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Głuchowska A, Kalenik B, Kulawiak B, Wrzosek A, Szewczyk A, Bednarczyk P, Mosieniak G. Lack of activity of the mitochondrial large-conductance calcium-regulated potassium channels in senescent vascular smooth muscle cells. Mech Ageing Dev 2023; 215:111871. [PMID: 37689317 DOI: 10.1016/j.mad.2023.111871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
A limited number of studies have shown functional changes in mitochondrial ion channels in aging and senescent cells. We have identified, for the first time, mitochondrial large-conductance calcium-regulated potassium channels in human smooth muscle mitochondria. This channel, with a conductance of 273 pS, was regulated by calcium ions and membrane potential. Additionally, it was activated by the potassium channel opener NS11021 and blocked by paxilline. Importantly, we have shown that senescence of these cells induced by hydrogen peroxide treatment leads to the disappearance of potassium channel protein levels and channel activity measured by the single channel patch-clamp technique. Our data suggest that disturbances in the expression of mitochondrial large conductance calcium-regulated potassium channels may be hallmarks of cellular senescence and contribute to the misregulation of mitochondrial function in senescent cells.
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Affiliation(s)
- Agata Głuchowska
- Laboratory of Molecular Bases of Aging, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Barbara Kalenik
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.
| | - Grażyna Mosieniak
- Laboratory of Molecular Bases of Aging, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland.
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2
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Sanghvi S, Szteyn K, Ponnalagu D, Sridharan D, Lam A, Hansra I, Chaudhury A, Majumdar U, Kohut AR, Gururaja Rao S, Khan M, Garg V, Singh H. Inhibition of BK Ca channels protects neonatal hearts against myocardial ischemia and reperfusion injury. Cell Death Dis 2022; 8:175. [PMID: 35393410 PMCID: PMC8989942 DOI: 10.1038/s41420-022-00980-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/15/2022] [Accepted: 03/23/2022] [Indexed: 11/30/2022]
Abstract
BKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes, which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL-positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.
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Affiliation(s)
- Shridhar Sanghvi
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Molecular Cellular and Developmental Biology, The Ohio State University, Columbus, OH, USA
| | - Kalina Szteyn
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Devasena Ponnalagu
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Divya Sridharan
- Department of Emergency Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Alexander Lam
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Inderjot Hansra
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ankur Chaudhury
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Uddalak Majumdar
- Center for Cardiovascular Research and The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Andrew R Kohut
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA.,Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shubha Gururaja Rao
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, Ada, OH, USA
| | - Mahmood Khan
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Emergency Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Vidu Garg
- Center for Cardiovascular Research and The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Harpreet Singh
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA. .,Department of Molecular Cellular and Developmental Biology, The Ohio State University, Columbus, OH, USA.
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3
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Sanghvi S, Szteyn K, Ponnalagu D, Sridharan D, Lam A, Hansra I, Chaudhury A, Majumdar U, Kohut AR, Rao SG, Khan M, Garg V, Singh H. Inhibition of BK Ca channels protects neonatal hearts against myocardial ischemia and reperfusion injury.. [DOI: 10.1101/2021.11.02.466585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
AbstractBKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.
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Combination of the Phosphodiesterase Inhibitors Sildenafil and Milrinone Induces Cardioprotection With Various Conditioning Strategies. J Cardiovasc Pharmacol 2021; 76:684-691. [PMID: 33002964 DOI: 10.1097/fjc.0000000000000919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ischemic preconditioning and postconditioning are strong measures preserving the heart against ischemia-reperfusion injury in experimental setting but are too invasive and impractical for clinical routine. The cardioprotective effects of ischemic preconditioning and postconditioning can be imitated pharmacologically, for example, with the phosphodiesterase inhibitors sildenafil and milrinone. We hypothesize that sildenafil-induced preconditioning is concentration dependent and further that a combined treatment of "nonprotective" versus "protective" concentrations of sildenafil and milrinone leads to a significant infarct size reduction. Experiments were performed on isolated hearts of male Wistar rats, randomized into 12 groups, mounted onto a Langendorff system, and perfused with Krebs-Henseleit buffer. All hearts underwent 33 minutes ischemia and 60 minutes of reperfusion. For determination of a concentration-dependent effect of sildenafil, hearts were perfused with increasing concentrations of sildenafil (0.1-1 µM) over 10 minutes before ischemia. In a second series of experiments, hearts were treated with 0.3 µM sildenafil or 1 µM milrinone as the "protective" concentrations. A higher concentration of respective drugs did not further reduce infarct size. In addition, a combination of "protective" and "nonprotective" concentrations of sildenafil and milrinone was applied. Sildenafil and milrinone in lower concentrations led to significant infarct size reduction, whereas combining both substances in cardioprotective concentrations did not enhance this effect. Sildenafil in a concentration of 0.3 µM induces myocardial protection. Furthermore, treatment with sildenafil and milrinone in lower concentrations had an equally strong cardioprotective effect regarding infarct size reduction compared with the administration of "protective" concentrations.
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Liu Y, Chen J, Fontes SK, Bautista EN, Cheng Z. Physiological And Pathological Roles Of Protein Kinase A In The Heart. Cardiovasc Res 2021; 118:386-398. [PMID: 33483740 DOI: 10.1093/cvr/cvab008] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/30/2020] [Accepted: 01/08/2021] [Indexed: 12/21/2022] Open
Abstract
Protein kinase A (PKA) is a central regulator of cardiac performance and morphology. Myocardial PKA activation is induced by a variety of hormones, neurotransmitters and stress signals, most notably catecholamines secreted by the sympathetic nervous system. Catecholamines bind β-adrenergic receptors to stimulate cAMP-dependent PKA activation in cardiomyocytes. Elevated PKA activity enhances Ca2+ cycling and increases cardiac muscle contractility. Dynamic control of PKA is essential for cardiac homeostasis, as dysregulation of PKA signaling is associated with a broad range of heart diseases. Specifically, abnormal PKA activation or inactivation contributes to the pathogenesis of myocardial ischemia, hypertrophy, heart failure, as well as diabetic, takotsubo, or anthracycline cardiomyopathies. PKA may also determine sex-dependent differences in contractile function and heart disease predisposition. Here, we describe the recent advances regarding the roles of PKA in cardiac physiology and pathology, highlighting previous study limitations and future research directions. Moreover, we discuss the therapeutic strategies and molecular mechanisms associated with cardiac PKA biology. In summary, PKA could serve as a promising drug target for cardioprotection. Depending on disease types and mechanisms, therapeutic intervention may require either inhibition or activation of PKA. Therefore, specific PKA inhibitors or activators may represent valuable drug candidates for the treatment of heart diseases.
