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Extract of Sheng-Mai-San Ameliorates Myocardial Ischemia-Induced Heart Failure by Modulating Ca 2+-Calcineurin-Mediated Drp1 Signaling Pathways. Int J Mol Sci 2017; 18:ijms18091825. [PMID: 28841143 PMCID: PMC5618477 DOI: 10.3390/ijms18091825] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 02/07/2023] Open
Abstract
Sheng-Mai-San (SMS) is a well-known traditional Chinese medicine (TCM) complex prescription used to treat heart failure (HF) and angina in clinic. However, its potential therapeutic mechanisms remain unclear. The present study evaluated the cardioprotection of extract of SMS (ESMS) on myocardial ischemia (MI)-induced HF, and explored the underlying molecular mechanisms. The results demonstrated that ESMS (728.0 mg/kg) significantly attenuated MI injury-induced HF by improving cardiac function and pathological changes, decreasing lactate dehydrogenase (LDH), creatine kinase (CK) activities, and brain natriuretic peptide (BNP) levels; increasing ATPase activity; and reducing intracellular Ca2+ levels in MI-induced HF mice model. It also significantly decreased the apoptotic index. In vitro, ESMS (400 μg/mL) inhibited mitochondrial-dependent myocardial apoptosis by modulating the expression of caspase-3 and the Bcl-2/Bax ratio, and improved mitochondrial function through increasing mitochondrial membrane potential and cellular ATP content. ESMS restored intracellular Ca2+ and downregulated the expression of Calcineurin A (CnA), thus inhibiting phosphorylation of dynamin-related protein 1 (Drp1) at Ser616 and increasing phosphorylation of Drp1 at Ser637 to prevent cardiomyocyte mitochondrial fission. Above-mentioned results demonstrated ESMS suppressed mitochondrial-mediated apoptosis in oxygen glucose deprivation (OGD) injured H9c2 cardiomyocytes. These findings suggested that ESMS attenuated MI-induced HF by regulating Ca2+ homeostasis and suppressing mitochondrial mediated apoptosis through the modulation of Ca2+-calcineurin-mediated Drp1 signaling pathways. Our results provide insight into the mechanism and clinical applications of SMS and suggest a potential therapeutic strategy for HF.
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Peng LQ, Li P, Zhang QL, Hong L, Liu LP, Cui X, Cui BR. cAMP induction by ouabain promotes endothelin-1 secretion via MAPK/ERK signaling in beating rabbit atria. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 20:9-14. [PMID: 26807018 PMCID: PMC4722196 DOI: 10.4196/kjpp.2016.20.1.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/31/2015] [Accepted: 04/16/2015] [Indexed: 11/20/2022]
Abstract
Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the Na+-K+-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain (3.0 µmol/L) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 (3.0 µmol/L), an inhibitor for reverse mode of Na+-Ca2+ exchangers (NCX), but did not by L-type Ca2+ channel blocker nifedipine (1.0 µmol/L) or protein kinase A (PKA) selective inhibitor H-89 (3.0 µmol/L). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline (100.0 µmol/L), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP (0.5 µmol/L) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 (30 µmol/L), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds.
