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Blaustein MP, Hamlyn JM. Sensational site: the sodium pump ouabain-binding site and its ligands. Am J Physiol Cell Physiol 2024; 326:C1120-C1177. [PMID: 38223926 PMCID: PMC11193536 DOI: 10.1152/ajpcell.00273.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Cardiotonic steroids (CTS), used by certain insects, toads, and rats for protection from predators, became, thanks to Withering's trailblazing 1785 monograph, the mainstay of heart failure (HF) therapy. In the 1950s and 1960s, we learned that the CTS receptor was part of the sodium pump (NKA) and that the Na+/Ca2+ exchanger was critical for the acute cardiotonic effect of digoxin- and ouabain-related CTS. This "settled" view was upended by seven revolutionary observations. First, subnanomolar ouabain sometimes stimulates NKA while higher concentrations are invariably inhibitory. Second, endogenous ouabain (EO) was discovered in the human circulation. Third, in the DIG clinical trial, digoxin only marginally improved outcomes in patients with HF. Fourth, cloning of NKA in 1985 revealed multiple NKA α and β subunit isoforms that, in the rodent, differ in their sensitivities to CTS. Fifth, the NKA is a cation pump and a hormone receptor/signal transducer. EO binding to NKA activates, in a ligand- and cell-specific manner, several protein kinase and Ca2+-dependent signaling cascades that have widespread physiological effects and can contribute to hypertension and HF pathogenesis. Sixth, all CTS are not equivalent, e.g., ouabain induces hypertension in rodents while digoxin is antihypertensinogenic ("biased signaling"). Seventh, most common rodent hypertension models require a highly ouabain-sensitive α2 NKA and the elevated blood pressure is alleviated by EO immunoneutralization. These numerous phenomena are enabled by NKA's intricate structure. We have just begun to understand the endocrine role of the endogenous ligands and the broad impact of the ouabain-binding site on physiology and pathophysiology.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
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2
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Garcia IJP, Kinoshita PF, Valadares JMDM, de Carvalho LED, Cortes VF, Barbosa LA, Scavone C, Santos HDL. Effect of Ouabain on Glutamate Transport in the Hippocampus of Rats with LPS-Induced Neuroinflammation. Biomedicines 2023; 11:biomedicines11030920. [PMID: 36979899 PMCID: PMC10045517 DOI: 10.3390/biomedicines11030920] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 03/19/2023] Open
Abstract
A lipopolysaccharide (LPS)-induced neuroinflammation rat model was used to study the effects of ouabain (OUA) at low concentrations, which can interact with the Na,K-ATPase, causing the modulation of intracellular signalling pathways in the Central Nervous System. Our study aimed to analyse the effects of OUA on glutamate transport in the hippocampus of rats with LPS-induced neuroinflammation. Adult male Wistar rats were divided into four groups: OUA (1.8 µg/kg), saline (CTR), LPS (200 µg/kg), and OUA + LPS (OUA 20 min before LPS). The animals were sacrificed after 2 h, and the hippocampus was collected for analysis. After treatment, we determined the activities of Na,K-ATPase and glutamine synthetase (GS). In addition, expression of the α1, α2, and α3 isoforms of Na,K-ATPase and the glutamate transporters, EAAT1 and EAAT2, were also analysed. Treatment with OUA caused a specific increase in the α2 isoform expression (~20%), whereas LPS decreased its expression (~22%), and treatment with OUA before LPS prevented the effects of LPS. Moreover, LPS caused a decrease of approximately 50% in GS activity compared with that in the CTR group; however, OUA pre-treatment attenuated this effect of LPS. Notably, it was found that treatment with OUA caused an increase in the expression of EAAT1 (~30%) and EAAT2 (~25%), whereas LPS caused a decrease in the expression of EAAT1 (~23%) and EAAT2 (~25%) compared with that in the CTR group. When treated with OUA, the effects of LPS were abrogated. In conclusion, the OUA pre-treatment abolished the effect caused by LPS, suggesting that this finding may be related to the restoration of the interaction between FXYD2 and the studied membrane proteins.