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Affiliation(s)
- Yuening Liu
- Department of Pharmaceutical Sciences, Washington State University, PBS 423, 412 E. Spokane Falls Blvd, ., Spokane, WA, 99202-2131, USA
| | - Jingrui Chen
- Department of Pharmaceutical Sciences, Washington State University, PBS 423, 412 E. Spokane Falls Blvd, ., Spokane, WA, 99202-2131, USA
| | - Shayne K Fontes
- Department of Pharmaceutical Sciences, Washington State University, PBS 423, 412 E. Spokane Falls Blvd, ., Spokane, WA, 99202-2131, USA
| | - Erika N Bautista
- Department of Pharmaceutical Sciences, Washington State University, PBS 423, 412 E. Spokane Falls Blvd, ., Spokane, WA, 99202-2131, USA
| | - Zhaokang Cheng
- Department of Pharmaceutical Sciences, Washington State University, PBS 423, 412 E. Spokane Falls Blvd, ., Spokane, WA, 99202-2131, USA
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Raupach A, Karakurt E, Torregroza C, Bunte S, Feige K, Stroethoff M, Brandenburger T, Heinen A, Hollmann MW, Huhn R. Dexmedetomidine Provides Cardioprotection During Early or Late Reperfusion Mediated by Different Mitochondrial K+-Channels. Anesth Analg 2021; 132:253-260. [PMID: 32889843 DOI: 10.1213/ane.0000000000005148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Cardioprotective interventions-such as pharmacological postconditioning-are a promising strategy to reduce deleterious consequences of ischemia and reperfusion injury (I/RI) in the heart, especially as timing and onset of myocardial infarction are unpredictable. Pharmacological postconditioning by treatment with dexmedetomidine (Dex), an α2-adrenoreceptor agonist, during reperfusion protects hearts from I/RI, independently of time point and duration of application during the reperfusion phase. The mitochondrial ATP-sensitive K (mKATP) and mitochondrial large-conductance calcium-sensitive potassium channel (mBKCa) play a pivotal role in mediating this cardioprotective effect. Therefore, we investigated whether Dex-induced cardioprotection during early or late reperfusion is mediated variously by these mitochondrial K-channels. METHODS Hearts of male Wistar rats were randomized into 8 groups and underwent a protocol of 15 minutes adaption, 33 minutes ischemia, and 60 minutes reperfusion in an in vitro Langendorff-system. A 10-minute treatment phase was started directly (first subgroup, early reperfusion) or 30 minutes (second subgroup, late reperfusion) after the onset of reperfusion. Control (Con) hearts received vehicle only. In the first subgroup, hearts were treated with 3 nM Dex, 100 µM mKATP-channel blocker 5-hydroxydecanoate (5HD) or 1 µM mBKCa-channel blocker Paxilline (Pax) alone or with respective combinations (5HD + Dex, Pax + Dex). Hearts of the second subgroup received Dex alone (Dex30') or in combination with the respective blockers (5HD + Dex30', Pax + Dex30'). Infarct size was determined with triphenyltetrazoliumchloride staining. Hemodynamic variables were recorded during the whole experiment. RESULTS During early reperfusion (first subgroup), the infarct size reducing effect of Dex (Con: 57% ± 9%, Dex: 31% ± 7%; P< .0001 versus Con) was completely abolished by 5HD and Pax (52% ± 6%; Pax + Dex: 53% ± 4%; each P< .0001 versus Dex), while both blockers alone had no effect on infarct size (5HD: 54% ± 8%, Pax: 53% ± 11%). During late reperfusion (second subgroup) the protective effect of Dex (Dex30': 33% ± 10%, P< .0001 versus Con) was fully abrogated by Pax (Pax + Dex30': 58% ± 7%, P < .0001 versus Dex30'), whereas 5HD did not block cardioprotection (5HD + Dex30': 36% ± 7%). Between groups and within each group throughout reperfusion no significant differences in hemodynamic variables were detected. CONCLUSIONS Cardioprotection by treatment with Dex during early reperfusion seems to be mediated by both mitochondrial K-channels, whereas during late reperfusion only mBKCa-channels are involved.
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Affiliation(s)
- Annika Raupach
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Elif Karakurt
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Carolin Torregroza
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Sebastian Bunte
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany.,Department of Internal Medicine, Elbe Clinics Stade-Buxtehude, Stade, Germany
| | - Katharina Feige
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Martin Stroethoff
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Timo Brandenburger
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - André Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Amsterdam University Medical Center (AUMC), Amsterdam, the Netherlands
| | - Ragnar Huhn
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
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Torregroza C, Raupach A, Feige K, Weber NC, Hollmann MW, Huhn R. Perioperative Cardioprotection: General Mechanisms and Pharmacological Approaches. Anesth Analg 2020; 131:1765-1780. [PMID: 33186163 DOI: 10.1213/ane.0000000000005243] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardioprotection encompasses a variety of strategies protecting the heart against myocardial injury that occurs during and after inadequate blood supply to the heart during myocardial infarction. While restoring reperfusion is crucial for salvaging myocardium from further damage, paradoxically, it itself accounts for additional cell death-a phenomenon named ischemia/reperfusion injury. Therefore, therapeutic strategies are necessary to render the heart protected against myocardial infarction. Ischemic pre- and postconditioning, by short periods of sublethal cardiac ischemia and reperfusion, are still the strongest mechanisms to achieve cardioprotection. However, it is highly impractical and far too invasive for clinical use. Fortunately, it can be mimicked pharmacologically, for example, by volatile anesthetics, noble gases, opioids, propofol, dexmedetomidine, and phosphodiesterase inhibitors. These substances are all routinely used in the clinical setting and seem promising candidates for successful translation of cardioprotection from experimental protocols to clinical trials. This review presents the fundamental mechanisms of conditioning strategies and provides an overview of the most recent and relevant findings on different concepts achieving cardioprotection in the experimental setting, specifically emphasizing pharmacological approaches in the perioperative context.