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Affiliation(s)
- Li-Qun Peng
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China.; KeErQinQu First People's Hospital, Tongliao, Neimenggu 028050, China
| | - Ping Li
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China
| | - Qiu-Li Zhang
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China
| | - Lan Hong
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China
| | - Li-Ping Liu
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China
| | - Xun Cui
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China.; Key Laboratory of Organism Functional Factors of the Changbai Mountain, Ministry of Education, Yanbian University, Yanji 133-002, China.; Cellular Function Research Center, Yanbian University, Yanji 133-002, China
| | - Bai-Ri Cui
- Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China.; Institue of Clinical Medicine, Yanbian University, Yanji 133000, China
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Gress S, Lemoine S, Puddu PE, Séralini GE, Rouet R. Cardiotoxic Electrophysiological Effects of the Herbicide Roundup(®) in Rat and Rabbit Ventricular Myocardium In Vitro. Cardiovasc Toxicol 2015; 15:324-35. [PMID: 25448876 DOI: 10.1007/s12012-014-9299-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Roundup (R), a glyphosate (G)-based herbicide (GBH), containing unknown adjuvants is widely dispersed around the world. Used principally by farmers, intoxications have increasingly been reported. We have studied R effects (containing 36 % of G) on right ventricular tissues (male Sprague-Dawley rats, up to 20,000 ppm and female New Zealand rabbits, at 25 and 50 ppm), to investigate R cardiac electrophysiological actions in vitro. We tested the reduced Ca(++) intracellular uptake mechanism as one potential cause of the electrical abnormalities after GBH superfusion, using the Na(+)/K(+)-ATPase inhibitor ouabain or the 1,4-dihydropyridine L-type calcium channel agonist BAY K 8644 which increases I Ca. R concentrations were selected based on human blood ranges found after acute intoxication. The study showed dose-dependent V max, APD50 and APD90 variations during 45 min of R superfusion. At the highest concentrations tested, there was a high incidence of conduction blocks, and 30-min washout with normal Tyrode solution did not restore excitability. We also observed an increased incidence of arrhythmias at different doses of R. Ouabain and BAY K 8644 prevented V max decrease, APD90 increase and the cardiac inexcitability induced by R 50 ppm. Glyphosate alone (18 and 180 ppm) had no significant electrophysiological effects. Thus, the action potential prolonging effect of R pointing to I Ca interference might explain both conduction blocks and proarrhythmia in vitro. These mechanisms may well be causative of QT prolongation, atrioventricular conduction blocks and arrhythmias in man after GBH acute intoxications as reported in retrospective hospital records.
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Affiliation(s)
- Steeve Gress
- Institute of Biology, Risk Pole, MRSH-CNRS, EA 2608 Estrogen, Reproduction and Cancer, University of Caen, Esplanade de la Paix, 14032, Caen Cedex, France
- Institute of Biology, EA 4650 Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, University of Caen, Esplanade de la Paix, 14032, Caen Cedex, France
| | - Sandrine Lemoine
- Institute of Biology, EA 4650 Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, University of Caen, Esplanade de la Paix, 14032, Caen Cedex, France
- Department of Anesthesiology and Critical Care Medicine, University Hospital of Caen, 14033, Caen Cedex, France
- Faculty of Medicine, University of Caen, Caen, France
| | - Paolo-Emilio Puddu
- Laboratory of Biotechnologies Applied to Cardiovascular Medicine, Department of Cardiovascular Sciences, Respiratory, Nephrological, Anesthesiological and Geriatric Sciences, Sapienza University of Rome, Viale del Policlinico, 155, 00161, Rome, Italy.
| | - Gilles-Eric Séralini
- Institute of Biology, Risk Pole, MRSH-CNRS, EA 2608 Estrogen, Reproduction and Cancer, University of Caen, Esplanade de la Paix, 14032, Caen Cedex, France
| | - René Rouet
- Institute of Biology, EA 4650 Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, University of Caen, Esplanade de la Paix, 14032, Caen Cedex, France
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Wu Y, Wang L, Ma J, Song Y, Zhang P, Luo A, Fu C, Cao Z, Wang X, Shryock JC, Belardinelli L. Protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II mediate the enlarged reverse INCX induced by ouabain-increased late sodium current in rabbit ventricular myocytes. Exp Physiol 2015; 100:399-409. [PMID: 25641541 DOI: 10.1113/expphysiol.2014.083972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/23/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the effects of protein kinase C (PKC) and Ca(2+) -calmodulin-dependent protein kinase II (CaMKII) on late sodium current (INaL ), reverse Na(+) -Ca(2+) exchange current (reverse INCX ) or intracellular Ca(2+) levels changed by ouabain? What is the main finding and its importance? Ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both PKC and CaMKII activities may mediate or modulate these processes. It has been reported that the cardiac glycoside ouabain can increase the late sodium current (INaL ), as well as the diastolic intracellular calcium concentration and contractile shortening. Whether an increase of INaL participates in a pathway that can mediate the positive inotropic response to ouabain is unknown. We therefore determined the effects of ouabain on INaL , reverse Na(+) -Ca(2+) exchange current (reverse INCX ), intracellular Ca(2+) ([Ca(2+) ]i ) levels and contractile shortening in rabbit isolated ventricular myocytes. Ouabain (0.1-8 μm) markedly increased INaL and reverse INCX in a concentration-dependent manner, with significant effects at concentrations as low as 0.5 and 1 μm. These effects of ouabain were suppressed by the INaL inhibitors TTX and ranolazine, the protein kinase C inhibitor bisindolylmaleimide and the Ca(2+) -calmodulin-dependent protein kinase II inhibitor KN-93. The enhancement by 0.5 μm ouabain of ventricular myocyte contractility and intracellular Ca(2+) transients was suppressed by 2.0 μm TTX. We conclude that ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II activities may mediate or modulate these processes.
