). Under these conditions, flavin-containing enzymes of the mitochondrial matrix, e.g. the mitochondrial 2-oxoglutaratedehydrogenase (OGDH), were major sources of ROS. With succinate as substrate, Mn2+ stimulated ROS production mainly at complex II, whereby the applied succinate concentration had a marked effect on the tendency for mPT. Also Ca2+ increased the rate of H2O2 emission by mPT, while no direct effect on ROS-production of complex II was observed. The present study reveals a complex scenario through which manganese affects mitochondrial H2O2 emission: stimulating its production from distinct sites (e.g. site IIQ), accelerating superoxide dismutation and enhancing the emission via mPT which also leads to the loss of soluble components of the mitochondrial antioxidant systems and favors the ROS production from flavin-containing oxidoreductases of the Krebs cycle.
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Affiliation(s)
- Erik Bonke
- Department of Anesthesiology, Intensive-Care Medicine and Pain Therapy, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany
| | - Ilka Siebels
- Department of Anesthesiology, Intensive-Care Medicine and Pain Therapy, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany
| | - Klaus Zwicker
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Stefan Dröse
- Department of Anesthesiology, Intensive-Care Medicine and Pain Therapy, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany.
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21
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Onukwufor JO, Stevens D, Kamunde C. Bioenergetic and volume regulatory effects of mitoKATP channel modulators protect against hypoxia-reoxygenation-induced mitochondrial dysfunction. ACTA ACUST UNITED AC 2016; 219:2743-51. [PMID: 27358470 DOI: 10.1242/jeb.140186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/26/2016] [Indexed: 12/19/2022]
Abstract
The mitochondrial ATP-sensitive K(+) (mitoKATP) channel plays a significant role in mitochondrial physiology and protects against ischemic reperfusion injury in mammals. Although fish frequently face oxygen fluctuations in their environment, the role of the mitoKATP channel in regulating the responses to oxygen stress is rarely investigated in this class of animals. To elucidate whether and how the mitoKATP channel protects against hypoxia-reoxygenation (H-R)-induced mitochondrial dysfunction in fish, we first determined the mitochondrial bioenergetic effects of two key modulators of the channel, diazoxide and 5-hydroxydecanoate (5-HD), using a wide range of doses. Subsequently, the effects of low and high doses of the modulators on mitochondrial bioenergetics and volume under normoxia and after H-R using buffers with and without magnesium and ATP (Mg-ATP) were tested. In the absence of Mg-ATP (mitoKATP channel open), both low and high doses of diazoxide improved mitochondrial coupling, but only the high dose of 5-HD reversed the post-H-R coupling-enhancing effect of diazoxide. In the presence of Mg-ATP (mitoKATP channel closed), diazoxide at the low dose improved coupling post-H-R, and this effect was abolished by 5-HD at the low dose. Interestingly, both low and high doses of diazoxide reversed H-R-induced swelling under mitoKATP channel open conditions, but this effect was not sensitive to 5-HD. Under mitoKATP channel closed conditions, diazoxide at the low dose protected the mitochondria from H-R-induced swelling and 5-HD at the low dose reversed this effect. In contrast, diazoxide at the high dose failed to reduce the swelling caused by H-R, and the addition of the high dose of 5-HD enhanced mitochondrial swelling. Overall, our study showed that in the presence of Mg-ATP, both opening of mitoKATP channels and bioenergetic effects of diazoxide were protective against H-R in fish mitochondria, while in the absence of Mg-ATP only the bioenergetic effect of diazoxide was protective.
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Affiliation(s)
- John O Onukwufor
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Don Stevens
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Collins Kamunde
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
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22
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Laskowski M, Augustynek B, Kulawiak B, Koprowski P, Bednarczyk P, Jarmuszkiewicz W, Szewczyk A. What do we not know about mitochondrial potassium channels? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1247-1257. [PMID: 26951942 DOI: 10.1016/j.bbabio.2016.03.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 01/14/2023]
Abstract
In this review, we summarize our knowledge about mitochondrial potassium channels, with a special focus on unanswered questions in this field. The following potassium channels have been well described in the inner mitochondrial membrane: ATP-regulated potassium channel, Ca(2+)-activated potassium channel, the voltage-gated Kv1.3 potassium channel, and the two-pore domain TASK-3 potassium channel. The primary functional roles of these channels include regulation of mitochondrial respiration and the alteration of membrane potential. Additionally, they modulate the mitochondrial matrix volume and the synthesis of reactive oxygen species by mitochondria. Mitochondrial potassium channels are believed to contribute to cytoprotection and cell death. In this paper, we discuss fundamental issues concerning mitochondrial potassium channels: their molecular identity, channel pharmacology and functional properties. Attention will be given to the current problems present in our understanding of the nature of mitochondrial potassium channels. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Michał Laskowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bartłomiej Augustynek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences - SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland
| | - Wieslawa Jarmuszkiewicz
- Laboratory of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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23
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Petruş A, Duicu OM, Sturza A, Noveanu L, Kiss L, Dănilă M, Baczkó I, Muntean DM, Jost N. Modulation of mitochondrial respiratory function and ROS production by novel benzopyran analogues. Can J Physiol Pharmacol 2015; 93:811-8. [DOI: 10.1139/cjpp-2015-0041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A substantial body of evidence indicates that pharmacological activation of mitochondrial ATP-sensitive potassium channels (mKATP) in the heart is protective in conditions associated with ischemia/reperfusion injury. Several mechanisms have been postulated to be responsible for cardioprotection, including the modulation of mitochondrial respiratory function. The aim of the present study was to characterize the dose-dependent effects of novel synthetic benzopyran analogues, derived from a BMS-191095, a selective mKATP opener, on mitochondrial respiration and reactive oxygen species (ROS) production in isolated rat heart mitochondria. Mitochondrial respiratory function was assessed by high-resolution respirometry, and H2O2 production was measured by the Amplex Red fluorescence assay. Four compounds, namely KL-1487, KL-1492, KL-1495, and KL-1507, applied in increasing concentrations (50, 75, 100, and 150 μmol/L, respectively) were investigated. When added in the last two concentrations, all compounds significantly increased State 2 and 4 respiratory rates, an effect that was not abolished by 5-hydroxydecanoate (5-HD, 100 μmol/L), the classic mKATP inhibitor. The highest concentration also elicited an important decrease of the oxidative phosphorylation in a K+ independent manner. Both concentrations of 100 and 150 μmol/L for KL-1487, KL-1492, and KL-1495, and the concentration of 150 μmol/L for KL-1507, respectively, mitigated the mitochondrial H2O2 release. In isolated rat heart mitochondria, the novel benzopyran analogues act as protonophoric uncouplers of oxidative phosphorylation and decrease the generation of reactive oxygen species in a dose-dependent manner.
