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Baron V, Sommer ST, Fiegle DJ, Pfeuffer AKM, Peyronnet R, Volk T, Seidel T. Effects of electro-mechanical uncouplers, hormonal stimulation and pacing rate on the stability and function of cultured rabbit myocardial slices. Front Bioeng Biotechnol 2024; 12:1363538. [PMID: 38646013 PMCID: PMC11026719 DOI: 10.3389/fbioe.2024.1363538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 03/18/2024] [Indexed: 04/23/2024] Open
Abstract
Introduction: Recent advances have enabled organotypic culture of beating human myocardial slices that are stable for weeks. However, human myocardial samples are rare, exhibit high variability and frequently originate from diseased hearts. Thus, there is a need to adapt long-term slice culture for animal myocardium. When applied to animal cardiac slices, studies in healthy or genetically modified myocardium will be possible. We present the culture of slices from rabbit hearts, which resemble the human heart in microstructure, electrophysiology and excitation-contraction coupling. Methods: Left ventricular myocardium from New Zealand White rabbits was cut using a vibratome and cultured in biomimetic chambers for up to 7 days (d). Electro-mechanical uncoupling agents 2,3-butanedione monoxime (BDM) and cytochalasin D (CytoD) were added during initiation of culture and effects on myocyte survival were quantified. We investigated pacing rates (0.5 Hz, 1 Hz, and 2 Hz) and hormonal supplements (cortisol, T3, catecholamines) at physiological plasma concentrations. T3 was buffered using BSA. Contractile force was recorded continuously. Glucose consumption and lactate production were measured. Whole-slice Ca2+ transients and action potentials were recorded. Effects of culture on microstructure were investigated with confocal microscopy and image analysis. Results: Protocols for human myocardial culture resulted in sustained contracture and myocyte death in rabbit slices within 24 h, which could be prevented by transient application of a combination of BDM and CytoD. Cortisol stabilized contraction amplitude and kinetics in culture. T3 and catecholaminergic stimulation did not further improve stability. T3 and higher pacing rates increased metabolic rate and lactate production. T3 stabilized the response to β-adrenergic stimulation over 7 d. Pacing rates above 1 Hz resulted in progredient decline in contraction force. Image analysis revealed no changes in volume fractions of cardiomyocytes or measures of fibrosis over 7 d. Ca2+ transient amplitudes and responsiveness to isoprenaline were comparable after 1 d and 7 d, while Ca2+ transient duration was prolonged after 7 d in culture. Conclusions: A workflow for rabbit myocardial culture has been established, preserving function for up to 7 d. This research underscores the importance of glucocorticoid signaling in maintaining tissue function and extending culture duration. Furthermore, BDM and CytoD appear to protect from tissue damage during the initiation phase of tissue culture.
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Affiliation(s)
- V. Baron
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - S. T. Sommer
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - D. J. Fiegle
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - A.-K. M. Pfeuffer
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - R. Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - T. Volk
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - T. Seidel
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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2
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Kabakov AY, Roder K, Bronk P, Turan NN, Dhakal S, Zhong M, Lu Y, Zeltzer ZA, Najman-Licht YB, Karma A, Koren G. E3 ubiquitin ligase rififylin has yin and yang effects on rabbit cardiac transient outward potassium currents (I to) and corresponding channel proteins. J Biol Chem 2024; 300:105759. [PMID: 38367666 PMCID: PMC10945274 DOI: 10.1016/j.jbc.2024.105759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/23/2024] [Accepted: 02/09/2024] [Indexed: 02/19/2024] Open
Abstract
Genome-wide association studies have reported a correlation between a SNP of the RING finger E3 ubiquitin protein ligase rififylin (RFFL) and QT interval variability in humans (Newton-Cheh et al., 2009). Previously, we have shown that RFFL downregulates expression and function of the human-like ether-a-go-go-related gene potassium channel and corresponding rapidly activating delayed rectifier potassium current (IKr) in adult rabbit ventricular cardiomyocytes. Here, we report that RFFL also affects the transient outward current (Ito), but in a peculiar way. RFFL overexpression in adult rabbit ventricular cardiomyocytes significantly decreases the contribution of its fast component (Ito,f) from 35% to 21% and increases the contribution of its slow component (Ito,s) from 65% to 79%. Since Ito,f in rabbits is mainly conducted by Kv4.3, we investigated the effect of RFFL on Kv4.3 expressed in HEK293A cells. We found that RFFL overexpression reduced Kv4.3 expression and corresponding Ito,f in a RING domain-dependent manner in the presence or absence of its accessory subunit Kv channel-interacting protein 2. On the other hand, RFFL overexpression in Kv1.4-expressing HEK cells leads to an increase in both Kv1.4 expression level and Ito,s, similarly in a RING domain-dependent manner. Our physiologically detailed rabbit ventricular myocyte computational model shows that these yin and yang effects of RFFL overexpression on Ito,f, and Ito,s affect phase 1 of the action potential waveform and slightly decrease its duration in addition to suppressing IKr. Thus, RFFL modifies cardiac repolarization reserve via ubiquitination of multiple proteins that differently affect various potassium channels and cardiac action potential duration.