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Affiliation(s)
- Ying Wu
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China
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Tight coupling of Na+/K+-ATPase with glycolysis demonstrated in permeabilized rat cardiomyocytes. PLoS One 2014; 9:e99413. [PMID: 24932585 PMCID: PMC4059654 DOI: 10.1371/journal.pone.0099413] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 05/14/2014] [Indexed: 12/19/2022] Open
Abstract
The effective integrated organization of processes in cardiac cells is achieved, in part, by the functional compartmentation of energy transfer processes. Earlier, using permeabilized cardiomyocytes, we demonstrated the existence of tight coupling between some of cardiomyocyte ATPases and glycolysis in rat. In this work, we studied contribution of two membrane ATPases and whether they are coupled to glycolysis--sarcoplasmic reticulum Ca2+ ATPase (SERCA) and plasmalemma Na+/K+-ATPase (NKA). While SERCA activity was minor in this preparation in the absence of calcium, major role of NKA was revealed accounting to ∼30% of the total ATPase activity which demonstrates that permeabilized cell preparation can be used to study this pump. To elucidate the contribution of NKA in the pool of ATPases, a series of kinetic measurements was performed in cells where NKA had been inhibited by 2 mM ouabain. In these cells, we recorded: ADP- and ATP-kinetics of respiration, competition for ADP between mitochondria and pyruvate kinase (PK), ADP-kinetics of endogenous PK, and ATP-kinetics of total ATPases. The experimental data was analyzed using a series of mathematical models with varying compartmentation levels. The results show that NKA is tightly coupled to glycolysis with undetectable flux of ATP between mitochondria and NKA. Such tight coupling of NKA to PK is in line with its increased importance in the pathological states of the heart when the substrate preference shifts to glucose.
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Saini-Chohan HK, Hryshko L, Xu YJ, Dhalla NS. Modification of Ca(2+)-handling in cardiomyocytes by redox sensitive mechanisms in response to ouabain. Can J Physiol Pharmacol 2013; 91:45-55. [PMID: 23367872 DOI: 10.1139/cjpp-2012-0215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We examined the role of redox-sensitive signal transduction mechanisms in modifying the changes in [Ca(2+)](i) produced by ouabain upon incubating adult rat cardiomyocytes with antioxidants or inhibitors of different protein kinases and monitoring alterations in fura-2 fluorescence. Ouabain increased basal [Ca(2+)](i), augmented the KCl-induced increase in [Ca(2+)](i), and promoted oxyradical production in cardiomyocytes. These actions of ouabain were attenuated by an oxyradical scavenging mixture (superoxide dismutase plus catalase), and the antioxidants (N-acetyl-L-cysteine and N-(2-mercaptoproprionyl)glycine). An inhibitor of MAP kinase (PD98059) depressed the ouabain-induced increase in [Ca(2+)], whereas inhibitors of tyrosine kinase (tyrphostin and genistein) and PI3 kinase (Wortmannin and LV294002) enhanced the ouabain-induced increase in [Ca(2+)](i). Inhibitors of protein kinase C (calphostin and bisindolylmalaimide) augmented the ouabain-induced increase in [Ca(2+)](i), whereas stimulation of protein kinase C by a phorbol ester (phorbol 12-myristate 13-acetate) depressed the action of ouabain. These results suggest that ouabain-induced inhibition of Na (+)-K(+) ATPase may alter the redox status of cardiomyocytes through the production of oxyradicals, and increase the activities of various protein kinases. Thus, these redox-sensitive signal transduction mechanisms involving different protein kinases may modify Ca(2+)-handling sites in cardiomyocytes and determine the magnitude of net increase in [Ca(2+)](i) in response to ouabain.