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Affiliation(s)
- Alexandra Petruş
- Department of Pathophysiology, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, 14, Tudor Vladimirescu st. 300173 Timisoara, Romania
| | - Oana M. Duicu
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
| | - Adrian Sturza
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
| | - Lavinia Noveanu
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
| | - Loránd Kiss
- Institute of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Szeged, Szeged, Hungary
| | - Maria Dănilă
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
| | - István Baczkó
- Department of Pathophysiology, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, 14, Tudor Vladimirescu st. 300173 Timisoara, Romania
| | - Danina M. Muntean
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
| | - Norbert Jost
- Department of Pathophysiology, Center for Translational Research and Systems Medicine, “Victor Babeş” University of Medicine and Pharmacy of Timişoara, Romania
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24
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Bonke E, Zwicker K, Dröse S. Manganese ions induce H2O2 generation at the ubiquinone binding site of mitochondrial complex II. Arch Biochem Biophys 2015; 580:75-83. [DOI: 10.1016/j.abb.2015.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 12/28/2022]
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25
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Bleier L, Wittig I, Heide H, Steger M, Brandt U, Dröse S. Generator-specific targets of mitochondrial reactive oxygen species. Free Radic Biol Med 2015; 78:1-10. [PMID: 25451644 DOI: 10.1016/j.freeradbiomed.2014.10.511] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
To understand the role of reactive oxygen species (ROS) in oxidative stress and redox signaling it is necessary to link their site of generation to the oxidative modification of specific targets. Here we have studied the selective modification of protein thiols by mitochondrial ROS that have been implicated as deleterious agents in a number of degenerative diseases and in the process of biological aging, but also as important players in cellular signal transduction. We hypothesized that this bipartite role might be based on different generator sites for "signaling" and "damaging" ROS and a directed release into different mitochondrial compartments. Because two main mitochondrial ROS generators, complex I (NADH:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc1 complex), are known to predominantly release superoxide and the derived hydrogen peroxide (H2O2) into the mitochondrial matrix and the intermembrane space, respectively, we investigated whether these ROS generators selectively oxidize specific protein thiols. We used redox fluorescence difference gel electrophoresis analysis to identify redox-sensitive targets in the mitochondrial proteome of intact rat heart mitochondria. We observed that the modified target proteins were distinctly different when complex I or complex III was employed as the source of ROS. These proteins are potential targets involved in mitochondrial redox signaling and may serve as biomarkers to study the generator-dependent dual role of mitochondrial ROS in redox signaling and oxidative stress.
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Affiliation(s)
- Lea Bleier
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Ilka Wittig
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Functional Proteomics, SFB815 Core Unit, Medical School, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Heinrich Heide
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Mirco Steger
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Ulrich Brandt
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Cluster of Excellence Frankfurt "Macromolecular Complexes," Goethe-University, D-60590 Frankfurt am Main, Germany; Radboud University Medical Center, Nijmegen Center for Mitochondrial Disorders, 6500 GA Nijmegen, The Netherlands
| | - Stefan Dröse
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Clinic of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Goethe-University Hospital, Frankfurt am Main, Germany.
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26
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Alleman RJ, Katunga LA, Nelson MAM, Brown DA, Anderson EJ. The "Goldilocks Zone" from a redox perspective-Adaptive vs. deleterious responses to oxidative stress in striated muscle. Front Physiol 2014; 5:358. [PMID: 25278906 PMCID: PMC4166897 DOI: 10.3389/fphys.2014.00358] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/02/2014] [Indexed: 01/17/2023] Open
Abstract
Consequences of oxidative stress may be beneficial or detrimental in physiological systems. An organ system's position on the “hormetic curve” is governed by the source and temporality of reactive oxygen species (ROS) production, proximity of ROS to moieties most susceptible to damage, and the capacity of the endogenous cellular ROS scavenging mechanisms. Most importantly, the resilience of the tissue (the capacity to recover from damage) is a decisive factor, and this is reflected in the disparate response to ROS in cardiac and skeletal muscle. In myocytes, a high oxidative capacity invariably results in a significant ROS burden which in homeostasis, is rapidly neutralized by the robust antioxidant network. The up-regulation of key pathways in the antioxidant network is a central component of the hormetic response to ROS. Despite such adaptations, persistent oxidative stress over an extended time-frame (e.g., months to years) inevitably leads to cumulative damages, maladaptation and ultimately the pathogenesis of chronic diseases. Indeed, persistent oxidative stress in heart and skeletal muscle has been repeatedly demonstrated to have causal roles in the etiology of heart disease and insulin resistance, respectively. Deciphering the mechanisms that underlie the divergence between adaptive and maladaptive responses to oxidative stress remains an active area of research for basic scientists and clinicians alike, as this would undoubtedly lead to novel therapeutic approaches. Here, we provide an overview of major types of ROS in striated muscle and the divergent adaptations that occur in response to them. Emphasis is placed on highlighting newly uncovered areas of research on this topic, with particular focus on the mitochondria, and the diverging roles that ROS play in muscle health (e.g., exercise or preconditioning) and disease (e.g., cardiomyopathy, ischemia, metabolic syndrome).
