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Lisin R, Balakin A, Mukhlynina E, Protsenko Y. Differences in Mechanical, Electrical and Calcium Transient Performance of the Isolated Right Atrial and Ventricular Myocardium of Guinea Pigs at Different Preloads (Lengths). Int J Mol Sci 2023; 24:15524. [PMID: 37958508 PMCID: PMC10650485 DOI: 10.3390/ijms242115524] [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: 09/29/2023] [Revised: 10/19/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
There are only a few studies devoted to the comparative and simultaneous study of the mechanisms of the length-dependent regulation of atrial and ventricular contractility. Therefore, an isometric force-length protocol was applied to isolated guinea pig right atrial (RA) strips and ventricular (RV) trabeculae, with a simultaneous measurement of force (Frank-Starling mechanism) and Ca2+ transients (CaT) or transmembrane action potentials (AP). Over the entire length-range studied, the duration of isometric contraction, CaT and AP, were shorter in the RA myocardium than in the RV myocardium. The RA myocardium was stiffer than the RV myocardium. With the increasing length of the RA and RV myocardium, the amplitude and duration of isometric contraction and CaT increased, as well as the amplitude and area of the "CaT difference curves" (shown for the first time). However, the rates of the tension development and relaxation decreased. No contribution of AP duration to the heterometric regulation of isometric tension was found in either the RA or RV myocardium of the guinea pig. Changes in the degree of overlap of the contractile proteins of the guinea pig RA and RV myocardium mainly affect CaT kinetics but not AP duration.
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Affiliation(s)
| | - Alexandr Balakin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 106 Pervomayskaya Str., Yekaterinburg 620049, Russia; (R.L.); (E.M.); (Y.P.)
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2
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Mazhar F, Bartolucci C, Regazzoni F, Paci M, Dedè L, Quarteroni A, Corsi C, Severi S. A detailed mathematical model of the human atrial cardiomyocyte: integration of electrophysiology and cardiomechanics. J Physiol 2023. [PMID: 37641426 DOI: 10.1113/jp283974] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 08/02/2023] [Indexed: 08/31/2023] Open
Abstract
Mechano-electric regulations (MER) play an important role in the maintenance of cardiac performance. Mechano-calcium and mechano-electric feedback (MCF and MEF) pathways adjust the cardiomyocyte contractile force according to mechanical perturbations and affects electro-mechanical coupling. MER integrates all these regulations in one unit resulting in a complex phenomenon. Computational modelling is a useful tool to accelerate the mechanistic understanding of complex experimental phenomena. We have developed a novel model that integrates the MER loop for human atrial cardiomyocytes with proper consideration of feedforward and feedback pathways. The model couples a modified version of the action potential (AP) Koivumäki model with the contraction model by Quarteroni group. The model simulates iso-sarcometric and isometric twitches and the feedback effects on AP and Ca2+ -handling. The model showed a biphasic response of Ca2+ transient (CaT) peak to increasing pacing rates and highlights the possible mechanisms involved. The model has shown a shift of the threshold for AP and CaT alternans from 4.6 to 4 Hz under post-operative atrial fibrillation, induced by depressed SERCA activity. The alternans incidence was dependent on a chain of mechanisms including RyRs availability time, MCF coupling, CaMKII phosphorylation, and the stretch levels. As a result, the model predicted a 10% slowdown of conduction velocity for a 20% stretch, suggesting a role of stretch in creation of substrate formation for atrial fibrillation. Overall, we conclude that the developed model provides a physiological CaT followed by a physiological twitch. This model can open pathways for the future studies of human atrial electromechanics. KEY POINTS: With the availability of human atrial cellular data, interest in atrial-specific model integration has been enhanced. We have developed a detailed mathematical model of human atrial cardiomyocytes including the mechano-electric regulatory loop. The model has gone through calibration and evaluation phases against a wide collection of available human in-vitro data. The usefulness of the model for analysing clinical problems has been preliminaryly tested by simulating the increased incidence of Ca2+ transient and action potential alternans at high rates in post-operative atrial fibrillation condition. The model determines the possible role of mechano-electric feedback in alternans incidence, which can increase vulnerability to atrial arrhythmias by varying stretch levels. We found that our physiologically accurate description of Ca2+ handling can reproduce many experimental phenomena and can help to gain insights into the underlying pathophysiological mechanisms.
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Affiliation(s)
- Fazeelat Mazhar
- Department of Electrical, Electronic and Information Engineering 'Guglielmo Marconi', University of Bologna, Cesena, Italy
| | - Chiara Bartolucci
- Department of Electrical, Electronic and Information Engineering 'Guglielmo Marconi', University of Bologna, Cesena, Italy
| | | | - Michelangelo Paci
- Department of Electrical, Electronic and Information Engineering 'Guglielmo Marconi', University of Bologna, Cesena, Italy
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Luca Dedè
- MOX - Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | - Alfio Quarteroni
- MOX - Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
- Mathematics Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Cristiana Corsi
- Department of Electrical, Electronic and Information Engineering 'Guglielmo Marconi', University of Bologna, Cesena, Italy
| | - Stefano Severi
- Department of Electrical, Electronic and Information Engineering 'Guglielmo Marconi', University of Bologna, Cesena, Italy
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Martin KE, Ravisankar P, Beerens M, MacRae CA, Waxman JS. Nr2f1a maintains atrial nkx2.5 expression to repress pacemaker identity within venous atrial cardiomyocytes of zebrafish. eLife 2023; 12:e77408. [PMID: 37184369 PMCID: PMC10185342 DOI: 10.7554/elife.77408] [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: 01/27/2022] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Maintenance of cardiomyocyte identity is vital for normal heart development and function. However, our understanding of cardiomyocyte plasticity remains incomplete. Here, we show that sustained expression of the zebrafish transcription factor Nr2f1a prevents the progressive acquisition of ventricular cardiomyocyte (VC) and pacemaker cardiomyocyte (PC) identities within distinct regions of the atrium. Transcriptomic analysis of flow-sorted atrial cardiomyocytes (ACs) from nr2f1a mutant zebrafish embryos showed increased VC marker gene expression and altered expression of core PC regulatory genes, including decreased expression of nkx2.5, a critical repressor of PC differentiation. At the arterial (outflow) pole of the atrium in nr2f1a mutants, cardiomyocytes resolve to VC identity within the expanded atrioventricular canal. However, at the venous (inflow) pole of the atrium, there is a progressive wave of AC transdifferentiation into PCs across the atrium toward the arterial pole. Restoring Nkx2.5 is sufficient to repress PC marker identity in nr2f1a mutant atria and analysis of chromatin accessibility identified an Nr2f1a-dependent nkx2.5 enhancer expressed in the atrial myocardium directly adjacent to PCs. CRISPR/Cas9-mediated deletion of the putative nkx2.5 enhancer leads to a loss of Nkx2.5-expressing ACs and expansion of a PC reporter, supporting that Nr2f1a limits PC differentiation within venous ACs via maintaining nkx2.5 expression. The Nr2f-dependent maintenance of AC identity within discrete atrial compartments may provide insights into the molecular etiology of concurrent structural congenital heart defects and associated arrhythmias.
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Affiliation(s)
- Kendall E Martin
- Molecular Genetics, Biochemistry, and Microbiology Graduate Program, University of Cincinnati College of MedicineCincinnatiUnited States
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Padmapriyadarshini Ravisankar
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Manu Beerens
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Calum A MacRae
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Joshua S Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Department of Pediatrics, University of Cincinnati College of MedicineCincinnatiUnited States
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Shiels HA. Avian cardiomyocyte architecture and what it reveals about the evolution of the vertebrate heart. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210332. [PMID: 36189815 PMCID: PMC9527935 DOI: 10.1098/rstb.2021.0332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/02/2022] [Indexed: 11/17/2022] Open
Abstract
Bird cardiomyocytes are long, thin and lack transverse (t)-tubules, which is akin to the cardiomyocyte morphology of ectothermic non-avian reptiles, who are typified by low maximum heart rates and low pressure development. However, birds can achieve greater contractile rates and developed pressures than mammals, whose wide cardiomyocytes contain a dense t-tubular network allowing for uniform excitation-contraction coupling and strong contractile force. To address this apparent paradox, this paper functionally links recent electrophysiological studies on bird cardiomyocytes with decades of ultrastructure measurements. It shows that it is the strong transsarcolemmal Ca2+ influx via the L-type Ca2+ current (ICaL) and the high gain of Ca2+-induced Ca2+ release from the sarcoplasmic reticulum (SR), coupled with an internal SR Ca2+ release relay system, that facilitates the strong fast contractions in the long thin bird cardiomyocytes, without the need for t-tubules. The maintenance of an elongated myocyte morphology following the post-hatch transition from ectothermy to endothermy in birds is discussed in relation to cardiac load, myocyte ploidy, and cardiac regeneration potential in adult cardiomyocytes. Overall, the paper shows how little we know about cellular Ca2+ dynamics in the bird heart and suggests how increased research efforts in this area would provide vital information in our quest to understand the role of myocyte architecture in the evolution of the vertebrate heart. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'. Please see glossary at the end of the paper for definitions of specialized terms.
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Affiliation(s)
- Holly A. Shiels
- Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
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Abstract
The global burden caused by cardiovascular disease is substantial, with heart disease representing the most common cause of death around the world. There remains a need to develop better mechanistic models of cardiac function in order to combat this health concern. Heart rhythm disorders, or arrhythmias, are one particular type of disease which has been amenable to quantitative investigation. Here we review the application of quantitative methodologies to explore dynamical questions pertaining to arrhythmias. We begin by describing single-cell models of cardiac myocytes, from which two and three dimensional models can be constructed. Special focus is placed on results relating to pattern formation across these spatially-distributed systems, especially the formation of spiral waves of activation. Next, we discuss mechanisms which can lead to the initiation of arrhythmias, focusing on the dynamical state of spatially discordant alternans, and outline proposed mechanisms perpetuating arrhythmias such as fibrillation. We then review experimental and clinical results related to the spatio-temporal mapping of heart rhythm disorders. Finally, we describe treatment options for heart rhythm disorders and demonstrate how statistical physics tools can provide insights into the dynamics of heart rhythm disorders.
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Affiliation(s)
- Wouter-Jan Rappel
- Department of Physics, University of California San Diego, La Jolla, CA 92037
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6
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Khokhlova A, Myachina T, Butova X, Kochurova A, Polyakova E, Galagudza M, Solovyova O, Kopylova G, Shchepkin D. The Acute Effects of Leptin on the Contractility of Isolated Rat Atrial and Ventricular Cardiomyocytes. Int J Mol Sci 2022; 23:ijms23158356. [PMID: 35955485 PMCID: PMC9369024 DOI: 10.3390/ijms23158356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/22/2022] [Accepted: 07/27/2022] [Indexed: 02/01/2023] Open
Abstract
Leptin is a pleiotropic peptide playing an important role in the regulation of cardiac functions. It is not clear whether leptin directly modulates the mechanical function of atrial cardiomyocytes. We compared the acute effects of leptin on the characteristics of mechanically non-loaded sarcomere shortening and cytosolic Ca2+ concentration ([Ca2+]i) transients in single rat atrial and ventricular cardiomyocytes. We also studied the functional properties of myosin obtained from cardiomyocytes using an in vitro motility assay and assessed the sarcomeric protein phosphorylation. Single cardiomyocytes were exposed to 5, 20, and 60 nM leptin for 60 min. In ventricular cardiomyocytes, 60 nM leptin depressed sarcomere shortening amplitude and decreased the rates of shortening and relaxation. These effects were accompanied by a decrease in the phosphorylation of cMyBP-C, an increase in Tpm phosphorylation, and a slowdown of the sliding velocity of thin filaments over myosin in the in vitro motility assay. In contrast, in atrial cardiomyocytes, the phosphorylation of cMyBP-C and TnI increased, and the characteristics of sarcomere shortening did not change. Leptin had no effect on the characteristics of [Ca2+]i transients in ventricular cardiomyocytes, while 5 nM leptin prolonged [Ca2+]i transients in atrial cardiomyocytes. Thus, leptin-induced changes in contractility of ventricular cardiomyocytes may be attributed to the direct effects of leptin on cross-bridge kinetics and sarcomeric protein properties rather than changes in [Ca2+]i. We also suggest that the observed differences between atrial and ventricular cardiomyocytes may be associated with the peculiarities of the expression of leptin receptors, as well as signaling pathways in the atrial and ventricular myocardium.