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Affiliation(s)
- Harjot K Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research and Department of Physiology, Faculty of Medicine, University of Manitoba, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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Soliman D, Wang L, Hamming KSC, Yang W, Fatehi M, Carter CC, Clanachan AS, Light PE. Late Sodium Current Inhibition Alone with Ranolazine Is Sufficient to Reduce Ischemia- and Cardiac Glycoside-Induced Calcium Overload and Contractile Dysfunction Mediated by Reverse-Mode Sodium/Calcium Exchange. J Pharmacol Exp Ther 2012; 343:325-32. [DOI: 10.1124/jpet.112.196949] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Nikolić L, Todorović N, Zakrzewska J, Stanić M, Rauš S, Kalauzi A, Janać B. Involvement of Na+/K+ pump in fine modulation of bursting activity of the snail Br neuron by 10 mT static magnetic field. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:525-40. [PMID: 22534773 DOI: 10.1007/s00359-012-0727-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/06/2012] [Accepted: 04/07/2012] [Indexed: 01/17/2023]
Abstract
The spontaneously active Br neuron from the brain-subesophageal ganglion complex of the garden snail Helix pomatia rhythmically generates regular bursts of action potentials with quiescent intervals accompanied by slow oscillations of membrane potential. We examined the involvement of the Na(+)/K(+) pump in modulating its bursting activity by applying a static magnetic field. Whole snail brains and Br neuron were exposed to the 10-mT static magnetic field for 15 min. Biochemical data showed that Na(+)/K(+)-ATPase activity increased almost twofold after exposure of snail brains to the static magnetic field. Similarly, (31)P NMR data revealed a trend of increasing ATP consumption and increase in intracellular pH mediated by the Na(+)/H(+) exchanger in snail brains exposed to the static magnetic field. Importantly, current clamp recordings from the Br neuron confirmed the increase in activity of the Na(+)/K(+) pump after exposure to the static magnetic field, as the magnitude of ouabain's effect measured on the membrane resting potential, action potential, and interspike interval duration was higher in neurons exposed to the magnetic field. Metabolic pathways through which the magnetic field influenced the Na(+)/K(+) pump could involve phosphorylation and dephosphorylation, as blocking these processes abolished the effect of the static magnetic field.
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Affiliation(s)
- Ljiljana Nikolić
- Department of Neurophysiology, Institute for Biological Research Siniša Stanković, University of Belgrade, Bulevar Despota Stefana 142, Belgrade, Serbia.
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Komniski MS, Yakushev S, Bogdanov N, Gassmann M, Bogdanova A. Interventricular heterogeneity in rat heart responses to hypoxia: the tuning of glucose metabolism, ion gradients, and function. Am J Physiol Heart Circ Physiol 2011; 300:H1645-52. [PMID: 21398597 DOI: 10.1152/ajpheart.00220.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The matching of energy supply and demand under hypoxic conditions is critical for sustaining myocardial function. Numerous reports indicate that basal energy requirements and ion handling may differ between the ventricles. We hypothesized that ventricular response to hypoxia shows interventricular differences caused by the heterogeneity in glucose metabolism and expression and activity of ion transporters. Thus we assessed glucose utilization rate, ATP, sodium and potassium concentrations, Na, K-ATPase activity, and tissue reduced:oxidized glutathione (GSH/GSSG) content in the right and left ventricles before and after the exposure of either the whole animals or isolated blood-perfused hearts to hypoxia. The hypoxia-induced boost in glucose utilization was more pronounced in the left ventricle compared with the right one. ATP levels in the right ventricle of hypoxic heart were lower than those in the left ventricle. Left ventricular sodium content was higher, and hydrolytic Na, K-ATPase activity was reduced compared with the right ventricle. Administration of the Na, K-ATPase blocker ouabain caused rapid increase in the right ventricular Na(+) and elimination of the interventricular Na(+) gradients. Exposure of the hearts to hypoxia made the interventricular heterogeneity in the Na(+) distribution even more pronounced. Furthermore, systemic hypoxia caused oxidative stress that was more pronounced in the right ventricle as revealed by GSH/GSSG ratios. On the basis of these findings, we suggest that the right ventricle is more prone to hypoxic damage, as it is less efficient in recruiting glucose as an alternative fuel and is particularly dependent on the efficient Na, K-ATPase function.