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Affiliation(s)
- Carolin Torregroza
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany.,Department of Anesthesiology, Amsterdam University Medical Centers (AUMC), Amsterdam, the Netherlands
| | - Annika Raupach
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Katharina Feige
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Nina C Weber
- Department of Anesthesiology, Amsterdam University Medical Centers (AUMC), Amsterdam, the Netherlands
| | - Markus W Hollmann
- Department of Anesthesiology, Amsterdam University Medical Centers (AUMC), Amsterdam, the Netherlands
| | - Ragnar Huhn
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
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Feige K, Raupach A, Torregroza C, Muehlenbernd J, Stroethoff M, Bunte S, Hollmann MW, Huhn R. Effluent from ischemic preconditioned hearts confers cardioprotection independent of the number of preconditioning cycles. PLoS One 2020; 15:e0243220. [PMID: 33270768 PMCID: PMC7714116 DOI: 10.1371/journal.pone.0243220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/17/2020] [Indexed: 11/17/2022] Open
Abstract
Coronary effluent collected from ischemic preconditioning (IPC) treated hearts induces myocardial protection in non-ischemic-preconditioned hearts. So far, little is known about the number of IPC cycles required for the release of cardioprotective factors into the coronary effluent to successfully induce cardioprotection. This study investigated the cardioprotective potency of effluent obtained after various IPC cycles in the rat heart. Experiments were performed on isolated hearts of male Wistar rats, mounted onto a Langendorff system and perfused with Krebs-Henseleit buffer. In a first part, effluent was taken before (Con) and after each IPC cycle (Eff 1, Eff 2, Eff 3). IPC was induced by 3 cycles of 5 min of global myocardial ischemia followed by 5 minutes of reperfusion. In a second part, hearts of male Wistar rats were randomized to four groups (each group n = 4–5) and underwent 33 min of global ischemia followed by 60 min of reperfusion. The previously obtained coronary effluent was administered for 10 minutes before ischemia as a preconditioning stimulus. Infarct size was determined at the end of reperfusion by triphenyltetrazoliumchloride (TTC) staining. Infarct size with control effluent was 54±12%. Effluent obtained after IPC confers a strong infarct size reduction independent of the number of IPC cycles (Eff 1: 27±5%; Eff 2: 35±7%; Eff 3: 35±8%, each P<0.05 vs. Con). Effluent extracted after one cycle IPC is comparably protective as after two or three cycles IPC.
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Affiliation(s)
- Katharina Feige
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Annika Raupach
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Carolin Torregroza
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Jan Muehlenbernd
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Martin Stroethoff
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Sebastian Bunte
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany.,Department of Internal Medicine, Elbe Clinics Stade-Buxtehude, Stade, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Amsterdam University Medical Center (AUMC), Amsterdam, The Netherlands
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
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The Melatonin Receptor Agonist Ramelteon Induces Cardioprotection that Requires MT2 Receptor Activation and Release of Reactive Oxygen Species. Cardiovasc Drugs Ther 2020; 34:303-310. [PMID: 32236860 PMCID: PMC7242242 DOI: 10.1007/s10557-020-06972-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose The melatonin receptor (MT) agonist ramelteon has a higher affinity to MT1 than for MT2 receptors and induces cardioprotection by involvement of mitochondrial potassium channels. Activation of mitochondrial potassium channels leads to release of free radicals. We investigated whether (1) ramelteon-induced cardioprotection is MT2 receptor specific and (2) if free radicals are involved in ramelteon-induced cardioprotection. Methods Hearts of male Wistar rats were randomized, placed on a Langendorff system, and perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. Before ischemia hearts were perfused with ramelteon (Ram) with or without the MT2 receptor inhibitor 4-phenyl-2-propionamidotetralin (4P-PDOT+Ram, 4P-PDOT). In subsequent experiments, ramelteon was administered together with the radical oxygen species (ROS) scavenger N-2-mercaptopropionylglycine (MPG+Ram). To determine whether the blockade of ramelteon-induced cardioprotection can be restored, we combined ramelteon and MPG with mitochondrial permeability transition pore (mPTP) inhibitor cyclosporine A (CsA) at different time points. Infarct size was determined by triphenyltetrazolium chloride (TTC) staining. Results Ramelteon-induced infarct size reduction was completely blocked by 4P-PDOT and MPG. Ramelteon and MPG combined with CsA before ischemia were not cardioprotective but CsA at the onset of reperfusion could restore infarct size reduction. Conclusions This study shows for the first time that despite the higher affinity to MT1 receptors, (1) ramelteon-induced cardioprotection involves MT2 receptors, (2) cardioprotection requires ROS release, and (3) inhibition of the mPTP can restore infarct size reduction.
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Activation of PKG and Akt Is Required for Cardioprotection by Ramelteon-Induced Preconditioning and Is Located Upstream of mKCa-Channels. Int J Mol Sci 2020; 21:ijms21072585. [PMID: 32276406 PMCID: PMC7177737 DOI: 10.3390/ijms21072585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/25/2020] [Accepted: 04/06/2020] [Indexed: 12/11/2022] Open
Abstract
Ramelteon is a Melatonin 1 (MT1)—and Melatonin 2 (MT2)—receptor agonist conferring cardioprotection by pharmacologic preconditioning. While activation of mitochondrial calcium-sensitive potassium (mKCa)-channels is involved in this protective mechanism, the specific upstream signaling pathway of Ramelteon-induced cardioprotection is unknown. In the present study, we (1) investigated whether Ramelteon-induced cardioprotection involves activation of protein kinase G (PKG) and/or protein kinase B (Akt) and (2) determined the precise sequence of PKG and Akt in the signal transduction pathway of Ramelteon-induced preconditioning. Hearts of male Wistar rats were randomized and placed on a Langendorff system, perfused with Krebs–Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. Before ischemia, hearts were perfused with Ramelteon (Ram) with or without the PKG or Akt inhibitor KT5823 and MK2206, respectively (KT5823 + Ram, KT5823, MK2206 + Ram, MK2206). To determine the precise signaling sequence, subsequent experiments were conducted with the guanylate cyclase activator BAY60-2770 and the mKCa-channel activator NS1619. Infarct size was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Ramelteon-induced infarct size reduction was completely blocked by KT5823 (p = 0.0012) and MK2206 (p = 0.0005). MK2206 with Ramelteon combined with BAY60-2770 reduced infarct size significantly (p = 0.0014) indicating that PKG activation takes place after Akt. Ramelteon and KT5823 (p = 0.0063) or MK2206 (p = 0.006) respectively combined with NS1619 also significantly reduced infarct size, indicating that PKG and Akt are located upstream of mKCa-channels. This study shows for the first time that Ramelteon-induced preconditioning (1) involves activation of PKG and Akt; (2) PKG is located downstream of Akt and (3) both enzymes are located upstream of mKCa-channels in the signal transduction pathway.
