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Ong SB, Dongworth RK, Cabrera-Fuentes HA, Hausenloy DJ. Role of the MPTP in conditioning the heart - translatability and mechanism. Br J Pharmacol 2015; 172:2074-84. [PMID: 25393318 PMCID: PMC4386982 DOI: 10.1111/bph.13013] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 01/06/2023] Open
Abstract
Mitochondria have long been known to be the gatekeepers of cell fate. This is particularly so in the response to acute ischaemia‐reperfusion injury (IRI). Following an acute episode of sustained myocardial ischaemia, the opening of the mitochondrial permeability transition pore (MPTP) in the first few minutes of reperfusion, mediates cell death. Preventing MPTP opening at the onset of reperfusion using either pharmacological inhibitors [such as cyclosporin A (CsA) ] or genetic ablation has been reported to reduce myocardial infarct (MI) size in animal models of acute IRI. Interestingly, the endogenous cardioprotective intervention of ischaemic conditioning, in which the heart is protected against MI by applying cycles of brief ischaemia and reperfusion to either the heart itself or a remote organ or tissue, appears to be mediated through the inhibition of MPTP opening at reperfusion. Small proof‐of‐concept clinical studies have demonstrated the translatability of this therapeutic approach to target MPTP opening using CsA in clinical settings of acute myocardial IRI. However, given that CsA is a not a specific MPTP inhibitor, more novel and specific inhibitors of the MPTP need to be discovered – the molecular identification of the MPTP should facilitate this. In this paper, we review the role of the MPTP as a target for cardioprotection, the potential mechanisms underlying MPTP inhibition in the setting of ischaemic conditioning, and the translatability of MPTP inhibition as a therapeutic approach in the clinical setting. Linked Articles This article is part of a themed section on Conditioning the Heart – Pathways to Translation. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue‐8
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Affiliation(s)
- S-B Ong
- The Hatter Cardiovascular Institute, University College London, London, UK
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Ong SB, Samangouei P, Kalkhoran SB, Hausenloy DJ. The mitochondrial permeability transition pore and its role in myocardial ischemia reperfusion injury. J Mol Cell Cardiol 2014; 78:23-34. [PMID: 25446182 DOI: 10.1016/j.yjmcc.2014.11.005] [Citation(s) in RCA: 241] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 12/27/2022]
Abstract
Ischemic heart disease (IHD) remains the leading cause of death and disability worldwide. For patients presenting with an acute myocardial infarction, the most effective treatment for limiting myocardial infarct (MI) size is timely reperfusion. However, in addition to the injury incurred during acute myocardial ischemia, the process of reperfusion can itself induce myocardial injury and cardiomyocyte death, termed 'myocardial reperfusion injury', the combination of which can be referred to as acute ischemia-reperfusion injury (IRI). Crucially, there is currently no effective therapy for preventing this form of injury, and novel cardioprotective therapies are therefore required to protect the heart against acute IRI in order to limit MI size and preserve cardiac function. The opening of the mitochondrial permeability transition pore (MPTP) in the first few minutes of reperfusion is known to be a critical determinant of IRI, contributing up to 50% of the final MI size. Importantly, preventing its opening at this time using MPTP inhibitors, such as cyclosporin-A, has been reported in experimental and clinical studies to reduce MI size and preserve cardiac function. However, more specific and novel MPTP inhibitors are required to translate MPTP inhibition as a cardioprotective strategy into clinical practice. In this article, we review the role of the MPTP as a mediator of acute myocardial IRI and as a therapeutic target for cardioprotection. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Affiliation(s)
- Sang-Bing Ong
- Hatter Cardiovascular Institute, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, University College London Hospital & Medical School, 67 Chenies Mews, London WC1E 6HX, UK
| | - Parisa Samangouei
- Hatter Cardiovascular Institute, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, University College London Hospital & Medical School, 67 Chenies Mews, London WC1E 6HX, UK
| | - Siavash Beikoghli Kalkhoran
- Hatter Cardiovascular Institute, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, University College London Hospital & Medical School, 67 Chenies Mews, London WC1E 6HX, UK
| | - Derek J Hausenloy
- Hatter Cardiovascular Institute, Institute of Cardiovascular Science, NIHR University College London Hospitals Biomedical Research Centre, University College London Hospital & Medical School, 67 Chenies Mews, London WC1E 6HX, UK; Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, Singapore.
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Testai L, Rapposelli S, Martelli A, Breschi M, Calderone V. Mitochondrial Potassium Channels as Pharmacological Target for Cardioprotective Drugs. Med Res Rev 2014; 35:520-53. [DOI: 10.1002/med.21332] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- L. Testai
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - S. Rapposelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - A. Martelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - M.C. Breschi
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - V. Calderone
- Department of Pharmacy; University of Pisa; Pisa Italy
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Fu Q, Sun Z, Zhang J, Gao N, Qi F, Che F, Ma G. Diazoxide preconditioning antagonizes cytotoxicity induced by epileptic seizures. Neural Regen Res 2014; 8:1000-6. [PMID: 25206393 PMCID: PMC4145886 DOI: 10.3969/j.issn.1673-5374.2013.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/05/2013] [Indexed: 01/15/2023] Open
Abstract
Diazoxide, an activator of mitochondrial ATP-sensitive potassium channels, can protect neurons and astrocytes against oxidative stress and apoptosis. In this study, we established a cellular model of epilepsy by culturing hippocampal neurons in magnesium-free medium, and used this to investigate effects of diazoxide preconditioning on the expression of inwardly rectifying potassium channel (Kir) subunits of the ATP-sensitive potassium. We found that neuronal viability was significantly reduced in the epileptic cells, whereas it was enhanced by diazoxide preconditioning. Double immunofluorescence and western blot showed a significant increase in the expression of Kir6.1 and Kir6.2 in epileptic cells, especially at 72 hours after seizures. Diazoxide pretreatment completely reversed this effect at 24 hours after seizures. In addition, Kir6.1 expression was significantly upregulated compared with Kir6.2 in hippocampal neurons after seizures. These findings indicate that diazoxide pretreatment may counteract epileptiform discharge-induced cytotoxicity by suppressing the expression of Kir subunits.
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Affiliation(s)
- Qingxi Fu
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Zhiqing Sun
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Jinling Zhang
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Naiyong Gao
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Faying Qi
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Fengyuan Che
- Department of Neurology, Linyi People's Hospital, Linyi 276003, Shandong Province, China
| | - Guozhao Ma
- Department of Neurology, Shandong Provincial Hospital, Shandong University, Jinan 250021, Shandong Province, China
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Huang X, Qin J, Lu S. Magnesium isoglycyrrhizinate protects hepatic L02 cells from ischemia/reperfusion induced injury. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:4755-4764. [PMID: 25197346 PMCID: PMC4152036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/02/2014] [Indexed: 06/03/2023]
Abstract
Human liver ischemia/reperfusion injury (IRI) is a common and major clinical problem complicating liver surgery and transplantation. The pathogenesis underlying IRI is complex, involving a series of signaling mediators and mechanisms. This study aimed to investigate the effects of Magnesium Isoglycyrrhizinate (MgIG) on the changes of oxidant stress and apoptosis induced by IRI in human hepatic L02 cells. L02 cells with IRI were treated with or without MgIG and mitoKATP (Mitochondrial adenosine triphosphate-dependent potassium) channel modulators. Cell viability was assessed using CCK-8 assay. Cell apoptosis was quantified by flow cytometry. The activity of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured. Effects of MgIG on the expression of Bax, Bcl-2, Caspase 3, PARP (poly ADP-ribose polymerase), Akt, and ERK in L02 cells with IRI were examined. Our results showed that MgIG treatment significantly reduced the population of apoptotic cells and the expression of apoptosis-related proteins in hepatic L02 cells with IRI. MgIG also counteract ischemia reperfusion induced oxidative challenge as it effectively reduced malondialdehyde (MDA) and increased the activities of SOD and GSH-Px. L02 cells treated with MgIG showed increased expression of p-Akt and p-ERK, indicating that the protective effect of MgIG might be associated with the activation of Akt and ERK pathways. Moreover, the addition of Diazoxide (DE), a mitoKATP channel opener, enhanced the cytoprotective activity of MgIG, while the mitoKATP blocker 5-hydroxydecanoate (5-HD) reduced the cytoprotective activity of MgIG.