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Affiliation(s)
- Rick J Alleman
- Departments of Physiology, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, East Carolina University Greenville, NC, USA
| | - Lalage A Katunga
- East Carolina Diabetes and Obesity Institute, East Carolina University Greenville, NC, USA ; Pharmacology and Toxicology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Margaret A M Nelson
- East Carolina Diabetes and Obesity Institute, East Carolina University Greenville, NC, USA ; Pharmacology and Toxicology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - David A Brown
- Departments of Physiology, East Carolina University Greenville, NC, USA ; East Carolina Diabetes and Obesity Institute, East Carolina University Greenville, NC, USA
| | - Ethan J Anderson
- East Carolina Diabetes and Obesity Institute, East Carolina University Greenville, NC, USA ; Pharmacology and Toxicology, Brody School of Medicine, East Carolina University Greenville, NC, USA
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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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Shin BS, Kim HG, Choi OH. Mitochondrial Channel Opener Diazoxide Attenuates Hypoxia-Induced sFlt-1 Release in Human Choriocarcinoma Cells. J Menopausal Med 2014; 20:21-31. [PMID: 25371888 PMCID: PMC4217563 DOI: 10.6118/jmm.2014.20.1.21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 11/16/2022] Open
Abstract
Objectives To examine the effect of diazoxide on hypoxia-induced soluble fms-like tyrosin kinase-1 (sFlt-1) release in JEG-3 choriocarcinoma cells. Methods Cells were cultured under normoxia (20% O2) or hypoxia (1% O2), and expression of sFlt-1 mRNA and protein release was determined by quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) assays and enzyme-linked immunosorbent assay (ELISA). Results Tumor necrosis factor-alpha (TNF-α) as well as hypoxia stimulated sFlt-1 release and diazoxide inhibited both of them. The selective inhibitor of mitochondrial adenosine triphosphat (ATP)-sensitive K+ channel opener (KATP) 5-hydroxydecanoate (5-HD) completely reversed the diazoxide-induced inhibition of hypoxia-stimulated sFlt-1 release. qRT-PCR and Western blot analyses showed that diazoxide up-regulated the heme oxygenase-1 (HO-1) expression. In addition, the HO-1 inducer cobalt protoporphyrin (CoPP) and the metabolic product of HO-1 bilirubin mimicked diazoxide to inhibit sFlt-1 release and reactive oxygen species (ROS) production under hypoxia, whereas the HO-1 inhibitor zinc protoporphyrin IX (ZnPP IX) antagonized the effect of diazoxide. In cells transfected with the HO-1 siRNA, diazoxide did not exert any effect on sFlt-1 release and ROS production under hypoxia. Conclusion These results, taken together, strongly suggest that up-regulation of the HO-1 expression is the crucial mechanism responsible for the diazoxide-induced inhibition of the sFlt-1 release and ROS production under hypoxia.
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Affiliation(s)
- Byeong Seop Shin
- Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Busan, Korea
| | - Hwi Gon Kim
- Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Busan, Korea
| | - Ook Hwan Choi
- Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Busan, Korea
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29
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Slocinska M, Lubawy J, Jarmuszkiewicz W, Rosinski G. Evidences for an ATP-sensitive potassium channel (KATP) in muscle and fat body mitochondria of insect. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:1125-1132. [PMID: 23973818 DOI: 10.1016/j.jinsphys.2013.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/08/2013] [Accepted: 08/13/2013] [Indexed: 06/02/2023]
Abstract
In the present study, we describe the existence of mitochondrial ATP-dependent K(+) channel (mitoKATP) in two different insect tissues, fat body and muscle of cockroach Gromphadorhina coquereliana. We found that pharmacological substances known to modulate potassium channel activity influenced mitochondrial resting respiration. In isolated mitochondria oxygen consumption increased by about 13% in the presence of potassium channel openers (KCOs) such as diazoxide and pinacidil. The opening of mitoKATP was reversed by glibenclamide (potassium channel blocker) and 1 mM ATP. Immunological studies with antibodies raised against the Kir6.1 and SUR1 subunits of the mammalian ATP-sensitive potassium channel, indicated the existence of mitoKATP in insect mitochondria. MitoKATP activation by KCOs resulted in a decrease in superoxide anion production, suggesting that protection against mitochondrial oxidative stress may be a physiological role of mitochondrial ATP-sensitive potassium channel in insects.
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Affiliation(s)
- Malgorzata Slocinska
- Department of Animal Physiology and Development, Adam Mickiewicz University, Poznan, Poland.
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30
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Nazarewicz RR, Dikalova AE, Bikineyeva A, Dikalov SI. Nox2 as a potential target of mitochondrial superoxide and its role in endothelial oxidative stress. Am J Physiol Heart Circ Physiol 2013; 305:H1131-40. [PMID: 23955717 DOI: 10.1152/ajpheart.00063.2013] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Superoxide (O2(·-)) production by the NADPH oxidases is implicated in the pathogenesis of many cardiovascular diseases, including hypertension. We have previously shown that activation of NADPH oxidases increases mitochondrial O2(·-) which is inhibited by the ATP-sensitive K(+) channel (mitoKATP) inhibitor 5-hydroxydecanoic acid and that scavenging of mitochondrial or cytoplasmic O2(·-) inhibits hypertension. We hypothesized that mitoKATP-mediated mitochondrial O2(·-) potentiates cytoplasmic O2(·-) by stimulation of NADPH oxidases. In this work we studied Nox isoforms as a potential target of mitochondrial O2(·-). We tested contribution of reverse electron transfer (RET) from complex II to complex I in mitochondrial O2(·-) production and NADPH oxidase activation in human aortic endothelial cells. Activation of mitoKATP with low dose of diazoxide (100 nM) decreased mitochondrial membrane potential (tetramethylrhodamine methyl ester probe) and increased production of mitochondrial and cytoplasmic O2(·-) measured by site-specific probes and mitoSOX. Inhibition of RET with complex II inhibitor (malonate) or complex I inhibitor (rotenone) attenuated the production of mitochondrial and cytoplasmic O2(·-). Supplementation with a mitochondria-targeted SOD mimetic (mitoTEMPO) or a mitochondria-targeted glutathione peroxidase mimetic (mitoEbselen) inhibited production of mitochondrial and cytoplasmic O2(·-). Inhibition of Nox2 (gp91ds) or Nox2 depletion with small interfering RNA but not Nox1, Nox4, or Nox5 abolished diazoxide-induced O2(·-) production in the cytoplasm. Treatment of angiotensin II-infused mice with RET inhibitor dihydroethidium (malate) significantly reduced blood pressure. Our study suggests that mitoKATP-mediated mitochondrial O2(·-) stimulates cytoplasmic Nox2, contributing to the development of endothelial oxidative stress and hypertension.