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Affiliation(s)
- Milena Segato Komniski
- Institute of Veterinary Physiology, Univ. of Zurich, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Saini-Chohan HK, Goyal RK, Dhalla NS. Involvement of sarcoplasmic reticulum in changing intracellular calcium due to Na+/K+-ATPase inhibition in cardiomyocytes. Can J Physiol Pharmacol 2010; 88:702-15. [PMID: 20651818 DOI: 10.1139/y10-055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Earlier studies have demonstrated that ouabain-induced increase in [Ca2+]i, as a consequence of sarcolemma (SL) Na+/K+-ATPase inhibition, is associated with activation of both the SL Na+/Ca2+ exchanger and SL Ca2+ channels. In view of the importance of sarcoplasmic reticulum (SR) in the regulation of [Ca2+]i, this study examined the role of SR in ouabain-induced increase in [Ca2+]i in both quiescent and KCl-depolarized cardiomyocytes. For this purpose, adult rat cardiomyocytes were loaded with fura-2 and ouabain-induced changes in [Ca2+]i were monitored upon treatment with or without different agents that are known to influence Ca2+ handling by the intracellular organelles. Ouabain not only increased the basal [Ca2+]i and augmented KCl-induced increase in [Ca2+]i but also produced similar effects on the ATP-induced increase in [Ca2+]i. Treatments of cardiomyocytes with caffeine, ryanodine, or cyclopiazonic acid, which affect SR Ca2+ stores, attenuated the ouabain-induced increase in basal Ca2+ as well as augmentation of the KCl response. Both ryanodine and cyclopiazonic acid produced additional effects, when used in combination with a SL Ca2+ channel inhibitor (verapamil), but not with a Na+/Ca2+ exchange inhibitor (KB-R7943). Inhibitors of Ca2+/calmodulin kinase, protein kinase A, and inositol-3-phosphate receptors were also observed to depress the ouabain-induced increase in [Ca2+]i in cardiomyocytes. On the other hand, mitochondrial Ca2+ transport inhibitors did not exert any effect on the ouabain-induced alterations in [Ca2+]i in cardiomyocytes. Furthermore, ouabain did not show any direct effect on the Ca2+ uptake and Ca2+ release activities of SR or mitochondria. These results suggest an indirect involvement of SR Ca2+ stores in the ouabain-induced increase in [Ca2+]i in cardiomyocytes and indicate the participation of both Ca2+-induced Ca2+ release and regulatory mechanisms in this action.
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Affiliation(s)
- Harjot K Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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Pritchard TJ, Bowman PS, Jefferson A, Tosun M, Lynch RM, Paul RJ. Na(+)-K(+)-ATPase and Ca(2+) clearance proteins in smooth muscle: a functional unit. Am J Physiol Heart Circ Physiol 2010; 299:H548-56. [PMID: 20543086 DOI: 10.1152/ajpheart.00527.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Na(+)-K(+)-ATPase (NKA) can affect intracellular Ca(2+) concentration regulation via coupling to the Na(+)-Ca(2+) exchanger and may be important in myogenic tone. We previously reported that in mice carrying a transgene for the NKA alpha(2)-isoform in smooth muscle (alpha(2sm+)), the alpha(2)-isoform protein as well as the alpha(1)-isoform (not contained in the transgene) increased to similar degrees (2-7-fold). Aortas from alpha(2sm+) mice relaxed faster from a KCl-induced contraction, hypothesized to be related to more rapid Ca(2+) clearance. To elucidate the mechanisms underlying this faster relaxation, we therefore measured the expression and distribution of proteins involved in Ca(2+) clearance. Na(+)-Ca(2+) exchanger, sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA), and plasma membrane Ca(2+)-ATPase (PMCA) proteins were all elevated up to approximately fivefold, whereas actin, myosin light chain, and calponin proteins were not changed in smooth muscle from alpha(2sm+) mice. Interestingly, the corresponding Ca(2+) clearance mRNA levels were unchanged. Immunocytochemical data indicate that the Ca(2+) clearance proteins are distributed similarly in wild-type and alpha(2sm+) aorta cells. In studies measuring relaxation half-times from a KCl-induced contraction in the presence of pharmacological inhibitors of SERCA and PMCA, we estimated that together these proteins were responsible for approximately 60-70% of relaxation in aorta. Moreover, the percent contribution of SERCA and PMCA to relaxation rates in alpha(2sm+) aorta was not significantly different from that in wild-type aorta. The coordinate expressions of NKA and Ca(2+) clearance proteins without change in the relative contributions of each individual protein to smooth muscle function suggest that NKA may be but one component of a larger functional Ca(2+) clearance system.