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Affiliation(s)
- Xinli Huang
- Center of Liver Transplantation, The First Affiliated Hospital of Nanjing Medical University, The Key Laboratory of Living Donor Liver Transplantation, Ministry of Health Nanjing 210029, China
| | - Jianjie Qin
- Center of Liver Transplantation, The First Affiliated Hospital of Nanjing Medical University, The Key Laboratory of Living Donor Liver Transplantation, Ministry of Health Nanjing 210029, China
| | - Sen Lu
- Center of Liver Transplantation, The First Affiliated Hospital of Nanjing Medical University, The Key Laboratory of Living Donor Liver Transplantation, Ministry of Health Nanjing 210029, China
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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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Busija DW, Katakam PV. Mitochondrial mechanisms in cerebral vascular control: shared signaling pathways with preconditioning. J Vasc Res 2014; 51:175-89. [PMID: 24862206 PMCID: PMC4149841 DOI: 10.1159/000360765] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 02/19/2014] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial-initiated events protect the neurovascular unit against lethal stress via a process called preconditioning, which independently promotes changes in cerebrovascular tone through shared signaling pathways. Activation of adenosine triphosphate (ATP)-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels) is a specific and dependable way to induce protection of neurons, astroglia, and cerebral vascular endothelium. Through the opening of mitoKATP channels, mitochondrial depolarization leads to activation of protein kinases and transient increases in cytosolic calcium (Ca(2+)) levels that activate terminal mechanisms that protect the neurovascular unit against lethal stress. The release of reactive oxygen species from mitochondria has similar protective effects. Signaling elements of the preconditioning pathways also are involved in the regulation of vascular tone. Activation of mitoKATP channels in cerebral arteries causes vasodilation, with cell-specific contributions from the endothelium, vascular smooth muscles, and nerves. Preexisting chronic conditions, such as insulin resistance and/or diabetes, prevent preconditioning and impair relaxation to mitochondrial-centered responses in cerebral arteries. Surprisingly, mitochondrial activation after anoxic or ischemic stress appears to protect cerebral vascular endothelium and promotes the restoration of blood flow; therefore, mitochondria may represent an important, but underutilized target in attenuating vascular dysfunction and brain injury in stroke patients.
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Affiliation(s)
- David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, La., USA
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Mitochondrial KATP channel involvement in angiotensin II-induced autophagy in vascular smooth muscle cells. Basic Res Cardiol 2014; 109:416. [PMID: 24847907 PMCID: PMC4090747 DOI: 10.1007/s00395-014-0416-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 02/07/2023]
Abstract
Autophagy has emerged as a powerful process in the response to cellular injury. The present study was designed to investigate signal transduction pathways in angiotensin II (Ang II)-induced autophagy. Rat vascular smooth muscle cells (VSMCs) were stimulated with different doses of Ang II (10(-9)-10(-5) mol/L) for different time periods (6-72 h). Incubation with Ang II increased the production of reactive oxygen species (ROS), increased the LC3-II to LC3-I ratio, increased beclin-1 expression, and decreased SQSTM1/p62 expression in a dose- and time-dependent manner. In addition, Ang II increased autophagosome formation. Increased ROS production induced by Ang II was inhibited by Ang II type 1 receptor (AT1) blockers (Olmesartan and Candesartan, ARB), a NADPH Oxidase inhibitor (apocynin), and mitochondrial KATP channels inhibitor (5-hydroxydecanoate, 5HD). Ang II (10(-7) mol/L, 48 h)-induced increase in the LC3-II to LC3-I ratio, the formation of autophagosomes, expression of beclin-1 and decrease in the expression of SQSTM1/p62 were also inhibited by pretreatment with 3-methyladenine or bafilomycin A1 (inhibitors of autophagy), olmesartan and candesartan (in dose-dependent manners), apocynin, 5HD, and siRNA Atg5. Our results indicate that Ang II increases autophagy levels via activation of AT1 receptor and NADPH oxidase. Mitochondrial KATP channels also play an important role in Ang II-induced autophagy. Our results may provide a new strategy for treatment of cardiovascular diseases with Ang II.
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The effect of sildenafil and udenafil on testicular damage following ischemia-reperfusion injury in rats. J Urol 2014; 192:1272-7. [PMID: 24742592 DOI: 10.1016/j.juro.2014.04.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2014] [Indexed: 11/21/2022]
Abstract
PURPOSE Ischemia-reperfusion injury can cause testicular damage and phosphodiesterase inhibitors are reported to regulate antioxidant activity. We investigated the prevention of ipsilateral and contralateral testicular damage using 2 phosphodiesterase inhibitors after testicular detorsion in rats. MATERIALS AND METHODS A total of 28 adult male rats were randomly divided into 4 groups of 7 each, including group 1-sham operation, group 2-testicular torsion and detorsion, group 3- testicular torsion and detorsion with sildenafil administration before detorsion and group 4- testicular torsion and detorsion with udenafil administration before detorsion. Tissue levels of malondialdehyde, total sulfhydryl and nitrite were evaluated, and histopathological changes in the groups were examined. RESULTS Compared to group 1 significantly increased tissue malondialdehyde (p = 0.001), significantly decreased total sulfhydryl (p = 0.038) and insignificantly increased nitrite were found in group 2. Compared to group 2 malondialdehyde decreased significantly and total sulfhydryl increased significantly in groups 3 and 4. The decrease in nitrite was insignificant in the latter 2 groups. Histopathology revealed increased hemorrhage, congestion and edema in group 2 rats. The testicular injury score was lower in groups 3 and 4. In group 2 grades II to IV injury was detected while most specimens in treated groups showed grade II injury. CONCLUSIONS This study indicates that intraperitoneal administration of sildenafil and udenafil efficiently suppresses radical production while decreasing histological changes after testicular ischemia-reperfusion injury.
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Fahrenbach JP, Stoller D, Kim G, Aggarwal N, Yerokun B, Earley JU, Hadhazy M, Shi NQ, Makielski JC, McNally EM. Abcc9 is required for the transition to oxidative metabolism in the newborn heart. FASEB J 2014; 28:2804-15. [PMID: 24648545 DOI: 10.1096/fj.13-244459] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The newborn heart adapts to postnatal life by shifting from a fetal glycolytic metabolism to a mitochondrial oxidative metabolism. Abcc9, an ATP-binding cassette family member, increases expression concomitant with this metabolic shift. Abcc9 encodes a membrane-associated receptor that partners with a potassium channel to become the major potassium-sensitive ATP channel in the heart. Abcc9 also encodes a smaller protein enriched in the mitochondria. We now deleted exon 5 of Abcc9 to ablate expression of both plasma membrane and mitochondria-associated Abcc9-encoded proteins, and found that the myocardium failed to acquire normal mature metabolism, resulting in neonatal cardiomyopathy. Unlike wild-type neonatal cardiomyocytes, mitochondria from Ex5 cardiomyocytes were unresponsive to the KATP agonist diazoxide, consistent with loss of KATP activity. When exposed to hydrogen peroxide to induce cell stress, Ex5 neonatal cardiomyocytes displayed a rapid collapse of mitochondria membrane potential, distinct from wild-type cardiomyocytes. Ex5 cardiomyocytes had reduced fatty acid oxidation, reduced oxygen consumption and reserve. Morphologically, Ex5 cardiac mitochondria exhibited an immature pattern with reduced cross-sectional area and intermitochondrial contacts. In the absence of Abcc9, the newborn heart fails to transition normally from fetal to mature myocardial metabolism.-Fahrenbach, J. P., Stoller, D., Kim, G., Aggarwal, N., Yerokun, B., Earley, J. U., Hadhazy, M., Shi, N.-Q., Makielski, J. C., McNally, E. M. Abcc9 is required for the transition to oxidative metabolism in the newborn heart.
