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Lukowski R, Cruz Santos M, Kuret A, Ruth P. cGMP and mitochondrial K + channels-Compartmentalized but closely connected in cardioprotection. Br J Pharmacol 2021; 179:2344-2360. [PMID: 33991427 DOI: 10.1111/bph.15536] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 01/01/2023] Open
Abstract
The 3',5'-cGMP pathway triggers cytoprotective responses and improves cardiomyocyte survival during myocardial ischaemia and reperfusion (I/R) injury. These beneficial effects were attributed to NO-sensitive GC induced cGMP production leading to activation of cGMP-dependent protein kinase I (cGKI). cGKI in turn phosphorylates many substrates, which eventually facilitate opening of mitochondrial ATP-sensitive potassium channels (mitoKATP ) and Ca2+ -activated potassium channels of the BK type (mitoBK). Accordingly, agents activating mitoKATP or mitoBK provide protection against I/R-induced damages. Here, we provide an up-to-date summary of the infarct-limiting actions exhibited by the GC/cGMP axis and discuss how mitoKATP and mitoBK, which are present at the inner mitochondrial membrane, confer mito- and cytoprotective effects on cardiomyocytes exposed to I/R injury. In view of this, we believe that the functional connection between the cGMP cascade and mitoK+ channels should be exploited further as adjunct to reperfusion therapy in myocardial infarction.
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Affiliation(s)
- Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Melanie Cruz Santos
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Anna Kuret
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
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Abstract
The 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type I (cGKI aka PKGI) is a major cardiac effector acting downstream of nitric oxide (NO)-sensitive soluble guanylyl cyclase and natriuretic peptides (NPs), which signal through transmembrane guanylyl cyclases. Consistent with the wide distribution of the cGMP-generating guanylyl cyclases, cGKI, which usually elicits its cellular effects by direct phosphorylation of its targets, is present in multiple cardiac cell types including cardiomyocytes (CMs). Although numerous targets of cGMP/cGKI in heart were identified in the past, neither their exact patho-/physiological functions nor cell-type specific roles are clear. Herein, we inform about the current knowledge on the signal transduction downstream of CM cGKI. We believe that better insights into the specific actions of cGMP and cGKI in these cells will help to guide future studies in the search for predictive biomarkers for the response to pharmacological cGMP pathway modulation. In addition, targets downstream of cGMP/cGKI may be exploited for refined and optimized diagnostic and therapeutic strategies in different types of heart disease and their causes. Importantly, key functions of these proteins and particularly sites of regulatory phosphorylation by cGKI should, at least in principle, remain intact, although upstream signaling through the second messenger cGMP is impaired or dysregulated in a stressed or diseased heart state.
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Rameshrad M, Omidkhoda SF, Razavi BM, Hosseinzadeh H. Evaluating the possible role of mitochondrial ATP-sensitive potassium channels in the cardioprotective effects of morin in the isolated rat heart. Life Sci 2021; 264:118659. [PMID: 33148418 DOI: 10.1016/j.lfs.2020.118659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/28/2022]
Abstract
AIMS During heart ischemia, the lack of oxygen in the myocardial cells causes pH and ion disturbances and cell death through opening mitochondrial permeability transition pores (mPTP). Considering the inhibitory effects of mitochondrial ATP-dependent potassium channels (mt-KATP) on these pores and anti-ischemic effects of morin, we hypothesized that it may exert its positive effects via activating mt-KATP as well as its anti-oxidative effects. MAIN METHODS Isolated rat hearts were perfused by Krebs-Henseleit solution enriched with the morin (0.25, 0.5 and 1 mg/L) or 5-hydroxydecanoate (5-HD, a mt-KATP blocker;100 μM) or both as needed 5 min before starting regional ischemia till the first 10 min of the reperfusion period. The reperfusion was developed with Krebs-Henseleit solution 60 or 120 min respectively for biochemical evaluations (lactate dehydrogenase and malondialdehyde level) or the assessment of myocardial infarct size. During the experiments, hemodynamic functions were recorded and cardiac arrhythmias were determined. KEY FINDINGS Our findings demonstrated that morin reduced the infarct size. Also, morin perfusion could remarkably prevent the malondialdehyde over-production during ischemia. Total ventricular ectopic beats had the same significant changes as the malondialdehyde level, in both ischemia and reperfusion phases. Morin could also relatively improve the ischemia-induced hemodynamic dysfunction. All mentioned protective effects of morin were reversed by concomitant perfusion of 5-HD. SIGNIFICANCE Morin has protective effects against ischemic hearts through anti-oxidative effects. It also suggests a link between the cardioprotective effects of morin and mt-KATP. However, additional studies are required to prove this preliminary hypothesis.