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Affiliation(s)
- Israel José Pereira Garcia
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
| | - Paula Fernanda Kinoshita
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo 05508-000, Brazil
| | - Jéssica Martins de Moura Valadares
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
| | - Luciana Estefani Drumond de Carvalho
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
| | - Vanessa Faria Cortes
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
| | - Leandro Augusto Barbosa
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
| | - Cristoforo Scavone
- Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo 05508-000, Brazil
- Correspondence: (C.S.); (H.d.L.S.)
| | - Hérica de Lima Santos
- Cellular Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Membrane and ATPase Biochemistry Laboratory, Federal University of São João del-Rei, Campus Cento-Oeste, Divinópolis 35501-296, Brazil
- Correspondence: (C.S.); (H.d.L.S.)
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3
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Vinod M, Berthier A, Maréchal X, Gheeraert C, Boutry R, Delhaye S, Annicotte JS, Duez H, Hovasse A, Cianférani S, Montaigne D, Eeckhoute J, Staels B, Lefebvre P. Timed use of digoxin prevents heart ischemia-reperfusion injury through a REV-ERBα-UPS signaling pathway. NATURE CARDIOVASCULAR RESEARCH 2022; 1:990-1005. [PMID: 38229609 PMCID: PMC7615528 DOI: 10.1038/s44161-022-00148-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 09/16/2022] [Indexed: 01/18/2024]
Abstract
Myocardial ischemia-reperfusion injury (MIRI) induces life-threatening damages to the cardiac tissue and pharmacological means to achieve cardioprotection are sorely needed. MIRI severity varies along the day-night cycle and is molecularly linked to components of the cellular clock including the nuclear receptor REV-ERBα, a transcriptional repressor. Here we show that digoxin administration in mice is cardioprotective when timed to trigger REV-ERBα protein degradation. In cardiomyocytes, digoxin increases REV-ERBα ubiquitinylation and proteasomal degradation, which depend on REV-ERBα ability to bind its natural ligand, heme. Inhibition of the membrane-bound Src tyrosine-kinase partially alleviated digoxin-induced REV-ERBα degradation. In untreated cardiomyocytes, REV-ERBα proteolysis is controlled by known (HUWE1, FBXW7, SIAH2) or novel (CBL, UBE4B) E3 ubiquitin ligases and the proteasome subunit PSMB5. Only SIAH2 and PSMB5 contributed to digoxin-induced degradation of REV-ERBα. Thus, controlling REV-ERBα proteostasis through the ubiquitin-proteasome system is an appealing cardioprotective strategy. Our data support the timed use of clinically-approved cardiotonic steroids in prophylactic cardioprotection.
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Affiliation(s)
- Manjula Vinod
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Alexandre Berthier
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Xavier Maréchal
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Céline Gheeraert
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Raphaёl Boutry
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 – RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, F-59000 Lille, France
| | - Stéphane Delhaye
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Jean-Sébastien Annicotte
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 – RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, F-59000 Lille, France
| | - Hélène Duez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Agnès Hovasse
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), IPHC, Université de Strasbourg, CNRS, UMR7178, 25 Rue Becquerel, F-67087 Strasbourg, France
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), IPHC, Université de Strasbourg, CNRS, UMR7178, 25 Rue Becquerel, F-67087 Strasbourg, France
| | - David Montaigne
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Jérôme Eeckhoute
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Bart Staels
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
| | - Philippe Lefebvre
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000 Lille, France
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Deisl C, Fine M, Moe OW, Hilgemann DW. Hypertrophy of human embryonic stem cell-derived cardiomyocytes supported by positive feedback between Ca 2+ and diacylglycerol signals. Pflugers Arch 2019; 471:1143-1157. [PMID: 31250095 PMCID: PMC6614165 DOI: 10.1007/s00424-019-02293-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/04/2019] [Accepted: 06/11/2019] [Indexed: 12/19/2022]
Abstract
Human embryonic stem cell-derived cardiomyocytes develop pronounced hypertrophy in response to angiotensin-2, endothelin-1, and a selected mix of three fatty acids. All three of these responses are accompanied by increases in both basal cytoplasmic Ca2+ and diacylglycerol, quantified with the Ca2+ sensor Fluo-4 and a FRET-based diacylglycerol sensor expressed in these cardiomyocytes. The heart glycoside, ouabain (30 nM), and a recently developed inhibitor of diacylglycerol lipases, DO34 (1 μM), cause similar hypertrophy responses, and both responses are accompanied by equivalent increases of basal Ca2+ and diacylglycerol. These results together suggest that basal Ca2+ and diacylglycerol form a positive feedback signaling loop that promotes execution of cardiac growth programs in these human myocytes. Given that basal Ca2+ in myocytes depends strongly on the Na+ gradient, we also tested whether nanomolar ouabain concentrations might stimulate Na+/K+ pumps, as described by others, and thereby prevent hypertrophy. However, stimulatory effects of nanomolar ouabain (1.5 nM) were not verified on Na+/K+ pump currents in stem cell-derived myocytes, nor did nanomolar ouabain block hypertrophy induced by endothelin-1. Thus, low-dose ouabain is not a "protective" intervention under the conditions of these experiments in this human myocyte model. To summarize, the major aim of this study has been to characterize the progression of hypertrophy in human embryonic stem cell-derived cardiac myocytes in dependence on diacylglycerol and Na+ gradient changes, developing a case that positive feedback coupling between these mechanisms plays an important role in the initiation of hypertrophy programs.