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Affiliation(s)
- Tracy J Pritchard
- Molecular and Cellular Physiology, Univ. of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0576, USA
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Shaikh S, Samanta K, Kar P, Roy S, Chakraborti T, Chakraborti S. m-Calpain-mediated cleavage of Na+/Ca2+ exchanger-1 in caveolae vesicles isolated from pulmonary artery smooth muscle. Mol Cell Biochem 2010; 341:167-80. [PMID: 20372982 DOI: 10.1007/s11010-010-0448-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 03/17/2010] [Indexed: 01/30/2023]
Abstract
Using m-calpain antibody, we have identified two major bands corresponding to the 80 kDa large and the 28 kDa small subunit of m-calpain in caveolae vesicles isolated from bovine pulmonary artery smooth muscle plasma membrane. In addition, 78, 35, and 18 kDa immunoreactive bands of m-calpain have also been detected. Casein zymogram studies also revealed the presence of m-calpain in the caveolae vesicles. We have also identified Na(+)/Ca(2+) exchanger-1 (NCX1) in the caveolae vesicles. Purification and N-terminal sequence analyses of these two proteins confirmed their identities as m-calpain and NCX1, respectively. We further sought to determine the role of m-calpain on calcium-dependent proteolytic cleavage of NCX1 in the caveolae vesicles. Treatment of the caveolae vesicles with the calcium ionophore, A23187 (1 microM) in presence of CaCl(2) (1 mM) appears to cleave NCX1 (120 kDa) to an 82 kDa fragment as revealed by immunoblot study using NCX1 monoclonal antibody; while pretreatment with the calpain inhibitors, calpeptin or MDL28170; or the Ca(2+) chelator, BAPTA-AM did not cause a discernible change in the NCX protein profile. In vitro cleavage of the purified NCX1 by the purified m-calpain supports this finding. The cleavage of NCX1 by m-calpain in the caveolae vesicles may be interpreted as an important mechanism of Ca(2+) overload, which could arise due to inhibition of Ca(2+) efflux by the forward-mode NCX and that could lead to sustained Ca(2+) overload in the smooth muscle leading to pulmonary hypertension.
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Affiliation(s)
- Soni Shaikh
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741235 West Bengal, India
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Singh RB, Dhalla NS. Ischemia–reperfusion-induced changes in sarcolemmal Na+/K+-ATPase are due to the activation of calpain in the heartThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease. Can J Physiol Pharmacol 2010; 88:388-97. [DOI: 10.1139/y10-012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Depression in cardiac performance due to ischemia–reperfusion (I/R) injury is associated with the development of oxidative stress and decreased sarcolemmal (SL) Na+/K+-ATPase activity. Since both I/R and oxidative stress have been reported to promote the occurrence of intracellular Ca2+ overload and activate proteases such as calpain, this study was undertaken to investigate whether the activation of calpain in I/R hearts is associated with alterations in the SL Na+/K+-ATPase activity and its isoform content. For this purpose, isolated rat hearts treated with and without 2 different calpain inhibitors (leupeptin and MDL28170) were subjected to 30 min ischemia followed by 60 min of reperfusion, and the cardiac function, SL Na+/K+-ATPase activity, Na+/K+-ATPase isoform protein content, and calpain activity were measured. The I/R-induced depressions in cardiac function, Na+/K+-ATPase activity, and protein content of Na+/K+-ATPase isoforms were associated with an increase in calpain activity , but were prevented by treatment of hearts with leupeptin. Incubation of SL membranes with calpain decreased the Na+/K+-ATPase activity and protein content of its isoforms; these changes were also attenuated by leupeptin. The I/R-induced alterations in cardiac function and the activity of SL Na+/K+-ATPase and calpain were Ca2+-dependent and were prevented by MDL28170, a specific inhibitor of calpain. The I/R-induced translocation of calpain isoforms (I and II) from the cytosol to SL and the changes in distribution of calpastatin were also attenuated by treatment with calpain inhibitors. These results suggest that the depression in cardiac function and SL Na+/K+-ATPase activity in I/R hearts may be due to changes in the activity and translocation of calpain.