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Affiliation(s)
- Rafal R Nazarewicz
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
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31
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Gispert S, Parganlija D, Klinkenberg M, Dröse S, Wittig I, Mittelbronn M, Grzmil P, Koob S, Hamann A, Walter M, Büchel F, Adler T, Hrabé de Angelis M, Busch DH, Zell A, Reichert AS, Brandt U, Osiewacz HD, Jendrach M, Auburger G. Loss of mitochondrial peptidase Clpp leads to infertility, hearing loss plus growth retardation via accumulation of CLPX, mtDNA and inflammatory factors. Hum Mol Genet 2013; 22:4871-87. [PMID: 23851121 PMCID: PMC7108587 DOI: 10.1093/hmg/ddt338] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The caseinolytic peptidase P (CLPP) is conserved from bacteria to humans. In the mitochondrial matrix, it multimerizes and forms a macromolecular proteasome-like cylinder together with the chaperone CLPX. In spite of a known relevance for the mitochondrial unfolded protein response, its substrates and tissue-specific roles are unclear in mammals. Recessive CLPP mutations were recently observed in the human Perrault variant of ovarian failure and sensorineural hearing loss. Here, a first characterization of CLPP null mice demonstrated complete female and male infertility and auditory deficits. Disrupted spermatogenesis already at the spermatid stage and ovarian follicular differentiation failure were evident. Reduced pre-/post-natal survival and marked ubiquitous growth retardation contrasted with only light impairment of movement and respiratory activities. Interestingly, the mice showed resistance to ulcerative dermatitis. Systematic expression studies detected up-regulation of other mitochondrial chaperones, accumulation of CLPX and mtDNA as well as inflammatory factors throughout tissues. T-lymphocytes in the spleen were activated. Thus, murine Clpp deletion represents a faithful Perrault model. The disease mechanism probably involves deficient clearance of mitochondrial components and inflammatory tissue destruction.
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Siebels I, Dröse S. Q-site inhibitor induced ROS production of mitochondrial complex II is attenuated by TCA cycle dicarboxylates. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1156-64. [PMID: 23800966 DOI: 10.1016/j.bbabio.2013.06.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 01/03/2023]
Abstract
The impact of complex II (succinate:ubiquinone oxidoreductase) on the mitochondrial production of reactive oxygen species (ROS) has been underestimated for a long time. However, recent studies with intact mitochondria revealed that complex II can be a significant source of ROS. Using submitochondrial particles from bovine heart mitochondria as a system that allows the precise setting of substrate concentrations we could show that mammalian complex II produces ROS at subsaturating succinate concentrations in the presence of Q-site inhibitors like atpenin A5 or when a further downstream block of the respiratory chain occurred. Upon inhibition of the ubiquinone reductase activity, complex II produced about 75% hydrogen peroxide and 25% superoxide. ROS generation was attenuated by all dicarboxylates that are known to bind competitively to the substrate binding site of complex II, suggesting that the oxygen radicals are mainly generated by the unoccupied flavin site. Importantly, the ROS production induced by the Q-site inhibitor atpenin A5 was largely unaffected by the redox state of the Q pool and the activity of other respiratory chain complexes. Hence, complex II has to be considered as an independent source of mitochondrial ROS in physiology and pathophysiology.
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Affiliation(s)
- Ilka Siebels
- Clinic of Anesthesiology, Intensive-Care Medicine and Pain Therapy, Goethe-University Hospital, Theodor-Stern Kai 7, Frankfurt am Main, Germany
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33
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Dröse S. Differential effects of complex II on mitochondrial ROS production and their relation to cardioprotective pre- and postconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:578-87. [DOI: 10.1016/j.bbabio.2013.01.004] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/04/2013] [Accepted: 01/09/2013] [Indexed: 11/30/2022]
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Heidler J, Strecker V, Csintalan F, Bleier L, Wittig I. Quantification of protein complexes by blue native electrophoresis. Methods Mol Biol 2013; 1033:363-379. [PMID: 23996189 DOI: 10.1007/978-1-62703-487-6_23] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Blue native electrophoresis (BNE) is a long established method for the analysis of native protein complexes. Applications of BNE range from investigating subunit composition, stoichiometry, and assembly of single protein complexes to profiling of whole complexomes. BNE is an indispensible tool to diagnostically analyze cells and tissues from patients with mitochondrial disorders or model organisms. Since functional proteomic studies often require quantification of protein complexes, we describe here different quantification methods subsequent to protein complex separation by BNE.