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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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Stroethoff M, Behmenburg F, Spittler K, Raupach A, Heinen A, Hollmann MW, Huhn R, Mathes A. Activation of Melatonin Receptors by Ramelteon Induces Cardioprotection by Postconditioning in the Rat Heart. Anesth Analg 2019; 126:2112-2115. [PMID: 29381514 DOI: 10.1213/ane.0000000000002625] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Activation of melatonin receptors protects the heart against ischemia-reperfusion injury. Ramelteon, a clinically used drug for insomnia, acts via activation of melatonin receptors. We investigated whether ramelteon induces acute infarct size reduction by postconditioning. Male Wistar rats were randomized to 6 groups. Hearts were treated with melatonin and ramelteon at the beginning of reperfusion. The melatonin receptor inhibitor luzindole was administered with and without melatonin and ramelteon, respectively. Ramelteon reduced infarct size to the same extent as melatonin. Both effects were completely abolished by luzindole. The results show for the first time that ramelteon induces cardioprotection by postconditioning.
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Affiliation(s)
- Martin Stroethoff
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Friederike Behmenburg
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Kerstin Spittler
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Annika Raupach
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - André Heinen
- Department of Cardiovascular Physiology, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands
| | - Ragnar Huhn
- From the Department of Anesthesiology, University Hospital Duesseldorf, Duesseldorf, Germany
| | - Alexander Mathes
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Cologne, Cologne, Germany
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13
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Raupach A, Reinle J, Stroethoff M, Mathes A, Heinen A, Hollmann MW, Huhn R, Bunte S. Milrinone-Induced Pharmacological Preconditioning in Cardioprotection: Hints for a Role of Mitochondrial Mechanisms. J Clin Med 2019; 8:jcm8040507. [PMID: 31013843 PMCID: PMC6517902 DOI: 10.3390/jcm8040507] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/29/2019] [Accepted: 04/10/2019] [Indexed: 02/06/2023] Open
Abstract
The activation of mitochondrial calcium-sensitive potassium (mBKCa) channels is crucially involved in cardioprotection induced by preconditioning. For milrinone (Mil)-induced preconditioning, the involvement of mBKCa-channels and further mitochondrial signaling is unknown. We hypothesize that (1) Mil-induced preconditioning is concentration-dependent and (2) that the activation of mBKCa-channels, release of reactive oxygen species (ROS), and the mitochondrial permeability transition pore (mPTP) could be involved. Isolated hearts of male Wistar rats were perfused with Krebs-Henseleit buffer and underwent 33 min of ischemia followed by 60 min of reperfusion. For determination of a concentration-dependent effect of Mil, hearts were perfused with different concentrations of Mil (0.3–10 µM) over 10 min before ischemia. In a second set of experiments, in addition to controls, hearts were pretreated with the lowest protective concentration of 1 µM Mil either alone or combined with the mBKCa-channel blocker paxilline (Pax + Mil), or paxilline alone (Pax). In additional groups, Mil was administered with and without the ROS scavenger N-2-mercaptopropionylglycine (MPG + Mil, MPG) or the mPTP inhibitor cyclosporine A (MPG + Mil + CsA, CsA + Mil), respectively. Infarct sizes were determined by triphenyltetrazolium chloride (TTC) staining. The lowest and most cardioprotective concentration was 1 µM Mil (Mil 1: 32 ± 6%; p < 0.05 vs. Con: 63 ± 8% and Mil 0.3: 49 ± 6%). Pax and MPG blocked the infarct size reduction of Mil (Pax + Mil: 53 ± 6%, MPG + Mil: 59 ± 7%; p < 0.05 vs. Mil: 34 ± 6%) without having an effect on infarct size when administered alone (Pax: 53 ± 7%, MPG: 58 ± 5%; ns vs. Con). The combined administration of CsA completely restored the MPG-inhibited cardioprotection of Mil (MPG + Mil + CsA: 35 ± 7%, p < 0.05 vs. MPG + Mil). Milrinone concentration-dependently induces preconditioning. Cardioprotection is mediated by the activation of mBKCa-channels, release of ROS and mPTP inhibition.
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Affiliation(s)
- Annika Raupach
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
| | - Julia Reinle
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
| | - Martin Stroethoff
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
| | - Alexander Mathes
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Cologne, Kerpener Str. 62, 50937 Cologne, Germany.
| | - André Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine-University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany.
| | - Markus W Hollmann
- Department of Anesthesiology, Amsterdam University Medical Center (AUMC), Location AMC, Meiberdreef 9, 1105 AZ Amsterdam, The Netherlands.
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
| | - Sebastian Bunte
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
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London E, Noguchi A, Springer D, Faidas M, Gavrilova O, Eisenhofer G, Stratakis CA. The Catalytic Subunit β of PKA Affects Energy Balance and Catecholaminergic Activity. J Endocr Soc 2019; 3:1062-1078. [PMID: 31073546 PMCID: PMC6503631 DOI: 10.1210/js.2019-00029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/22/2019] [Indexed: 01/20/2023] Open
Abstract
The protein kinase A (PKA) signaling system mediates the effects of numerous hormones, neurotransmitters, and other molecules to regulate metabolism, cardiac function, and more. PKA defects may lead to diverse phenotypes that largely depend on the unique expression profile of the affected subunit. Deletion of the Prkarcb gene, which codes for PKA catalytic subunit β (Cβ), protects against diet-induced obesity (DIO), yet the mechanism for this phenotype remains unclear. We hypothesized that metabolic rate would be increased in Cβ knockout (KO) mice, which could explain DIO resistance. Male, but not female, CβKO mice had increased energy expenditure, and female but not male CβKO mice had increased subcutaneous temperature and increased locomotor activity compared with wild-type (WT) littermates. Urinary norepinephrine (NE) and normetanephrine were elevated in female CβKO mice. CβKO mice had increased heart rate (HR); blocking central NE release normalized HR to that of untreated WT mice. Basal and stimulated PKA enzymatic activities were unchanged in adipose tissue and heart and varied in different brain regions, suggesting that Prkacb deletion may mediate signaling changes in specific brain nuclei and may be less important in the peripheral regulation of PKA expression and activity. This is a demonstration of a distinct effect of the PKA Cβ catalytic subunit on catecholamines and sympathetic nerve signaling. The data provide an unexpected explanation for the metabolic phenotype of CβKO mice. Finally, the sexual dimorphism is consistent with mouse models of other PKA subunits and adds to the importance of these findings regarding the PKA system in human metabolism.