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Affiliation(s)
- Christine Deisl
- Departments of Physiology and Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75235, USA.
| | - Michael Fine
- Departments of Physiology and Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75235, USA
| | - Orson W Moe
- Departments of Physiology and Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75235, USA
| | - Donald W Hilgemann
- Departments of Physiology and Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75235, USA.
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5
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Abstract
Ouabain preconditioning (OPC) initiated by low concentrations of the cardiac glycoside (CG) ouabain binding to Na/K-ATPase is relayed by a unique intracellular signaling and protects cardiac myocytes against ischemia/reperfusion injury. To explore more clinically applicable protocols based on CG properties, we tested whether the FDA-approved CG digoxin could trigger cardioprotective effects comparable with those of ouabain using PC, preconditioning and PostC, postconditioning protocols in the Langendorff-perfused mouse heart subjected to global ischemia and reperfusion. Ouabain or digoxin at 10 μmol/L inhibited Na/K-ATPase activity by approximately 30% and activated PKCε translocation by approximately 50%. Digoxin-induced PC (DigPC), initiated by a transient exposure before 40 minutes of ischemia, was as effective as OPC as suggested by the recovery of left ventricular developed pressure, end-diastolic pressure, and cardiac Na/K-ATPase activity after 30 minutes of reperfusion. DigPC also significantly decreased lactate dehydrogenase release and reduced infarct size, comparable with OPC. PostC protocols consisting of a single bolus injection of 100 nmoles of ouabain or digoxin in the coronary tree at the beginning of reperfusion both improved significantly the recovery of left ventricular developed pressure and decreased lactate dehydrogenase release, demonstrating a functional and structural protection comparable with the one provided by OPC. Given the unique signaling triggered by OPC, these results suggest that DigPostC could be considered for patients with risk factors and/or concurrent treatments that may limit effectiveness of ischemic PostC.
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6
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Comment on: Endogenous Ouabain and Related Genes in the Translation from Hypertension to Renal Diseases, Int. J. Mol. Sci. 2018, 19, 1948. Int J Mol Sci 2019; 20:ijms20030505. [PMID: 30682854 PMCID: PMC6386956 DOI: 10.3390/ijms20030505] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/17/2019] [Indexed: 11/17/2022] Open
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7
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Ellermann C, Wolfes J, Puckhaber D, Bögeholz N, Leitz P, Lange PS, Eckardt L, Frommeyer G. Digitalis Promotes Ventricular Arrhythmias in Flecainide- and Ranolazine-Pretreated Hearts. Cardiovasc Toxicol 2018; 19:237-243. [DOI: 10.1007/s12012-018-9494-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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8
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Marck PV, Pierre SV. Na/K-ATPase Signaling and Cardiac Pre/Postconditioning with Cardiotonic Steroids. Int J Mol Sci 2018; 19:ijms19082336. [PMID: 30096873 PMCID: PMC6121447 DOI: 10.3390/ijms19082336] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/05/2018] [Accepted: 08/06/2018] [Indexed: 12/13/2022] Open
Abstract
The first reports of cardiac Na/K-ATPase signaling, published 20 years ago, have opened several major fields of investigations into the cardioprotective action of low/subinotropic concentrations of cardiotonic steroids (CTS). This review focuses on the protective cardiac Na/K-ATPase-mediated signaling triggered by low concentrations of ouabain and other CTS, in the context of the enduring debate over the use of CTS in the ischemic heart. Indeed, as basic and clinical research continues to support effectiveness and feasibility of conditioning interventions against ischemia/reperfusion injury in acute myocardial infarction (AMI), the mechanistic information available to date suggests that unique features of CTS-based conditioning could be highly suitable, alone /or as a combinatory approach.