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Affiliation(s)
- Juliana Heidler
- Department of Molecular Hematology, University of Frankfurt Medical School, Frankfurt, Germany
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35
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Bleier L, Dröse S. Superoxide generation by complex III: from mechanistic rationales to functional consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1320-31. [PMID: 23269318 DOI: 10.1016/j.bbabio.2012.12.002] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/05/2012] [Accepted: 12/12/2012] [Indexed: 01/21/2023]
Abstract
Apart from complex I (NADH:ubiquinone oxidoreductase) the mitochondrial cytochrome bc1 complex (complex III; ubiquinol:cytochrome c oxidoreductase) has been identified as the main producer of superoxide and derived reactive oxygen species (ROS) within the mitochondrial respiratory chain. Mitochondrial ROS are generally linked to oxidative stress, aging and other pathophysiological settings like in neurodegenerative diseases. However, ROS produced at the ubiquinol oxidation center (center P, Qo site) of complex III seem to have additional physiological functions as signaling molecules during cellular processes like the adaptation to hypoxia. The molecular mechanism of superoxide production that is mechanistically linked to the electron bifurcation during ubiquinol oxidation is still a matter of debate. Some insight comes from extensive kinetic studies with mutated complexes from yeast and bacterial cytochrome bc1 complexes. This review is intended to bridge the gap between those mechanistic studies and investigations on complex III ROS in cellular signal transduction and highlights factors that impact superoxide generation. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Lea Bleier
- Molecular Bioenergetics Group, Medical School, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
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36
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Moghtadaei M, Habibey R, Ajami M, Soleimani M, Ebrahimi SA, Pazoki-Toroudi H. Skeletal muscle post-conditioning by diazoxide, anti-oxidative and anti-apoptotic mechanisms. Mol Biol Rep 2012; 39:11093-103. [PMID: 23053996 DOI: 10.1007/s11033-012-2015-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 10/01/2012] [Indexed: 11/27/2022]
Abstract
Pretreatment with diazoxide, K(ATP) channel opener, increases tissue tolerance against ischemia reperfusion (IR) injury. In clinical settings pretreatment is rarely an option therefore we evaluated the effect of post-ischemic treatment with diazoxide on skeletal muscle IR injury. Rats were treated with either saline, diazoxide (K(ATP) opener; 40 mg/kg) or 5-hydroxydecanoate (5-HD; mitochondrial K(ATP) inhibitor; 40 mg/kg) after skeletal muscle ischemia (3 h) and reperfusion (6, 24 or 48 h). Tissue contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities, Bax and Bcl-2 protein expression and muscle histology were determined. Apoptosis was examined (24 and 48 h) after ischemia. IR induced severe histological damage, increased MDA content and Bax expression (24 and 48 h; p < 0.01) and decreased CAT and SOD activities (6 and 24 h, p < 0.01 and 48 h, p < 0.05), with no significant effect on Bcl-2 expression. Diazoxide reversed IR effects on MDA (6 and 24 h; p < 0.05), SOD (6 and 24 h; p < 0.01) and CAT (6 and 48 h, p < 0.05 and 24 h p < 0.01) and tissue damage. Diazoxide also decreased Bax (24 and 48 h; p < 0.05) and increased Bcl-2 protein expression (24 and 48 h; p < 0.01). Post-ischemic treatment with 5-HD had no significant effect on IR injury. Number of apoptotic nuclei in IR and 5-HD treated groups significantly increased (p < 0.001) while diazoxide decreased apoptosis (p < 0.01). The results suggested that post-ischemic treatment with diazoxide decrease oxidative stress in acute phase which modulates expression of apoptotic proteins in the late phase of reperfusion injury. Involvement of KATP channels in this effect require further evaluations.
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Affiliation(s)
- Mehdi Moghtadaei
- Department of Orthopedic Surgery, Tehran University of Medical Sciences, Tehran, Iran
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37
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Heide H, Bleier L, Steger M, Ackermann J, Dröse S, Schwamb B, Zörnig M, Reichert AS, Koch I, Wittig I, Brandt U. Complexome profiling identifies TMEM126B as a component of the mitochondrial complex I assembly complex. Cell Metab 2012; 16:538-49. [PMID: 22982022 DOI: 10.1016/j.cmet.2012.08.009] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 05/09/2012] [Accepted: 08/17/2012] [Indexed: 11/20/2022]
Abstract
Macromolecular complexes are essential players in numerous biological processes. They are often large, dynamic, and rather labile; approaches to study them are scarce. Covering masses up to ∼30 MDa, we separated the native complexome of rat heart mitochondria by blue-native and large-pore blue-native gel electrophoresis to analyze its constituents by mass spectrometry. Similarities in migration patterns allowed hierarchical clustering into interaction profiles representing a comprehensive analysis of soluble and membrane-bound complexes of an entire organelle. The power of this bottom-up approach was validated with well-characterized mitochondrial multiprotein complexes. TMEM126B was found to comigrate with known assembly factors of mitochondrial complex I, namely CIA30, Ecsit, and Acad9. We propose terming this complex mitochondrial complex I assembly (MCIA) complex. Furthermore, we demonstrate that TMEM126B is required for assembly of complex I. In summary, complexome profiling is a powerful and unbiased technique allowing the identification of previously overlooked components of large multiprotein complexes.