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Affiliation(s)
- Anastasia Khokhlova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
- Correspondence:
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
| | - Xenia Butova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
| | - Anastasia Kochurova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
| | - Ekaterina Polyakova
- Almazov National Medical Research Centre, Institute of Experimental Medicine, Akkuratova Str. 2, 197341 Saint-Petersburg, Russia; (E.P.); (M.G.)
| | - Michael Galagudza
- Almazov National Medical Research Centre, Institute of Experimental Medicine, Akkuratova Str. 2, 197341 Saint-Petersburg, Russia; (E.P.); (M.G.)
| | - Olga Solovyova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
| | - Galina Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
| | - Daniil Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomajskaya Str. 106, 620049 Yekaterinburg, Russia; (T.M.); (X.B.); (A.K.); (O.S.); (G.K.); (D.S.)
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7
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Brandenburg S, Pawlowitz J, Steckmeister V, Subramanian H, Uhlenkamp D, Scardigli M, Mushtaq M, Amlaz SI, Kohl T, Wegener JW, Arvanitis DA, Sanoudou D, Sacconi L, Hasenfuss G, Voigt N, Nikolaev VO, Lehnart SE. A junctional cAMP compartment regulates rapid Ca 2+ signaling in atrial myocytes. J Mol Cell Cardiol 2022; 165:141-157. [PMID: 35033544 DOI: 10.1016/j.yjmcc.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 12/15/2021] [Accepted: 01/08/2022] [Indexed: 10/19/2022]
Abstract
Axial tubule junctions with the sarcoplasmic reticulum control the rapid intracellular Ca2+-induced Ca2+ release that initiates atrial contraction. In atrial myocytes we previously identified a constitutively increased ryanodine receptor (RyR2) phosphorylation at junctional Ca2+ release sites, whereas non-junctional RyR2 clusters were phosphorylated acutely following β-adrenergic stimulation. Here, we hypothesized that the baseline synthesis of 3',5'-cyclic adenosine monophosphate (cAMP) is constitutively augmented in the axial tubule junctional compartments of atrial myocytes. Confocal immunofluorescence imaging of atrial myocytes revealed that junctin, binding to RyR2 in the sarcoplasmic reticulum, was densely clustered at axial tubule junctions. Interestingly, a new transgenic junctin-targeted FRET cAMP biosensor was exclusively co-clustered in the junctional compartment, and hence allowed to monitor cAMP selectively in the vicinity of junctional RyR2 channels. To dissect local cAMP levels at axial tubule junctions versus subsurface Ca2+ release sites, we developed a confocal FRET imaging technique for living atrial myocytes. A constitutively high adenylyl cyclase activity sustained increased local cAMP levels at axial tubule junctions, whereas β-adrenergic stimulation overcame this cAMP compartmentation resulting in additional phosphorylation of non-junctional RyR2 clusters. Adenylyl cyclase inhibition, however, abolished the junctional RyR2 phosphorylation and decreased L-type Ca2+ channel currents, while FRET imaging showed a rapid cAMP decrease. In conclusion, FRET biosensor imaging identified compartmentalized, constitutively augmented cAMP levels in junctional dyads, driving both the locally increased phosphorylation of RyR2 clusters and larger L-type Ca2+ current density in atrial myocytes. This cell-specific cAMP nanodomain is maintained by a constitutively increased adenylyl cyclase activity, contributing to the rapid junctional Ca2+-induced Ca2+ release, whereas β-adrenergic stimulation overcomes the junctional cAMP compartmentation through cell-wide activation of non-junctional RyR2 clusters.
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Affiliation(s)
- Sören Brandenburg
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.
| | - Jan Pawlowitz
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Vanessa Steckmeister
- Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Dennis Uhlenkamp
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Marina Scardigli
- Department of Physics and Astronomy, University of Florence, Florence, Italy; European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy
| | - Mufassra Mushtaq
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Saskia I Amlaz
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Tobias Kohl
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Jörg W Wegener
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Demetrios A Arvanitis
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy; Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Gerd Hasenfuss
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Niels Voigt
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany; Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany; BioMET, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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Kaplan AD, Joca HC, Boyman L, Greiser M. Calcium Signaling Silencing in Atrial Fibrillation: Implications for Atrial Sodium Homeostasis. Int J Mol Sci 2021; 22:10513. [PMID: 34638854 PMCID: PMC8508839 DOI: 10.3390/ijms221910513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting more than 33 million people worldwide. Despite important advances in therapy, AF's incidence remains high, and treatment often results in recurrence of the arrhythmia. A better understanding of the cellular and molecular changes that (1) trigger AF and (2) occur after the onset of AF will help to identify novel therapeutic targets. Over the past 20 years, a large body of research has shown that intracellular Ca2+ handling is dramatically altered in AF. While some of these changes are arrhythmogenic, other changes counteract cellular arrhythmogenic mechanisms (Calcium Signaling Silencing). The intracellular Na+ concentration ([Na+])i is a key regulator of intracellular Ca2+ handling in cardiac myocytes. Despite its importance in the regulation of intracellular Ca2+ handling, little is known about [Na+]i, its regulation, and how it might be changed in AF. Previous work suggests that there might be increases in the late component of the atrial Na+ current (INa,L) in AF, suggesting that [Na+]i levels might be high in AF. Indeed, a pharmacological blockade of INa,L has been suggested as a treatment for AF. Here, we review calcium signaling silencing and changes in intracellular Na+ homeostasis during AF. We summarize the proposed arrhythmogenic mechanisms associated with increases in INa,L during AF and discuss the evidence from clinical trials that have tested the pharmacological INa,L blocker ranolazine in the treatment of AF.
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Affiliation(s)
- Aaron D. Kaplan
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Humberto C. Joca
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Maura Greiser
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
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9
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Fong SPT, Agrawal S, Gong M, Zhao J. Modulated Calcium Homeostasis and Release Events Under Atrial Fibrillation and Its Risk Factors: A Meta-Analysis. Front Cardiovasc Med 2021; 8:662914. [PMID: 34355025 PMCID: PMC8329373 DOI: 10.3389/fcvm.2021.662914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/11/2021] [Indexed: 12/26/2022] Open
Abstract
Background: Atrial fibrillation (AF) is associated with calcium (Ca2+) handling remodeling and increased spontaneous calcium release events (SCaEs). Nevertheless, its exact mechanism remains unclear, resulting in suboptimal primary and secondary preventative strategies. Methods: We searched the PubMed database for studies that investigated the relationship between SCaEs and AF and/or its risk factors. Meta-analysis was used to examine the Ca2+ mechanisms involved in the primary and secondary AF preventative groups. Results: We included a total of 74 studies, out of the identified 446 publications from inception (1982) until March 31, 2020. Forty-five were primary and 29 were secondary prevention studies for AF. The main Ca2+ release events, calcium transient (standardized mean difference (SMD) = 0.49; I2 = 35%; confidence interval (CI) = 0.33–0.66; p < 0.0001), and spark amplitude (SMD = 0.48; I2 = 0%; CI = −0.98–1.93; p = 0.054) were enhanced in the primary diseased group, while calcium transient frequency was increased in the secondary group. Calcium spark frequency was elevated in both the primary diseased and secondary AF groups. One of the key cardiac currents, the L-type calcium current (ICaL) was significantly downregulated in primary diseased (SMD = −1.07; I2 = 88%; CI = −1.94 to −0.20; p < 0.0001) and secondary AF groups (SMD = −1.28; I2 = 91%; CI = −2.04 to −0.52; p < 0.0001). Furthermore, the sodium–calcium exchanger (INCX) and NCX1 protein expression were significantly enhanced in the primary diseased group, while only NCX1 protein expression was shown to increase in the secondary AF studies. The phosphorylation of the ryanodine receptor at S2808 (pRyR-S2808) was significantly elevated in both the primary and secondary groups. It was increased in the primary diseased and proarrhythmic subgroups (SMD = 0.95; I2 = 64%; CI = 0.12–1.79; p = 0.074) and secondary AF group (SMD = 0.66; I2 = 63%; CI = 0.01–1.31; p < 0.0001). Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) expression was elevated in the primary diseased and proarrhythmic drug subgroups but substantially reduced in the secondary paroxysmal AF subgroup. Conclusions: Our study identified that ICaL is reduced in both the primary and secondary diseased groups. Furthermore, pRyR-S2808 and NCX1 protein expression are enhanced. The remodeling leads to elevated Ca2+ functional activities, such as increased frequencies or amplitude of Ca2+ spark and Ca2+ transient. The main difference identified between the primary and secondary diseased groups is SERCA expression, which is elevated in the primary diseased group and substantially reduced in the secondary paroxysmal AF subgroup. We believe our study will add new evidence to AF mechanisms and treatment targets.
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Affiliation(s)
- Sarah Pei Ting Fong
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Shaleka Agrawal
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Mengqi Gong
- Department of Cardiology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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10
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Dai W, Kesaraju S, Weber CR. Transcriptional factors in calcium mishandling and atrial fibrillation development. Pflugers Arch 2021; 473:1177-1197. [PMID: 34003377 DOI: 10.1007/s00424-021-02553-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/19/2021] [Accepted: 02/05/2021] [Indexed: 12/19/2022]
Abstract
Healthy cardiac conduction relies on the coordinated electrical activity of distinct populations of cardiomyocytes. Disruption of cell-cell conduction results in cardiac arrhythmias, a leading cause of morbidity and mortality worldwide. Recent genetic studies have highlighted a major heritable component and identified numerous loci associated with risk of atrial fibrillation, including transcription factor genes, particularly those important in cardiac development, microRNAs, and long noncoding RNAs. Identification of such genetic factors has prompted the search to understand the mechanisms that underlie the genetic component of AF. Recent studies have found several mechanisms by which genetic alterations can result in AF formation via disruption of calcium handling. Loss of developmental transcription factors in adult cardiomyocytes can result in disruption of SR calcium ATPase, sodium calcium exchanger, calcium channels, among other ion channels, which underlie action potential abnormalities and triggered activity that can contribute to AF. This review aims to summarize the complex network of transcription factors and their roles in calcium handling.
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Affiliation(s)
- Wenli Dai
- Department of Pathology, University of Chicago, Chicago, IL, USA
| | - Sneha Kesaraju
- Department of Pathology, University of Chicago, Chicago, IL, USA
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11
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Zhou X, Li A, Lin PH, Zhou J, Ma J. TRIC-A regulates intracellular Ca 2+ homeostasis in cardiomyocytes. Pflugers Arch 2021; 473:547-556. [PMID: 33474637 PMCID: PMC7940156 DOI: 10.1007/s00424-021-02513-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 01/26/2023]
Abstract
Trimeric intracellular cation (TRIC) channels have been identified as monovalent cation channels that are located in the ER/SR membrane. Two isoforms discovered in mammals are TRIC-A (TMEM38a) and TRIC-B (TMEM38b). TRIC-B ubiquitously expresses in all tissues, and TRIC-B-/- mice is lethal at the neonatal stage. TRIC-A mainly expresses in excitable cells. TRIC-A-/- mice survive normally but show abnormal SR Ca2+ handling in both skeletal and cardiac muscle cells. Importantly, TRIC-A mutations have been identified in human patients with stress-induced arrhythmia. In the past decade, important discoveries have been made to understand the structure and function of TRIC channels, especially its role in regulating intracellular Ca2+ homeostasis. In this review article, we focus on the potential roles of TRIC-A in regulating cardiac function, particularly its effects on intracellular Ca2+ signaling of cardiomyocytes and discuss the current knowledge gaps.