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Affiliation(s)
- Anatoli Y Kabakov
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karim Roder
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Peter Bronk
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Nilüfer N Turan
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Saroj Dhakal
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Mingwang Zhong
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Yichun Lu
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Zachary A Zeltzer
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Yonatan B Najman-Licht
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Alain Karma
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Gideon Koren
- Division of Cardiology, Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.
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3
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Robinson P, Sparrow AJ, Psaras Y, Steeples V, Simon JN, Broyles CN, Chang YF, Brook FA, Wang YJ, Blease A, Zhang X, Abassi YA, Geeves MA, Toepfer CN, Watkins H, Redwood C, Daniels MJ. Comparing the effects of chemical Ca 2+ dyes and R-GECO on contractility and Ca 2+ transients in adult and human iPSC cardiomyocytes. J Mol Cell Cardiol 2023; 180:44-57. [PMID: 37127261 PMCID: PMC10659987 DOI: 10.1016/j.yjmcc.2023.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/13/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
We compared commonly used BAPTA-derived chemical Ca2+ dyes (fura2, Fluo-4, and Rhod-2) with a newer genetically encoded indicator (R-GECO) in single cell models of the heart. We assessed their performance and effects on cardiomyocyte contractility, determining fluorescent signal-to-noise ratios and sarcomere shortening in primary ventricular myocytes from adult mouse and guinea pig, and in human iPSC-derived cardiomyocytes. Chemical Ca2+ dyes displayed dose-dependent contractile impairment in all cell types, and we observed a negative correlation between contraction and fluorescence signal-to-noise ratio, particularly for fura2 and Fluo-4. R-GECO had no effect on sarcomere shortening. BAPTA-based dyes, but not R-GECO, inhibited in vitro acto-myosin ATPase activity. The presence of fura2 accentuated or diminished changes in contractility and Ca2+ handling caused by small molecule modulators of contractility and intracellular ionic homeostasis (mavacamten, levosimendan, and flecainide), but this was not observed when using R-GECO in adult guinea pig left ventricular cardiomyocytes. Ca2+ handling studies are necessary for cardiotoxicity assessments of small molecules intended for clinical use. Caution should be exercised when interpreting small molecule studies assessing contractile effects and Ca2+ transients derived from BAPTA-like chemical Ca2+ dyes in cellular assays, a common platform for cardiac toxicology testing and mechanistic investigation of cardiac disease physiology and treatment.
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Affiliation(s)
- Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK.
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yiangos Psaras
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Connor N Broyles
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yu-Fen Chang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Frances A Brook
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Ying-Jie Wang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Andrew Blease
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Xiaoyu Zhang
- Agilent Biosciences, Inc., San Diego, CA 92121, USA
| | | | | | - Christopher N Toepfer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK; Department of Cardiovascular Sciences, University of Manchester, Manchester, UK.