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Affiliation(s)
- Maryam Rameshrad
- Natural Products and Medicinal Plants Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Seyedeh Farzaneh Omidkhoda
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bibi Marjan Razavi
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hossein Hosseinzadeh
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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4
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Chow LWC, Leung YM. The versatile Kv channels in the nervous system: actions beyond action potentials. Cell Mol Life Sci 2020; 77:2473-2482. [PMID: 31894358 PMCID: PMC11104815 DOI: 10.1007/s00018-019-03415-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/16/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022]
Abstract
Voltage-gated K+ (Kv) channel opening repolarizes excitable cells by allowing K+ efflux. Over the last two decades, multiple Kv functions in the nervous system have been found to be unrelated to or beyond the immediate control of excitability, such as shaping action potential contours or regulation of inter-spike frequency. These functions include neuronal exocytosis and neurite formation, neuronal cell death, regulation of astrocyte Ca2+, glial cell and glioma proliferation. Some of these functions have been shown to be independent of K+ conduction, that is, they suggest the non-canonical functions of Kv channels. In this review, we focus on neuronal or glial plasmalemmal Kv channel functions which are unrelated to shaping action potentials or immediate control of excitability. Similar functions in other cell types will be discussed to some extent in appropriate contexts.
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Affiliation(s)
- Louis W C Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
- UNIMED Medical Institute, Hong Kong, China
- Organisation for Oncology and Translational Research, Hong Kong, China
| | - Yuk- Man Leung
- Department of Physiology, China Medical University, Taichung, 40402, Taiwan.
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5
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Mitigating effect of paxilline against injury produced by Cd 2+ in rat pheochromocytoma PC12 and ascites hepatoma AS-30D cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 196:110519. [PMID: 32244116 DOI: 10.1016/j.ecoenv.2020.110519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/15/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023]
Abstract
On two rat cell lines, pheochromocytoma PC12 and ascites hepatoma AS-30D, and on rat liver mitochondria we studied action of paxilline (lipophilic mycotoxin from fungus Penicillium paxilli which is blocker of large-conductance potassium channels) against harmful effects of Cd(II) - one of the most dangerous toxic metals and environmental pollutants. We investigated an influence of paxilline on cell viability and mitochondrial function in the presence and in the absence of Cd2+. As found, paxilline protected partially from the Cd2+-induced cytotoxicity, namely taken in concentration of 1 μM it decreased the Cd2+-induced cell necrosis in average by 10-14 or 13-23% for AS-30D and PC12 cells, respectively. Nevertheless, paxilline did not affect the Cd2+-induced apoptosis of AS-30D cells. The alleviating concentration of paxilline reduced an intracellular production of reactive oxygen species (ROS) in PC12 cells intoxicated by Cd2+ and enhanced the ROS production in control AS-30D cells; however, it weakly affected mitochondrial membrane potential of the cells in the absence and in the presence of Cd2+. The ameliorative concentration of paxilline decreased the maximal respiration rates of control cells of both types after short-term (3-5 h) treatment with it while the rates reached their control levels after long-term (24-48 h) incubation with the drug. Paxilline was not protective against the Cd2+-induced membrane permeability and respiration rate changes in isolated rat liver mitochondria. As result, the mitochondrial electron transport chain was concluded to contribute in the mitigating effect of paxilline against the Cd2+-produced cell injury.
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Specific BK Channel Activator NS11021 Protects Rat Renal Proximal Tubular Cells from Cold Storage-Induced Mitochondrial Injury In Vitro. Biomolecules 2019; 9:biom9120825. [PMID: 31817165 PMCID: PMC6995623 DOI: 10.3390/biom9120825] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/14/2022] Open
Abstract
Kidneys from deceased donors used for transplantation are placed in cold storage (CS) solution during the search for a matched recipient. However, CS causes mitochondrial injury, which may exacerbate renal graft dysfunction. Here, we explored whether adding NS11021, an activator of the mitochondrial big-conductance calcium-activated K+ (mitoBK) channel, to CS solution can mitigate CS-induced mitochondrial injury. We used normal rat kidney proximal tubular epithelial (NRK) cells as an in vitro model of renal cold storage (18 h) and rewarming (2 h) (CS + RW). Western blots detected the pore-forming α subunit of the BK channel in mitochondrial fractions from NRK cells. The fluorescent K+-binding probe, PBFI-AM, revealed that isolated mitochondria from NRK cells exhibited mitoBK-mediated K+ uptake, which was impaired ~70% in NRK cells subjected to CS + RW compared to control NRK cells maintained at 37 °C. Importantly, the addition of 1 μM NS11021 to CS solution prevented CS + RW-induced impairment of mitoBK-mediated K+ uptake. The NS11021–treated NRK cells also exhibited less cell death and mitochondrial injury after CS + RW, including mitigated mitochondrial respiratory dysfunction, depolarization, and superoxide production. In summary, these new data show for the first time that mitoBK channels may represent a therapeutic target to prevent renal CS-induced injury.
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Korotkov SM, Brailovskaya IV, Nesterov VP, Soroko SI. Effects of Pinacidil and Calcium on Succinate-Energized Rat Heart Mitochondria in the Presence of Rotenone. DOKL BIOCHEM BIOPHYS 2019; 487:277-281. [PMID: 31559597 DOI: 10.1134/s1607672919040070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Indexed: 11/23/2022]
Abstract
The effect of pinacidil was studied on calcium-loaded rat heart mitochondria (RHM) in the presence of succinate and rotenone. In experiments with pinacidil, the swelling of these mitochondria increased in media with NH4NO3 or K-acetate, but the inner membrane potential (ΔΨmito) and the respiration in 3 or 2,4-dinitrophenol-stimulated states of these organelles decreased due to the opening of the mitochondrial permeability transition pore (MPTP) in their inner membrane. These effects were inhibited by cyclosporin A and ADP. It was concluded that the protective effect of pinacidil in the cardiac muscle under ischemia/reperfusion may be associated with both the stimulation of mitochondrial swelling and a decrease in RHM calcium overload resulted in ΔΨmito fall due to mild uncoupling effect of pinacidil.