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Affiliation(s)
- Xinyu Zhou
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Pei-Hui Lin
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Jianjie Ma
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA.
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12
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Martin KE, Waxman JS. Atrial and Sinoatrial Node Development in the Zebrafish Heart. J Cardiovasc Dev Dis 2021; 8:jcdd8020015. [PMID: 33572147 PMCID: PMC7914448 DOI: 10.3390/jcdd8020015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/31/2021] [Accepted: 02/04/2021] [Indexed: 12/11/2022] Open
Abstract
Proper development and function of the vertebrate heart is vital for embryonic and postnatal life. Many congenital heart defects in humans are associated with disruption of genes that direct the formation or maintenance of atrial and pacemaker cardiomyocytes at the venous pole of the heart. Zebrafish are an outstanding model for studying vertebrate cardiogenesis, due to the conservation of molecular mechanisms underlying early heart development, external development, and ease of genetic manipulation. Here, we discuss early developmental mechanisms that instruct appropriate formation of the venous pole in zebrafish embryos. We primarily focus on signals that determine atrial chamber size and the specialized pacemaker cells of the sinoatrial node through directing proper specification and differentiation, as well as contemporary insights into the plasticity and maintenance of cardiomyocyte identity in embryonic zebrafish hearts. Finally, we integrate how these insights into zebrafish cardiogenesis can serve as models for human atrial defects and arrhythmias.
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Affiliation(s)
- Kendall E. Martin
- Molecular Genetics, Biochemistry, and Microbiology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joshua S. Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
- Correspondence:
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13
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Blatter LA, Kanaporis G, Martinez-Hernandez E, Oropeza-Almazan Y, Banach K. Excitation-contraction coupling and calcium release in atrial muscle. Pflugers Arch 2021; 473:317-329. [PMID: 33398498 DOI: 10.1007/s00424-020-02506-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/16/2020] [Indexed: 01/02/2023]
Abstract
In cardiac muscle, the process of excitation-contraction coupling (ECC) describes the chain of events that links action potential induced myocyte membrane depolarization, surface membrane ion channel activation, triggering of Ca2+ induced Ca2+ release from the sarcoplasmic reticulum (SR) Ca2+ store to activation of the contractile machinery that is ultimately responsible for the pump function of the heart. Here we review similarities and differences of structural and functional attributes of ECC between atrial and ventricular tissue. We explore a novel "fire-diffuse-uptake-fire" paradigm of atrial ECC and Ca2+ release that assigns a novel role to the SR SERCA pump and involves a concerted "tandem" activation of the ryanodine receptor Ca2+ release channel by cytosolic and luminal Ca2+. We discuss the contribution of the inositol 1,4,5-trisphosphate (IP3) receptor Ca2+ release channel as an auxiliary pathway to Ca2+ signaling, and we review IP3 receptor-induced Ca2+ release involvement in beat-to-beat ECC, nuclear Ca2+ signaling, and arrhythmogenesis. Finally, we explore the topic of electromechanical and Ca2+ alternans and its ramifications for atrial arrhythmia.
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Affiliation(s)
- L A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA.
| | - G Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - E Martinez-Hernandez
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - Y Oropeza-Almazan
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - K Banach
- Department of Internal Medicine/Cardiology, Rush University Medical Center, Chicago, IL, 60612, USA
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14
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Alpha and beta myosin isoforms and human atrial and ventricular contraction. Cell Mol Life Sci 2021; 78:7309-7337. [PMID: 34704115 PMCID: PMC8629898 DOI: 10.1007/s00018-021-03971-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 01/15/2023]
Abstract
Human atrial and ventricular contractions have distinct mechanical characteristics including speed of contraction, volume of blood delivered and the range of pressure generated. Notably, the ventricle expresses predominantly β-cardiac myosin while the atrium expresses mostly the α-isoform. In recent years exploration of the properties of pure α- & β-myosin isoforms have been possible in solution, in isolated myocytes and myofibrils. This allows us to consider the extent to which the atrial vs ventricular mechanical characteristics are defined by the myosin isoform expressed, and how the isoform properties are matched to their physiological roles. To do this we Outline the essential feature of atrial and ventricular contraction; Explore the molecular structural and functional characteristics of the two myosin isoforms; Describe the contractile behaviour of myocytes and myofibrils expressing a single myosin isoform; Finally we outline the outstanding problems in defining the differences between the atria and ventricles. This allowed us consider what features of contraction can and cannot be ascribed to the myosin isoforms present in the atria and ventricles.
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15
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Filatova TS, Abramochkin DV, Shiels HA. Warmer, faster, stronger: Ca 2+ cycling in avian myocardium. J Exp Biol 2020; 223:jeb228205. [PMID: 32843363 DOI: 10.1242/jeb.228205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/17/2020] [Indexed: 11/20/2022]
Abstract
Birds occupy a unique position in the evolution of cardiac design. Their hearts are capable of cardiac performance on par with, or exceeding that of mammals, and yet the structure of their cardiomyocytes resembles those of reptiles. It has been suggested that birds use intracellular Ca2+ stored within the sarcoplasmic reticulum (SR) to power contractile function, but neither SR Ca2+ content nor the cross-talk between channels underlying Ca2+-induced Ca2+ release (CICR) have been studied in adult birds. Here we used voltage clamp to investigate the Ca2+ storage and refilling capacities of the SR and the degree of trans-sarcolemmal and intracellular Ca2+ channel interplay in freshly isolated atrial and ventricular myocytes from the heart of the Japanese quail (Coturnix japonica). A trans-sarcolemmal Ca2+ current (ICa) was detectable in both quail atrial and ventricular myocytes, and was mediated only by L-type Ca2+ channels. The peak density of ICa was larger in ventricular cells than in atrial cells, and exceeded that reported for mammalian myocardium recorded under similar conditions. Steady-state SR Ca2+ content of quail myocardium was also larger than that reported for mammals, and reached 750.6±128.2 μmol l-1 in atrial cells and 423.3±47.2 μmol l-1 in ventricular cells at 24°C. We observed SR Ca2+-dependent inactivation of ICa in ventricular myocytes, indicating cross-talk between sarcolemmal Ca2+ channels and ryanodine receptors in the SR. However, this phenomenon was not observed in atrial myocytes. Taken together, these findings help to explain the high-efficiency avian myocyte excitation-contraction coupling with regard to their reptilian-like cellular ultrastructure.
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Affiliation(s)
- Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova str.,1, Moscow 117997, Russia
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova str.,1, Moscow 117997, Russia
- Ural Federal University, Mira 19, Ekaterinburg 620002, Russia
- Laboratory of Cardiac Physiology, Institute of Physiology of komi Science Centre of the Ural Branch of the Russian Academy of Sciences, FRC Komi SC UB RAS, Pervomayskaya str., 50, 167982 Syktyvkar, Komi Republic, Russia
| | - Holly A Shiels
- Faculty of Biology, Medicine and Health, Core Technology Facility, 46 Grafton Street, University of Manchester, Manchester M13 9NT, UK
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16
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Oropeza-Almazán Y, Blatter LA. Mitochondrial calcium uniporter complex activation protects against calcium alternans in atrial myocytes. Am J Physiol Heart Circ Physiol 2020; 319:H873-H881. [PMID: 32857593 DOI: 10.1152/ajpheart.00375.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cardiac alternans, defined as beat-to-beat alternations in action potential duration, cytosolic Ca transient (CaT) amplitude, and cardiac contraction is associated with atrial fibrillation (AF) and sudden cardiac death. At the cellular level, cardiac alternans is linked to abnormal intracellular calcium handling during excitation-contraction coupling. We investigated how pharmacological activation or inhibition of cytosolic Ca sequestration via mitochondrial Ca uptake and mitochondrial Ca retention affects the occurrence of pacing-induced CaT alternans in isolated rabbit atrial myocytes. Cytosolic CaTs were recorded using Fluo-4 fluorescence microscopy. Alternans was quantified as the alternans ratio (AR = 1 - CaTsmall/CaTlarge, where CaTsmall and CaTlarge are the amplitudes of the small and large CaTs of a pair of alternating CaTs). Inhibition of mitochondrial Ca sequestration via mitochondrial Ca uniporter complex (MCUC) with Ru360 enhanced the severity of CaT alternans (AR increase) and lowered the pacing frequency threshold for alternans. In contrast, stimulation of MCUC mediated mitochondrial Ca uptake with spermine-rescued alternans (AR decrease) and increased the alternans pacing threshold. Direct measurement of mitochondrial [Ca] in membrane permeabilized myocytes with Fluo-4 loaded mitochondria revealed that spermine enhanced and accelerated mitochondrial Ca uptake. Stimulation of mitochondrial Ca retention by preventing mitochondrial Ca efflux through the mitochondrial permeability transition pore with cyclosporin A also protected from alternans and increased the alternans pacing threshold. Pharmacological manipulation of MCUC activity did not affect sarcoplasmic reticulum Ca load. Our results suggest that activation of Ca sequestration by mitochondria protects from CaT alternans and could be a potential therapeutic target for cardiac alternans and AF prevention.NEW & NOTEWORTHY This study provides conclusive evidence that mitochondrial Ca uptake and retention protects from Ca alternans, whereas uptake inhibition enhances Ca alternans. The data suggest pharmacological mitochondrial Ca cycling modulation as a potential therapeutic strategy for alternans-related cardiac arrhythmia prevention.
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Affiliation(s)
| | - Lothar A Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois
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17
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Lee Y, Chakraborty S, Muthuchamy M. Roles of sarcoplasmic reticulum Ca 2+ ATPase pump in the impairments of lymphatic contractile activity in a metabolic syndrome rat model. Sci Rep 2020; 10:12320. [PMID: 32704072 PMCID: PMC7378550 DOI: 10.1038/s41598-020-69196-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 07/09/2020] [Indexed: 12/18/2022] Open
Abstract
The intrinsic lymphatic contractile activity is necessary for proper lymph transport. Mesenteric lymphatic vessels from high-fructose diet-induced metabolic syndrome (MetSyn) rats exhibited impairments in its intrinsic phasic contractile activity; however, the molecular mechanisms responsible for the weaker lymphatic pumping activity in MetSyn conditions are unknown. Several metabolic disease models have shown that dysregulation of sarcoplasmic reticulum Ca2+ ATPase (SERCA) pump is one of the key determinants of the phenotypes seen in various muscle tissues. Hence, we hypothesized that a decrease in SERCA pump expression and/or activity in lymphatic muscle influences the diminished lymphatic vessel contractions in MetSyn animals. Results demonstrated that SERCA inhibitor, thapsigargin, significantly reduced lymphatic phasic contractile frequency and amplitude in control vessels, whereas, the reduced MetSyn lymphatic contractile activity was not further diminished by thapsigargin. While SERCA2a expression was significantly decreased in MetSyn lymphatic vessels, myosin light chain 20, MLC20 phosphorylation was increased in these vessels. Additionally, insulin resistant lymphatic muscle cells exhibited elevated intracellular calcium and decreased SERCA2a expression and activity. The SERCA activator, CDN 1163 partially restored lymphatic contractile activity in MetSyn lymphatic vessel by increasing phasic contractile frequency. Thus, our data provide the first evidence that SERCA2a modulates the lymphatic pumping activity by regulating phasic contractile amplitude and frequency, but not the lymphatic tone. Diminished lymphatic contractile activity in the vessels from the MetSyn animal is associated with the decreased SERCA2a expression and impaired SERCA2 activity in lymphatic muscle.