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Affiliation(s)
- Heinrich Heide
- Molecular Bioenergetics Group, Medical School, Cluster of Excellence Frankfurt Macromolecular Complexes, Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
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38
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Stowe DF, Gadicherla AK, Zhou Y, Aldakkak M, Cheng Q, Kwok WM, Jiang MT, Heisner JS, Yang M, Camara AKS. Protection against cardiac injury by small Ca(2+)-sensitive K(+) channels identified in guinea pig cardiac inner mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:427-42. [PMID: 22982251 DOI: 10.1016/j.bbamem.2012.08.031] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 11/24/2022]
Abstract
We tested if small conductance, Ca(2+)-sensitive K(+) channels (SK(Ca)) precondition hearts against ischemia reperfusion (IR) injury by improving mitochondrial (m) bioenergetics, if O(2)-derived free radicals are required to initiate protection via SK(Ca) channels, and, importantly, if SK(Ca) channels are present in cardiac cell inner mitochondrial membrane (IMM). NADH and FAD, superoxide (O(2)(-)), and m[Ca(2+)] were measured in guinea pig isolated hearts by fluorescence spectrophotometry. SK(Ca) and IK(Ca) channel opener DCEBIO (DCEB) was given for 10 min and ended 20 min before IR. Either TBAP, a dismutator of O(2)()(-), NS8593, an antagonist of SK(Ca) isoforms, or other K(Ca) and K(ATP) channel antagonists, were given before DCEB and before ischemia. DCEB treatment resulted in a 2-fold increase in LV pressure on reperfusion and a 2.5 fold decrease in infarct size vs. non-treated hearts associated with reduced O(2)(-) and m[Ca(2+)], and more normalized NADH and FAD during IR. Only NS8593 and TBAP antagonized protection by DCEB. Localization of SK(Ca) channels to mitochondria and IMM was evidenced by a) identification of purified mSK(Ca) protein by Western blotting, immuno-histochemical staining, confocal microscopy, and immuno-gold electron microscopy, b) 2-D gel electrophoresis and mass spectroscopy of IMM protein, c) [Ca(2+)]-dependence of mSK(Ca) channels in planar lipid bilayers, and d) matrix K(+) influx induced by DCEB and blocked by SK(Ca) antagonist UCL1684. This study shows that 1) SK(Ca) channels are located and functional in IMM, 2) mSK(Ca) channel opening by DCEB leads to protection that is O(2)(-) dependent, and 3) protection by DCEB is evident beginning during ischemia.
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Affiliation(s)
- David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.
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39
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Ahmad Waza A, Andrabi K, Ul Hussain M. Adenosine-triphosphate-sensitive K+ channel (Kir6.1): a novel phosphospecific interaction partner of connexin 43 (Cx43). Exp Cell Res 2012; 318:2559-66. [PMID: 22960107 DOI: 10.1016/j.yexcr.2012.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 08/21/2012] [Accepted: 08/22/2012] [Indexed: 01/30/2023]
Abstract
Connexin 43 (Cx43) is a phosphoprotein expressed in a wide variety of cells. Cx43 and adenosine-triphosphate-sensitive K(+)channels [K(+)(ATP)] are part of same signaling pathway that regulates cell survival during stress and ischemia preconditioning. Molecular mechanism for their coordinated role in ischemia/hypoxia preconditioning is not well known. Using pull down, co-immunoprecipitation assays and co-localization studies we provide evidence, for the first time that Kir6.1, a K(+)(ATP) channel protein component, can interact with Cx43. Further we show that the interaction was phospho-specific such that Cx43 phosphorylated at serine 262 (S262) interacted with Kir6.1 in preference to the unphosphorylated form of Cx43. Introduction of phospho-deficient mutation at serine 262 (S262A) in Cx43 completely abolished the interaction. Our data provide an interesting lead about a possible partnership between Cx43 and Kir6.1, which will help in better understanding their role in ischemia/hypoxia preconditioning.
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Maffit SK, Sellitto AD, Al-Dadah AS, Schuessler RB, Damiano RJ, Lawton JS. Diazoxide maintains human myocyte volume homeostasis during stress. J Am Heart Assoc 2012; 1:jah312. [PMID: 23130119 PMCID: PMC3487366 DOI: 10.1161/jaha.112.000778] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 02/14/2012] [Indexed: 11/30/2022]
Abstract
Background Exposure to hypothermic hyperkalemic cardioplegia, hyposmotic stress, or metabolic inhibition results in significant animal myocyte swelling (6% to10%) and subsequent reduced contractility (10% to 20%). Both are eliminated by the adenosine triphosphate-sensitive potassium channel opener diazoxide (DZX). The relationship between swelling and reduced contractility suggests that the structural change may represent one mechanism of postoperative myocardial stunning. This study evaluated human myocyte volume during stress to investigate if similar phenomena exist in human myocytes. Methods and Results Human atrial myocytes isolated from tissue obtained during cardiac surgery were perfused with Tyrode's physiological solution (20 minutes, 37°C), test solution (20 minutes), and Tyrode's (37°C, 20 minutes). Test solutions (n=6 to 12 myocytes each) included Tyrode's (37°C or 9°C), Tyrode's+DZX (9°C), hyperkalemic cardioplegia (9°C)±DZX, cardioplegia+DZX+HMR 1098 (sarcolemmal adenosine triphosphate-sensitive potassium channel inhibitor, 9°C), cardioplegia+DZX+5-hydroxydeconoate (mitochondrial adenosine triphosphate-sensitive potassium channel inhibitor, 9°C), mild hyposmotic solution±DZX, metabolic inhibition±DZX, and metabolic inhibition+DZX+5-hydroxydeconoate. Myocyte volume was recorded every 5 minutes. Exposure to hypothermic hyperkalemic cardioplegia, hyposmotic stress, or metabolic inhibition resulted in significant human myocyte swelling (8%, 7%, and 6%, respectively; all P<0.05 vs control). In all groups, the swelling was eliminated or lessened by DZX. The addition of channel inhibitors did not significantly alter results. Conclusions DZX maintains human myocyte volume homeostasis during stress via an unknown mechanism. DZX may prove to be clinically useful following the elucidation of its specific mechanism of action. (J Am Heart Assoc. 2012;1:jah3-e000778 doi: 10.1161/JAHA.112.000778.)
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Affiliation(s)
- Sara K Maffit
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
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Zeng Z, Huang HF, He F, Wu LX, Lin J, Chen MQ. Diazoxide attenuates ischemia/reperfusion injury via upregulation of heme oxygenase-1 after liver transplantation in rats. World J Gastroenterol 2012; 18:1765-72. [PMID: 22553400 PMCID: PMC3332289 DOI: 10.3748/wjg.v18.i15.1765] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/17/2012] [Accepted: 04/09/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the effects of diazoxide on ischemia/reperfusion (I/R)-injured hepatocytes and further elucidate its underlying mechanisms.