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Affiliation(s)
- Edra London
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Audrey Noguchi
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Danielle Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Maria Faidas
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Graeme Eisenhofer
- Department of Medicine III Techniche Universität Dresden, Dresden, Germany.,Institute of Clinical Chemistry and Laboratory Medicine, Techniche Universitat Dresden, Dresden, Germany
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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15
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Behmenburg F, Trefz L, Dorsch M, Ströthoff M, Mathes A, Raupach A, Heinen A, Hollmann MW, Berger MM, Huhn R. Milrinone-Induced Postconditioning Requires Activation of Mitochondrial Ca 2+-sensitive Potassium (mBK Ca) Channels. J Cardiothorac Vasc Anesth 2018; 32:2142-2148. [PMID: 29306618 DOI: 10.1053/j.jvca.2017.11.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Indexed: 01/25/2023]
Abstract
OBJECTIVES Cardioprotection by postconditioning requires activation of mitochondrial large-conductance Ca2+-sensitive potassium (mBKCa) channels. The involvement of these channels in milrinone-induced postconditioning is unknown. The authors determined whether cardioprotection by milrinone-induced postconditioning involves activation of mBKCa channels in the rat heart in vitro. DESIGN Randomized, prospective, blinded laboratory investigation. SETTING Experimental laboratory. PARTICIPANTS Male Wistar rats. INTERVENTIONS Hearts of male Wistar rats were randomized, placed on a Langendorff system, and perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 minutes of global ischemia and 60 minutes of reperfusion. At the onset of reperfusion, hearts were perfused with different concentrations of milrinone (0.3-100 μM) for determination of a dose-effect curve. In a second set of experiments, 3 μM milrinone was administered in combination with the mBKCa channel inhibitor paxilline (1 μM). Infarct size was determined by triphenyltetrazoliumchloride staining. MEASUREMENTS AND MAIN RESULTS In control animals, infarct size was 37 ± 7%. Milrinone at a concentration of 3 μM reduced infarct size to 22 ± 7% (p < 0.05 v control). Higher milrinone concentrations did not confer stronger protection. Paxilline completely blocked milrinone-induced cardioprotection whereas paxilline alone had no effect on infarct size. CONCLUSIONS This study shows that activation of mBKCa channels plays a pivotal role in milrinone-induced postconditioning.
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Affiliation(s)
| | - Lara Trefz
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Marianne Dorsch
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Martin Ströthoff
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Alexander Mathes
- Department of Anesthesiology, University Hospital Cologne, Cologne, Germany
| | - Annika Raupach
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - André Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands
| | - Marc M Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria; Department of Anesthesiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany.
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16
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Bunte S, Behmenburg F, Bongartz A, Stroethoff M, Raupach A, Heinen A, Minol JP, Hollmann MW, Huhn R, Sixt SU. Preconditioning by Levosimendan is Mediated by Activation of Mitochondrial Ca2+-Sensitive Potassium (mBKCa) Channels. Cardiovasc Drugs Ther 2018; 32:427-434. [DOI: 10.1007/s10557-018-6819-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Melatonin Receptor Agonist Ramelteon Reduces Ischemia-Reperfusion Injury Through Activation of Mitochondrial Potassium Channels. J Cardiovasc Pharmacol 2018; 72:106-111. [DOI: 10.1097/fjc.0000000000000600] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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18
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Heinen A, Behmenburg F, Aytulun A, Dierkes M, Zerbin L, Kaisers W, Schaefer M, Meyer-Treschan T, Feit S, Bauer I, Hollmann MW, Huhn R. The release of cardioprotective humoral factors after remote ischemic preconditioning in humans is age- and sex-dependent. J Transl Med 2018; 16:112. [PMID: 29703217 PMCID: PMC5921545 DOI: 10.1186/s12967-018-1480-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/10/2018] [Indexed: 01/27/2023] Open
Abstract
Background Preclinical and proof-of-concept studies suggest a cardioprotective effect of remote ischemic preconditioning (RIPC). However, two major clinical trials (ERICCA and RIPHeart) failed to show cardioprotection by RIPC. Aging and gender might be confounding factors of RIPC affecting the inter-organ signalling. Theoretically, confounding factors might prevent the protective potency of RIPC by interfering with cardiac signalling pathways, i.e. at the heart, and/or by affecting the release of humoral factor(s) from the remote organ, e.g. from the upper limb. This study investigated the effect of age and sex on the release of cardioprotective humoral factor(s) after RIPC in humans. Methods Blood samples were taken from young and aged, male and female volunteers before (control) and after RIPC (RIPC). To investigate the protective potency of the different plasma groups obtained from the human volunteers, isolated perfused hearts of young rats were used as bioassay. For this, hearts were perfused with the volunteer plasma (0.5% of coronary flow) before hearts underwent global ischemia and reperfusion. In addition, to characterize the protective potency of humoral factor(s) after RIPC to initiate protection not only in young but also aged hearts, plasma from young male volunteers were transferred to isolated hearts of aged rats. At the end of the experimental protocol, infarct sizes were determined by TTC-staining (expressed as % of left ventricle). Results RIPC plasma of young male volunteers reduced infarct size in young rat hearts from 47 ± 5 to 31 ± 10% (p = 0.02). In contrast, RIPC plasma of aged male volunteers had no protective effect. Infarct size after application of control plasma of young female volunteers was 33 ± 10%, and female RIPC plasma did not lead to an infarct size reduction. RIPC plasma of old female initiated no cardioprotection. RIPC plasma of young male volunteers reduced infarct size in isolated hearts from aged rats (41 ± 5% vs. 51 ± 5%; p < 0.001). Conclusions The release of humoral factor(s) into the blood after RIPC in humans is affected by both age and sex. In addition, these blood borne factor(s) are capable to initiate cardioprotection within the aged heart. Electronic supplementary material The online version of this article (10.1186/s12967-018-1480-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- André Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.,Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Friederike Behmenburg
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
| | - Aykut Aytulun
- Department of Neurology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Maximilian Dierkes
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Lea Zerbin
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Wolfgang Kaisers
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Maximilian Schaefer
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Tanja Meyer-Treschan
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Susanne Feit
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Inge Bauer
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Academic Medical Center (AMC), University of Amsterdam, Meibergdreef 9, 1105, Amsterdam, The Netherlands
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
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Zhang ZY, Qian LL, Wang RX. Molecular Mechanisms Underlying Renin-Angiotensin-Aldosterone System Mediated Regulation of BK Channels. Front Physiol 2017; 8:698. [PMID: 28955251 PMCID: PMC5601423 DOI: 10.3389/fphys.2017.00698] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/30/2017] [Indexed: 12/21/2022] Open
Abstract
Large-conductance calcium-activated potassium channels (BK channels) belong to a family of Ca2+-sensitive voltage-dependent potassium channels and play a vital role in various physiological activities in the human body. The renin-angiotensin-aldosterone system is acknowledged as being vital in the body's hormone system and plays a fundamental role in the maintenance of water and electrolyte balance and blood pressure regulation. There is growing evidence that the renin-angiotensin-aldosterone system has profound influences on the expression and bioactivity of BK channels. In this review, we focus on the molecular mechanisms underlying the regulation of BK channels mediated by the renin-angiotensin-aldosterone system and its potential as a target for clinical drugs.