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Affiliation(s)
- Pauline V Marck
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, WV 25701, USA.
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, WV 25701, USA.
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9
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Yu H, Cui X, Zhang J, Xie JX, Banerjee M, Pierre SV, Xie Z. Heterogeneity of signal transduction by Na-K-ATPase α-isoforms: role of Src interaction. Am J Physiol Cell Physiol 2018; 314:C202-C210. [PMID: 29118027 PMCID: PMC5866435 DOI: 10.1152/ajpcell.00124.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 11/22/2022]
Abstract
Of the four Na-K-ATPase α-isoforms, the ubiquitous α1 Na-K-ATPase possesses both ion transport and Src-dependent signaling functions. Mechanistically, we have identified two putative pairs of domain interactions between α1 Na-K-ATPase and Src that are critical for α1 signaling function. Our subsequent report that α2 Na-K-ATPase lacks these putative Src-binding sites and fails to carry on Src-dependent signaling further supported our proposed model of direct interaction between α1 Na-K-ATPase and Src but fell short of providing evidence for a causative role. This hypothesis was specifically tested here by introducing key residues of the two putative Src-interacting domains present on α1 but not α2 sequence into the α2 polypeptide, generating stable cell lines expressing this mutant, and comparing its signaling properties to those of α2-expressing cells. The mutant α2 was fully functional as a Na-K-ATPase. In contrast to wild-type α2, the mutant gained α1-like signaling function, capable of Src interaction and regulation. Consistently, the expression of mutant α2 redistributed Src into caveolin-1-enriched fractions and allowed ouabain to activate Src-mediated signaling cascades, unlike wild-type α2 cells. Finally, mutant α2 cells exhibited a growth phenotype similar to that of the α1 cells and proliferated much faster than wild-type α2 cells. These findings reveal the structural requirements for the Na-K-ATPase to function as a Src-dependent receptor and provide strong evidence of isoform-specific Src interaction involving the identified key amino acids. The sequences surrounding the putative Src-binding sites in α2 are highly conserved across species, suggesting that the lack of Src binding may play a physiologically important and isoform-specific role.
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Affiliation(s)
- Hui Yu
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Cui
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Jue Zhang
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Joe X Xie
- Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia
| | - Moumita Banerjee
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
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10
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Belliard A, Gulati GK, Duan Q, Alves R, Brewer S, Madan N, Sottejeau Y, Wang X, Kalisz J, Pierre SV. Ischemia/reperfusion-induced alterations of enzymatic and signaling functions of the rat cardiac Na+/K+-ATPase: protection by ouabain preconditioning. Physiol Rep 2017; 4:4/19/e12991. [PMID: 27702882 PMCID: PMC5064143 DOI: 10.14814/phy2.12991] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/12/2016] [Indexed: 11/24/2022] Open
Abstract
Cardiac glycosides (CG) are traditionally known as positive cardiac inotropes that inhibit Na+/K+‐ATPase‐dependent ion transport. CG also trigger‐specific signaling pathways through the cardiac Na+/K+‐ATPase, with beneficial effects in ischemia/reperfusion (I/R) injury (e.g., ouabain preconditioning, known as OPC) and hypertrophy. Our current understanding of hypersensitivity to CG and subsequent toxicity in the ischemic heart is mostly based on specific I/R‐induced alterations of the Na+/K+‐ATPase enzymatic function and has remained incomplete. The primary goal of this study was to investigate and compare the impact of I/R on Na+/K+‐ATPase enzymatic and signaling functions. Second, we assessed the impact of OPC on both functions. Langendorff‐perfused rat hearts were exposed to 30 min of ischemia and 30 min of reperfusion. At the inotropic concentration of 50 μmol/L, ouabain increased ERK and Akt phosphorylation in control hearts. In I/R hearts, this concentration did not induced positive inotropy and failed to induce Akt or ERK phosphorylation. The inotropic response to dobutamine as well as insulin signaling persisted, suggesting specific alterations of Na+/K+‐ATPase. Indeed, Na+/K+‐ATPase protein expression was intact, but the enzyme activity was decreased by 60% and the enzymatic function of the isoform with high affinity for ouabain was abolished following I/R. Strikingly, OPC prevented all I/R‐induced alterations of the receptor. Further studies are needed to reveal the respective roles of I/R‐induced modulations of Na+/K+‐ATPase enzymatic and signaling functions in cardiomyocyte death.