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Affiliation(s)
| | - Douglas Stoller
- Department of Medicine, Division of Cardiovascular Medicine, and
| | - Gene Kim
- Department of Medicine, Division of Cardiovascular Medicine, and
| | - Nitin Aggarwal
- Department of Medicine, Division of Cardiology, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Judy U Earley
- Department of Medicine, Division of Cardiovascular Medicine, and
| | - Michele Hadhazy
- Department of Medicine, Division of Cardiovascular Medicine, and
| | - Nian-Qing Shi
- Department of Medicine, Division of Cardiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Jonathan C Makielski
- Department of Medicine, Division of Cardiology, University of Wisconsin, Madison, Wisconsin, USA
| | - Elizabeth M McNally
- Department of Medicine, Division of Cardiovascular Medicine, and Department of Human Genetics, The University of Chicago, Chicago, Illinois, USA; and
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Bereiter-Hahn J. Do we age because we have mitochondria? PROTOPLASMA 2014; 251:3-23. [PMID: 23794102 DOI: 10.1007/s00709-013-0515-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
The process of aging remains a great riddle. Production of reactive oxygen species (ROS) by mitochondria is an inevitable by-product of respiration, which has led to a hypothesis proposing the oxidative impairment of mitochondrial components (e.g., mtDNA, proteins, lipids) that initiates a vicious cycle of dysfunctional respiratory complexes producing more ROS, which again impairs function. This does not exclude other processes acting in parallel or targets for ROS action in other organelles than mitochondria. Given that aging is defined as the process leading to death, the role of mitochondria-based impairments in those organ systems responsible for human death (e.g., the cardiovascular system, cerebral dysfunction, and cancer) is described within the context of "garbage" accumulation and increasing insulin resistance, type 2 diabetes, and glycation of proteins. Mitochondrial mass, fusion, and fission are important factors in coping with impaired function. Both biogenesis of mitochondria and their degradation are important regulatory mechanisms stimulated by physical exercise and contribute to healthy aging. The hypothesis of mitochondria-related aging should be revised to account for the limitations of the degradative capacity of the lysosomal system. The processes involved in mitochondria-based impairments are very similar across a large range of organisms. Therefore, studies on model organisms from yeast, fungi, nematodes, flies to vertebrates, and from cells to organisms also add considerably to the understanding of human aging.
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Affiliation(s)
- Jürgen Bereiter-Hahn
- Institut für Zellbiologie und Neurowissenschaften, Goethe Universität Frankfurt am Main, Max-von-Lauestrasse 13, 60438, Frankfurt am Main, Germany,
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Costa JF, Fontes-Carvalho R, Leite-Moreira AF. Myocardial remote ischemic preconditioning: From pathophysiology to clinical application. REVISTA PORTUGUESA DE CARDIOLOGIA (ENGLISH EDITION) 2013. [DOI: 10.1016/j.repce.2013.10.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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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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Costa JF, Fontes-Carvalho R, Leite-Moreira AF. Pré-condicionamento isquémico remoto do miocárdio: dos mecanismos fisiopatológicos à aplicação na prática clínica. Rev Port Cardiol 2013; 32:893-904. [DOI: 10.1016/j.repc.2013.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 12/14/2022] Open
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Sevoflurane preconditioning attenuates the fall in adenosine triphosphate levels, but does not alter the changes in sodium and potassium levels during hypoxia in rat hippocampal slices. Anesthesiology 2013; 119:119-28. [PMID: 23459218 DOI: 10.1097/aln.0b013e31828ce844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Sevoflurane preconditioning improves recovery after hypoxia. Sevoflurane administered before and during hypoxia improved recovery and attenuated the changes in intracellular sodium, potassium, and adenosine triphosphate (ATP) levels during hypoxia. In this study, the authors examine the effects of sevoflurane applied only before hypoxia on sodium, potassium, and ATP. METHODS Hippocampal slices from adult male Sprague-Dawley rats were pretreated with 4% sevoflurane, washed, and then subjected to hypoxia (n≥8 animals/group). The cornus ammonis 1 regions of the hippocampal slices were micro-dissected and sodium, potassium, and ATP concentrations measured. RESULTS Pretreatment with sevoflurane for 15 or 60 min did not attenuate the increase in intracellular sodium or the decrease in intracellular potassium during hypoxia. After 60 min of preconditioning and 5 min of hypoxia, sodium increased 57% (vs. nonpreconditioned hypoxia 54% increase) and potassium decreased 31% (vs. 26%). These changes were not statistically significant versus untreated hypoxia. The 60-min sevoflurane preconditioning group had statistically significant higher ATP levels at 5 min of hypoxia (3.8 nmol/mg dry wt.) when compared to untreated hypoxic tissue (2.1 nmol/mg). There was no significant difference in ATP levels between the sevoflurane preconditioned and the untreated tissue before hypoxia (8.9 vs. 8.5 nmoles/mg, respectively). CONCLUSION Preconditioning with sevoflurane for 60 min before hypoxia does not alter changes in intracellular sodium and potassium during hypoxia but does attenuate the fall in intracellular ATP levels during hypoxia. Thus, there are differences between anesthetic preconditioning and when anesthetics are present before and during hypoxia.
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Pasello G, Urso L, Conte P, Favaretto A. Effects of sulfonylureas on tumor growth: a review of the literature. Oncologist 2013; 18:1118-25. [PMID: 24043597 DOI: 10.1634/theoncologist.2013-0177] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Type 2 diabetes mellitus patients are at higher cancer risk, probably because of hyperinsulinemia and insulin growth factor 1 pathway activation. The effects of antidiabetic drugs on cancer risk have been described and discussed in several studies suggesting opposite effects of the biguanide metformin and sulfonylureas on cancer incidence and mortality. The anticancer mechanisms of metformin have been clarified, and some clinical studies, particularly in breast cancer patients, have been published or are currently ongoing; however, data about the effects of sulfonylureas on cancer growth are less consistent. The aims of this work are to review preclinical evidence of second-generation sulfonylureas effects on tumor growth, to clarify the potential mechanisms of action, and to identify possible metabolic targets for patient selection. Most evidence is on the adenosine triphosphate-sensitive potassium channels inhibitor glibenclamide, which interacts with reactive oxygen species production thus inducing cancer cell death. Among diarylsulfonylureas, next-generation DW2282 derivatives are particularly promising because of the proapoptotic activity in multidrug-resistant cells.
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Affiliation(s)
- Giulia Pasello
- Second Medical Oncology Unit, Istituto Oncologico Veneto, Padua, Italy
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Wang Y, Wang S, Harvat T, Kinzer K, Zhang L, Feng F, Qi M, Oberholzer J. Diazoxide, a K(ATP) channel opener, prevents ischemia-reperfusion injury in rodent pancreatic islets. Cell Transplant 2013; 24:25-36. [PMID: 24070013 DOI: 10.3727/096368913x673441] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Diazoxide (DZ) is a pharmacological opener of ATP-sensitive K(+) channels that has been used for mimicking ischemic preconditioning and shows protection against ischemic damage. Here we investigated whether diazoxide supplementation to University of Wisconsin (UW) solution has cellular protection during islet isolation and improves in vivo islet transplant outcomes in a rodent ischemia model. C57/B6 mice pancreata were flushed with UW or UW + DZ solution and cold preserved for 6 or 10 h prior to islet isolation. Islet yield, in vitro and in vivo function, mitochondrial morphology, and apoptosis were evaluated. Significantly higher islet yields were observed in the UW + DZ group than in the UW group (237.5 ± 25.6 vs. 108.7 ± 49.3, p < 0.01). The islets from the UW + DZ group displayed a significantly higher glucose-induced insulin secretion (0.97 ng/ml ± 0.15 vs. 0.758 ng/ml ± 0.21, p = 0.009) and insulin content (60.96 ng/islet ± 13.94 vs. 42.09 ng/islet ± 8.15, p = 0.002). The DZ-treated islets had well-preserved mitochondrial morphology with superior responses of mitochondrial potentials, and calcium influx responded to glucose. A higher number of living cells and less late apoptotic cells were observed in the UW + DZ group (p < 0.05). Additionally, the islets from the UW + DZ group had a significantly higher cure rate and improved glucose tolerance. This study is the first to report mitoprotective effects of DZ for pancreas preservation and islet isolation. In the future, it will be necessary to further understand the underlying mechanism for the mitoprotection and to test this promising approach for pancreas preservation and the islet isolation process in nonhuman primates and ultimately humans.
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Affiliation(s)
- Yong Wang
- University of Illinois at Chicago Department of Transplant/Surgery, Chicago, IL, USA
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Yamanaka R, Shindo Y, Hotta K, Suzuki K, Oka K. NO/cGMP/PKG signaling pathway induces magnesium release mediated by mitoKATP channel opening in rat hippocampal neurons. FEBS Lett 2013; 587:2643-8. [PMID: 23831575 DOI: 10.1016/j.febslet.2013.06.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/26/2013] [Accepted: 06/26/2013] [Indexed: 11/19/2022]
Abstract
Intracellular Mg²⁺ concentration ([Mg²⁺]i) and NO regulate cell survival and death. To reveal the involvement of NO in intracellular Mg²⁺ regulation, we visualized intracellular Mg²⁺ using the fluorescent Mg²⁺ indicator KMG-104-AM in rat hippocampal neurons. Pharmacological experiments using SNAP, 8-Br-cGMP, diazoxide and several inhibitors revealed that the NO/cGMP/Protein kinsase G (PKG) signaling pathway triggers an increase in [Mg²⁺]i, and that Mg²⁺ mobilization is due to Mg²⁺ release from mitochondria induced by mitoKATP channel opening. In addition, Mg²⁺ release is potentiated by the positive feedback loop including mitoKATP channel opening, mitochondrial depolarization and PKC activation.