METHODS: Male Sprague-Dawley rats were randomized (8 for donor and recipient per group) into five groups: I/R group (4 h of liver cold ischemia followed by 6 h of reperfusion); heme oxygenase-1 (HO-1) small interfering RNA (siRNA) group (injection of siRNA via donor portal vein 48 h prior to harvest); diazoxide (DZ) group (injection of DZ via donor portal vein 10 min prior to harvest); HO-1 siRNA + DZ group; and siRNA control group. Blood and liver samples were collected at 6 h after reperfusion. The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting, and tissue morphology was examined by light and transmission electron microscopy. Serum transaminases level and cytokines concentration were also measured.
RESULTS: We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA + DZ group when compared with I/R group, while the increases were prominent in the DZ group. Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA + DZ groups compared with DZ group. Serum alanine aminotransferase, aspartate transaminase, tumor necrosis factor-α and interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA + DZ groups, and decreased in the DZ group.
CONCLUSION: The protective effect of DZ may be induced by upregulation of HO-1. By inhibiting expression of HO-1, this protection pretreated with DZ was abolished.
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The mitochondrial K(ATP) channel--fact or fiction? J Mol Cell Cardiol 2012; 52:578-83. [PMID: 22240339 DOI: 10.1016/j.yjmcc.2011.12.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 12/21/2011] [Accepted: 12/21/2011] [Indexed: 01/25/2023]
Abstract
The mitochondrial ATP-dependent K(+) channel (mitoK(ATP)) is widely considered by many to play a central role in cardioprotection by ischemic and pharmacological preconditioning and by ischemic postconditioning. Nevertheless, several laboratories have questioned the existence of mitoK(ATP). This article summarizes the evidence for and against and addresses two key questions: How strong is the evidence for the presence of a K(ATP) channel in mitochondria? Are the pharmacological agents used to modulate mitoK(ATP) activity sufficiently specific to allow the role of these channels in cardioprotection to be established?
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Dröse S, Brandt U. Molecular mechanisms of superoxide production by the mitochondrial respiratory chain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:145-69. [PMID: 22729857 DOI: 10.1007/978-1-4614-3573-0_6] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mitochondrial respiratory chain is a major source of reactive oxygen species (ROS) in eukaryotic cells. Mitochondrial ROS production associated with a dysfunction of respiratory chain complexes has been implicated in a number of degenerative diseases and biological aging. Recent findings suggest that mitochondrial ROS can be integral components of cellular signal transduction as well. Within the respiratory chain, complexes I (NADH:ubiquinone oxidoreductase) and III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc (1) complex) are generally considered as the main producers of superoxide anions that are released into the mitochondrial matrix and the intermembrane space, respectively. The primary function of both respiratory chain complexes is to employ energy supplied by redox reactions to drive the vectorial transfer of protons into the mitochondrial intermembrane space. This process involves a set of distinct electron carriers designed to minimize the unwanted leak of electrons from reduced cofactors onto molecular oxygen and hence ROS generation under normal circumstances. Nevertheless, it seems plausible that superoxide is derived from intermediates of the normal catalytic cycles of complexes I and III. Therefore, a detailed understanding of the molecular mechanisms driving these enzymes is required to understand mitochondrial ROS production during oxidative stress and redox signalling. This review summarizes recent findings on the chemistry and control of the reactions within respiratory complexes I and III that result in increased superoxide generation. Regulatory contributions of other components of the respiratory chain, especially complex II (succinate:ubiquinone oxidoreductase) and the redox state of the ubiquinone pool (Q-pool) will be briefly discussed.
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Affiliation(s)
- Stefan Dröse
- Center for Membrane Proteomics, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
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Guerrero-Castillo S, Cabrera-Orefice A, Vázquez-Acevedo M, González-Halphen D, Uribe-Carvajal S. During the stationary growth phase, Yarrowia lipolytica prevents the overproduction of reactive oxygen species by activating an uncoupled mitochondrial respiratory pathway. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:353-62. [PMID: 22138628 DOI: 10.1016/j.bbabio.2011.11.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 12/01/2022]
Abstract
In the branched mitochondrial respiratory chain from Yarrowia lipolytica there are two alternative oxido-reductases that do not pump protons, namely an external type II NADH dehydrogenase (NDH2e) and the alternative oxidase (AOX). Direct electron transfer between these proteins is not coupled to ATP synthesis and should be avoided in most physiological conditions. However, under low energy-requiring conditions an uncoupled high rate of oxygen consumption would be beneficial, as it would prevent overproduction of reactive oxygen species (ROS). In mitochondria from high energy-requiring, logarithmic-growth phase cells, most NDH2e was associated to cytochrome c oxidase and electrons from NADH were channeled to the cytochromic pathway. In contrast, in the low energy requiring, late stationary-growth phase, complex IV concentration decreased, the cells overexpressed NDH2e and thus a large fraction of this enzyme was found in a non-associated form. Also, the NDH2e-AOX uncoupled pathway was activated and the state IV external NADH-dependent production of ROS decreased. Association/dissociation of NDH2e to/from complex IV is proposed to be the switch that channels electrons from external NADH to the coupled cytochrome pathway or allows them to reach an uncoupled, alternative, ΔΨ-independent pathway.