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Affiliation(s)
- S M Korotkov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.
| | - I V Brailovskaya
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia
| | - V P Nesterov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia
| | - S I Soroko
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia
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Soustek MS, Balsa E, Barrow JJ, Jedrychowski M, Vogel R, Jan Smeitink, Gygi SP, Puigserver P. Inhibition of the ER stress IRE1α inflammatory pathway protects against cell death in mitochondrial complex I mutant cells. Cell Death Dis 2018; 9:658. [PMID: 29855477 PMCID: PMC5981317 DOI: 10.1038/s41419-018-0696-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/27/2018] [Accepted: 05/02/2018] [Indexed: 12/25/2022]
Abstract
Mitochondrial mutations cause bioenergetic defects associated with failures to use the electron transfer chain and oxidize substrates. These defects are exacerbated under energetic stress conditions and ultimately cause cell deterioration and death. However, little is known about cellular strategies that rescue mitochondrial stress failures and maintain cell survival under these conditions. Here, we have designed and performed a high-throughput chemical screen to identify small molecules that rescue human mitochondrial complex I mutations from energetic stress-induced cell death. The top positive hits were a series of sulfonylureas that efficiently maintain prolonged cell survival and growth under energetic stress conditions. The addition of galactose instead of glucose, to experimentally force mitochondrial respiration, triggered an initial ER stress response that was associated with IRE1α-dependent inflammatory signals including JNK and p38 MAP kinases in mutant cells. Sulfonylureas, similar to inhibition of IRE1α and p38 MAP kinase, potently blocked this ER stress inflammatory and cell death pathway and maintained viability and cell growth under severe energetic stress conditions. These studies reveal that sulfonylureas and specific inhibition of the IRE1α inflammatory pathway protect against cell death and can be used to rescue bioenergetic failures in mitochondrial complex I-mutated cells under stress conditions.
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Affiliation(s)
- Meghan S Soustek
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02215, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA
| | - Eduardo Balsa
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02215, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA
| | - Joeva J Barrow
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02215, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA
| | - Mark Jedrychowski
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA
| | - Rutger Vogel
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - Jan Smeitink
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - Steve P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02215, USA. .,Department of Cell Biology, Harvard Medical School, Boston, MA, 02215, USA.
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10
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The Slo(w) path to identifying the mitochondrial channels responsible for ischemic protection. Biochem J 2017; 474:2067-2094. [PMID: 28600454 DOI: 10.1042/bcj20160623] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
Abstract
Mitochondria play an important role in tissue ischemia and reperfusion (IR) injury, with energetic failure and the opening of the mitochondrial permeability transition pore being the major causes of IR-induced cell death. Thus, mitochondria are an appropriate focus for strategies to protect against IR injury. Two widely studied paradigms of IR protection, particularly in the field of cardiac IR, are ischemic preconditioning (IPC) and volatile anesthetic preconditioning (APC). While the molecular mechanisms recruited by these protective paradigms are not fully elucidated, a commonality is the involvement of mitochondrial K+ channel opening. In the case of IPC, research has focused on a mitochondrial ATP-sensitive K+ channel (mitoKATP), but, despite recent progress, the molecular identity of this channel remains a subject of contention. In the case of APC, early research suggested the existence of a mitochondrial large-conductance K+ (BK, big conductance of potassium) channel encoded by the Kcnma1 gene, although more recent work has shown that the channel that underlies APC is in fact encoded by Kcnt2 In this review, we discuss both the pharmacologic and genetic evidence for the existence and identity of mitochondrial K+ channels, and the role of these channels both in IR protection and in regulating normal mitochondrial function.