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Affiliation(s)
- Ryu Yamanaka
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Keio University, Yokohama, Kanagawa, Japan
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69
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Morota S, Manolopoulos T, Eyjolfsson A, Kimblad PO, Wierup P, Metzsch C, Blomquist S, Hansson MJ. Functional and pharmacological characteristics of permeability transition in isolated human heart mitochondria. PLoS One 2013; 8:e67747. [PMID: 23840770 PMCID: PMC3695980 DOI: 10.1371/journal.pone.0067747] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/22/2013] [Indexed: 11/18/2022] Open
Abstract
The objective of the present study was to validate the presence and explore the characteristics of mitochondrial permeability transition (mPT) in isolated mitochondria from human heart tissue in order to investigate if previous findings in animal models of cardiac disorders are translatable to human disease. Mitochondria were rapidly isolated from fresh atrial tissue samples obtained from 14 patients undergoing Maze surgery due to atrial fibrillation. Human heart mitochondria exhibited typical mPT characteristics upon calcium overload such as swelling, evaluated by changes in light scattering, inhibition of respiration and loss of respiratory coupling. Swelling was a morphologically reversible event following transient calcium challenge. Calcium retention capacity (CRC), a quantitative measure of mPT sensitivity assayed by following extramitochondrial [Ca(2+)] and changes in respiration during a continuous calcium infusion, was significantly increased by cyclophilin D (CypD) inhibitors. The thiol-reactive oxidant phenylarsine oxide sensitized mitochondria to calcium-induced mPT. Release of the pro-apoptotic intermembrane protein cytochrome c was increased after, but not before, calcium discharge and respiratory inhibition in the CRC assay. From the present study, we conclude that adult viable heart mitochondria have a CypD- and oxidant-regulated mPT. The findings support that inhibition of mPT may be a relevant pharmacological target in human cardiac disease and may underlie the beneficial effect of cyclosporin A in reperfusion injury.
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Affiliation(s)
- Saori Morota
- Mitochondrial Pathophysiology Unit, Skåne University Hospital & Lund University, Lund, Sweden
| | - Theodor Manolopoulos
- Department of Cardiothoracic Anesthesiology and Intensive Care, Skåne University Hospital & Lund University, Lund, Sweden
| | - Atli Eyjolfsson
- Department of Cardiothoracic Surgery, Skåne University Hospital & Lund University, Lund, Sweden
| | - Per-Ola Kimblad
- Department of Cardiothoracic Surgery, Skåne University Hospital & Lund University, Lund, Sweden
| | - Per Wierup
- Department of Cardiothoracic Surgery, Skåne University Hospital & Lund University, Lund, Sweden
| | - Carsten Metzsch
- Department of Cardiothoracic Anesthesiology and Intensive Care, Skåne University Hospital & Lund University, Lund, Sweden
| | - Sten Blomquist
- Department of Cardiothoracic Anesthesiology and Intensive Care, Skåne University Hospital & Lund University, Lund, Sweden
| | - Magnus J. Hansson
- Mitochondrial Pathophysiology Unit, Skåne University Hospital & Lund University, Lund, Sweden
- Department of Clinical Physiology, Skåne University Hospital & Lund University, Lund, Sweden
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Targeting microglial K(ATP) channels to treat neurodegenerative diseases: a mitochondrial issue. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:194546. [PMID: 23844272 PMCID: PMC3697773 DOI: 10.1155/2013/194546] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/26/2013] [Accepted: 05/08/2013] [Indexed: 12/11/2022]
Abstract
Neurodegeneration is a complex process involving different cell types and neurotransmitters. A common characteristic of neurodegenerative disorders is the occurrence of a neuroinflammatory reaction in which cellular processes involving glial cells, mainly microglia and astrocytes, are activated in response to neuronal death. Microglia do not constitute a unique cell population but rather present a range of phenotypes closely related to the evolution of neurodegeneration. In a dynamic equilibrium with the lesion microenvironment, microglia phenotypes cover from a proinflammatory activation state to a neurotrophic one directly involved in cell repair and extracellular matrix remodeling. At each moment, the microglial phenotype is likely to depend on the diversity of signals from the environment and of its response capacity. As a consequence, microglia present a high energy demand, for which the mitochondria activity determines the microglia participation in the neurodegenerative process. As such, modulation of microglia activity by controlling microglia mitochondrial activity constitutes an innovative approach to interfere in the neurodegenerative process. In this review, we discuss the mitochondrial KATP channel as a new target to control microglia activity, avoid its toxic phenotype, and facilitate a positive disease outcome.
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Boengler K, Ungefug E, Heusch G, Leybaert L, Schulz R. Connexin 43 impacts on mitochondrial potassium uptake. Front Pharmacol 2013; 4:73. [PMID: 23760924 PMCID: PMC3674322 DOI: 10.3389/fphar.2013.00073] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/17/2013] [Indexed: 11/13/2022] Open
Abstract
In cardiomyocytes, connexin 43 (Cx43) forms gap junctions and unopposed hemichannels at the plasma membrane, but the protein is also present at the inner membrane of subsarcolemmal mitochondria (SSM). Both inhibition and genetic ablation of Cx43 reduce ADP-stimulated complex 1 respiration. Since mitochondrial potassium influx impacts on oxygen consumption, we investigated whether or not inhibition or ablation of mitochondrial Cx43 alters mitochondrial potassium uptake. SSM were isolated from rat left ventricular myocardium and loaded with the potassium-sensitive dye PBFI (potassium-binding benzofuran isophthalate). Intramitochondrial potassium was replaced by tetraethylammonium. Mitochondria were incubated under control conditions or treated with 250 μM Gap19, a peptide that specifically inhibits Cx43-based hemichannels at plasma membranes. Subsequently, 140 mM KCl was added and the slope of the increase in PBFI fluorescence over time was calculated. The slope of the PBFI fluorescence of the control mitochondria was set to 100%. In the presence of Gap19, the mitochondrial potassium influx was reduced from 100 ± 11.6% in control mitochondria to 65.5 ± 10.7% (n = 6, p < 0.05). In addition to the pharmacological inhibition of Cx43, potassium influx was studied in mitochondria isolated from conditional Cx43 knockout mice. Here, the ablation of Cx43 was achieved by the injection of 4-hydroxytamoxifen (4-OHT; Cx43(Cre-ER(T)/fl) + 4-OHT). The mitochondria of the Cx43(Cre-ER(T)/fl) + 4-OHT mice contained 3 ± 1% Cx43 (n = 6) of that in control mitochondria (100 ± 11%, n = 8, p < 0.05). The ablation of Cx43 (n = 5) reduced the velocity of the potassium influx from 100 ± 11.2% in control mitochondria (n = 9) to 66.6 ± 5.5% (p < 0.05). Taken together, our data indicate that both pharmacological inhibition and genetic ablation of Cx43 reduce mitochondrial potassium influx.