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Affiliation(s)
- Yang Lee
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, 77807, USA
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Sanjukta Chakraborty
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, 77807, USA
| | - Mariappan Muthuchamy
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, 77807, USA.
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18
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Vermij SH, Rougier JS, Agulló-Pascual E, Rothenberg E, Delmar M, Abriel H. Single-Molecule Localization of the Cardiac Voltage-Gated Sodium Channel Reveals Different Modes of Reorganization at Cardiomyocyte Membrane Domains. Circ Arrhythm Electrophysiol 2020; 13:e008241. [PMID: 32536203 PMCID: PMC7368852 DOI: 10.1161/circep.119.008241] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Mutations in the gene encoding the cardiac voltage-gated sodium channel Nav1.5 cause various cardiac arrhythmias. This variety may arise from different determinants of Nav1.5 expression between cardiomyocyte domains. At the lateral membrane and T-tubules, Nav1.5 localization and function remain insufficiently characterized. METHODS We used novel single-molecule localization microscopy and computational modeling to define nanoscale features of Nav1.5 localization and distribution at the lateral membrane, the lateral membrane groove, and T-tubules in cardiomyocytes from wild-type (N=3), dystrophin-deficient (mdx; N=3) mice, and mice expressing C-terminally truncated Nav1.5 (ΔSIV; N=3). We moreover assessed T-tubules sodium current by recording whole-cell sodium currents in control (N=5) and detubulated (N=5) wild-type cardiomyocytes. RESULTS We show that Nav1.5 organizes as distinct clusters in the groove and T-tubules which density, distribution, and organization partially depend on SIV and dystrophin. We found that overall reduction in Nav1.5 expression in mdx and ΔSIV cells results in a nonuniform redistribution with Nav1.5 being specifically reduced at the groove of ΔSIV and increased in T-tubules of mdx cardiomyocytes. A T-tubules sodium current could, however, not be demonstrated. CONCLUSIONS Nav1.5 mutations may site-specifically affect Nav1.5 localization and distribution at the lateral membrane and T-tubules, depending on site-specific interacting proteins. Future research efforts should elucidate the functional consequences of this redistribution.
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Affiliation(s)
- Sarah H Vermij
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland (S.H.V., J.-S.R., H.A.)
| | - Jean-Sébastien Rougier
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland (S.H.V., J.-S.R., H.A.)
| | | | - Eli Rothenberg
- Department of Biochemistry and Pharmacology (E.R.), New York University School of Medicine, NY
| | - Mario Delmar
- Department of Cardiology (M.D.), New York University School of Medicine, NY
| | - Hugues Abriel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland (S.H.V., J.-S.R., H.A.)
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19
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Silva-Palacios A, Zazueta C, Pedraza-Chaverri J. ER membranes associated with mitochondria: Possible therapeutic targets in heart-associated diseases. Pharmacol Res 2020; 156:104758. [PMID: 32200027 DOI: 10.1016/j.phrs.2020.104758] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/06/2020] [Accepted: 03/16/2020] [Indexed: 12/14/2022]
Abstract
Cardiovascular system cell biology is tightly regulated and mitochondria play a relevant role in maintaining heart function. In recent decades, associations between such organelles and the sarco/endoplasmic reticulum (SR) have been raised great interest. Formally identified as mitochondria-associated SR membranes (MAMs), these structures regulate different cellular functions, including calcium management, lipid metabolism, autophagy, oxidative stress, and management of unfolded proteins. In this review, we highlight MAMs' alterations mainly in cardiomyocytes, linked with cardiovascular diseases, such as cardiac ischemia-reperfusion, heart failure, and dilated cardiomyopathy. We also describe proteins that are part of the MAMs' machinery, as the FUN14 domain containing 1 (FUNDC1), the sigma 1 receptor (Sig-1R) and others, which might be new molecular targets to preserve the function and structure of the heart in such diseases. Understanding the machinery of MAMs and its function demands our attention, as such knowledge might contribute to strengthen the role of these relative novel structures in heart diseases.
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Affiliation(s)
- Alejandro Silva-Palacios
- Department of Cardiovascular Biomedicine, National Institute of Cardiology-Ignacio Chávez, Mexico City, Mexico.
| | - Cecilia Zazueta
- Department of Cardiovascular Biomedicine, National Institute of Cardiology-Ignacio Chávez, Mexico City, Mexico
| | - José Pedraza-Chaverri
- Department of Biology, Faculty of Chemistry, National Autonomous University of Mexico, Circuito Exterior S/N, C. U., 04510, Mexico City, Mexico.
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20
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Weber N, Kowalski K, Holler T, Radocaj A, Fischer M, Thiemann S, de la Roche J, Schwanke K, Piep B, Peschel N, Krumm U, Lingk A, Wendland M, Greten S, Schmitto JD, Ismail I, Warnecke G, Zywietz U, Chichkov B, Meißner J, Haverich A, Martin U, Brenner B, Zweigerdt R, Kraft T. Advanced Single-Cell Mapping Reveals that in hESC Cardiomyocytes Contraction Kinetics and Action Potential Are Independent of Myosin Isoform. Stem Cell Reports 2020; 14:788-802. [PMID: 32302556 PMCID: PMC7220955 DOI: 10.1016/j.stemcr.2020.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/12/2020] [Accepted: 03/17/2020] [Indexed: 01/14/2023] Open
Abstract
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) represent an attractive model to investigate CM function and disease mechanisms. One characteristic marker of ventricular specificity of human CMs is expression of the ventricular, slow β-myosin heavy chain (MyHC), as opposed to the atrial, fast α-MyHC. The main aim of this study was to investigate at the single-cell level whether contraction kinetics and electrical activity of hESC-CMs are influenced by the relative expression of α-MyHC versus β-MyHC. For effective assignment of functional parameters to the expression of both MyHC isoforms at protein and mRNA levels in the very same hESC-CMs, we developed a single-cell mapping technique. Surprisingly, α- versus β-MyHC was not related to specific contractile or electrophysiological properties of the same cells. The multiparametric cell-by-cell analysis suggests that in hESC-CMs the expression of genes associated with electrical activity, contraction, calcium handling, and MyHCs is independently regulated.
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Affiliation(s)
- Natalie Weber
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany.
| | - Kathrin Kowalski
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Tim Holler
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Ante Radocaj
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Martin Fischer
- Institute of Neurophysiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Stefan Thiemann
- Institute of Neurophysiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Jeanne de la Roche
- Institute of Neurophysiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Kristin Schwanke
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Birgit Piep
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Neele Peschel
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Uwe Krumm
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Alexander Lingk
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Meike Wendland
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Stephan Greten
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Jan Dieter Schmitto
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Issam Ismail
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Gregor Warnecke
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Urs Zywietz
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Boris Chichkov
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Joachim Meißner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Axel Haverich
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Ulrich Martin
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Bernhard Brenner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Robert Zweigerdt
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
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21
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Kirschner Peretz N, Segal S, Yaniv Y. May the Force Not Be With You During Culture: Eliminating Mechano-Associated Feedback During Culture Preserves Cultured Atrial and Pacemaker Cell Functions. Front Physiol 2020; 11:163. [PMID: 32265724 PMCID: PMC7100534 DOI: 10.3389/fphys.2020.00163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/12/2020] [Indexed: 01/24/2023] Open
Abstract
Cultured cardiomyocytes have been shown to possess significant potential as a model for characterization of mechano-Ca2+, mechano-electric, and mechano-metabolic feedbacks in the heart. However, the majority of cultured cardiomyocytes exhibit impaired electrical, mechanical, biochemical, and metabolic functions. More specifically, the cells do not beat spontaneously (pacemaker cells) or beat at a rate far lower than their physiological counterparts and self-oscillate (atrial and ventricular cells) in culture. Thus, efforts are being invested in ensuring that cultured cardiomyocytes maintain the shape and function of freshly isolated cells. Elimination of contraction during culture has been shown to preserve the mechano-Ca2+, mechano-electric, and mechano-metabolic feedback loops of cultured cells. This review focuses on pacemaker cells, which reside in the sinoatrial node (SAN) and generate regular heartbeat through the initiation of the heart’s electrical, metabolic, and biochemical activities. In parallel, it places emphasis on atrial cells, which are responsible for bridging the electrical conductance from the SAN to the ventricle. The review provides a summary of the main mechanisms responsible for mechano-electrical, Ca2+, and metabolic feedback in pacemaker and atrial cells and of culture methods existing for both cell types. The work concludes with an explanation of how the elimination of mechano-electrical, mechano-Ca2+, and mechano-metabolic feedbacks during culture results in sustained cultured cell function.
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Affiliation(s)
- Noa Kirschner Peretz
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
| | - Sofia Segal
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
| | - Yael Yaniv
- Biomedical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel
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22
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Gilbert G, Demydenko K, Dries E, Puertas RD, Jin X, Sipido K, Roderick HL. Calcium Signaling in Cardiomyocyte Function. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035428. [PMID: 31308143 DOI: 10.1101/cshperspect.a035428] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rhythmic increases in intracellular Ca2+ concentration underlie the contractile function of the heart. These heart muscle-wide changes in intracellular Ca2+ are induced and coordinated by electrical depolarization of the cardiomyocyte sarcolemma by the action potential. Originating at the sinoatrial node, conduction of this electrical signal throughout the heart ensures synchronization of individual myocytes into an effective cardiac pump. Ca2+ signaling pathways also regulate gene expression and cardiomyocyte growth during development and in pathology. These fundamental roles of Ca2+ in the heart are illustrated by the prevalence of altered Ca2+ homeostasis in cardiovascular diseases. Indeed, heart failure (an inability of the heart to support hemodynamic needs), rhythmic disturbances, and inappropriate cardiac growth all share an involvement of altered Ca2+ handling. The prevalence of these pathologies, contributing to a third of all deaths in the developed world as well as to substantial morbidity makes understanding the mechanisms of Ca2+ handling and dysregulation in cardiomyocytes of great importance.
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Affiliation(s)
- Guillaume Gilbert
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Kateryna Demydenko
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Eef Dries
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Rosa Doñate Puertas
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Xin Jin
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Karin Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
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23
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Abstract
Changes of intracellular Ca2+ concentration regulate many aspects of cardiac myocyte function. About 99% of the cytoplasmic calcium in cardiac myocytes is bound to buffers, and their properties will therefore have a major influence on Ca2+ signaling. This article considers the fundamental properties and identities of the buffers and how to measure them. It reviews the effects of buffering on the systolic Ca2+ transient and how this may change physiologically, and in heart failure and both atrial and ventricular arrhythmias, as well. It is concluded that the consequences of this strong buffering may be more significant than currently appreciated, and a fuller understanding is needed for proper understanding of cardiac calcium cycling and contractility.
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Affiliation(s)
- Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, UK (G.L.S.)
| | - David A Eisner
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, University of Manchester, UK (D.A.E.)