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11
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Wu KC, Cheng KS, Wang YW, Chen YF, Wong KL, Su TH, Chan P, Leung YM. Perturbation of Akt Signaling, Mitochondrial Potential, and ADP/ATP Ratio in Acidosis-Challenged Rat Cortical Astrocytes. J Cell Biochem 2017; 118:1108-1117. [PMID: 27608291 DOI: 10.1002/jcb.25725] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 09/07/2016] [Indexed: 12/17/2022]
Abstract
Cells switch to anaerobic glycolysis when there is a lack of oxygen during brain ischemia. Extracellular pH thus drops and such acidosis causes neuronal cell death. The fate of astrocytes, mechanical, and functional partners of neurons, in acidosis is less studied. In this report, we investigated the signaling in acidosis-challenged rat cortical astrocytes and whether these signals were related to mitochondrial dysfunction and cell death. Exposure to acidic pH (6.8, 6.0) caused Ca2+ release and influx, p38 MAPK activation, and Akt inhibition. Mitochondrial membrane potential was hyperpolarized after astrocytes were exposed to acidic pH as soon as 1 h and lasted for 24 h. Such mitochondrial hyperpolarization was prevented by SC79 (an Akt activator) but not by SB203580 (a p38 inhibitor) nor by cytosolic Ca2+ chelation by BAPTA, suggesting that only the perturbation in Akt signaling was causally related to mitochondrial hyperpolarization. SC79, SB203580, and BAPTA did not prevent acidic pH-induced cell death. Acidic pH suppressed ROS production, thus ruling out the role of ROS in cytotoxicity. Interestingly, pH 6.8 caused an increase in ADP/ATP ratio and apoptosis; pH 6.0 caused a further increase in ADP/ATP ratio and necrosis. Therefore, astrocyte cell death in acidosis did not result from mitochondrial potential collapse; in case of acidosis at pH 6.0, necrosis might partly result from mitochondrial hyperpolarization and subsequent suppressed ATP production. J. Cell. Biochem. 118: 1108-1117, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- King-Chuen Wu
- Department of Anesthesiology, Chang Gung Memorial Hospital, Chiayi, Taiwan.,Chang Gung University of Science and Technology, Chiayi, Taiwan
| | - Ka-Shun Cheng
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan.,Department of Anesthesiology, The Qingdao University Yuhuangding Hospital, Yantai, Shandong, China
| | - Yu-Wen Wang
- Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan
| | - Yuh-Fung Chen
- Department of Pharmacology, China Medical University, Taichung, Taiwan
| | - Kar-Lok Wong
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Tzu-Hui Su
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Paul Chan
- Division of Cardiology, Department of Medicine, Taipei Medical University Wan Fang Hospital, Taipei, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan
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Rasheed MZ, Tabassum H, Parvez S. Mitochondrial permeability transition pore: a promising target for the treatment of Parkinson's disease. PROTOPLASMA 2017; 254:33-42. [PMID: 26825389 DOI: 10.1007/s00709-015-0930-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 12/10/2015] [Indexed: 06/05/2023]
Abstract
Among the neurodegenerative diseases (ND), Parkinson's disease affects 6.3 million people worldwide characterized by the progressive loss of dopaminergic neurons in substantia nigra. The mitochondrial permeability transition pore (mtPTP) is a non-selective voltage-dependent mitochondrial channel whose opening modifies the permeability properties of the mitochondrial inner membrane. It is recognized as a potent pharmacological target for diseases associated with mitochondrial dysfunction and excessive cell death including ND such as Parkinson's disease (PD). Imbalance in Ca2+ concentration, change in mitochondrial membrane potential, overproduction of reactive oxygen species (ROS), or mutation in mitochondrial genome has been implicated in the pathophysiology of the opening of the mtPTP. Different proteins are released by permeability transition including cytochrome c which is responsible for apoptosis. This review aims to discuss the importance of PTP in the pathophysiology of PD and puts together different positive as well as negative aspects of drugs such as pramipexole, ropinirole, minocyclin, rasagilin, and safinamide which act as a blocker or modifier for mtPTP. Some of them may be detrimental in their neuroprotective nature.
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Affiliation(s)
- Md Zeeshan Rasheed
- Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), New Delhi, 110 062, India
| | - Heena Tabassum
- Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), New Delhi, 110 062, India
- Department of Biochemistry, Jamia Hamdard (Hamdard University), New Delhi, 110 062, India
| | - Suhel Parvez
- Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), New Delhi, 110 062, India.
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Waseem M, Tabassum H, Parvez S. Melatonin modulates permeability transition pore and 5-hydroxydecanoate induced KATP channel inhibition in isolated brain mitochondria. Mitochondrion 2016; 31:1-8. [DOI: 10.1016/j.mito.2016.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 06/16/2016] [Accepted: 08/11/2016] [Indexed: 12/22/2022]
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Derksen M, Vorwerk C, Siemen D. Calpeptin, not calpain, directly inhibits an ion channel of the inner mitochondrial membrane. PROTOPLASMA 2016; 253:835-843. [PMID: 26108743 DOI: 10.1007/s00709-015-0846-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
The permeability transition pore (PTP) of inner mitochondrial membranes is a large conductance pathway for ions up to 1500 Da which opening is responsible for ion equilibration and loss of membrane potential in apoptosis and thus in several neurodegenerative diseases. The PTP can be regulated by the Ca(2+)-activated mitochondrial K channel (BK). Calpains are Ca(2+)-activated cystein proteases; calpeptin is an inhibitor of calpains. We wondered whether calpain or calpeptin can modulate activity of PTP or BK. Patch clamp experiments were performed on mitoplasts of rat liver (PTP) and of an astrocytoma cell line (BK). Channel-independent open probability (P(o)) was determined (PTP) and, taking into account the number of open levels, NP(o) by single channel analysis (BK). We find that PTP in the presence of Ca(2+) (200 μM) is uninfluenced by calpain (13 nM) and shows insignificant decrease by the calpain inhibitor calpeptin (1 μM). The NP(o) of the BK is insensitive to calpain (54 nM), too. However, it is significantly and reversibly inhibited by the calpain inhibitor calpeptin (IC50 = 42 μM). The results agree with calpeptin-induced activation of the PTP via inhibition of the BK. Screening experiments with respirometry show calpeptin effects, fitting to inhibition of the BK by calpeptin, and strong inhibition of state 3 respiration.
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Affiliation(s)
- Maria Derksen
- Department of Neurology, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | | | - Detlef Siemen
- Department of Neurology, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany.