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Affiliation(s)
- Zhen-Ye Zhang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical UniversityWuxi, China
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20
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Li Y, Wang XL, Sun X, Chai Q, Li J, Thompson B, Shen WK, Lu T, Lee HC. Regulation of vascular large-conductance calcium-activated potassium channels by Nrf2 signalling. Diab Vasc Dis Res 2017; 14:353-362. [PMID: 28429615 DOI: 10.1177/1479164117703903] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BK channels are major ionic determinants of vasodilation. BK channel function is impaired in diabetic vessels due to accelerated proteolysis of its beta-1 (BK-β1) subunits in response to increased oxidative stress. The nuclear factor E2-related factor-2 (Nrf2) signalling pathway has emerged as a master regulator of cellular redox status, and we hypothesized that it plays a central role in regulating BK channel function in diabetic vessels. We found that Nrf2 expression was markedly reduced in db/db diabetic mouse aortas, and this was associated with significant downregulation of BK-β1. In addition, the muscle ring finger protein 1 (MuRF1), a known E-3 ligase targeting BK-β1 ubiquitination and proteasomal degradation, was significantly augmented. These findings were reproduced by knockdown of Nrf2 by siRNA in cultured human coronary artery smooth muscle cells. In contrast, adenoviral transfer of Nrf2 gene in these cells downregulated MuRF1 and upregulated BK-β1 expression. Activation of Nrf2 by dimethyl fumarate preserved BK-β1 expression and protected BK channel and vascular function in db/db coronary arteries. These results indicate that expression of BK-β1 is closely regulated by Nrf2 and vascular BK channel function can be restored by Nrf2 activation. Nrf2 should be considered a novel therapeutic target in the treatment of diabetic vasculopathy.
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Affiliation(s)
- Yong Li
- 1 Department of Cardiology, Affiliated Wujin Hospital of Jiangsu University, Changzhou, China
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Xiao-Li Wang
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Xiaojing Sun
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Qiang Chai
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- 3 Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Jingchao Li
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- 4 Department of Emergency Medicine, Henan Provincial People's Hospital, Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Benjamin Thompson
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Win-Kuang Shen
- 5 Department of Cardiovascular Medicine, Mayo Clinic, Scottsdale, AZ, USA
| | - Tong Lu
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Hon-Chi Lee
- 2 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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21
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Behmenburg F, Hölscher N, Flögel U, Hollmann MW, Heinen A, Huhn R. Opening of calcium-activated potassium channels improves long-term left-ventricular function after coronary artery occlusion in mice. Int J Cardiol 2017; 241:351-357. [PMID: 28487150 DOI: 10.1016/j.ijcard.2017.04.084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/13/2017] [Accepted: 04/24/2017] [Indexed: 01/03/2023]
Abstract
BACKGROUND Opening of mitochondrial calcium-activated potassium channels (BKCa) reduces infarct size after myocardial ischemia/reperfusion injury (I/R). It is unknown if targeting BKCa-channels improves cardiac performance in the long-term after I/R. METHODS Experiments were conducted in compliance with institutional and national guidelines in C57BL/6 mice (n=7-8/group). Animals were randomized into two groups. Preconditioning was induced by intraperitoneal application of NS1619 (NS, 1μg/g bw) 10min before ischemia, control animals (Con) received the vehicle. All animals underwent 45min of myocardial ischemia and four weeks of reperfusion. Transthoracal Echocardiography (TTE) was conducted one and four weeks after ischemia (TTEW1/TTEW4) and additionally a cardiac MRI was done in week four. At the end of experiments the infarction scar was determined by AZAN staining. RESULTS TTE revealed that NS1619 improved ejection fraction one week (Con: 36±4%, NS: 45±4%; P<0.05) and four weeks after I/R (Con: 33±11%, NS: 46±8%; P<0.05). Preconditioning with NS1619 reduced end-diastolic volume at both time points (TTEW1: Con: 60±12μl, NS: 45±8μl; TTEW4: Con: 82±31μl, NS: 44±8μl; each P<0.05) and increased fractional shortening after four weeks (TTEW4: Con: 12±6%, NS: 24±8%; P<0.05). MRI-analysis after four weeks confirmed the echocardiographic results. NS1619 increased ejection fraction by 45% (MRI: Con: 29±6%, NS: 42±9%; P<0.05 vs. Con) and reduced end-diastolic and -systolic volume (EDV, ESV) compared to control (MRI: EDV: Con: 110±19μl, NS: 88±16μl; ESV: Con: 79±19μl, NS: 53±18μl; each P<0.05). Preconditioning reduced infarction scar after four weeks by 25% (Con: 12±3%, NS: 9±2%; P<0.05). CONCLUSIONS Preconditioning by opening of BKCa-channels with NS1619 improves cardiac performance after four weeks of reperfusion and reduces myocardial infarction scar.