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Affiliation(s)
- Raja B. Singh
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Naranjan S. Dhalla
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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Saini-Chohan HK, Dhalla NS. Attenuation of ischemia-reperfusion-induced alterations in intracellular Ca2+ in cardiomyocytes from hearts treated with N-acetylcysteine and N-mercaptopropionylglycine. Can J Physiol Pharmacol 2010; 87:1110-9. [PMID: 20029548 DOI: 10.1139/y09-103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This study was undertaken to test whether Ca(2+)-handling abnormalities in cardiomyocytes after ischemia-reperfusion (I/R) are prevented by antioxidants such as N-acetyl L-cysteine (NAC), which is known to reduce oxidative stress by increasing the glutathione redox status, and N-(2-mercaptopropionyl)-glycine (MPG), which scavenges both peroxynitrite and hydroxyl radicals. For this purpose, isolated rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion, and cardiomyocytes were prepared to monitor changes in the intracellular concentration of free Ca(2+) ([Ca(2+)](i)). Marked depression in the left ventricular developed pressure and elevation in the left ventricular end-diastolic pressure in I/R hearts were attenuated by treatment with NAC or MPG. Cardiomyocytes obtained from I/R hearts showed an increase in the basal level of [Ca(2+)](i) as well as augmentation of the low Na(+)-induced increase in [Ca(2+)](i), with no change in the KCl-induced increase in [Ca(2+)](i). These I/R-induced alterations in Ca(2+) handling by cardiomyocytes were attenuated by treatment of hearts with NAC or MPG. Furthermore, reduction in the isoproterenol-, ATP-, ouabain-, and caffeine-induced increases in [Ca(2+)](i) in cardiomyocytes from I/R hearts were limited by treatment with NAC or MPG. The increases in the basal [Ca(2+)](i), unlike the KCl-induced increase in [Ca(2+)](i), were fully or partially prevented by both NAC and MPG upon exposing cardiomyocytes to hypoxia-reoxygenation, H(2)O(2), or a mixture of xanthine and xanthine oxidase. These results suggest that improvement in cardiac function of I/R hearts treated with NAC or MPG was associated with attenuation of changes in Ca(2+) handling by cardiomyocytes, and the results support the view that oxidative stress due to oxyradical generation and peroxynitrite formation plays an important role in the development of intracellular Ca(2+) overload in cardiomyocytes as a consequence of I/R injury.