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Affiliation(s)
- Kerstin Boengler
- Physiologisches Institut, Justus-Liebig-Universität Giessen Giessen, Germany
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72
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Cardiac KATP channel alterations associated with acclimation to hypoxia in goldfish (Carassius auratus L.). Comp Biochem Physiol A Mol Integr Physiol 2013; 164:554-64. [DOI: 10.1016/j.cbpa.2012.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/24/2012] [Accepted: 12/25/2012] [Indexed: 01/21/2023]
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Wojtovich AP, Smith CO, Haynes CM, Nehrke KW, Brookes PS. Physiological consequences of complex II inhibition for aging, disease, and the mKATP channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:598-611. [PMID: 23291191 DOI: 10.1016/j.bbabio.2012.12.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/14/2012] [Accepted: 12/17/2012] [Indexed: 12/21/2022]
Abstract
In recent years, it has become apparent that there exist several roles for respiratory complex II beyond metabolism. These include: (i) succinate signaling, (ii) reactive oxygen species (ROS) generation, (iii) ischemic preconditioning, (iv) various disease states and aging, and (v) a role in the function of the mitochondrial ATP-sensitive K(+) (mKATP) channel. This review will address the involvement of complex II in each of these areas, with a focus on how complex II regulates or may be involved in the assembly of the mKATP. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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74
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Diabetes mellitus reduces the function and expression of ATP-dependent K⁺ channels in cardiac mitochondria. Life Sci 2012; 92:664-8. [PMID: 23261529 DOI: 10.1016/j.lfs.2012.11.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/21/2012] [Accepted: 11/24/2012] [Indexed: 11/20/2022]
Abstract
AIM Our goal was to determine the effects of type I diabetes mellitus on the function and expression of ATP-dependent K(+) channels in cardiac mitochondria (mitoKATP), composed of a pore-forming subunit (Kir6.1) and a diazoxide-sensitive sulphonylurea receptor (SUR1). We tested the hypothesis that diabetes reduces Kir6.1 and SUR1 expression as well as diazoxide-induced depolarization of mitochondrial membrane potential (ΔΨm). MAIN METHODS Male FVB mice were made diabetic for 5weeks with multiple low dose injections of streptozotocin. Cardiac mitochondria were separated into two populations: subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). mitoKATP expression was determined via Western blot analysis of Kir6.1 and SUR1 proteins. mitoKATP function was determined by measuring ΔΨm with the potentiometric dye rhodamine 123. KEY FINDINGS Diabetes reduced Kir6.1 and SUR1 expression in IFM by over 40% (p<0.05 for both). Similarly, diabetes reduced Kir6.1 expression in SSM by approximately 40% (p<0.05); however, SUR1 expression was unaffected. Opening mitoKATP with diazoxide (100μM) depolarized control IFM ΔΨm by 80% of the valinomycin maximum; diabetic IFM depolarized only 30% (p<0.05). Diazoxide-induced depolarization was much less in SSM (20-30%) and unaffected by diabetes. SIGNIFICANCE Our data indicate that diabetes reduces mitoKATP expression and function in IFM. These changes in mitoKATP may provide an opportunity to understand mechanisms leading to diabetic cardiomyopathy and loss of cardioprotective mechanisms in the diabetic heart.
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The mitochondrial permeability transition pore (PTP) — An example of multiple molecular exaptation? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:2072-86. [DOI: 10.1016/j.bbabio.2012.06.620] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 11/21/2022]
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Zuo XR, Wang Q, Cao Q, Yu YZ, Wang H, Bi LQ, Xie WP, Wang H. Nicorandil prevents right ventricular remodeling by inhibiting apoptosis and lowering pressure overload in rats with pulmonary arterial hypertension. PLoS One 2012; 7:e44485. [PMID: 22970229 PMCID: PMC3436887 DOI: 10.1371/journal.pone.0044485] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 08/08/2012] [Indexed: 11/18/2022] Open
Abstract
Background Most of the deaths among patients with severe pulmonary arterial hypertension (PAH) are caused by progressive right ventricular (RV) pathological remodeling, dysfunction, and failure. Nicorandil can inhibit the development of PAH by reducing pulmonary artery pressure and RV hypertrophy. However, whether nicorandil can inhibit apoptosis in RV cardiomyocytes and prevent RV remodeling has been unclear. Methodology/Principal Findings RV remodeling was induced in rats by intraperitoneal injection of monocrotaline (MCT). RV systolic pressure (RVSP) was measured at the end of each week after MCT injection. Blood samples were drawn for brain natriuretic peptide (BNP) ELISA analysis. The hearts were excised for histopathological, ultrastructural, immunohistochemical, and Western blotting analyses. The MCT-injected rats exhibited greater mortality and less weight gain and showed significantly increased RVSP and RV hypertrophy during the second week. These worsened during the third week. MCT injection for three weeks caused pathological RV remodeling, characterized by hypertrophy, fibrosis, dysfunction, and RV mitochondrial impairment, as indicated by increased levels of apoptosis. Nicorandil improved survival, weight gain, and RV function, ameliorated RV pressure overload, and prevented maladaptive RV remodeling in PAH rats. Nicorandil also reduced the number of apoptotic cardiomyocytes, with a concomitant increase in Bcl-2/Bax ratio. 5-hydroxydecanoate (5-HD) reversed these beneficial effects of nicorandil in MCT-injected rats. Conclusions/Significance Nicorandil inhibits PAH-induced RV remodeling in rats not only by reducing RV pressure overload but also by inhibiting apoptosis in cardiomyocytes through the activation of mitochondrial ATP-sensitive K+ (mitoKATP) channels. The use of a mitoKATP channel opener such as nicorandil for PAH-associated RV remodeling and dysfunction may represent a new therapeutic strategy for the amelioration of RV remodeling during the early stages of PAH.
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Affiliation(s)
- Xiang-Rong Zuo
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
- Department of Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Qiang Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Quan Cao
- Department of Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Yan-Zhe Yu
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Hui Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Li-Qing Bi
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
| | - Wei-Ping Xie
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
- * E-mail: (HW); (WX)
| | - Hong Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China
- * E-mail: (HW); (WX)
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Korotkov SM, Emel'yanova LV, Brailovskaya IV, Nesterov VP. Effects of pinacidil and calcium on isolated rat heart mitochondria. DOKL BIOCHEM BIOPHYS 2012; 443:113-7. [PMID: 22562638 DOI: 10.1134/s1607672912020147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Indexed: 11/23/2022]
Affiliation(s)
- S M Korotkov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Morisa Toreza 44, St. Petersburg, 194223 Russia
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Husainy MA, Dickenson JM, Galiñanes M. The MPTP Status During Early Reoxygenation is Critical for Cardioprotection. J Surg Res 2012; 174:62-72. [DOI: 10.1016/j.jss.2010.11.879] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/22/2010] [Accepted: 11/05/2010] [Indexed: 10/18/2022]
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80
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Tsounapi P, Saito M, Dimitriadis F, Kitatani K, Kinoshita Y, Shomori K, Takenaka A, Satoh K. The role of KATP channels on ischemia-reperfusion injury in the rat testis. Life Sci 2012; 90:649-56. [DOI: 10.1016/j.lfs.2012.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/16/2012] [Accepted: 02/28/2012] [Indexed: 12/30/2022]
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81
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Ohmasa F, Saito M, Oiwa H, Tsounapi P, Shomori K, Kitatani K, Dimitriadis F, Kinoshita Y, Satoh K. Pharmacological preconditioning of ATP-sensitive potassium channel openers on acute urinary retention-induced bladder dysfunction in the rat. BJU Int 2012; 110:E245-52. [DOI: 10.1111/j.1464-410x.2012.10965.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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82
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Higuchi S, Ii M, Zhu P, Ashraf M. Delta-Opioid Receptor Activation Promotes Mesenchymal Stem Cell Survival via PKC/STAT3 Signaling Pathway. Circ J 2012; 76:204-12. [DOI: 10.1253/circj.cj-11-0309] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Masaaki Ii
- Department of Pharmacology, Osaka Medical College
| | - Ping Zhu
- Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Science
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83
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Griffiths EJ. Mitochondria and heart disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 942:249-67. [PMID: 22399426 DOI: 10.1007/978-94-007-2869-1_11] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mitochondria play a key role in the normal functioning of the heart, and in the pathogenesis and development of various types of heart disease. Physiologically, mitochondrial ATP supply needs to be matched to the often sudden changes in ATP demand of the heart, and this is mediated to a large extent by the mitochondrial Ca(2+) transport pathways allowing elevation of mitochondrial [Ca(2+)] ([Ca(2+)](m)). In turn this activates dehydrogenase enzymes to increase NADH and hence ATP supply. Pathologically, [Ca(2+)](m) is also important in generation of reactive oxygen species, and in opening of the mitochondrial permeability transition pore (MPTP); factors involved in both ischaemia-reperfusion injury and in heart failure. The MPTP has proved a promising target for protective strategies, with inhibitors widely used to show cardioprotection in experimental, and very recently human, studies. Similarly mitochondrially-targeted antioxidants have proved protective in various animal models of disease and await clinical trials. The mitochondrial Ca(2+) transport pathways, although in theory promising therapeutic targets, cannot yet be targeted in human studies due to non-specific effects of drugs used experimentally to inhibit them. Finally, specific mitochondrial cardiomyopathies due to mutations in mtDNA have been identified, usually in a gene for a tRNA, which, although rare, are almost always very severe once the mutation has exceeded its threshold.
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de Tullio P, Servais AC, Fillet M, Gillotin F, Somers F, Chiap P, Lebrun P, Pirotte B. Hydroxylated Analogues of ATP-Sensitive Potassium Channel Openers Belonging to the Group of 6- and/or 7-Substituted 3-Isopropylamino-4H-1,2,4-benzothiadiazine 1,1-Dioxides: Toward an Improvement in Sulfonylurea Receptor 1 Selectivity and Metabolism Stability. J Med Chem 2011; 54:8353-61. [DOI: 10.1021/jm200786z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pascal de Tullio
- Drug Research Center, Laboratoire de Chimie Pharmaceutique, Université de Liège, Centre Hospitalier Universitaire de Liège, 1 Avenue de l'Hôpital, B36, 4000 Liège, Belgium.