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Akopova O, Nosar V, Gavenauskas B, Bratus L, Kolchinskaya L, Mankovska I, Sagach V. The effect of atp-dependent potassium uptake on mitochondrial functions under acute hypoxia. J Bioenerg Biomembr 2016; 48:67-75. [PMID: 26739597 DOI: 10.1007/s10863-015-9642-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022]
Abstract
The opening of mitochondrial K(+) АТР-channel (mtK(+) АТР-channel) is supposed to be important in the modulation of mitochondrial functions under hypoxia, but the underlying mechanisms have not been clarified yet. The aim of this work was to study the effect of acute hypoxia on mtK(+) АТР-channel activity and to estimate the contribution of the channel in the modulation of mitochondrial functions. MtK(+) АТР-channel activity was assessed polarographically from the rate of State 4 respiration and by potentiometric monitoring of potassium efflux from deenergized mitochondria. It was shown that hypoxia reliably increased mtK(+) АТР-channel activity, which resulted in the changes of respiration rates (increase of State 4 and suppression of State 3 respiration), uncoupling (the decrease of respiratory control ratio) and suppression of phosphorylation. These effects were well mimicked by mtK(+) АТР-channel opener diazoxide (DZ) in isolated rat liver mitochondria. MtK(+) АТР-channel opening in vitro suppressed phosphorylation too, but increased phosphorylation efficiency, while mtK(+) АТР-channel blockers reduced it dramatically. The correlation was established between mtK(+) АТР-channel activity and the endurance of the rats to physical training under hypoxia. Hypoxia improved physical endurance, but treatment by mtK(+) АТР-channel blockers glibenklamide and 5-hydroxydecanoate (5-HD) prior to hypoxia strongly reduced both the channel activity and the endurance limits. This was in accord with the observation that under glibenklamide and 5-HD administration hypoxia failed to restore mtK(+) АТР-channel activity. Based on the experiments, we came to the conclusion that mtK(+) АТР-channel opening played a decisive role in the regulation of energy metabolism under acute hypoxia via the modulation of phosphorylation system in mitochondria.
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Affiliation(s)
- Olga Akopova
- Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, 01601, Kiev, Ukraine.
| | - Valentina Nosar
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Bronislav Gavenauskas
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Larissa Bratus
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Liudmila Kolchinskaya
- Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, 01601, 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, 01601, Kiev, Ukraine
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The Roles of Mitochondrial Cation Channels Under Physiological Conditions and in Cancer. Handb Exp Pharmacol 2016; 240:47-69. [PMID: 27995386 DOI: 10.1007/164_2016_92] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bioenergetics has become central to our understanding of pathological mechanisms as well as the development of new therapeutic strategies and as a tool for gauging disease progression in neurodegeneration, diabetes, cancer, and cardiovascular disease. The view is emerging that inner mitochondrial membrane (IMM) cation channels have a profound effect on mitochondrial function and, consequently, on the metabolic state and survival of the whole cell. Since disruption of the sustained integrity of mitochondria is strongly linked to human disease, pharmacological intervention offers a new perspective concerning neurodegenerative and cardiovascular diseases as well as cancer. This review summarizes our current knowledge regarding IMM cation channels and their roles under physiological conditions as well as in cancer, with special emphasis on potassium channels and the mammalian mitochondrial calcium uniporter.
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Belyaeva EA. The effect of modulators of large-conductance Ca2+-modulated K+ channels on rat AS-30D ascites hepatoma cells and isolated liver mitochondria treated with Cd2+. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015040018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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18
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Leanza L, Venturini E, Kadow S, Carpinteiro A, Gulbins E, Becker KA. Targeting a mitochondrial potassium channel to fight cancer. Cell Calcium 2015; 58:131-8. [DOI: 10.1016/j.ceca.2014.09.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 12/11/2022]
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19
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Closure of mitochondrial potassium channels favors opening of the Tl+-induced permeability transition pore in Ca2+-loaded rat liver mitochondria. J Bioenerg Biomembr 2015; 47:243-54. [DOI: 10.1007/s10863-015-9611-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/30/2015] [Indexed: 12/23/2022]
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20
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Soltysinska E, Bentzen BH, Barthmes M, Hattel H, Thrush AB, Harper ME, Qvortrup K, Larsen FJ, Schiffer TA, Losa-Reyna J, Straubinger J, Kniess A, Thomsen MB, Brüggemann A, Fenske S, Biel M, Ruth P, Wahl-Schott C, Boushel RC, Olesen SP, Lukowski R. KCNMA1 encoded cardiac BK channels afford protection against ischemia-reperfusion injury. PLoS One 2014; 9:e103402. [PMID: 25072914 PMCID: PMC4114839 DOI: 10.1371/journal.pone.0103402] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/01/2014] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial potassium channels have been implicated in myocardial protection mediated through pre-/postconditioning. Compounds that open the Ca2+- and voltage-activated potassium channel of big-conductance (BK) have a pre-conditioning-like effect on survival of cardiomyocytes after ischemia/reperfusion injury. Recently, mitochondrial BK channels (mitoBKs) in cardiomyocytes were implicated as infarct-limiting factors that derive directly from the KCNMA1 gene encoding for canonical BKs usually present at the plasma membrane of cells. However, some studies challenged these cardio-protective roles of mitoBKs. Herein, we present electrophysiological evidence for paxilline- and NS11021-sensitive BK-mediated currents of 190 pS conductance in mitoplasts from wild-type but not BK-/- cardiomyocytes. Transmission electron microscopy of BK-/- ventricular muscles fibres showed normal ultra-structures and matrix dimension, but oxidative phosphorylation capacities at normoxia and upon re-oxygenation after anoxia were significantly attenuated in BK-/- permeabilized cardiomyocytes. In the absence of BK, post-anoxic reactive oxygen species (ROS) production from cardiomyocyte mitochondria was elevated indicating that mitoBK fine-tune the oxidative state at hypoxia and re-oxygenation. Because ROS and the capacity of the myocardium for oxidative metabolism are important determinants of cellular survival, we tested BK-/- hearts for their response in an ex-vivo model of ischemia/reperfusion (I/R) injury. Infarct areas, coronary flow and heart rates were not different between wild-type and BK-/- hearts upon I/R injury in the absence of ischemic pre-conditioning (IP), but differed upon IP. While the area of infarction comprised 28±3% of the area at risk in wild-type, it was increased to 58±5% in BK-/- hearts suggesting that BK mediates the beneficial effects of IP. These findings suggest that cardiac BK channels are important for proper oxidative energy supply of cardiomyocytes at normoxia and upon re-oxygenation after prolonged anoxia and that IP might indeed favor survival of the myocardium upon I/R injury in a BK-dependent mode stemming from both mitochondrial post-anoxic ROS modulation and non-mitochondrial localizations.