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24
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Ladd D, Tilūnaitė A, Roderick HL, Soeller C, Crampin EJ, Rajagopal V. Assessing Cardiomyocyte Excitation-Contraction Coupling Site Detection From Live Cell Imaging Using a Structurally-Realistic Computational Model of Calcium Release. Front Physiol 2019; 10:1263. [PMID: 31632297 PMCID: PMC6783691 DOI: 10.3389/fphys.2019.01263] [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] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/17/2019] [Indexed: 01/11/2023] Open
Abstract
Calcium signaling plays a pivotal role in cardiomyocytes, coupling electrical excitation to mechanical contraction of the heart. Determining locations of active calcium release sites, and how their recruitment changes in response to stimuli and in disease states is therefore of central interest in cardiac physiology. Current algorithms for detecting release sites from live cell imaging data are however not easily validated against a known “ground truth,” which makes interpretation of the output of such algorithms, in particular the degree of confidence in site detection, a challenging task. Computational models are capable of integrating findings from multiple sources into a consistent, predictive framework. In cellular physiology, such models have the potential to reveal structure and function beyond the temporal and spatial resolution limitations of individual experimental measurements. Here, we create a spatially detailed computational model of calcium release in an eight sarcomere section of a ventricular cardiomyocyte, using electron tomography reconstruction of cardiac ultrastructure and confocal imaging of protein localization. This provides a high-resolution model of calcium diffusion from intracellular stores, which can be used as a platform to simulate confocal fluorescence imaging in the context of known ground truth structures from the higher resolution model. We use this capability to evaluate the performance of a recently proposed method for detecting the functional response of calcium release sites in live cells. Model permutations reveal how calcium release site density and mitochondria acting as diffusion barriers impact the detection performance of the algorithm. We demonstrate that site density has the greatest impact on detection precision and recall, in particular affecting the effective detectable depth of sites in confocal data. Our findings provide guidance on how such detection algorithms may best be applied to experimental data and give insights into limitations when using two-dimensional microscopy images to analyse three-dimensional cellular structures.
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Affiliation(s)
- David Ladd
- Systems Biology Lab, Department of Biomedical Engineering, School of Mathematics and Statistics, University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemical and Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia.,Cell Structure and Mechanobiology Group, Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
| | - Agnė Tilūnaitė
- Systems Biology Lab, Department of Biomedical Engineering, School of Mathematics and Statistics, University of Melbourne, Melbourne, VIC, Australia
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Christian Soeller
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Edmund J Crampin
- Systems Biology Lab, Department of Biomedical Engineering, School of Mathematics and Statistics, University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemical and Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
| | - Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
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25
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Krzesiak A, Cognard C, Sebille S, Carré G, Bosquet L, Delpech N. High-intensity intermittent training is as effective as moderate continuous training, and not deleterious, in cardiomyocyte remodeling of hypertensive rats. J Appl Physiol (1985) 2019; 126:903-915. [PMID: 30702976 DOI: 10.1152/japplphysiol.00131.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exercise training offers possible nonpharmacological therapy for cardiovascular diseases including hypertension. High-intensity intermittent exercise (HIIE) training has been shown to have as much or even more beneficial cardiovascular effect in patients with cardiovascular diseases than moderate-intensity continuous exercise (CMIE) training. The aim of this study was to investigate the effects of the two types of training on cardiac remodeling of spontaneously hypertensive rats (SHR) induced by hypertension. Eight-week-old male SHR and normotensive Wistar-Kyoto rats (WKY) were divided into four groups: normotensive and hypertensive control (WKY and SHR-C) and hypertensive trained with CMIE (SHR-T CMIE) or HIIE (SHR-T HIIE). After 8 wk of training or inactivity, maximal running speed (MRS), arterial pressure, and heart weight were all assessed. CMIE or HIIE protocols not only increased final MRS and left ventricular weight/body weight ratio but also reduced mean arterial pressure compared with sedentary group. Then, left ventricular tissue was enzymatically dissociated, and isolated cardiomyocytes were used to highlight the changes induced by physical activity at morphological, mechanical, and molecular levels. Both types of training induced restoration of transverse tubule regularity, decrease in spark site density, and reduction in half-relaxation time of calcium transients. HIIE training, in particular, decreased spark amplitude and width, and increased cardiomyocyte contractility and the expression of sarco(endo)plasmic reticulum Ca2+-ATPase and phospholamban phosphorylated on serine 16. NEW & NOTEWORTHY High-intensity intermittent exercise training induces beneficial remodeling of the left ventricular cardiomyocytes of spontaneously hypertensive rats at the morphological, mechanical, and molecular levels. Results also confirm, at the cellular level, that this type of training, as it appears not to be deleterious, could be applied in rehabilitation of hypertensive patients.
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Affiliation(s)
- A Krzesiak
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France.,Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - C Cognard
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - S Sebille
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - G Carré
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - L Bosquet
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - N Delpech
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
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26
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Jones PP, MacQuaide N, Louch WE. Dyadic Plasticity in Cardiomyocytes. Front Physiol 2018; 9:1773. [PMID: 30618792 PMCID: PMC6298195 DOI: 10.3389/fphys.2018.01773] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/23/2018] [Indexed: 11/13/2022] Open
Abstract
Contraction of cardiomyocytes is dependent on sub-cellular structures called dyads, where invaginations of the surface membrane (t-tubules) form functional junctions with the sarcoplasmic reticulum (SR). Within each dyad, Ca2+ entry through t-tubular L-type Ca2+ channels (LTCCs) elicits Ca2+ release from closely apposed Ryanodine Receptors (RyRs) in the SR membrane. The efficiency of this process is dependent on the density and macroscale arrangement of dyads, but also on the nanoscale organization of LTCCs and RyRs within them. We presently review accumulating data demonstrating the remarkable plasticity of these structures. Dyads are known to form gradually during development, with progressive assembly of both t-tubules and junctional SR terminals, and precise trafficking of LTCCs and RyRs. While dyads can exhibit compensatory remodeling when required, dyadic degradation is believed to promote impaired contractility and arrythmogenesis in cardiac disease. Recent data indicate that this plasticity of dyadic structure/function is dependent on the regulatory proteins junctophilin-2, amphiphysin-2 (BIN1), and caveolin-3, which critically arrange dyadic membranes while stabilizing the position and activity of LTCCs and RyRs. Indeed, emerging evidence indicates that clustering of both channels enables "coupled gating", implying that nanoscale localization and function are intimately linked, and may allow fine-tuning of LTCC-RyR crosstalk. We anticipate that improved understanding of dyadic plasticity will provide greater insight into the processes of cardiac compensation and decompensation, and new opportunities to target the basic mechanisms underlying heart disease.
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Affiliation(s)
- Peter P. Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Niall MacQuaide
- Institute of Cardiovascular Sciences, University of Glasgow, Glasgow, United Kingdom
- Clyde Biosciences, Glasgow, United Kingdom
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
- KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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27
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Bode D, Guthof T, Pieske BM, Heinzel FR, Hohendanner F. Isolation of Atrial Cardiomyocytes from a Rat Model of Metabolic Syndrome-related Heart Failure with Preserved Ejection Fraction. J Vis Exp 2018. [PMID: 30102264 DOI: 10.3791/57953] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In this article, we describe an optimized, Langendorff-based procedure for the isolation of single-cell atrial cardiomyocytes (ACMs) from a rat model of metabolic syndrome (MetS)-related heart failure with preserved ejection fraction (HFpEF). The prevalence of MetS-related HFpEF is rising, and atrial cardiomyopathies associated with atrial remodeling and atrial fibrillation are clinically highly relevant as atrial remodeling is an independent predictor of mortality. Studies with isolated single-cell cardiomyocytes are frequently used to corroborate and complement in vivo findings. Circulatory vessel rarefication and interstitial tissue fibrosis pose a potentially limiting factor for the successful single-cell isolation of ACMs from animal models of this disease. We have addressed this issue by employing a device capable of manually regulating the intraluminal pressure of cardiac cavities during the isolation procedure, substantially increasing the yield of morphologically and functionally intact ACMs. The acquired cells can be used in a variety of different experiments, such as cell culture and functional Calcium imaging (i.e., excitation-contraction-coupling). We provide the researcher with a step-by-step protocol, a list of optimized solutions, thorough instructions to prepare the necessary equipment, and a comprehensive troubleshooting guide. While the initial implementation of the procedure might be rather difficult, a successful adaptation will allow the reader to perform state-of-the-art ACM isolations in a rat model of MetS-related HFpEF for a broad spectrum of experiments.
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Affiliation(s)
- David Bode
- Department of Internal Medicine and Cardiology, Charité University Medicine; German Center for Cardiovascular Research (DZHK)
| | - Tim Guthof
- Department of Internal Medicine and Cardiology, Charité University Medicine
| | - Burkert M Pieske
- Department of Internal Medicine and Cardiology, Charité University Medicine; German Center for Cardiovascular Research (DZHK)
| | - Frank R Heinzel
- Department of Internal Medicine and Cardiology, Charité University Medicine; German Center for Cardiovascular Research (DZHK)
| | - Felix Hohendanner
- Department of Internal Medicine and Cardiology, Charité University Medicine; German Center for Cardiovascular Research (DZHK);
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28
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Gurgul S, Buyukakilli B, Komur M, Okuyaz C, Balli E, Ozcan T. Does Levetiracetam Administration Prevent Cardiac Damage in Adulthood Rats Following Neonatal Hypoxia/Ischemia-Induced Brain Injury? ACTA ACUST UNITED AC 2018; 54:medicina54020012. [PMID: 30344243 PMCID: PMC6037241 DOI: 10.3390/medicina54020012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/12/2022]
Abstract
Cardiovascular abnormalities are widespread when a newborn is exposed to a hypoxic-ischemic injury in the neonatal period. Although the neuroprotective effects of levetiracetam (LEV) have been reported after hypoxia, the cardioprotective effects of LEV have not been documented. Therefore, we aimed to investigate whether levetiracetam (LEV) has a protective effect on cardiac-contractility and ultrastructure of heart muscle in rats exposed to hypoxia-ischemia (HI) during the neonatal period. A total of 49 seven-day-old rat pups were separated into four groups. For HI induction, a combination of right common carotid artery ligation with 8% oxygen in seven-day-old rat pups for 2 h was performed for saline, LEV100, and LEV200 groups. Just after hypoxia, LEV100 and LEV200 groups were administered with 100 mg/kg and 200 mg/kg of LEV, respectively. The arteries of rats in the control group were only detected; no ligation or hypoxia was performed. At the end of the 16th week after HI, cardiac mechanograms were recorded, and samples of tissue were explored by electronmicroscopy.While ventricular contractility in the control group was similar to LEV100, there were significant decreases in both saline and LEV200 groups (p < 0.05). Although ventricular contractile duration of the control and saline groups was found to be similar, durations in the LEV100 and LEV200 groups were significantly higher (p < 0.05). After HI, mitochondrial damage and ultrastructural deteriorative alterations in ventricles and atriums of the LEV-administered groups were significantly less severe than the saline group. The present study showed that neonatal HI caused long-term cardiac dysfunction and ultrastructural deteriorations in cardiac muscles. LEV administration just after HI might possess some protective effects against myocardial damage and contractility.
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Affiliation(s)
- Serkan Gurgul
- Department of Biophysics, Faculty of Medicine, Gaziantep University, TR-27310 Gaziantep, Turkey.
| | - Belgin Buyukakilli
- Department of Biophysics, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Mustafa Komur
- Department of Child Health and Disease, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Cetin Okuyaz
- Department of Child Health and Disease, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Ebru Balli
- Department of Histology and Embryology, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Tuba Ozcan
- Department of Histology and Embryology, Faculty of Medicine, K. Sütcü Imam University, TR-46040 Kahramanmaraş, Turkey.