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Affiliation(s)
- Aude Belliard
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Gaurav K Gulati
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Qiming Duan
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Rosana Alves
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio Marshall Institute for Interdisciplinary Research, Huntington, West Virginia
| | - Shannon Brewer
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Namrata Madan
- Marshall Institute for Interdisciplinary Research, Huntington, West Virginia
| | - Yoann Sottejeau
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Xiaoliang Wang
- Marshall Institute for Interdisciplinary Research, Huntington, West Virginia
| | - Jennifer Kalisz
- Department of Biochemistry and Cancer Biology, College of Medicine, University of Toledo, Toledo, Ohio
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Huntington, West Virginia
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11
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Frommeyer G, Puckhaber D, Ellermann C, Dechering DG, Kochhäuser S, Leitz P, Reinke F, Eckardt L. Interactions of digitalis and class-III antiarrhythmic drugs: Amiodarone versus dronedarone. Int J Cardiol 2017; 228:74-79. [DOI: 10.1016/j.ijcard.2016.11.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/04/2016] [Indexed: 02/07/2023]
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12
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Aperia A, Akkuratov EE, Fontana JM, Brismar H. Na+-K+-ATPase, a new class of plasma membrane receptors. Am J Physiol Cell Physiol 2016; 310:C491-5. [PMID: 26791490 DOI: 10.1152/ajpcell.00359.2015] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Na(+)-K(+)-ATPase (NKA) differs from most other ion transporters, not only in its capacity to maintain a steep electrochemical gradient across the plasma membrane, but also as a receptor for a family of cardiotonic steroids, to which ouabain belongs. Studies from many groups, performed during the last 15 years, have demonstrated that ouabain, a member of the cardiotonic steroid family, can activate a network of signaling molecules, and that NKA will also serve as a signal transducer that can provide a feedback loop between NKA and the mitochondria. This brief review summarizes the current knowledge and controversies with regard to the understanding of NKA signaling.
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Affiliation(s)
- Anita Aperia
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Evgeny E Akkuratov
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Jacopo Maria Fontana
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
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13
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Xie J, Ye Q, Cui X, Madan N, Yi Q, Pierre SV, Xie Z. Expression of rat Na-K-ATPase α2 enables ion pumping but not ouabain-induced signaling in α1-deficient porcine renal epithelial cells. Am J Physiol Cell Physiol 2015; 309:C373-82. [PMID: 26108663 DOI: 10.1152/ajpcell.00103.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 06/13/2015] [Indexed: 11/22/2022]
Abstract
Na-K-ATPase is a fundamental component of ion transport. Four α isoforms of the Na-K-ATPase catalytic α subunit are expressed in human cells. The ubiquitous Na-K-ATPase α1 was recently discovered to also mediate signal transduction through Src kinase. In contrast, α2 expression is limited to a few cell types including myocytes, where it is coupled to the Na(+)/Ca(2+) exchanger. To test whether rat Na-K-ATPase α2 is capable of cellular signaling like its α1 counterpart in a recipient mammalian system, we used an α1 knockdown pig renal epithelial cell (PY-17) to create an α2-expressing cell line with no detectable level of α1 expression. These cells exhibited normal ouabain-sensitive ATPase, but failed to effectively regulate Src. In contrast to α1-expressing cells, ouabain did not stimulate Src kinase or downstream effectors such as ERK and Akt in α2 cells, although their signaling apparatus was intact as evidenced by EGF-mediated signal transduction. Additionally, α2 cells were unable to rescue caveolin-1. Unlike the NaKtide sequence derived from Na-K-ATPase α1, which downregulates basal Src activity, the corresponding α2 NaKtide was unable to inhibit Src in vitro. Finally, coimmunoprecipitation of cellular Src was diminished in α2 cells. These findings indicate that Na-K-ATPase α2 does not regulate Src and, therefore, may not serve the same role in signal transduction as α1. This further implies that the signaling mechanism of Na-K-ATPase is isoform specific, thereby supporting a model where α1 and α2 isoforms play distinct roles in mediating contraction and signaling in myocytes.