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Szabò I, Leanza L, Gulbins E, Zoratti M. Physiology of potassium channels in the inner membrane of mitochondria. Pflugers Arch 2011; 463:231-46. [PMID: 22089812 DOI: 10.1007/s00424-011-1058-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 10/30/2011] [Indexed: 02/06/2023]
Abstract
The inner membrane of the ATP-producing organelles of endosymbiotic origin, mitochondria, has long been considered to be poorly permeable to cations and anions, since the strict control of inner mitochondrial membrane permeability is crucial for efficient ATP synthesis. Over the past 30 years, however, it has become clear that various ion channels--along with antiporters and uniporters--are present in the mitochondrial inner membrane, although at rather low abundance. These channels are important for energy supply, and some are a decisive factor in determining whether a cell lives or dies. Their electrophysiological and pharmacological characterisations have contributed importantly to the ongoing elucidation of their pathophysiological roles. This review gives an overview of recent advances in our understanding of the functions of the mitochondrial potassium channels identified so far. Open issues concerning the possible molecular entities giving rise to the observed activities and channel protein targeting to mitochondria are also discussed.
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Affiliation(s)
- Ildikò Szabò
- Department of Biology, University of Padova, Padova, Italy.
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Terzic A, Alekseev AE, Yamada S, Reyes S, Olson TM. Advances in cardiac ATP-sensitive K+ channelopathies from molecules to populations. Circ Arrhythm Electrophysiol 2011; 4:577-85. [PMID: 21846889 DOI: 10.1161/circep.110.957662] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Andre Terzic
- Marriott Heart Disease Research Program, Division of Cardiovascular Diseases, Department of Internal Medicine, Department of Molecular Pharmacology and Experimental Therapeutics, Department of Medical Genetics, Mayo Clinic, Rochester, MN, 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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Gouriou Y, Demaurex N, Bijlenga P, De Marchi U. Mitochondrial calcium handling during ischemia-induced cell death in neurons. Biochimie 2011; 93:2060-7. [PMID: 21846486 DOI: 10.1016/j.biochi.2011.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/03/2011] [Indexed: 12/18/2022]
Abstract
Mitochondria sense and shape cytosolic Ca(2+) signals by taking up and subsequently releasing Ca(2+) ions during physiological and pathological Ca(2+) elevations. Sustained elevations in the mitochondrial matrix Ca(2+) concentration are increasingly recognized as a defining feature of the intracellular cascade of lethal events that occur in neurons during cerebral ischemia. Here, we review the recently identified transport proteins that mediate the fluxes of Ca(2+) across mitochondria and discuss the implication of the permeability transition pore in decoding the abnormally sustained mitochondrial Ca(2+) elevations that occur during cerebral ischemia.
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Affiliation(s)
- Yves Gouriou
- Department of Cell Physiology and Metabolism, University of Geneva, rue Michel-Servet 1, Genève, Switzerland
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89
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Guo W, Ge D, Wang Q, Xu S, Xue L, Lu C, Tan L. Diazoxide decreases ischemia-reperfusion injury in a rat model of lung transplantation. Transplant Proc 2011; 43:2510-6. [PMID: 21911115 DOI: 10.1016/j.transproceed.2011.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 04/21/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Ischemia-reperfusion injury (IRI) is a significant factor contributing to primary graft failure in lung transplantation. Given a pivotal role of mitochondria in IRI-related molecular events, the effects of diazoxide, a selective opener of mitochondrial adenosine-5'-triphosphate (ATP)-sensitive potassium channels (mitoK(ATP)), on IRI were investigated in a rat model of lung transplantation. METHODS The 108 rats were randomly assigned to 5 groups; a sham-operated, 2 control, and 2 experimental groups that received either diazoxide alone or a combination of diazoxide with 5-hydroxydecanoate sodium salt. Lung injuries were assessed by multiple parameters at 2 hours or 24 hours after reperfusion, including oxygenation index, wet/dry weight ratio of transplanted lungs, lung morphology, as well as measurements of myeloperoxidase, malondialdehyde, total antioxidant capacity, tumor necrosis factor-α, and interleukin-6. RESULTS Compared with the sham group, the 2 control groups revealed significant changes among most parameters of lung injury measured at either 2 hours or 24 hours after reperfusion. The extent of the changes was dramatically reduced by the administration of diazoxide. Importantly, the protective effect of diazoxide was almost completely reversed by co-administration of 5-hydroxydecanoate sodium salt, a selective blocker of mitoK(ATP). CONCLUSIONS These data provide evidence for substantial protective effects of diazoxide in an in vivo rat lung IRI model. Pharmacological modulation of mitoK(ATP) may be a potential strategy to reduce IRI-induced primary graft failure in lung transplantation.
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Affiliation(s)
- W Guo
- Department of Thoracic Surgery, The Affiliated Zhongshan Hospital of Fudan University, Xuhui District, Shanghai, China
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90
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Yıldız H, Durmus AS, Şimşek H, Yaman M. Dose-dependent protective effect of sildenafil citrate on testicular injury after torsion/detorsion in rats. Andrologia 2011; 44 Suppl 1:300-6. [PMID: 21749432 DOI: 10.1111/j.1439-0272.2011.01181.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
This experiment was designed to investigate the effect of sildenafil citrate on testicular injury after unilateral testicular torsion/detorsion (T/D). Thirty-seven adult male Wistar albino rats were divided into four groups: sham operated group (group 1), T/D+ saline (group 2), T/D+ 0.7 mg sildenafil citrate (group 3) and T/D+ 1.4 mg sildenafil citrate (group 4). Testicular torsion was created by rotating the right testis 720° in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. The level of GSH (P < 0.05) in the testis in the group 2 were significantly lower (P < 0.05) and the levels of MDA and NO (P < 0.01 for both) in the testis were significantly higher when compared with those of the group 1. Administration of low dose sildenafil citrate prevented the increases in MDA and NO levels and decreases in GSH values induced by testicular torsion. However, administration of high dose sildenafil citrate did not have any effect on these testicular tissue parameters (P > 0.05). Also, mean values of seminiferous tubules diameters, germinal cell layer thicknesses and mean testicular biopsy score were significantly better in group 3 than groups 2 and 4. These results suggest that T/D injury occurred in testis after unilateral testicular T/D and that administration of low dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular torsion. Sildenafil citrate probably acts through reduction of reactive oxygen species and support antioxidant enzyme systems.
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Affiliation(s)
- H Yıldız
- Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Fırat University, Elazig, Turkey.
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91
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Murphy E, Steenbergen C. What makes the mitochondria a killer? Can we condition them to be less destructive? BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:1302-8. [PMID: 20837069 PMCID: PMC3398608 DOI: 10.1016/j.bbamcr.2010.09.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 08/10/2010] [Accepted: 09/01/2010] [Indexed: 12/22/2022]
Abstract
Cardioprotection, such as preconditioning and postconditioning, has been shown to result in a significant reduction in cell death. Many of the signaling pathways activated by cardioprotection have been elucidated, but there is still a lack of understanding of the mechanisms by which these signaling pathways reduce cell death. Mitochondria have been reported to be an important player in many types of apoptotic and necrotic cell death. If mitochondria play an important role in cell death, then it seems reasonable to consider that cardioprotective mechanisms might act, at least in part, by opposing mitochondrial cell death pathways. One of the major mechanisms of cell death in ischemia-reperfusion is suggested to be the opening of a large conductance pore in the inner mitochondrial membrane, known as the mitochondrial permeability transition pore. Inhibition of this mitochondrial pore appears to be one of the major mechanisms by which cardioprotection reduces cell death. Cardioprotection activates a number of signaling pathways that reduce the level of triggers (reactive oxygen species and calcium) or enhances inhibitors of the mitochondrial permeability transition pore at the start of reperfusion. This article is part of a Special Issue entitled: Mitochondria and Cardioprotection.
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Affiliation(s)
- Elizabeth Murphy
- Translational Medicine Branch, NHLBI, NIH, Bethesda, MD 20892, USA.