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Kabakov AY, Sengun E, Lu Y, Roder K, Bronk P, Baggett B, Turan NN, Moshal KS, Koren G. Three-Week-Old Rabbit Ventricular Cardiomyocytes as a Novel System to Study Cardiac Excitation and EC Coupling. Front Physiol 2021; 12:672360. [PMID: 34867432 PMCID: PMC8637404 DOI: 10.3389/fphys.2021.672360] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/06/2021] [Indexed: 01/14/2023] Open
Abstract
Cardiac arrhythmias significantly contribute to cardiovascular morbidity and mortality. The rabbit heart serves as an accepted model system for studying cardiac cell excitation and arrhythmogenicity. Accordingly, primary cultures of adult rabbit ventricular cardiomyocytes serve as a preferable model to study molecular mechanisms of human cardiac excitation. However, the use of adult rabbit cardiomyocytes is often regarded as excessively costly. Therefore, we developed and characterized a novel low-cost rabbit cardiomyocyte model, namely, 3-week-old ventricular cardiomyocytes (3wRbCMs). Ventricular myocytes were isolated from whole ventricles of 3-week-old New Zealand White rabbits of both sexes by standard enzymatic techniques. Using wheat germ agglutinin, we found a clear T-tubule structure in acutely isolated 3wRbCMs. Cells were adenovirally infected (multiplicity of infection of 10) to express Green Fluorescent Protein (GFP) and cultured for 48 h. The cells showed action potential duration (APD90 = 253 ± 24 ms) and calcium transients similar to adult rabbit cardiomyocytes. Freshly isolated and 48-h-old-cultured cells expressed critical ion channel proteins: calcium voltage-gated channel subunit alpha1 C (Cavα1c), sodium voltage-gated channel alpha subunit 5 (Nav1.5), potassium voltage-gated channel subfamily D member 3 (Kv4.3), and subfamily A member 4 (Kv1.4), and also subfamily H member 2 (RERG. Kv11.1), KvLQT1 (K7.1) protein and inward-rectifier potassium channel (Kir2.1). The cells displayed an appropriate electrophysiological phenotype, including fast sodium current (I Na), transient outward potassium current (I to), L-type calcium channel peak current (I Ca,L), rapid and slow components of the delayed rectifier potassium current (I Kr and I Ks), and inward rectifier (I K1). Although expression of the channel proteins and some currents decreased during the 48 h of culturing, we conclude that 3wRbCMs are a new, low-cost alternative to the adult-rabbit-cardiomyocytes system, which allows the investigation of molecular mechanisms of cardiac excitation on morphological, biochemical, genetic, physiological, and biophysical levels.
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Affiliation(s)
- Anatoli Y. Kabakov
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Elif Sengun
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Department of Pharmacology, Institute of Graduate Studies in Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Yichun Lu
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Karim Roder
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Peter Bronk
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Brett Baggett
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Nilüfer N. Turan
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Karni S. Moshal
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Gideon Koren
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, United States
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Guo J, Tian Q, Barth M, Xian W, Ruppenthal S, Schaefers HJ, Chen Z, Moretti A, Laugwitz KL, Lipp P. Human BIN1 isoforms grow, maintain and regenerate excitation-contraction couplons in adult rat and human stem cell-derived cardiomyocytes. Cardiovasc Res 2021; 118:1479-1491. [PMID: 34152414 DOI: 10.1093/cvr/cvab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Indexed: 12/31/2022] Open
Abstract
AIMS In ventricular myocytes, Transverse-tubules (T-tubules) are instrumental for excitation-contraction (EC) coupling and their disarray is a hallmark of cardiac diseases. BIN1 is a key contributor to their biogenesis. Our study set out to investigate the role of human BIN1 splice variants in the maintenance and regeneration of EC-coupling in rat adult ventricular myocytes and human induced pluripotent stem cell-derived cardiac myocytes (hiPS-CMs). METHODS AND RESULTS In heart samples from healthy human donors expression patterns of 5 BIN1 splice variants were identified. Following viral transduction of human BIN1 splice variants in cellular models of T-tubular disarray we employed high-speed confocal calcium imaging and Ca-CLEAN analysis to identify functional EC-coupling sites and T-tubular architecture. Adult rat ventricular myocytes were used to investigate the regeneration after loss and maintenance of EC-coupling while we studied the enhancement of EC-coupling in hiPS-CMs. All five human BIN1 splice variants induced de novo generation of T-tubules in both cell types. Isoforms with the phosphoinositide binding motif (PI) were most potent in maintenance and regeneration of T-tubules and functional EC-coupling in adult rat myocytes. In hiPSC-CMs, BIN1 variants with PI motiv induced de-novo generation of T-tubules, functional EC-coupling sites and enhanced calcium handling. CONCLUSION(S) BIN1 is essential for the maintenance, regeneration, and de-novo generation of functional T-tubules, especially isoforms with PI motifs. These T-tubules trigger the development of functional EC couplons resulting in enhanced calcium handling. TRANSLATIONAL PERSPECTIVE Cardiomyopathy and heart failure are among the most frequent causes of death in modern societies. Gene therapies and hiPSC technology are becoming increasingly promising, both for treatment and therapy development. On the cellular level, one of the common denominators of cardiac diseases is the concurrent loss of T-tubules essential for efficient EC-coupling. While initial approaches in animal models employing gene therapy with BIN1 have depicted encouraging improvements the expression pattern of BIN1 isoforms in the human heart is still elusive. The present study identifies a unique set of five distinct BIN1 isoforms in healthy human hearts and demonstrates their potency in both, T-tubule maintenance and re-generation after loss resulting in efficient EC-coupling. Noteworthy, PI-motif containing isoforms were potent trigger of de-novo generation of T-tubules and establishment of efficient EC-coupling in hiPSC-CMs. Therefore, the expression of BIN1 might be novel and promising for pharmaceutical treatment and gene therapy.