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Affiliation(s)
- Friederike Behmenburg
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany.
| | - Nina Hölscher
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany
| | - Ulrich Flögel
- Department of Molecular Cardiology, Heinrich-Heine-University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Markus W Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Centre (AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - André Heinen
- Institute of Cardiovascular Physiology, Heinrich-Heine-University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany
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The Cardioprotective Effect of Dexmedetomidine in Rats Is Dose-Dependent and Mediated by BKCa Channels. J Cardiovasc Pharmacol 2017; 69:228-235. [DOI: 10.1097/fjc.0000000000000466] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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23
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Testai L, Da Pozzo E, Piano I, Pistelli L, Gargini C, Breschi MC, Braca A, Martini C, Martelli A, Calderone V. The Citrus Flavanone Naringenin Produces Cardioprotective Effects in Hearts from 1 Year Old Rat, through Activation of mitoBK Channels. Front Pharmacol 2017; 8:71. [PMID: 28289383 PMCID: PMC5326774 DOI: 10.3389/fphar.2017.00071] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/03/2017] [Indexed: 11/15/2022] Open
Abstract
Background and Purpose: Incidence of cardiovascular disorders increases with age, because of a dramatic fall of endogenous self-defense mechanisms and increased vulnerability of myocardium. Conversely, the effectiveness of many cardioprotective drugs is blunted in hearts of 1 year old rat. The Citrus flavanone naringenin (NAR) was reported to promote cardioprotective effects against ischemia/reperfusion (I/R) injury, through the activation of mitochondrial large conductance calcium-activated potassium channel (mitoBK). These effects were observed in young adult rats, but no data are available about the possible cardioprotective effects of NAR in aged animals. Experimental Approach: This study aimed at evaluating the potential cardioprotective effects of NAR against I/R damage in 1 year old rats, and the possible involvement of mitoBK. Key Results: Naringenin protected the hearts of 1 year old rats in both ex vivo and in vivo I/R protocols. Noteworthy, these effects were antagonized by paxilline, a selective BK-blocker. The cardioprotective effects of NAR were also observed in senescent H9c2 cardiomyoblasts. In isolated mitochondria from hearts of 1 year old, NAR exhibited the typical profile of a mitoBK opener. Finally, Western Blot analysis confirmed a significant (albeit reduced) presence of BK-forming alpha and beta subunits, both in cardiac tissue of 1 year old rats and in senescent H9c2 cells. Conclusion and Implications: This is the first work reporting cardioprotective effects of NAR in 1 year old rats. Although further studies are needed to better understand the whole pathway involved in the NAR-mediated cardioprotection, these preliminary data represent a promising perspective for a rational nutraceutical use of NAR in aging.
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Affiliation(s)
- Lara Testai
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | - Eleonora Da Pozzo
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | - Ilaria Piano
- Department of Pharmacy, University of Pisa Pisa, Italy
| | - Luisa Pistelli
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | | | | | - Alessandra Braca
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | - Alma Martelli
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
| | - Vincenzo Calderone
- Department of Pharmacy, University of PisaPisa, Italy; Interdepartmental Research Center "Nutraceuticals and Food for Health"Pisa, Italy
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Lu T, Jiang B, Wang XL, Lee HC. Coronary arterial BK channel dysfunction exacerbates ischemia/reperfusion-induced myocardial injury in diabetic mice. Appl Physiol Nutr Metab 2016; 41:992-1001. [PMID: 27574914 DOI: 10.1139/apnm-2016-0048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
The large conductance Ca(2+)-activated K(+) (BK) channels, abundantly expressed in coronary artery smooth muscle cells (SMCs), play a pivotal role in regulating coronary circulation. A large body of evidence indicates that coronary arterial BK channel function is diminished in both type 1 and type 2 diabetes. However, the consequence of coronary BK channel dysfunction in diabetes is not clear. We hypothesized that impaired coronary BK channel function exacerbates myocardial ischemia/reperfusion (I/R) injury in streptozotocin-induced diabetic mice. Combining patch-clamp techniques and cellular biological approaches, we found that diabetes facilitated the colocalization of angiotensin II (Ang II) type 1 receptors and BK channel α-subunits (BK-α), but not BK channel β1-subunits (BK-β1), in the caveolae of coronary SMCs. This caveolar compartmentation in vascular SMCs not only enhanced Ang II-mediated inhibition of BK-α but also produced a physical disassociation between BK-α and BK-β1, leading to increased infarct size in diabetic hearts. Most importantly, genetic ablation of caveolae integrity or pharmacological activation of coronary BK channels protected the cardiac function of diabetic mice from experimental I/R injury in both in vivo and ex vivo preparations. Our results demonstrate a vascular ionic mechanism underlying the poor outcome of myocardial injury in diabetes. Hence, activation of coronary BK channels may serve as a therapeutic target for cardiovascular complications of diabetes.
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MESH Headings
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Animals
- Benzimidazoles/pharmacology
- Caveolae/drug effects
- Caveolae/metabolism
- Cells, Cultured
- Coronary Vessels/drug effects
- Coronary Vessels/metabolism
- Coronary Vessels/pathology
- Coronary Vessels/physiopathology
- Diabetic Cardiomyopathies/drug therapy
- Diabetic Cardiomyopathies/metabolism
- Diabetic Cardiomyopathies/pathology
- Diabetic Cardiomyopathies/physiopathology
- HEK293 Cells
- Humans
- Kv1.3 Potassium Channel
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/agonists
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/antagonists & inhibitors
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/agonists
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/antagonists & inhibitors
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Mutation
- Myocardial Reperfusion Injury/drug therapy
- Myocardial Reperfusion Injury/metabolism
- Myocardial Reperfusion Injury/pathology
- Myocardial Reperfusion Injury/physiopathology
- Protein Transport/drug effects
- Receptor, Angiotensin, Type 1/agonists
- Receptor, Angiotensin, Type 1/metabolism
- Recombinant Proteins/metabolism
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Affiliation(s)
- Tong Lu
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Bin Jiang
- a Department of Cardiology, The First Affiliated Hospital of Soochow University, 108 Shixin Street, Soochow, Jiangsu 215006, P.R. China
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Xiao-Li Wang
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Hon-Chi Lee
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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25
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Dorsch M, Behmenburg F, Raible M, Blase D, Grievink H, Hollmann MW, Heinen A, Huhn R. Morphine-Induced Preconditioning: Involvement of Protein Kinase A and Mitochondrial Permeability Transition Pore. PLoS One 2016; 11:e0151025. [PMID: 26968004 PMCID: PMC4788451 DOI: 10.1371/journal.pone.0151025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 02/23/2016] [Indexed: 11/20/2022] Open