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Affiliation(s)
- Joe Xie
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Qiqi Ye
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio
| | - Xiaoyu Cui
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio
| | - Namrata Madan
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio
| | - Qiying Yi
- Laboratory Animal Center, Chongqing Medical University, Chongqing, PR China; and
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia
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Frommeyer G, Milberg P, Schulze Grotthoff J, Dechering DG, Kochhäuser S, Stypmann J, Fehr M, Breithardt G, Eckardt L. Dronedarone and digitalis: individually reduced post-repolarization refractoriness enhances life-threatening arrhythmias. Europace 2015; 17:1300-8. [DOI: 10.1093/europace/euu393] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 12/12/2014] [Indexed: 11/13/2022] Open
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Kumar A, Jaggi AS, Singh N. Pharmacology of Src family kinases and therapeutic implications of their modulators. Fundam Clin Pharmacol 2015; 29:115-30. [PMID: 25545125 DOI: 10.1111/fcp.12097] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 11/18/2014] [Accepted: 12/02/2014] [Indexed: 12/23/2022]
Abstract
Src family kinases (SFKs), the largest family of nonreceptor tyrosine kinases, include 10 members. Src was the first gene product discovered to have intrinsic protein tyrosine kinase activity. Src is widely expressed in many cell types and can have different locations within a cell; the subcellular location of Src can affect its function. Src can associate with cellular membranes, such as the plasma membrane, the perinuclear membrane, and the endosomal membrane. SFKs actions on mammalian cells are pleiotropic and include effect on cell morphology, adhesion, migration, invasion, proliferation, differentiation, and survival. SFKs at one end have been documented to play some important physiological functions; on the other end, they have been described in the pathophysiology of some disorders. In this review article, an exhaustive attempt has been made to unearth pharmacology of SFKs and therapeutic implications of SFKs modulators.
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Affiliation(s)
- Amit Kumar
- CNS and CVS Research Laboratory, Pharmacology Division, Department of Pharmaceutical Sciences and Drug Research, Faculty of Medicine, Punjabi University, Patiala, 147002, Punjab, India
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Role of phosphoinositide 3-kinase IA (PI3K-IA) activation in cardioprotection induced by ouabain preconditioning. J Mol Cell Cardiol 2015; 80:114-25. [PMID: 25575882 DOI: 10.1016/j.yjmcc.2014.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/06/2014] [Accepted: 12/26/2014] [Indexed: 11/23/2022]
Abstract
Acute myocardial infarction, the clinical manifestation of ischemia-reperfusion (IR) injury, is a leading cause of death worldwide. Like ischemic preconditioning (IPC) induced by brief episodes of ischemia and reperfusion, ouabain preconditioning (OPC) mediated by Na/K-ATPase signaling protects the heart against IR injury. Class I PI3K activation is required for IPC, but its role in OPC has not been investigated. While PI3K-IB is critical to IPC, studies have suggested that ouabain signaling is PI3K-IA-specific. Hence, a pharmacological approach was used to test the hypothesis that OPC and IPC rely on distinct PI3K-I isoforms. In Langendorff-perfused mouse hearts, OPC was initiated by 4 min of ouabain 10 μM and IPC was triggered by 4 cycles of 5 min ischemia and reperfusion prior to 40 min of global ischemia and 30 min of reperfusion. Without affecting PI3K-IB, ouabain doubled PI3K-IA activity and Akt phosphorylation at Ser(473). IPC and OPC significantly preserved cardiac contractile function and tissue viability as evidenced by left ventricular developed pressure and end-diastolic pressure recovery, reduced lactate dehydrogenase release, and decreased infarct size. OPC protection was blunted by the PI3K-IA inhibitor PI-103, but not by the PI3K-IB inhibitor AS-604850. In contrast, IPC-mediated protection was not affected by PI-103 but was blocked by AS-604850, suggesting that PI3K-IA activation is required for OPC while PI3K-IB activation is needed for IPC. Mechanistically, PI3K-IA activity is required for ouabain-induced Akt activation but not PKCε translocation. However, in contrast to PKCε translocation which is critical to protection, Akt activity was not required for OPC. Further studies shall reveal the identity of the downstream targets of this new PI3K IA-dependent branch of OPC. These findings may be of clinical relevance in patients at risk for myocardial infarction with underlying diseases and/or medication that could differentially affect the integrity of cardiac PI3K-IA and IB pathways.