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Affiliation(s)
- Harjot K Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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HASDEMIR CAN, AYDIN HIKMETH, CELIK HANDANA, SIMSEK EVRIM, PAYZIN SERDAR, KAYIKCIOGLU MERAL, AYDIN MEHMET, KULTURSAY HAKAN, CAN LEVENTH. Transcriptional Profiling of Septal Wall of the Right Ventricular Outflow Tract in Patients with Idiopathic Ventricular Arrhythmias. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:159-67. [DOI: 10.1111/j.1540-8159.2009.02606.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Dhalla NS, Saini-Chohan HK, Duhamel TA. Strategies for the regulation of intracellular calcium in ischemic heart disease. Future Cardiol 2009; 4:339-45. [PMID: 19804313 DOI: 10.2217/14796678.4.4.339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Makazan Z, Saini-Chohan HK, Dhalla NS. Mitochondrial oxidative phosphorylation in hearts subjected to Ca2+ depletion and Ca2+ repletionThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba. Can J Physiol Pharmacol 2009; 87:789-97. [DOI: 10.1139/y09-050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Repletion of Ca2+ in the Ca2+-depleted heart has been shown to produce cardiac dysfunction, myocardial cell damage, intracellular Ca2+ overload, and defects in sarcolemmal and sarcoplasmic reticulum function (Ca2+ paradox). Although these alterations in the Ca2+-paradox heart are associated with a depression in the high-energy phosphate stores, little information regarding changes in mitochondrial oxidative phosphorylation is available. Perfusion of rat hearts with Ca2+-free medium for 5 min followed by reperfusion with a medium containing 1.25 mmol/L Ca2+ for 10 min depressed mitochondrial state 3 respiration, respiratory control index, ADP/O ratio, and rate of oxidative phosphorylation without any change in state 4 respiration. These alterations were partially prevented when the reperfusion was carried out with a medium containing low Ca2+ (0.10–0.50 mmol/L). Treatment of heart with inhibitors of sarcolemmal Ca2+ channels (verapamil and diltiazem) or inhibitors of Na+/Ca2+ exchange (KB-R7943) and Na+/H+ exchange (amiloride) failed to modify changes in mitochondrial function due to Ca2+ paradox. Likewise, antioxidants N-acetylcysteine and N-(2-mercaptopropionyl)-glycine and an oxyradical-scavenging mixture of superoxide dismutase and catalase were ineffective in preventing the mitochondrial alterations in the Ca2+-paradox heart. Incubation of mitochondria with various concentrations of Ca2+ inhibited oxidative phosphorylation; this Ca2+-induced change in mitochondrial function was not affected by different oxyradical-scavenging systems. These observations suggest that defects in mitochondrial function in the Ca2+-paradox heart may be due to the occurrence of intracellular Ca2+ overload rather than the development of oxidative stress.
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Affiliation(s)
- Zhanna Makazan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | - Harjot K. Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | - Naranjan S. Dhalla
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Ca2+ influx mechanisms in caveolae vesicles of pulmonary smooth muscle plasma membrane under inhibition of alpha2beta1 isozyme of Na+/K+-ATPase by ouabain. Life Sci 2008; 84:139-48. [PMID: 19059418 DOI: 10.1016/j.lfs.2008.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 09/23/2008] [Accepted: 11/12/2008] [Indexed: 11/21/2022]
Abstract
AIMS We sought to determine the mechanisms of an increase in Ca(2+) level in caveolae vesicles in pulmonary smooth muscle plasma membrane during Na(+)/K(+)-ATPase inhibition by ouabain. MAIN METHODS The caveolae vesicles isolated by density gradient centrifugation were characterized by electron microscopic and immunologic studies and determined ouabain induced increase in Na(+) and Ca(2+) levels in the vesicles with fluorescent probes, SBFI-AM and Fura2-AM, respectively. KEY FINDINGS We identified the alpha(2)beta(1) and alpha(1)beta(1) isozymes of Na(+)/K(+)-ATPase in caveolae vesicles, and only the alpha(1)beta(1) isozyme in noncaveolae fraction of the plasma membrane. The alpha(2)-isoform contributes solely to the enzyme inhibition in the caveolae vesicles at 40 nM ouabain. Methylisobutylamiloride (Na(+)/H(+)-exchange inhibitor) and tetrodotoxin (voltage-gated Na(+)-channel inhibitor) pretreatment prevented ouabain induced increase in Na(+) and Ca(2+) levels. Ouabain induced increase in Ca(2+) level was markedly, but not completely, inhibited by KB-R7943 (reverse-mode Na(+)/Ca(2+)-exchange inhibitor) and verapamil (L-type Ca(2+)-channel inhibitor). However, pretreatment with tetrodotoxin in conjunction with KB-R7943 and verapamil blunted ouabain induced increase in Ca(2+) level in the caveolae vesicles, indicating that apart from Na(+)/Ca(+)-exchanger and L-type Ca(2+)-channels, "slip-mode conductance" of Na(+) channels could also be involved in this scenario. SIGNIFICANCE Inhibition of alpha(2) isoform of Na(+)/K(+)-ATPase by ouabain plays a crucial role in modulating the Ca(2+) influx regulatory components in the caveolae microdomain for marked increase in (Ca(2+))(i) in the smooth muscle, which could be important for the manifestation of pulmonary hypertension.
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