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29
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Smyrnias I, Goodwin N, Wachten D, Skogestad J, Aronsen JM, Robinson EL, Demydenko K, Segonds-Pichon A, Oxley D, Sadayappan S, Sipido K, Bootman MD, Roderick HL. Contractile responses to endothelin-1 are regulated by PKC phosphorylation of cardiac myosin binding protein-C in rat ventricular myocytes. J Mol Cell Cardiol 2018; 117:1-18. [DOI: 10.1016/j.yjmcc.2018.02.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/02/2018] [Accepted: 02/16/2018] [Indexed: 01/07/2023]
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30
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Bond AR, Iacobazzi D, Abdul-Ghani S, Ghorbel MT, Heesom KJ, George SJ, Caputo M, Suleiman MS, Tulloh RM. The cardiac proteome in patients with congenital ventricular septal defect: A comparative study between right atria and right ventricles. J Proteomics 2018; 191:107-113. [PMID: 29572163 DOI: 10.1016/j.jprot.2018.03.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/08/2018] [Accepted: 03/19/2018] [Indexed: 01/24/2023]
Abstract
Right ventricle (RV) remodelling occurs in neonatal patients born with ventricular septal defect (VSD). The presence of a defect between the two ventricles allows for shunting of blood from the left to right side. The resulting RV hypertrophy leads to molecular remodelling which has thus far been largely investigated using right atrial (RA) tissue. In this study we used proteomic and phosphoproteomic analysis in order to determine any difference between the proteomes for RA and RV. Samples were therefore taken from the RA and RV of five infants (0.34 ± 0.05 years, mean ± SEM) with VSD who were undergoing cardiac surgery to repair the defect. Significant differences in protein expression between RV and RA were seen. 150 protein accession numbers were identified which were significantly lower in the atria, whereas none were significantly higher in the atria compared to the ventricle. 19 phosphorylation sites (representing 19 phosphoproteins) were also lower in RA. This work has identified differences in the proteome between RA and RV which reflect differences in contractile activity and metabolism. As such, caution should be used when drawing conclusions based on analysis of the RA and extrapolating to the hypertrophied RV. SIGNIFICANCE: RV hypertrophy occurs in neonatal patients born with VSD. Very little is known about how the atria responds to RV hypertrophy, especially at the protein level. Access to tissue from age-matched groups of patients is very rare, and we are in the unique position of being able to get tissue from both the atria and ventricle during reparative surgery of these infants. Our findings will be beneficial to future research into heart chamber malformations in congenital heart defects.
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Affiliation(s)
- A R Bond
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - D Iacobazzi
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - S Abdul-Ghani
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - M T Ghorbel
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - K J Heesom
- Proteomics Facility, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - S J George
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - M Caputo
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom; Department of Congenital Heart Disease, King David Building, Upper Maudlin Street, Bristol BS2 8BJ, United Kingdom
| | - M-S Suleiman
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom
| | - R M Tulloh
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, United Kingdom; Department of Congenital Heart Disease, King David Building, Upper Maudlin Street, Bristol BS2 8BJ, United Kingdom.
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31
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Wang Y, Wilson C, Cartwright EJ, Lei M. Plasma membrane Ca 2+ -ATPase 1 is required for maintaining atrial Ca 2+ homeostasis and electrophysiological stability in the mouse. J Physiol 2017; 595:7383-7398. [PMID: 29023784 PMCID: PMC5730856 DOI: 10.1113/jp274110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 10/06/2017] [Indexed: 11/22/2022] Open
Abstract
Key points The role of plasma membrane Ca2+‐ATPase 1 (PMCA1) in Ca2+ homeostasis and electrical stability in atrial tissue has been investigated at both organ and cellular levels in mice with cardiomyocyte‐specific deletion of PMCA1 (PMCA1cko) The PMCA1cko hearts became more susceptible to atrial arrhythmic stress conditions than PMCA1loxP/loxP hearts. PMCA1 deficiency alters cellular Ca2+ homeostasis under both baseline and stress conditions. PMCA1 is required for maintaining cellular Ca2+ homeostasis and electrical stability in murine atria under stress conditions.
Abstract To determine the role of plasma membrane Ca2+‐ATPase 1 (PMCA1) in maintaining Ca2+ homeostasis and electrical stability in the atrium under physiological and stress conditions, mice with a cardiomyocyte‐specific deletion of PMCA1 (PMCA1cko) and their control littermates (PMCA1loxP/loxP) were studied at the organ and cellular levels. At the organ level, the PMCA1cko hearts became more susceptible to atrial arrhythmias under rapid programmed electrical stimulation compared with the PMCA1loxP/loxP hearts, and such arrhythmic events became more severe under Ca2+ overload conditions. At the cellular level, the occurrence of irregular‐type action potentials of PMCA1cko atrial myocytes increased significantly under Ca2+ overload conditions and/or at higher frequency of stimulation. The decay of Na+/Ca2+ exchanger current that followed a stimulation protocol was significantly prolonged in PMCA1cko atrial myocytes under basal conditions, with Ca2+ overload leading to even greater prolongation. In conclusion, PMCA1 is required for maintaining Ca2+ homeostasis and electrical stability in the atrium. This is particularly critical during fast removal of Ca2+ from the cytosol, which is required under stress conditions. The role of plasma membrane Ca2+‐ATPase 1 (PMCA1) in Ca2+ homeostasis and electrical stability in atrial tissue has been investigated at both organ and cellular levels in mice with cardiomyocyte‐specific deletion of PMCA1 (PMCA1cko) The PMCA1cko hearts became more susceptible to atrial arrhythmic stress conditions than PMCA1loxP/loxP hearts. PMCA1 deficiency alters cellular Ca2+ homeostasis under both baseline and stress conditions. PMCA1 is required for maintaining cellular Ca2+ homeostasis and electrical stability in murine atria under stress conditions.
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Affiliation(s)
- Yanwen Wang
- Department of Pharmacology, University of Oxford, Oxford, UK.,Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Claire Wilson
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, UK
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32
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Blatter LA. The intricacies of atrial calcium cycling during excitation-contraction coupling. J Gen Physiol 2017; 149:857-865. [PMID: 28798277 PMCID: PMC5583713 DOI: 10.1085/jgp.201711809] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 07/12/2017] [Indexed: 12/20/2022] Open
Abstract
Blatter discusses the initiation and spread of Ca release, Ca store depletion, and release termination in atrial myocytes.
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Affiliation(s)
- Lothar A Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL
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33
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Kane C, Terracciano CMN. Concise Review: Criteria for Chamber-Specific Categorization of Human Cardiac Myocytes Derived from Pluripotent Stem Cells. Stem Cells 2017; 35:1881-1897. [PMID: 28577296 PMCID: PMC5575566 DOI: 10.1002/stem.2649] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/25/2017] [Accepted: 05/12/2017] [Indexed: 11/30/2022]
Abstract
Human pluripotent stem cell‐derived cardiomyocytes (PSC‐CMs) have great potential application in almost all areas of cardiovascular research. A current major goal of the field is to build on the past success of differentiation strategies to produce CMs with the properties of those originating from the different chambers of the adult human heart. With no anatomical origin or developmental pathway to draw on, the question of how to judge the success of such approaches and assess the chamber specificity of PSC‐CMs has become increasingly important; commonly used methods have substantial limitations and are based on limited evidence to form such an assessment. In this article, we discuss the need for chamber‐specific PSC‐CMs in a number of areas as well as current approaches used to assess these cells on their likeness to those from different chambers of the heart. Furthermore, describing in detail the structural and functional features that distinguish the different chamber‐specific human adult cardiac myocytes, we propose an evidence‐based tool to aid investigators in the phenotypic characterization of differentiated PSC‐CMs. Stem Cells2017;35:1881–1897
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Affiliation(s)
- Christopher Kane
- Imperial College London, National Heart and Lung Institute, Hammersmith Campus, BHF Centre for Regenerative Medicine, London, United Kingdom
| | - Cesare M N Terracciano
- Imperial College London, National Heart and Lung Institute, Hammersmith Campus, BHF Centre for Regenerative Medicine, London, United Kingdom
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34
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Non-linear actions of physiological agents: Finite disarrangements elicit fitness benefits. Redox Biol 2017; 13:235-243. [PMID: 28595161 PMCID: PMC5460745 DOI: 10.1016/j.redox.2017.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/11/2017] [Indexed: 12/16/2022] Open
Abstract
Finite disarrangements of important (vital) physiological agents and nutrients can induce plethora of beneficial effects, exceeding mere attenuation of the specific stress. Such response to disrupted homeostasis appears to be universally conserved among species. The underlying mechanism of improved fitness and longevity, when physiological agents act outside their normal range is similar to hormesis, a phenomenon whereby toxins elicit beneficial effects at low doses. Due to similarity with such non-linear response to toxins described with J-shaped curve, we have coined a new term “mirror J-shaped curves” for non-linear response to finite disarrangement of physiological agents. Examples from the clinical trials and basic research are provided, along with the unifying mechanisms that tie classical non-linear response to toxins with the non-linear response to physiological agents (glucose, oxygen, osmolarity, thermal energy, calcium, body mass, calorie intake and exercise). Reactive oxygen species and cytosolic calcium seem to be common triggers of signaling pathways that result in these beneficial effects. Awareness of such phenomena and exploring underlying mechanisms can help physicians in their everyday practice. It can also benefit researchers when designing studies and interpreting growing number of scientific data showing non-linear responses to physiological agents.
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Kallepitis C, Bergholt MS, Mazo MM, Leonardo V, Skaalure SC, Maynard SA, Stevens MM. Quantitative volumetric Raman imaging of three dimensional cell cultures. Nat Commun 2017; 8:14843. [PMID: 28327660 PMCID: PMC5364421 DOI: 10.1038/ncomms14843] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 02/03/2017] [Indexed: 02/07/2023] Open
Abstract
The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell-material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.
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Affiliation(s)
- Charalambos Kallepitis
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Mads S. Bergholt
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Manuel M. Mazo
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Vincent Leonardo
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Stacey C. Skaalure
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Stephanie A. Maynard
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Molly M. Stevens
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
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36
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Kofron CM, Mende U. In vitro models of the cardiac microenvironment to study myocyte and non-myocyte crosstalk: bioinspired approaches beyond the polystyrene dish. J Physiol 2017; 595:3891-3905. [PMID: 28116799 DOI: 10.1113/jp273100] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/22/2016] [Indexed: 12/17/2022] Open
Abstract
The heart is a complex pluricellular organ composed of cardiomyocytes and non-myocytes including fibroblasts, endothelial cells and immune cells. Myocytes are responsible for electrical conduction and contractile force generation, while the other cell types are responsible for matrix deposition, vascularization, and injury response. Myocytes and non-myocytes are known to communicate and exert mutual regulatory effects. In concert, they determine the structural, electrical and mechanical characteristics in the healthy and remodelled myocardium. Dynamic crosstalk between myocytes and non-myocytes plays a crucial role in stress/injury-induced hypertrophy and fibrosis development that can ultimately lead to heart failure and arrhythmias. Investigations of heterocellular communication in the myocardium are hampered by the intricate interspersion of the different cell types and the complexity of the tissue architecture. In vitro models have facilitated investigations of cardiac cells in a direct and controllable manner and have provided important functional and mechanistic insights. However, these cultures often lack regulatory input from the other cell types as well as additional topographical, electrical, mechanical and biochemical cues from the cardiac microenvironment that all contribute to modulating cell differentiation, maturation, alignment, function and survival. Advancements in the development of more complex pluricellular physiological platforms that incorporate diverse cues from the myocardial microenvironment are expected to lead to more physiologically relevant cardiac tissue-like in vitro models for mechanistic biological research, disease modelling, therapeutic target identification, drug testing and regeneration.