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Fürstenwerth H. Letter to the editor: "Why isn't clinical experience with ouabain more widely accepted?". Am J Physiol Heart Circ Physiol 2014; 307:H1262-3. [PMID: 25320335 DOI: 10.1152/ajpheart.00525.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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18
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Abstract
Digoxin and digitoxin are widely used in the treatment of heart diseases. The exact mechanism of action of these drugs has remained an enigma. Ouabain has become the standard tool to investigate the mode of action of cardiotonic steroids, and results with ouabain are regarded as generally valid for all cardiac glycosides. However, there are marked differences between the effects of ouabain and digitalis glycosides. Ouabain has a different therapeutic profile from digitalis derivatives. Unlike digitalis glycosides, ouabain has a fast onset of action and stimulates myocardial metabolism. The inotropic effect of cardiotonic steroids is not related to inhibition of the Na-K-ATPase. Ouabain and digitalis derivatives develop their effects in different cellular spaces. Digitalis glycosides increase the intracellular calcium concentration by entering the cell interior and acting on the ryanodine receptors and by forming transmembrane calcium channels. Ouabain, by activation of the Na-K-ATPase from the extracellular side, triggers release of calcium from intracellular stores via signal transduction pathways and activates myocardial metabolism. These data no longer support the concept that all cardiotonic steroids exhibit their therapeutic effects by partial inhibition of the ion-pumping function of the Na-K-ATPase. Hence, it is suggested that this deeply rooted dogma be revised.
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Zholobenko A, Modriansky M. Silymarin and its constituents in cardiac preconditioning. Fitoterapia 2014; 97:122-32. [DOI: 10.1016/j.fitote.2014.05.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 01/28/2023]
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Kumar A, Jaggi AS, Singh N. Pharmacological investigations on possible role of Src kinases in neuroprotective mechanism of ischemic postconditioning in mice. Int J Neurosci 2014; 124:777-86. [DOI: 10.3109/00207454.2013.879869] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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21
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Bueno-Orovio A, Sánchez C, Pueyo E, Rodriguez B. Na/K pump regulation of cardiac repolarization: insights from a systems biology approach. Pflugers Arch 2013; 466:183-93. [PMID: 23674099 DOI: 10.1007/s00424-013-1293-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 11/26/2022]
Abstract
The sodium-potassium pump is widely recognized as the principal mechanism for active ion transport across the cellular membrane of cardiac tissue, being responsible for the creation and maintenance of the transarcolemmal sodium and potassium gradients, crucial for cardiac cell electrophysiology. Importantly, sodium-potassium pump activity is impaired in a number of major diseased conditions, including ischemia and heart failure. However, its subtle ways of action on cardiac electrophysiology, both directly through its electrogenic nature and indirectly via the regulation of cell homeostasis, make it hard to predict the electrophysiological consequences of reduced sodium-potassium pump activity in cardiac repolarization. In this review, we discuss how recent studies adopting the systems biology approach, through the integration of experimental and modeling methodologies, have identified the sodium-potassium pump as one of the most important ionic mechanisms in regulating key properties of cardiac repolarization and its rate dependence, from subcellular to whole organ levels. These include the role of the pump in the biphasic modulation of cellular repolarization and refractoriness, the rate control of intracellular sodium and calcium dynamics and therefore of the adaptation of repolarization to changes in heart rate, as well as its importance in regulating pro-arrhythmic substrates through modulation of dispersion of repolarization and restitution. Theoretical findings are consistent across a variety of cell types and species including human, and widely in agreement with experimental findings. The novel insights and hypotheses on the role of the pump in cardiac electrophysiology obtained through this integrative approach could eventually lead to novel therapeutic and diagnostic strategies.