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MESH Headings
- Animals
- Cell Hypoxia
- Disease Models, Animal
- Energy Metabolism
- Indoles/pharmacology
- Ischemic Preconditioning
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism
- Large-Conductance Calcium-Activated Potassium Channels/chemistry
- Large-Conductance Calcium-Activated Potassium Channels/genetics
- Large-Conductance Calcium-Activated Potassium Channels/metabolism
- Membrane Potential, Mitochondrial/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondria, Heart/metabolism
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/metabolism
- Myocardium/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Oxidative Phosphorylation/drug effects
- Reactive Oxygen Species/metabolism
- Reperfusion Injury/metabolism
- Reperfusion Injury/pathology
- Tetrazoles/pharmacology
- Thiourea/analogs & derivatives
- Thiourea/pharmacology
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Affiliation(s)
- Ewa Soltysinska
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Maria Barthmes
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Helle Hattel
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A. Brianne Thrush
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Klaus Qvortrup
- Department of Biomedical Sciences, Core Facility for Integrated Microscopy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip J. Larsen
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Tomas A. Schiffer
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jose Losa-Reyna
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Julia Straubinger
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Angelina Kniess
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Morten Bækgaard Thomsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Stefanie Fenske
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Christian Wahl-Schott
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Robert Christopher Boushel
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren-Peter Olesen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (SPO); (RL)
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
- * E-mail: (SPO); (RL)
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21
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Akopova OV, Nosar' VI, Man'kovskaia IN, Sagach VF. [The effect of Ca(2+)-induced opening of cyclosporine-sensitive pore on the oxygen consumption and functional state of rat liver mitochondria]. UKRAINIAN BIOCHEMICAL JOURNAL 2014; 85:37-49. [PMID: 24479321 DOI: 10.15407/ubj85.05.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The effect of Ca(2+)-induced opening of cyclosporine-sensitive pore (mitochondrial permeability transition pore, MPTP) on the oxygen consumption and mitochondrial functional state was studied in the rat liver mitochondria. It was shown that, with the use of glutamate as oxidation substrate, in the absence of depolarization MPTP opening results in the increase of steady state respiration rate because of the activation of cyclosporine-sensitive Ca2+/H(+)-exchange and Ca2+ cycling, which was supported by the simultaneous work of MPTP and Ca(2+)-uniporter. With the aid of selective blockers, cyclosporine A and ruthenium red, it was shown that MPTP and Ca(2+)-uniporter contribute equally to the Ca(2+)-cycling and mitochondrial respiration. It was shown that bioenergetic effects of MPTP opening under steady state conditions (increase in the oxygen consumption rate under substrate oxidation without ADP, decrease in respiratory control ratio as well as the effectiveness of ATP synthesis, P/O) are close to the functional alterations, which result from the increase of endogenous proton conductance of mitochondrial membrane. Uncoupling effect of MPTP opening, by itself, had no effect on phosphorylation rate, which remains relatively stable because the fall of P/O is compensated by the activation of respiratory chain and the increase in the rate of state 3 respiration. It was concluded that under physiologically normal conditions MPTP might function as the endogenous mechanism of mild uncoupling of respiratory chain.