Abstract
Background Morphine induces myocardial preconditioning (M-PC) via activation of mitochondrial large conductance Ca2+-sensitive potassium (mKCa) channels. An upstream regulator of mKCa channels is protein kinase A (PKA). Furthermore, mKCa channel activation regulates mitochondrial bioenergetics and thereby prevents opening of the mitochondrial permeability transition pore (mPTP). Here, we investigated in the rat heart in vivo whether 1) M-PC is mediated by activation of PKA, and 2) pharmacological opening of the mPTP abolishes the cardioprotective effect of M-PC and 3) M-PC is critically dependent on STAT3 activation, which is located upstream of mPTP within the signalling pathway. Methods Male Wistar rats were randomised to six groups (each n = 6). All animals underwent 25 minutes of regional myocardial ischemia and 120 minutes of reperfusion. Control animals (Con) were not further treated. Morphine preconditioning was initiated by intravenous administration of 0.3 mg/kg morphine (M-PC). The PKA blocker H-89 (10 μg/kg) was investigated with and without morphine (H-89+M-PC, H-89). We determined the effect of mPTP opening with atractyloside (5 mg/kg) with and without morphine (Atr+M-PC, Atr). Furthermore, the effect of morphine on PKA activity was tested in isolated adult rat cardiomyocytes. In further experiments in isolated hearts we tested the protective properties of morphine in the presence of STAT3 inhibition, and whether pharmacological prevention of the mPTP-opening by cyclosporine A (CsA) is cardioprotective in the presence of STAT3 inhibition. Results Morphine reduced infarct size from 64±5% to 39±9% (P<0.05 vs. Con). H-89 completely blocked preconditioning by morphine (64±9%; P<0.05 vs. M-PC), but H-89 itself had not effect on infarct size (61±10%; P>0.05 vs. Con). Also, atractyloside abolished infarct size reduction of morphine completely (65±9%; P<0.05 vs. M-PC) but had no influence on infarct size itself (64±5%; P>0.05 vs. Con). In isolated hearts STAT3 inhibitor Stattic completely abolished morphine-induced preconditioning. Administration of Stattic and mPTP inhibitor cyclosporine A reduced infarct size to 31±6% (Stat+CsA, P<0.05 vs. Con). Cyclosporine A alone reduced infarct size to 26±7% (CsA P<0.05 vs. Con). In cardiomyocytes, PKA activity was increased by morphine. Conclusion Our data suggest that morphine-induced cardioprotection is mediated by STAT3-activation and inhibition of mPTP, with STA3 located upstream of mPTP. There is some evidence that protein kinase A is involved within the signalling pathway.
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Affiliation(s)
- Marianne Dorsch
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Friederike Behmenburg
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
- * E-mail:
| | - Miriam Raible
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Dominic Blase
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Hilbert Grievink
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
- Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital, Jerusalem, Israel
- Department of Biochemistry and Molecular Biology, The Hebrew University of Jerusalem, Ein Kerem Campus, Jerusalem, Israel
| | - Markus W. Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Academic Medical Center (AMC), University of Amsterdam, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands
| | - André Heinen
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
- Institute of Cardiovascular Physiology, Heinrich-Heine-University, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
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26
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Impact of Mitochondrial Ca2+-Sensitive Potassium (mBKCa) Channels in Sildenafil-Induced Cardioprotection in Rats. PLoS One 2015; 10:e0144737. [PMID: 26671662 PMCID: PMC4684397 DOI: 10.1371/journal.pone.0144737] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 11/23/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mitochondrial large-conductance Ca2+-sensitive potassium (mBKCa) channels are involved in myocardial ischemic preconditioning. Their role in sildenafil-induced cardioprotection is unknown. We investigated whether sildenafil-induced acute cardioprotection is mediated by activation of mBKCa channels in the rat heart in vitro. METHODS Male Wistar rats (n = 8 per group) were randomized and anesthetized with pentobarbital (90 mg/kg). Hearts were isolated, mounted on a Langendorff system and perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. Hearts underwent 30 min of global ischemia followed by 60 min of reperfusion. At the end of the experiments infarct size was determined by TTC staining. In the control group rats were not further treated. Sildenafil (3 μM) was administered over 10 min before the beginning of ischemia. The mBKCa channel inhibitor paxilline (1 μM) was administered with and without sildenafil before the onset of ischemia. The pathway underlying sildenafil-induced cardioprotection was further investigated with the protein kinase G blocker KT5823 (1 μM). Myocardial cGMP concentration was measured by ELISA. Data (mean±SD) were analysed with a one and two-way analysis of variance as appropriate. RESULTS In control animals infarct size was 52±8%. Sildenafil increased cGMP concentration and reduced infarct size to 35±6% (P<0.05 vs. control). Paxilline and KT5823 completely blocked sildenafil-induced cardioprotection (paxilline+sildenafil: 50±8%, KT5823+sildenafil: 45±8%; both P<0.05 vs. sildenafil). Functional heart parameters and coronary flow were not different between the study groups. CONCLUSION This study shows that in male rats protein kinase G-dependent opening of mBKCa channels plays a pivotal role in sildenafil-induced cardioprotection.
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27
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Bentzen BH, Olesen SP, Rønn LCB, Grunnet M. BK channel activators and their therapeutic perspectives. Front Physiol 2014; 5:389. [PMID: 25346695 PMCID: PMC4191079 DOI: 10.3389/fphys.2014.00389] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/19/2014] [Indexed: 01/05/2023] Open
Abstract
The large conductance calcium- and voltage-activated K+ channel (KCa1.1, BK, MaxiK) is ubiquitously expressed in the body, and holds the ability to integrate changes in intracellular calcium and membrane potential. This makes the BK channel an important negative feedback system linking increases in intracellular calcium to outward hyperpolarizing potassium currents. Consequently, the channel has many important physiological roles including regulation of smooth muscle tone, neurotransmitter release and neuronal excitability. Additionally, cardioprotective roles have been revealed in recent years. After a short introduction to the structure, function and regulation of BK channels, we review the small organic molecules activating BK channels and how these tool compounds have helped delineate the roles of BK channels in health and disease.
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Affiliation(s)
- Bo H Bentzen
- Department of Biomedical Sciences, Faculty of Health Sciences, Danish Arrhythmia Research Centre, University of Copenhagen Copenhagen, Denmark ; Acesion Pharma Copenhagen, Denmark
| | - Søren-Peter Olesen
- Department of Biomedical Sciences, Faculty of Health Sciences, Danish Arrhythmia Research Centre, University of Copenhagen Copenhagen, Denmark
| | | | - Morten Grunnet
- Acesion Pharma Copenhagen, Denmark ; H. Lundbeck A/S Copenhagen, Denmark
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