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Affiliation(s)
- Alfonso Bueno-Orovio
- Department of Computer Science, University of Oxford, Wolfson Building, Parks Road, Oxford, OX1 3QD, UK,
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Belliard A, Sottejeau Y, Duan Q, Karabin JL, Pierre SV. Modulation of cardiac Na+,K+-ATPase cell surface abundance by simulated ischemia-reperfusion and ouabain preconditioning. Am J Physiol Heart Circ Physiol 2012; 304:H94-103. [PMID: 23086991 DOI: 10.1152/ajpheart.00374.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na(+),K(+)-ATPase and cell survival were investigated in a cellular model of ischemia-reperfusion (I/R)-induced injury and protection by ouabain-induced preconditioning (OPC). Rat neonatal cardiac myocytes were subjected to 30 min of substrate and coverslip-induced ischemia followed by 30 min of simulated reperfusion. This significantly compromised cell viability as documented by lactate dehydrogenase release and Annexin V/propidium iodide staining. Total Na(+),K(+)-ATPase α(1)- and α(3)-polypeptide expression remained unchanged, but cell surface biotinylation and immunostaining studies revealed that α(1)-cell surface abundance was significantly decreased. Na(+),K(+)-ATPase-activity in crude homogenates and (86)Rb(+) transport in live cells were both significantly decreased by about 30% after I/R. OPC, induced by a 4-min exposure to 10 μM ouabain that ended 8 min before the beginning of ischemia, increased cell viability in a PKCε-dependent manner. This was comparable with the protective effect of OPC previously reported in intact heart preparations. OPC prevented I/R-induced decrease of Na(+),K(+)-ATPase activity and surface expression. This model also revealed that Na(+),K(+)-ATPase-mediated (86)Rb(+) uptake was not restored to control levels in the OPC group, suggesting that the increased viability was not conferred by an increased Na(+),K(+)-ATPase-mediated ion transport capacity at the cell membrane. Consistent with this observation, transient expression of an internalization-resistant mutant form of Na(+),K(+)-ATPase α(1) known to have increased surface abundance without increased ion transport activity successfully reduced I/R-induced cell death. These results suggest that maintenance of Na(+),K(+)-ATPase cell surface abundance is critical to myocyte survival after an ischemic attack and plays a role in OPC-induced protection. They further suggest that the protection conferred by increased surface expression of Na(+),K(+)-ATPase may be independent of ion transport.
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Affiliation(s)
- Aude Belliard
- Department of Biochemistry, College of Medicine, University of Toledo, 3000 Arlington Ave., Toledo, OH 43614, USA
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Abstract
Based on a wealth of mechanistic evidence supported by the fact that ouabain mimics the spleen-liver effect in this article, the hypothesis is established that the endogenous hormone ouabain not only mimics the effects of ischemic preconditioning but also may be an ideal drug for the prevention of ischemic diseases. Moreover, it is argued that the spleen-liver effect may represent a general protective mechanism for the protection of organisms against oxygen deficiency. Investigating the spleen-liver mechanism offers a new approach to decipher the secrets of ischemic conditioning. Preconditioning represents a basic mechanism to protect a wide variety of cells against stressful stimuli such as ischemia. The ability to undergo preconditioning is almost ubiquitous in tissues and is highly conserved across species. Reinvestigation of the "spleen-liver mechanism" will allow the study of metabolic inhibitors and hormone mimics that all could help to transform ischemic preconditioning into a cure of the epidemic ischemic heart disease. Ouabain mimics the effects of the spleen factor. Cardioprotection induced by ouabain is due to the activation of pathways that are also activated in ischemic preconditioning. Just like ischemic preconditioning, ouabain activates the reperfusion injury salvage kinase pathway. Activation of nuclear factor kappa B and other transcription factors contribute to the long lasting effects of ouabain. The endogenous hormone ouabain just like preconditioning offers multiorgan protection based on innate mechanisms, which warrants clinical investigation. Clinical studies with ouabain that correspond to current standards are warranted.
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