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22
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New fluorine-containing openers of ATP-sensitive potassium channels flokalin and tioflokalin inhibit calcium-induced mitochondrial pore opening in rat hearts [. ACTA ACUST UNITED AC 2014. [DOI: 10.15407/fz59.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Korotkov SM, Nesterov VP, Brailovskaya IV, Furaev VV, Novozhilov AV. Tl+ induces both cationic and transition pore permeability in the inner membrane of rat heart mitochondria. J Bioenerg Biomembr 2013; 45:531-9. [DOI: 10.1007/s10863-013-9526-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
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24
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Dolga AM, Netter MF, Perocchi F, Doti N, Meissner L, Tobaben S, Grohm J, Zischka H, Plesnila N, Decher N, Culmsee C. Mitochondrial small conductance SK2 channels prevent glutamate-induced oxytosis and mitochondrial dysfunction. J Biol Chem 2013; 288:10792-804. [PMID: 23430260 PMCID: PMC3624460 DOI: 10.1074/jbc.m113.453522] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 02/08/2013] [Indexed: 11/06/2022] Open
Abstract
Small conductance calcium-activated potassium (SK2/K(Ca)2.2) channels are known to be located in the neuronal plasma membrane where they provide feedback control of NMDA receptor activity. Here, we provide evidence that SK2 channels are also located in the inner mitochondrial membrane of neuronal mitochondria. Patch clamp recordings in isolated mitoplasts suggest insertion into the inner mitochondrial membrane with the C and N termini facing the intermembrane space. Activation of SK channels increased mitochondrial K(+) currents, whereas channel inhibition attenuated these currents. In a model of glutamate toxicity, activation of SK2 channels attenuated the loss of the mitochondrial transmembrane potential, blocked mitochondrial fission, prevented the release of proapoptotic mitochondrial proteins, and reduced cell death. Neuroprotection was blocked by specific SK2 inhibitory peptides and siRNA targeting SK2 channels. Activation of mitochondrial SK2 channels may therefore represent promising targets for neuroprotective strategies in conditions of mitochondrial dysfunction.
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Affiliation(s)
- Amalia M. Dolga
- From the Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Michael F. Netter
- Institut für Physiologie und Pathophysiologie, Vegetative Physiologie, Fachbereich Medizin, Philipps-Universität Marburg, D-35037 Marburg, Germany
| | - Fabiana Perocchi
- Department of Systems Biology and Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
- Gene Center, Ludwig Maximilians University, Feodor-Lynen Strasse 25, 81377 Munich, Germany
| | - Nunzianna Doti
- From the Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, D-35032 Marburg, Germany
- Department of Neurodegeneration, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Institute of Biostructures and Bioimaging, National Research Council (CNR), 16-80131 Naples, Italy
| | - Lilja Meissner
- Institute of Stroke and Dementia Research, University of Munich Medical School, D-81377 Munich, Germany, and
| | - Svenja Tobaben
- From the Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Julia Grohm
- From the Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Hans Zischka
- Institute of Toxicology, Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), D-85764 Neuherberg, Germany
| | - Nikolaus Plesnila
- Department of Neurodegeneration, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Institute of Stroke and Dementia Research, University of Munich Medical School, D-81377 Munich, Germany, and
| | - Niels Decher
- Institut für Physiologie und Pathophysiologie, Vegetative Physiologie, Fachbereich Medizin, Philipps-Universität Marburg, D-35037 Marburg, Germany
| | - Carsten Culmsee
- From the Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, D-35032 Marburg, Germany
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25
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Akopova OV, Kolchinskaya LI, Nosar VI, Bouryi VA, Mankovskaya IN, Sagach VF. Effect of potential-dependent potassium uptake on calcium accumulation in rat brain mitochondria. BIOCHEMISTRY (MOSCOW) 2013; 78:80-90. [PMID: 23379563 DOI: 10.1134/s0006297913010100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of potential-dependent potassium uptake at 0-120 mM K+ on matrix Ca2+ accumulation in rat brain mitochondria was studied. An increase in oxygen consumption and proton extrusion rates as well as increase in matrix pH with increase in K+ content in the medium was observed due to K+ uptake into the mitochondria. The accumulation of Ca2+ was shown to depend on K+ concentration in the medium. At K+ concentration ≤30 mM, Ca2+ uptake is decreased due to K+-induced membrane depolarization, whereas at higher K+ concentrations, up to 120 mM K+, Ca2+ uptake is increased in spite of membrane depolarization caused by matrix alkalization due to K+ uptake. Mitochondrial K+(ATP)-channel blockers (glibenclamide and 5-hydroxydecanoic acid) diminish K+ uptake as well as K+-induced depolarization and matrix alkalization, which results in attenuation of the potassium-induced effects on matrix Ca2+ uptake, i.e. increase in Ca2+ uptake at low K+ content in the medium due to the smaller membrane depolarization and decrease in Ca2+ uptake at high potassium concentrations because of restricted rise in matrix pH. The results show the importance of potential-dependent potassium uptake, and especially the K+(ATP) channel, in the regulation of calcium accumulation in rat brain mitochondria.
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Affiliation(s)
- O V Akopova
- Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev-24, Ukraine.