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92
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Modulation of myocardial mitochondrial mechanisms during severe polymicrobial sepsis in the rat. PLoS One 2011; 6:e21285. [PMID: 21712982 PMCID: PMC3119671 DOI: 10.1371/journal.pone.0021285] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/24/2011] [Indexed: 01/13/2023] Open
Abstract
Background We tested the hypothesis that 5-Hydroxydecanoic acid (5HD), a putative mitoKATP channel blocker, will reverse sepsis-induced cardiodynamic and adult rat ventricular myocyte (ARVM) contractile dysfunction, restore mitochondrial membrane permeability alterations and improve survival. Methodology/Principal Findings Male Sprague-Dawley rats (350–400 g) were made septic using 400 mg/kg cecal inoculum, ip. Sham animals received 5% dextrose water, ip. The Voltage Dependent Anion Channels (VDAC1), Bax and cytochrome C levels were determined in isolated single ARVMs obtained from sham and septic rat heart. Mitochondria and cytosolic fractions were isolated from ARVMs treated with norepinephrine (NE, 10 µmoles) in the presence/absence of 5HD (100 µmoles). A continuous infusion of 5HD using an Alzet pump reversed sepsis-induced mortality when administered at the time of induction of sepsis (−40%) and at 6 hr post-sepsis (−20%). Electrocardiography revealed that 5HD reversed sepsis-induced decrease in the average ejection fraction, Simpsons+m Mode (53.5±2.5 in sepsis and 69.2±1.2 at 24 hr in sepsis+5HD vs. 79.9±1.5 basal group) and cardiac output (63.3±1.2 mL/min sepsis and 79.3±3.9 mL/min at 24 hr in sepsis+5HD vs. 85.8±1.5 mL/min basal group). The treatment of ARVMs with 5HD also reversed sepsis-induced depressed contractility in both the vehicle and NE-treated groups. Sepsis produced a significant downregulation of VDAC1, and upregulation of Bax levels, along with mitochondrial membrane potential collapse in ARVMs. Pretreatment of septic ARVMs with 5HD blocked a NE-induced decrease in the VDAC1 and release of cytochrome C. Conclusion The data suggest that Bax activation is an upstream event that may precede the opening of the mitoKATP channels in sepsis. We concluded that mitoKATP channel inhibition via decreased mitochondrial membrane potential and reduced release of cytochrome C provided protection against sepsis-induced ARVM and myocardial contractile dysfunction.
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93
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Sanbe A, Marunouchi T, Yamauchi J, Tanonaka K, Nishigori H, Tanoue A. Cardioprotective effect of nicorandil, a mitochondrial ATP-sensitive potassium channel opener, prolongs survival in HSPB5 R120G transgenic mice. PLoS One 2011; 6:e18922. [PMID: 21541347 PMCID: PMC3081834 DOI: 10.1371/journal.pone.0018922] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 03/17/2011] [Indexed: 11/29/2022] Open
Abstract
Background Transgenic (TG) mice with overexpression of an arg120gly (R120G) missense mutation in HSPB5 display desmin-related cardiomyopathy, which is characterized by formation of aggresomes. It is also known that progressive mitochondrial abnormalities and apoptotic cell death occur in the hearts of R120G TG mice. The role of mitochondrial dysfunction and apoptosis in disease progression, however, remains uncertain. Methods and Results Mitochondrial abnormalities and apoptotic cell death induced by overexpression of HSPB5 R120G were analyzed in neonatal rat cardiomyocytes. Overexpression of mutant HSPB5 led to development of aggresomes with a concomitant reduction in cell viability in the myocytes. Overexpression of mutant HSPB5 induced a reduction in the cytochrome c level in the mitochondrial fraction and a corresponding increase in the cytoplasmic fraction in the myocytes. Down-regulation of BCL2 and up-regulation of BAX were detected in the myocytes expressing the mutant HSPB5. Concomitant with mitochondrial abnormality, the activation of caspase-3 and increased apoptotic cell death was observed. Cell viability was dose-dependently recovered in myocytes overexpressing HSPB5 R120G by treatment with nicorandil a mitochondrial ATP-sensitive potassium channel opener. Nicorandil treatment also inhibited the increase in BAX, the decrease in BCL2, activation of caspase-3 and apoptotic cell death by mutant HSPB5. To confirm the results of the in-vitro study, we analyzed the effect of nicorandil in HSPB5 R120G TG mice. Nicorandil treatment appeared to reduce mitochondrial impairment and apoptotic cell death and prolonged survival in HSPB5 R120G TG mice. Conclusions Nicorandil may prolong survival in HSPB5 R120G TG mice by protecting against mitochondrial impairments.
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Affiliation(s)
- Atsushi Sanbe
- Department of Pharmacotherapeutics, School of Pharmacy, Iwate Medical University, Iwate, Japan.
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94
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Pirotte B, de Tullio P, Boverie S, Michaux C, Lebrun P. Impact of the nature of the substituent at the 3-position of 4H-1,2,4-benzothiadiazine 1,1-dioxides on their opening activity toward ATP-sensitive potassium channels. J Med Chem 2011; 54:3188-99. [PMID: 21428460 DOI: 10.1021/jm200100c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of diversely substituted 3-isopropoxy-, 3-isopropylsulfanyl-, 3-isopropylsulfinyl-, and 3-isobutyl-4H-1,2,4-benzothiadiazine 1,1-dioxides is described. Their activity on pancreatic β-cells (inhibitory effect on the insulin releasing process) and on vascular and uterine smooth muscle tissues (myorelaxant effects) was compared to that of previously reported K(ATP) channel openers belonging to 3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides. The present study aimed at evaluating the impact on biological activity of the isosteric replacement of the NH group of 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides by a O, S, S(═O), or CH(2) group. By comparing compounds bearing identical substituents, the following rank order of potency on pancreatic β-cells was observed: 3-isopropylamino > 3-isobutyl > 3-isopropoxy > 3-isopropylsulfanyl > 3-isopropylsulfinyl-substituted 4H-1,2,4-benzothiadiazine 1,1-dioxides (NH > CH(2) > O > S > S(═O)). A molecular modeling study revealed that 3-isopropoxy-, 3-isopropylsulfanyl-, and 3-isopropylamino-substituted compounds adopted a similar low-energy conformation (preferred orientation of the isopropyl chain). Moreover, no direct relationship was detected between the conformational freedom of the different classes of benzothiadiazines (from the most to the lowest conformationally constrained compounds: NH > O > S > CH(2)) and their biological activity on insulin-secreting cells. Therefore, the present study confirmed the critical role of the NH group at the 3-position for the establishment of a strong hydrogen bond responsible for optimal activity expressed by 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides on insulin-secreting cells. Radioisotopic and fluorimetric experiments conducted with 7-chloro-3-isopropoxy-4H-1,2,4-benzothiadiazine 1,1-dioxide 10c demonstrated that such a compound, bearing a short branched O-alkyl group instead of the NH-alkyl group at the 3-position, also behaved as a specific K(ATP) channel opener. Lastly, the present work further identified 3-(alkyl/aralkyl)sulfanyl-substituted 7-chloro-4H-1,2,4-benzothiadiazine 1,1-dioxides as a class of promising myorelaxant drugs acting on uterine smooth muscles, at least in part, through the activation of K(ATP) channels.
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Affiliation(s)
- Bernard Pirotte
- Laboratoire de Chimie Pharmaceutique, Centre Interfacultaire de Recherche du Médicament (Drug Research Center), Université de Liège , C.H.U., 1 Avenue de l'Hôpital, B-4000 Liège, Belgium.
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95
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Abstract
Several signal transduction pathways are activated by cardioprotective stimuli, including ischemic or pharmacological postconditioning. These pathways converge on a common target, the mitochondria, and cardioprotection by postconditioning is associated with preserved mitochondrial function after ischemia/reperfusion. The present review discusses the role of mitochondria in cardioprotection, especially the involvement of ATP-dependent potassium channels, reactive oxygen species, and the mitochondrial permeability transition pore, and focuses on the effects of postconditioning on mitochondrial function (i.e., their oxygen consumption and calcium retention capacity). The contribution of mitochondria to loss of protection by postconditioning in diseased or aged myocardium is also addressed.
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Affiliation(s)
- Kerstin Boengler
- Institut für Pathophysiologie, Universitätsklinikum Essen, Hufelandstrasse 55, Essen, Germany.