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Affiliation(s)
- Celinda M Kofron
- Cardiovascular Research Center, Cardiovascular Institute, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI, USA
| | - Ulrike Mende
- Cardiovascular Research Center, Cardiovascular Institute, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI, USA
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Maxwell JT, Blatter LA. A novel mechanism of tandem activation of ryanodine receptors by cytosolic and SR luminal Ca 2+ during excitation-contraction coupling in atrial myocytes. J Physiol 2017; 595:3835-3845. [PMID: 28028837 DOI: 10.1113/jp273611] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/01/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS In atrial myocytes excitation-contraction coupling is strikingly different from ventricle because atrial myocytes lack a transverse tubule membrane system: Ca2+ release starts in the cell periphery and propagates towards the cell centre by Ca2+ -induced Ca2+ release from the sarcoplasmic reticulum (SR) Ca2+ store. The cytosolic Ca2+ sensitivity of the ryanodine receptor (RyRs) Ca2+ release channel is low and it is unclear how Ca2+ release can be activated in the interior of atrial cells. Simultaneous confocal imaging of cytosolic and intra-SR calcium revealed a transient elevation of store Ca2+ that we termed 'Ca2+ sensitization signal'. We propose a novel paradigm of atrial ECC that is based on tandem activation of the RyRs by cytosolic and luminal Ca2+ through a 'fire-diffuse-uptake-fire' (or FDUF) mechanism: Ca2+ uptake by SR Ca2+ pumps at the propagation front elevates Ca2+ inside the SR locally, leading to luminal RyR sensitization and lowering of the cytosolic Ca2+ activation threshold. ABSTRACT In atrial myocytes Ca2+ release during excitation-contraction coupling (ECC) is strikingly different from ventricular myocytes. In many species atrial myocytes lack a transverse tubule system, dividing the sarcoplasmic reticulum (SR) Ca2+ store into the peripheral subsarcolemmnal junctional (j-SR) and the much more abundant central non-junctional (nj-SR) SR. Action potential (AP)-induced Ca2+ entry activates Ca2+ -induced Ca2+ release (CICR) from j-SR ryanodine receptor (RyR) Ca2+ release channels. Peripheral elevation of [Ca2+ ]i initiates CICR from nj-SR and sustains propagation of CICR to the cell centre. Simultaneous confocal measurements of cytosolic ([Ca2+ ]i ; with the fluorescent Ca2+ indicator rhod-2) and intra-SR ([Ca2+ ]SR ; fluo-5N) Ca2+ in rabbit atrial myocytes revealed that Ca2+ release from j-SR resulted in a cytosolic Ca2+ transient of higher amplitude compared to release from nj-SR; however, the degree of depletion of j-SR [Ca2+ ]SR was smaller than nj-SR [Ca2+ ]SR . Similarly, Ca2+ signals from individual release sites of the j-SR showed a larger cytosolic amplitude (Ca2+ sparks) but smaller depletion (Ca2+ blinks) than release from nj-SR. During AP-induced Ca2+ release the rise of [Ca2+ ]i detected at individual release sites of the nj-SR preceded the depletion of [Ca2+ ]SR , and during this latency period a transient elevation of [Ca2+ ]SR occurred. We propose that Ca2+ release from nj-SR is activated by cytosolic and luminal Ca2+ (tandem RyR activation) via a novel 'fire-diffuse-uptake-fire' (FDUF) mechanism. This novel paradigm of atrial ECC predicts that Ca2+ uptake by sarco-endoplasmic reticulum Ca2+ -ATPase (SERCA) at the propagation front elevates local [Ca2+ ]SR , leading to luminal RyR sensitization and lowering of the activation threshold for cytosolic CICR.
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Affiliation(s)
- Joshua T Maxwell
- Department of Molecular Biophysics and Physiology, Rush University Medical Centre, Chicago, IL, 60612, USA
| | - Lothar A Blatter
- Department of Molecular Biophysics and Physiology, Rush University Medical Centre, Chicago, IL, 60612, USA
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Crocini C, Ferrantini C, Coppini R, Sacconi L. Electrical defects of the transverse-axial tubular system in cardiac diseases. J Physiol 2017; 595:3815-3822. [PMID: 27981580 PMCID: PMC5471422 DOI: 10.1113/jp273042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/21/2016] [Indexed: 01/20/2023] Open
Abstract
Electrical excitability is an essential feature of cardiomyocytes and the homogenous propagation of the action potential is guaranteed by a complex network of membrane invaginations called the transverse-axial tubular system (TATS). TATS structural remodelling is a hallmark of cardiac diseases and we demonstrated that this can be accompanied by electrical defects at single T-tubular level. Using a random-access multi-photon (RAMP) microscope, we found that pathological T-tubules can fail to conduct action potentials, which delays local Ca2+ release. Although the underlying causes for T-tubular electrical failure are still unknown, our findings suggest that they are likely to be related to local ultrastructural alterations. Here, we first review the experimental approach that allowed us to observe and dissect the consequences of TATS electrical dysfunction and then propose two different strategies to unveil the reasons for T-tubular electrical failures. The first strategy consists in a correlative approach, in which the failing T-tubule identified with the RAMP microscope is then imaged with electron microscopy. The second approach exploits the diffusion of molecules within TATS to gain insights into the local TATS structure, even without a thorough reconstruction of the tubular network. Although challenging, the local electrical failure occurring at single T-tubules is a fundamental question that needs to be addressed and could provide novel insights in cardiac pathophysiology.
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Affiliation(s)
- Claudia Crocini
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino, Italy.,National Institute of Optics, National Research Council, 50125, Florence, Italy
| | - Cecilia Ferrantini
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, 50134, Florence, Italy
| | - Raffaele Coppini
- Division of Pharmacology, Department 'NeuroFarBa', University of Florence, 50139, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino, Italy.,National Institute of Optics, National Research Council, 50125, Florence, Italy
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Larsen J, Bushnell P, Steffensen J, Pedersen M, Qvortrup K, Brill R. Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes: smooth dogfish (Mustelus canis), sandbar shark (Carcharhinus plumbeus), and clearnose skate (Raja eglanteria). J Comp Physiol B 2016; 187:291-313. [PMID: 27686667 DOI: 10.1007/s00360-016-1034-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 08/25/2016] [Accepted: 09/13/2016] [Indexed: 01/15/2023]
Abstract
We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca2+ release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy. In tissues from smooth dogfish, net force (per cross-sectional area) and measures of the speeds of contraction and relaxation were all higher in atrial than ventricular myocardium at both temperatures. Atrial-ventricular differences were evident in the other two species primarily in measures of the rates of contraction and relaxation. Ryanodine-thapsigargin treatment reduced net force and its maximum positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark at 30 °C; indicating that SR involvement in excitation-contraction (EC) coupling is species- and temperature-specific in elasmobranch fishes, as it is in teleost fishes. Atrial and ventricular myocardium from all three species displayed a negative force-frequency relationship, but there was no evidence that SR involvement in EC coupling was influenced by heart rate. SR was evident in electron micrographs, generally located in proximity to mitochondria and intercalated discs, and to a lesser extent between the myofibrils; with mitochondria being more numerous in ventricular than atrial myocardium in all three species.
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Affiliation(s)
- Julie Larsen
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Peter Bushnell
- Department of Biology, Indiana University South Bend, 1700 Mishawaka Avenue, South Bend, IN, 46634-7111, USA
| | - John Steffensen
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Morten Pedersen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark
| | - Klaus Qvortrup
- Department of Biomedical Sciences/CFIM, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Richard Brill
- Behavioral Ecology Branch, Ecosystems Processes Division, Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Sandy Hook, NJ, USA. .,Virginia Institute of Marine Science, PO Box 1346, Gloucester Point, VA, 23062, USA.
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40
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Arora R, Aistrup GL, Supple S, Frank C, Singh J, Tai S, Zhao A, Chicos L, Marszalec W, Guo A, Song LS, Wasserstrom JA. Regional distribution of T-tubule density in left and right atria in dogs. Heart Rhythm 2016; 14:273-281. [PMID: 27670628 DOI: 10.1016/j.hrthm.2016.09.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND The peculiarities of transverse tubule (T-tubule) morphology and distribution in the atrium-and how they contribute to excitation-contraction coupling-are just beginning to be understood. OBJECTIVES The objectives of this study were to determine T-tubule density in the intact, live right and left atria in a large animal and to determine intraregional differences in T-tubule organization within each atrium. METHODS Using confocal microscopy, T-tubules were imaged in both atria in intact, Langendorf-perfused normal dog hearts loaded with di-4-ANEPPS. T-tubules were imaged in large populations of myocytes from the endocardial surface of each atrium. Computerized data analysis was performed using a new MatLab (Mathworks, Natick, MA) routine, AutoTT. RESULTS There was a large percentage of myocytes that had no T-tubules in both atria with a higher percentage in the right atrium (25.1%) than in the left atrium (12.5%) (P < .02). The density of transverse and longitudinal T-tubule elements was low in cells that did contain T-tubules, but there were no significant differences in density between the left atrial appendage, the pulmonary vein-posterior left atrium, the right atrial appendage, and the right atrial free wall. In contrast, there were significant differences in sarcomere spacing and cell width between different regions of the atria. CONCLUSION There is a sparse T-tubule network in atrial myocytes throughout both dog atria, with significant numbers of myocytes in both atria-the right atrium more so than the left atrium-having no T-tubules at all. These regional differences in T-tubule distribution, along with differences in cell width and sarcomere spacing, may have implications for the emergence of substrate for atrial fibrillation.
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Affiliation(s)
- Rishi Arora
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois,.
| | - Gary L Aistrup
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stephen Supple
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Caleb Frank
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Jasleen Singh
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Shannon Tai
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Anne Zhao
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Laura Chicos
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - William Marszalec
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Ang Guo
- Division of Cardiology, University of Iowa School of Medicine, Iowa City, Iowa
| | - Long-Sheng Song
- Division of Cardiology, University of Iowa School of Medicine, Iowa City, Iowa
| | - J Andrew Wasserstrom
- Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Molina CE, Heijman J, Dobrev D. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis. Arrhythm Electrophysiol Rev 2016; 5:14-9. [PMID: 27403288 DOI: 10.15420/aer.2016.8.2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca(2+) handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis.