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26
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Siemen D, Ziemer M. What is the nature of the mitochondrial permeability transition poreand What is it Not? IUBMB Life 2013; 65:255-62. [DOI: 10.1002/iub.1130] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/07/2012] [Indexed: 12/23/2022]
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27
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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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28
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Leanza L, Henry B, Sassi N, Zoratti M, Chandy KG, Gulbins E, Szabò I. Inhibitors of mitochondrial Kv1.3 channels induce Bax/Bak-independent death of cancer cells. EMBO Mol Med 2012; 4:577-93. [PMID: 22496117 PMCID: PMC3407946 DOI: 10.1002/emmm.201200235] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 02/17/2012] [Accepted: 02/21/2012] [Indexed: 02/01/2023] Open
Abstract
Overcoming the resistance of tumours to chemotherapy, often due to downregulation of Bax and Bak, represents a significant clinical challenge. It is therefore important to identify novel apoptosis inducers that bypass Bax and Bak. Potassium channels are emerging as oncological targets and a crucial role of mitochondrial Kv1.3 in apoptosis has been demonstrated. Here we report for the first time that Psora-4, PAP-1 and clofazimine, three distinct membrane-permeant inhibitors of Kv1.3, induce death by directly targeting the mitochondrial channel in multiple human and mouse cancer cell lines. Importantly, these drugs activated the intrinsic apoptotic pathway also in the absence of Bax and Bak, a result in agreement with the current mechanistic model for mitochondrial Kv1.3 action. Genetic deficiency or short interfering RNA (siRNA)-mediated downregulation of Kv1.3 abrogated the effects of the drugs. Intraperitoneal injection of clofazimine reduced tumour size by 90% in an orthotopic melanoma B16F10 mouse model in vivo, while no adverse effects were observed in several healthy tissues. The study indicates that inhibition of mitochondrial Kv1.3 might be a novel therapeutic option for the induction of cancer cell death independent of Bax and Bak.
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Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
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29
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Thiede A, Gellerich FN, Schönfeld P, Siemen D. Complex effects of 17β-estradiol on mitochondrial function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1747-53. [PMID: 22414665 DOI: 10.1016/j.bbabio.2012.02.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/23/2012] [Accepted: 02/25/2012] [Indexed: 01/01/2023]
Abstract
Existing literature on estradiol indicates that it affects mitochondrial functions at low micromolar concentrations. Particularly blockade of the permeability transition pore (PTP) or modulation of the enzymatic activity of one or more complexes of the respiratory chain were suspicious. We prepared mitoplasts from rat liver mitochondria (RLM) to study by single-channel patch-clamp techniques the PTP, and from rat astrocytes to study the potassium BK-channel said to modulate the PTP. Additionally, we measured respiration of intact RLM. After application of 17β-estradiol (βE) our single-channel results reveal a transient increase of activity of both, the BK-channel and the PTP followed by their powerful inhibition. Respiration measurements demonstrate inhibition of the Ca(2+)-induced permeability transition, as well, though only at higher concentrations (≥30μM). At lower concentrations, we observed an increase of endogenous- and state 2-respiration. Furthermore, we show that βE diminishes the phosphorylating respiration supported by complex I-substrates (glutamate/malate) or by the complex II-substrate succinate. Taken together the results suggest that βE affects mitochondria by several modes, including partial inhibition of the activities of ion channels of the inner membrane and of respiration. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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Affiliation(s)
- Anika Thiede
- Dept. of Neurology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
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30
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Cheng Y, Gulbins E, Siemen D. Activation of the Permeability Transition Pore by Bax via Inhibition of the Mitochondrial BK Channel. Cell Physiol Biochem 2011; 27:191-200. [DOI: 10.1159/000327944] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2011] [Indexed: 01/07/2023] Open
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31
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Szabò I, Soddemann M, Leanza L, Zoratti M, Gulbins E. Single-point mutations of a lysine residue change function of Bax and Bcl-xL expressed in Bax- and Bak-less mouse embryonic fibroblasts: novel insights into the molecular mechanisms of Bax-induced apoptosis. Cell Death Differ 2010; 18:427-38. [PMID: 20885444 DOI: 10.1038/cdd.2010.112] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Members of the Bcl-2 family play key roles as proapoptotic (e.g., Bax) and antiapoptotic (e.g., Bcl-x(L)) regulators of programmed cell death. We previously identified the mitochondrial potassium channel Kv1.3 as a novel target of Bax. Incubating Kv1.3-positive isolated mitochondria with Bax triggered apoptotic events, whereas Kv1.3-deficient mitochondria were resistant to this stimulus. Mutation of Bax at lysine 128 (BaxK128E) abrogated its effects on Kv1.3 and the induction of apoptotic changes in mitochondria. These data indicate a toxin-like action of Bax on Kv1.3 to trigger at least some of the mitochondrial changes typical for apoptosis. To gain insight into the mechanism of Bax-Kv1.3 interaction, we mutated Glu158 of Bcl-x(L) (corresponding to K128 in Bax) to lysine. This substitution turned Bcl-x(L) proapoptotic. Transfection of double knockout (Bax(-/-)/Bak(-/-)) mouse embryonic fibroblasts (DKO MEFs) with either wild-type Bax, BaxK128E, or Bcl-x(L)E158K showed that apoptosis induced by various stimuli was defective in DKO MEFs and BaxK128E-transfected cells, but was recovered upon transfection with Bcl-xLE158K or wild-type Bax. Both wild-type Bax and BaxK128E can form similar ion-conducting pores upon incorporation into planar lipid bilayers. Our results point to a physiologically relevant interaction of Bax with Kv1.3 and further indicate a crucial role of a distinct lysine in determining the proapoptotic character of Bcl2-family proteins.
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Affiliation(s)
- I Szabò
- Department of Biology, University of Padova, Padova, Italy.
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