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Hirata N, Shim YH, Pravdic D, Lohr NL, Pratt PF, Weihrauch D, Kersten JR, Warltier DC, Bosnjak ZJ, Bienengraeber M. Isoflurane differentially modulates mitochondrial reactive oxygen species production via forward versus reverse electron transport flow: implications for preconditioning. Anesthesiology 2011; 115:531-40. [PMID: 21862887 PMCID: PMC3337729 DOI: 10.1097/aln.0b013e31822a2316] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Reactive oxygen species (ROS) mediate the effects of anesthetic precondition to protect against ischemia and reperfusion injury, but the mechanisms of ROS generation remain unclear. In this study, the authors investigated if mitochondria-targeted antioxidant (mitotempol) abolishes the cardioprotective effects of anesthetic preconditioning. Further, the authors investigated the mechanism by which isoflurane alters ROS generation in isolated mitochondria and submitochondrial particles. METHODS Rats were pretreated with 0.9% saline, 3.0 mg/kg mitotempol in the absence or presence of 30 min exposure to isoflurane. Myocardial infarction was induced by left anterior descending artery occlusion for 30 min followed by reperfusion for 2 h and infarct size measurements. Mitochondrial ROS production was determined spectrofluorometrically. The effect of isoflurane on enzymatic activity of mitochondrial respiratory complexes was also determined. RESULTS Isoflurane reduced myocardial infarct size (40 ± 9% = mean ± SD) compared with control experiments (60 ± 4%). Mitotempol abolished the cardioprotective effects of anesthetic preconditioning (60 ± 9%). Isoflurane enhanced ROS generation in submitochondrial particles with nicotinamide adenine dinucleotide (reduced form), but not with succinate, as substrate. In intact mitochondria, isoflurane enhanced ROS production in the presence of rotenone, antimycin A, or ubiquinone when pyruvate and malate were substrates, but isoflurane attenuated ROS production when succinate was substrate. Mitochondrial respiratory experiments and electron transport chain complex assays revealed that isoflurane inhibited only complex I activity. CONCLUSIONS The results demonstrated that isoflurane produces ROS at complex I and III of the respiratory chain via the attenuation of complex I activity. The action on complex I decreases unfavorable reverse electron flow and ROS release in myocardium during reperfusion.
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Affiliation(s)
- Naoyuki Hirata
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Inhibitors of succinate: quinone reductase/Complex II regulate production of mitochondrial reactive oxygen species and protect normal cells from ischemic damage but induce specific cancer cell death. Pharm Res 2011; 28:2695-730. [PMID: 21863476 DOI: 10.1007/s11095-011-0566-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 08/10/2011] [Indexed: 12/23/2022]
Abstract
Succinate:quinone reductase (SQR) of Complex II occupies a unique central point in the mitochondrial respiratory system as a major source of electrons driving reactive oxygen species (ROS) production. It is an ideal pharmaceutical target for modulating ROS levels in normal cells to prevent oxidative stress-induced damage or alternatively,increase ROS in cancer cells, inducing cell death.The value of drugs like diazoxide to prevent ROS production,protecting normal cells, whereas vitamin E analogues promote ROS in cancer cells to kill them is highlighted. As pharmaceuticals these agents may prevent degenerative disease and their modes of action are presently being fully explored. The evidence that SDH/Complex II is tightly coupled to the NADH/NAD+ ratio in all cells,impacted by the available supplies of Krebs cycle intermediates as essential NAD-linked substrates, and the NAD+-dependent regulation of SDH/Complex II are reviewed, as are links to the NAD+-dependent dehydrogenases, Complex I and the E3 dihiydrolipoamide dehydrogenase to produce ROS. This review collates and discusses diverse sources of information relating to ROS production in different biological systems, focussing on evidence for SQR as the main source of ROS production in mitochondria, particularly its relevance to protection from oxidative stress and to the mitochondrial-targeted anti cancer drugs (mitocans) as novel cancer therapies [corrected].
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Dröse S, Bleier L, Brandt U. A Common Mechanism Links Differently Acting Complex II Inhibitors to Cardioprotection: Modulation of Mitochondrial Reactive Oxygen Species Production. Mol Pharmacol 2011; 79:814-22. [DOI: 10.1124/mol.110.070342] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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González G, Zaldívar D, Carrillo E, Hernández A, García M, Sánchez J. Pharmacological preconditioning by diazoxide downregulates cardiac L-type Ca(2+) channels. Br J Pharmacol 2010; 161:1172-85. [PMID: 20636393 PMCID: PMC2998696 DOI: 10.1111/j.1476-5381.2010.00960.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 05/18/2010] [Accepted: 06/29/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Pharmacological preconditioning (PPC) with mitochondrial ATP-sensitive K(+) (mitoK(ATP) ) channel openers such as diazoxide, leads to cardioprotection against ischaemia. However, effects on Ca(2+) homeostasis during PPC, particularly changes in Ca(2+) channel activity, are poorly understood. We investigated the effects of PPC on cardiac L-type Ca(2+) channels. EXPERIMENTAL APPROACH PPC was induced in isolated hearts and enzymatically dissociated cardiomyocytes from adult rats by preincubation with diazoxide. We measured reactive oxygen species (ROS) production and Ca(2+) signals associated with action potentials using fluorescent probes, and L-type currents using a whole-cell patch-clamp technique. Levels of the α(1c) subunit of L-type channels in the cellular membrane were measured by Western blot. KEY RESULTS PPC was accompanied by a 50% reduction in α(1c) subunit levels, and by a reversible fall in L-type current amplitude and Ca(2+) transients. These effects were prevented by the ROS scavenger N-acetyl-L-cysteine (NAC), or by the mitoK(ATP) channel blocker 5-hydroxydecanoate (5-HD). PPC significantly reduced infarct size, an effect blocked by NAC and 5-HD. Nifedipine also conferred protection against infarction when applied during the reperfusion period. Downregulation of the α(1c) subunit and Ca(2+) channel function were prevented in part by the protease inhibitor leupeptin. CONCLUSIONS AND IMPLICATIONS PPC downregulated the α(1c) subunit, possibly through ROS. Downregulation involved increased degradation of the Ca(2+) channel, which in turn reduced Ca(2+) influx, which may attenuate Ca(2+) overload during reperfusion.
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Affiliation(s)
- G González
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del I.P.N. México, México
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Affiliation(s)
- Mitsuhiko Yamada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Shinshu, Japan.
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