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Affiliation(s)
- Cristina E Molina
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Jordi Heijman
- Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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42
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Goette A, Kalman JM, Aguinaga L, Akar J, Cabrera JA, Chen SA, Chugh SS, Corradi D, D'Avila A, Dobrev D, Fenelon G, Gonzalez M, Hatem SN, Helm R, Hindricks G, Ho SY, Hoit B, Jalife J, Kim YH, Lip GYH, Ma CS, Marcus GM, Murray K, Nogami A, Sanders P, Uribe W, Van Wagoner DR, Nattel S. EHRA/HRS/APHRS/SOLAECE expert consensus on Atrial cardiomyopathies: Definition, characterisation, and clinical implication. J Arrhythm 2016; 32:247-78. [PMID: 27588148 PMCID: PMC4996910 DOI: 10.1016/j.joa.2016.05.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Andreas Goette
- Departement of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital Paderborn, Working Group: Molecular Electrophysiology, University Hospital Magdeburg, Germany
| | - Jonathan M Kalman
- University of Melbourne, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | | | | | | | | | - Sumeet S Chugh
- The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | | | | | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | | | - Mario Gonzalez
- Penn State Heart and Vascular Institute, Penn State University, Hershey, PA, USA
| | - Stephane N Hatem
- Department of Cardiology, Assistance Publique - Hô pitaux de Paris, Pitié-Salpêtrière Hospital, Sorbonne University, INSERM UMR_S1166, Institute of Cardiometabolism and Nutrition-ICAN, Paris, France
| | - Robert Helm
- Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
| | | | - Siew Yen Ho
- Royal Brompton Hospital and Imperial College London, London, UK
| | - Brian Hoit
- UH Case Medical Center, Cleveland, OH, USA
| | | | | | | | | | | | | | | | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - William Uribe
- Electrophysiology Deparment at Centros Especializados de San Vicente Fundació n and Clínica CES. Universidad CES, Universidad Pontificia Bolivariana (UPB), Medellin, Colombia
| | | | - Stanley Nattel
- Université de Montréal, Montreal Heart Institute Research Center and McGill University, Montreal, Quebec, Canada; Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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43
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Goette A, Kalman JM, Aguinaga L, Akar J, Cabrera JA, Chen SA, Chugh SS, Corradi D, D'Avila A, Dobrev D, Fenelon G, Gonzalez M, Hatem SN, Helm R, Hindricks G, Ho SY, Hoit B, Jalife J, Kim YH, Lip GYH, Ma CS, Marcus GM, Murray K, Nogami A, Sanders P, Uribe W, Van Wagoner DR, Nattel S. EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication. Europace 2016; 18:1455-1490. [PMID: 27402624 DOI: 10.1093/europace/euw161] [Citation(s) in RCA: 426] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Andreas Goette
- Departement of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital Paderborn, Working Group: Molecular Electrophysiology, University Hospital Magdeburg, Germany
| | - Jonathan M Kalman
- University of Melbourne, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | | | | | | | | | - Sumeet S Chugh
- The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | | | | | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | | | - Mario Gonzalez
- Penn State Heart and Vascular Institute, Penn State University, Hershey, PA, USA
| | - Stephane N Hatem
- Department of Cardiology, Assistance Publique - Hôpitaux de Paris, Pitié-Salpêtrière Hospital; Sorbonne University; INSERM UMR_S1166; Institute of Cardiometabolism and Nutrition-ICAN, Paris, France
| | - Robert Helm
- Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
| | | | - Siew Yen Ho
- Royal Brompton Hospital and Imperial College London, London, UK
| | - Brian Hoit
- UH Case Medical Center, Cleveland, OH, USA
| | | | | | | | | | | | | | | | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - William Uribe
- Electrophysiology Deparment at Centros Especializados de San Vicente Fundación and Clínica CES. Universidad CES, Universidad Pontificia Bolivariana (UPB), Medellin, Colombia
| | | | - Stanley Nattel
- Université de Montréal, Montreal Heart Institute Research Center and McGill University, Montreal, Quebec, Canada .,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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44
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EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: Definition, characterization, and clinical implication. Heart Rhythm 2016; 14:e3-e40. [PMID: 27320515 DOI: 10.1016/j.hrthm.2016.05.028] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Indexed: 12/21/2022]
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Ryan AJ, Brougham CM, Garciarena CD, Kerrigan SW, O'Brien FJ. Towards 3D in vitro models for the study of cardiovascular tissues and disease. Drug Discov Today 2016; 21:1437-1445. [PMID: 27117348 DOI: 10.1016/j.drudis.2016.04.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 04/01/2016] [Accepted: 04/18/2016] [Indexed: 01/15/2023]
Abstract
The field of tissue engineering is developing biomimetic biomaterial scaffolds that are showing increasing therapeutic potential for the repair of cardiovascular tissues. However, a major opportunity exists to use them as 3D in vitro models for the study of cardiovascular tissues and disease in addition to drug development and testing. These in vitro models can span the gap between 2D culture and in vivo testing, thus reducing the cost, time, and ethical burden of current approaches. Here, we outline the progress to date and the requirements for the development of ideal in vitro 3D models for blood vessels, heart valves, and myocardial tissue.
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Affiliation(s)
- Alan J Ryan
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland; Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - Claire M Brougham
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland; Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; School of Mechanical and Design Engineering, Dublin Institute of Technology, Bolton Street, Dublin 1, Ireland
| | - Carolina D Garciarena
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - Steven W Kerrigan
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - Fergal J O'Brien
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland; Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland.
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Hohendanner F, Maxwell JT, Blatter LA. Cytosolic and nuclear calcium signaling in atrial myocytes: IP3-mediated calcium release and the role of mitochondria. Channels (Austin) 2016; 9:129-38. [PMID: 25891132 DOI: 10.1080/19336950.2015.1040966] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In rabbit atrial myocytes Ca signaling has unique features due to the lack of transverse (t) tubules, the spatial arrangement of mitochondria and the contribution of inositol-1,4,5-trisphosphate (IP3) receptor-induced Ca release (IICR). During excitation-contraction coupling action potential-induced elevation of cytosolic [Ca] originates in the cell periphery from Ca released from the junctional sarcoplasmic reticulum (j-SR) and then propagates by Ca-induced Ca release from non-junctional (nj-) SR toward the cell center. The subsarcolemmal region between j-SR and the first array of nj-SR Ca release sites is devoid of mitochondria which results in a rapid propagation of activation through this domain, whereas the subsequent propagation through the nj-SR network occurs at a velocity typical for a propagating Ca wave. Inhibition of mitochondrial Ca uptake with the Ca uniporter blocker Ru360 accelerates propagation and increases the amplitude of Ca transients (CaTs) originating from nj-SR. Elevation of cytosolic IP3 levels by rapid photolysis of caged IP3 has profound effects on the magnitude of subcellular CaTs with increased Ca release from nj-SR and enhanced CaTs in the nuclear compartment. IP3 uncaging restricted to the nucleus elicites 'mini'-Ca waves that remain confined to this compartment. Elementary IICR events (Ca puffs) preferentially originate in the nucleus in close physical association with membrane structures of the nuclear envelope and the nucleoplasmic reticulum. The data suggest that in atrial myocytes the nucleus is an autonomous Ca signaling domain where Ca dynamics are primarily governed by IICR.
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Key Words
- 2-APB, 2-aminoethoxydiphenyl borate
- AP, action potential
- CICR, Ca-induced Ca release
- CRU, Ca release units
- CT, central
- CaT, Ca transient
- ECC, excitation-contraction coupling
- IICR
- IICR, IP3R-induced Ca release
- IP3
- IP3R, Inositol-1,4,5-trisphosphate receptor
- LCC, L-type Ca channels
- MCU, mitochondrial Ca uniporter
- NE, nuclear envelope
- NFAT, nuclear factor of activated T cells
- NPR, nucleoplasmic reticulum
- RyR, ryanodine receptor
- SR, sarcoplasmic reticulum
- SS, subsarcolemmal
- TF50, time to half-maximal amplitude
- TZ, transition zone.
- [Ca]i, cytosolic Ca concentration
- [Ca]mito, mitochondrial Ca concentration
- atria
- excitation-contraction coupling
- j-SR, junctional SR
- mitochondria
- nj-SR, non-junctional SR
- nuclear calcium
- t-tubule, transverse tubule
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Affiliation(s)
- Felix Hohendanner
- a Department of Molecular Biophysics and Physiology ; Rush University Medical Center ; Chicago , IL USA
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Asensio-López MC, Soler F, Sánchez-Más J, Pascual-Figal D, Fernández-Belda F, Lax A. Early oxidative damage induced by doxorubicin: Source of production, protection by GKT137831 and effect on Ca(2+) transporters in HL-1 cardiomyocytes. Arch Biochem Biophys 2016; 594:26-36. [PMID: 26906075 DOI: 10.1016/j.abb.2016.02.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/04/2016] [Accepted: 02/18/2016] [Indexed: 01/26/2023]
Abstract
In atrial-derived HL-1 cells, ryanodine receptor and Na(+)/Ca(2+)-exchanger were altered early by 5 μM doxorubicin. The observed effects were an increase of cytosolic Ca(2+) at rest, ensuing ryanodine receptor phosphorylation, and the slowing of Ca(2+) transient decay after caffeine addition. Doxorubicin triggered a linear rise of reactive oxygen species (ROS) with no early effect on mitochondrial inner membrane potential. Doxorubicin and ROS were both detected in mitochondria by colocalization with fluorescence probes and doxorubicin-induced ROS was totally blocked by mitoTEMPO. The NADPH oxidase activity in the mitochondrial fraction was sensitive to inhibition by GKT137831, and doxorubicin-induced ROS decreased gradually as the GKT137831 concentration added in preincubation was increased. When doxorubicin-induced ROS was prevented by GKT137831, the kinetic response revealed a permanent degree of protection that was consistent with mitochondrial NADPH oxidase inhibition. In contrast, the ROS induction by doxorubicin after melatonin preincubation was totally eliminated at first but the effect was completely reversed with time. Limiting the source of ROS production is a better alternative for dealing with oxidative damage than using ROS scavengers. The short-term effect of doxorubicin on Ca(2+) transporters involved in myocardiac contractility was dependent on oxidative damage, and so the impairment was subsequent to ROS production.
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Affiliation(s)
- Mari C Asensio-López
- Cardiología Clínica y Experimental, Departamento de Medicina Interna, Facultad de Medicina, Universidad de Murcia, Campus de El Palmar, 30120, Murcia, Spain
| | - Fernando Soler
- Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia, Campus de Espinardo, 30071, Murcia, Spain
| | - Jesús Sánchez-Más
- Cardiología Clínica y Experimental, Departamento de Medicina Interna, Facultad de Medicina, Universidad de Murcia, Campus de El Palmar, 30120, Murcia, Spain
| | - Domingo Pascual-Figal
- Cardiología Clínica y Experimental, Departamento de Medicina Interna, Facultad de Medicina, Universidad de Murcia, Campus de El Palmar, 30120, Murcia, Spain; Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, 30120, El Palmar, Murcia, Spain
| | - Francisco Fernández-Belda
- Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia, Campus de Espinardo, 30071, Murcia, Spain.
| | - Antonio Lax
- Cardiología Clínica y Experimental, Departamento de Medicina Interna, Facultad de Medicina, Universidad de Murcia, Campus de El Palmar, 30120, Murcia, Spain
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Heijman J, Erfanian Abdoust P, Voigt N, Nattel S, Dobrev D. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation. J Physiol 2015; 594:537-53. [PMID: 26582329 DOI: 10.1113/jp271404] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/08/2015] [Indexed: 11/08/2022] Open
Abstract
The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and provide ideas about potential future directions.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Pegah Erfanian Abdoust
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Stanley Nattel
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,Department of Medicine, Montreal Heart Institute and Université de Montréal, Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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Brandenburg S, Arakel EC, Schwappach B, Lehnart SE. The molecular and functional identities of atrial cardiomyocytes in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1882-93. [PMID: 26620800 DOI: 10.1016/j.bbamcr.2015.11.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 12/28/2022]
Abstract
Atrial cardiomyocytes are essential for fluid homeostasis, ventricular filling, and survival, yet their cell biology and physiology are incompletely understood. It has become clear that the cell fate of atrial cardiomyocytes depends significantly on transcription programs that might control thousands of differentially expressed genes. Atrial muscle membranes propagate action potentials and activate myofilament force generation, producing overall faster contractions than ventricular muscles. While atria-specific excitation and contractility depend critically on intracellular Ca(2+) signalling, voltage-dependent L-type Ca(2+) channels and ryanodine receptor Ca(2+) release channels are each expressed at high levels similar to ventricles. However, intracellular Ca(2+) transients in atrial cardiomyocytes are markedly heterogeneous and fundamentally different from ventricular cardiomyocytes. In addition, differential atria-specific K(+) channel expression and trafficking confer unique electrophysiological and metabolic properties. Because diseased atria have the propensity to perpetuate fast arrhythmias, we discuss our understanding about the cell-specific mechanisms that lead to metabolic and/or mitochondrial dysfunction in atrial fibrillation. Interestingly, recent work identified potential atria-specific mechanisms that lead to early contractile dysfunction and metabolic remodelling, suggesting highly interdependent metabolic, electrical, and contractile pathomechanisms. Hence, the objective of this review is to provide an integrated model of atrial cardiomyocytes, from tissue-specific cell properties, intracellular metabolism, and excitation-contraction (EC) coupling to early pathological changes, in particular metabolic dysfunction and tissue remodelling due to atrial fibrillation and aging. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Eric C Arakel
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany.
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50
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The molecular interaction of heart LIM protein (HLP) with RyR2 and caveolin-3 is essential for Ca 2+ -induced Ca 2+ release in the heart. Biochem Biophys Res Commun 2015; 463:975-81. [DOI: 10.1016/j.bbrc.2015.06.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/06/2015] [Indexed: 11/20/2022]
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