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96
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Wang L, Zhu QL, Wang GZ, Deng TZ, Chen R, Liu MH, Wang SW. The protective roles of mitochondrial ATP-sensitive potassium channels during hypoxia-ischemia-reperfusion in brain. Neurosci Lett 2011; 491:63-7. [PMID: 21215294 DOI: 10.1016/j.neulet.2010.12.065] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/14/2010] [Accepted: 12/31/2010] [Indexed: 11/27/2022]
Abstract
The role of ATP-sensitive potassium (K(ATP)) channels in cerebral ischemia-reperfusion has been well documented. K(ATP) channel openers protect neuron by mimicking ischemic preconditioning. However, the different protection between the mitochondrial and sarcolemma K(ATP) openers has been seldom studied. In the experiment, we investigated the effects of K(ATP) channel openers diazoxide and pinacidil on the hypoxia-ischemia-reperfusion in cultured hippocampal neurons and gerbil brain. The cultured hippocampal neurons and gerbil brain were pretreated with diazoxide or pinacidil before oxygen-glucose deprivation (OGD) and cerebral ischemia-reperfusion, respectively. Survival rate, apoptosis rate and lactate dehydrogenase (LDH) releasing after the reperfusion were subsequently detected. Then the subunits mRNA was detected by RT-PCR. The survival rate and LDH content in diazoxide group increased more than that in pinacidil group (86.21±2.73% vs. 78.59±1.94%, P<0.05; 133.29±15.00 U/L vs. 193.47±3.39 U/L, P<0.01). The apoptosis rate in diazoxide group decreased significantly more than that in pinacidil group (23.82±0.14% vs. 37.05±0.67%, P<0.01). Diazoxide pretreatment increased the expression of Kir6.1 mRNA obviously. The results suggested that mitoK(ATP) channels opener diazoxide played a major protective role on cerebral ischemia-reperfusion. Furthermore, diazoxide might become a new treatment for cerebral ischemia diseases through increasing the expression of Kir6.1 mRNA.
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Affiliation(s)
- Lin Wang
- Institute of Geriatric Cardiology, Chinese PLA General Hospital, Fuxing Road 28, Beijing 100853, China
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97
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De Marchi U, Checchetto V, Zanetti M, Teardo E, Soccio M, Formentin E, Giacometti GM, Pastore D, Zoratti M, Szabò I. ATP-sensitive cation-channel in wheat (Triticum durum Desf.): identification and characterization of a plant mitochondrial channel by patch-clamp. Cell Physiol Biochem 2011; 26:975-82. [PMID: 21220928 DOI: 10.1159/000324010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2010] [Indexed: 11/19/2022] Open
Abstract
Indirect evidence points to the presence of K(+) channels in plant mitochondria. In the present study, we report the results of the first patch clamp experiments on plant mitochondria. Single-channel recordings in 150 mM potassium gluconate have allowed the biophysical characterization of a channel with a conductance of 150 pS in the inner mitochondrial membrane of mitoplasts obtained from wheat (Triticum durum Desf.). The channel displayed sharp voltage sensitivity, permeability to potassium and cation selectivity. ATP in the mM concentration range completely abolished the activity. We discuss the possible molecular identity of the channel and its possible role in the defence mechanisms against oxidative stress in plants.
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Affiliation(s)
- Umberto De Marchi
- Department of Experimental Biomedical Sciences, CNR Institute of Neuroscience, University of Padova, Padova, Italy.
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98
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Yíldíz H, Durmus AS, Simşek H, Yaman M. Protective effect of sildenafil citrate on contralateral testis injury after unilateral testicular torsion/detorsion. Clinics (Sao Paulo) 2011; 66:137-42. [PMID: 21437450 PMCID: PMC3044577 DOI: 10.1590/s1807-59322011000100024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/10/2010] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVES This study was designed to investigate prevention of contralateral testicular injury with sildenafil citrate after unilateral testicular torsion/detorsion. METHODS Thirty-seven adult male rats were divided into four groups: sham operated (group 1, n = 7), torsion/detorsion + saline (group 2, n = 10), torsion/detorsion + 0.7 mg of sildenafil citrate (group 3, n = 10) and torsion/detorsion + 1.4 mg of sildenafil citrate (group 4, n = 10). Unilateral testicular torsion was created by rotating the right testis 720º in a clockwise direction for 2 h in other groups, except for group 1, which was served as sham group. After torsion (2 h) and detorsion (2 h) periods, rats were killed. RESULTS The level of reduced glutathion (GSH) (p < 0.05) and the activities of catalase (p < 0.01) and glutathione peroxidase (p < 0.05) in the contralateral testis from group 2 were significantly lower and nitric oxide (NO) (p < 0.05) level in the contralateral testis were significantly higher than those of group 1. Administration of low-dose sildenafil citrate (group 3) prevented the increases in malondialdehyde and NO levels and decreases in glutathione peroxidase activities and GSH values induced by testicular torsion. However, administration of high-dose sildenafil citrate (group 4) had no effect on these testicular parameters (p > 0.05). Histopathological changes were detected in groups 2, 3 and 4. CONCLUSION These results suggest that biochemically and histologically torsion/detorsion injury occurs in the contralateral testis following 2-h torsion and 2-h detorsion and that administration of low-dose sildenafil citrate before detorsion prevents ischemia/reperfusion cellular damage in testicular tissue.
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Affiliation(s)
- Hamit Yíldíz
- Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Fírat University, Elazíğ, Turkey.
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López-Barneo J, Nurse CA, Nilsson GE, Buck LT, Gassmann M, Bogdanova AY. First aid kit for hypoxic survival: sensors and strategies. Physiol Biochem Zool 2010; 83:753-63. [PMID: 20578845 DOI: 10.1086/651584] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Survival success under conditions of acute oxygen deprivation depends on efficiency of the central and peripheral chemoreception, optimization of oxygen extraction from the hypoxic environment and its delivery to the periphery, and adjustments of energy production and consumption. This article uses a comparative approach to assess the efficiency of adaptive strategies used by anoxia-tolerant and hypoxia-sensitive species to support survival during the first minutes to 1 h of oxygen deprivation. An aquatic environment is much more demanding in terms of diurnal and seasonal variations of the ambient oxygen availability from anoxia to hyperoxia than is an air environment. Therefore, fishes and aquatic turtles have developed a number of adaptive responses, which are lacking in most of the terrestrial mammals, to cope with these extreme conditions. These include efficient central and peripheral chemoreception, acute changes in respiratory rate and amplitude, and acute increase of the gas-exchange interface. A special set of adaptive mechanisms are engaged in reduction of the energy expenditure of the major oxygen-consuming organs: the brain and the heart. Both reduction of ATP consumption and a switch to alterative energy sources contribute to the maintenance of ATP and ion balance in hypoxia-tolerant animals. Hypoxia and hyperoxia are conditions favoring development of oxidative stress. Efficient protection from oxidation in anoxia-tolerant species includes reduction in the glutamate levels in the brain, stabilization of the mitochondrial function, and maintenance of nitric oxide production under conditions of oxygen deprivation. We give an overview of the current state of knowledge on some selected molecular and cellular acute adaptive mechanisms. These include the mechanisms of chemoreception in adult and neonatal mammals and in fishes, acute metabolic adaptive responses in the brain, and the role of nitrite in the preservation of heart function under hypoxic conditions.
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Abstract
The mitochondrion is a powerhouse of the cell, a platform of cell signaling and decision-maker of cell death, including death by ischemia/reperfusion. Ischemia shuts off ATP production by mitochondria, and cell viability is compromised by energy deficiency and build-up of cytotoxic metabolites during ischemia. Furthermore, the mitochondrial permeability transition pore (mPTP) is primed by ischemia to open upon reperfusion, leading to reperfusion-induced cell necrosis. mPTP opening can be suppressed by ischemic preconditioning (IPC) and other interventions that induce phosphorylation of GSK-3beta. Activation of the mitochondrial ATP-sensitive K(+) channel (mK(ATP) channel) is an important signaling step in a trigger phase of IPC, which ultimately enhances GSK-3beta phosphorylation upon reperfusion, and this channel functions as a mediator of cytoprotection as well. The mitochondrial Ca(2+)-activated K(+) channel appears to play roles similar to those of the mK(ATP) channel, though regulatory mechanisms of the channels are different. Phosphorylated GSK-3beta inhibits mPTP opening presumably by multiple mechanisms, including preservation of hexokinase II in mPTP complex, prevention of interaction of cyclophilin-D with adenine nucleotide translocase, inhibition of p53 activation and attenuation of ATP hydrolysis during ischemia. However, cytoprotective signaling pathways to GSK-3beta phosphorylation and other mPTP regulatory factors are modified by co-morbidities, including type 2 diabetes, and such modification makes the myocardium refractory to IPC and other cardioprotective agents. Regulatory mechanisms of mPTP, and their alterations by morbidities frequently associated with ischemic heart disease need to be further characterized for translation of mitochondrial and mPTP biology to the clinical arena.
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