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Affiliation(s)
- Jia Guo
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Qinghai Tian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Monika Barth
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Wenying Xian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Sandra Ruppenthal
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Hans-Joachim Schaefers
- Department of Thoracic and Cardiovascular Surgery, Saarland University Medical Center, Homburg/Saar, Germany
| | - Zhifen Chen
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Alessandra Moretti
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Karl-Ludwig Laugwitz
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Peter Lipp
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
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Mechanisms and Regulation of Cardiac Ca V1.2 Trafficking. Int J Mol Sci 2021; 22:ijms22115927. [PMID: 34072954 PMCID: PMC8197997 DOI: 10.3390/ijms22115927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/28/2021] [Accepted: 05/29/2021] [Indexed: 01/05/2023] Open
Abstract
During cardiac excitation contraction coupling, the arrival of an action potential at the ventricular myocardium triggers voltage-dependent L-type Ca2+ (CaV1.2) channels in individual myocytes to open briefly. The level of this Ca2+ influx tunes the amplitude of Ca2+-induced Ca2+ release from ryanodine receptors (RyR2) on the junctional sarcoplasmic reticulum and thus the magnitude of the elevation in intracellular Ca2+ concentration and ultimately the downstream contraction. The number and activity of functional CaV1.2 channels at the t-tubule dyads dictates the amplitude of the Ca2+ influx. Trafficking of these channels and their auxiliary subunits to the cell surface is thus tightly controlled and regulated to ensure adequate sarcolemmal expression to sustain this critical process. To that end, recent discoveries have revealed the existence of internal reservoirs of preformed CaV1.2 channels that can be rapidly mobilized to enhance sarcolemmal expression in times of acute stress when hemodynamic and metabolic demand increases. In this review, we provide an overview of the current thinking on CaV1.2 channel trafficking dynamics in the heart. We highlight the numerous points of control including the biosynthetic pathway, the endosomal recycling pathway, ubiquitination, and lysosomal and proteasomal degradation pathways, and discuss the effects of β-adrenergic and angiotensin receptor signaling cascades on this process.
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7
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Wang J, Hertz L, Ruppenthal S, El Nemer W, Connes P, Goede JS, Bogdanova A, Birnbaumer L, Kaestner L. Lysophosphatidic Acid-Activated Calcium Signaling Is Elevated in Red Cells from Sickle Cell Disease Patients. Cells 2021; 10:456. [PMID: 33672679 PMCID: PMC7924404 DOI: 10.3390/cells10020456] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 12/15/2022] Open
Abstract
(1) Background: It is known that sickle cells contain a higher amount of Ca2+ compared to healthy red blood cells (RBCs). The increased Ca2+ is associated with the most severe symptom of sickle cell disease (SCD), the vaso-occlusive crisis (VOC). The Ca2+ entry pathway received the name of Psickle but its molecular identity remains only partly resolved. We aimed to map the involved Ca2+ signaling to provide putative pharmacological targets for treatment. (2) Methods: The main technique applied was Ca2+ imaging of RBCs from healthy donors, SCD patients and a number of transgenic mouse models in comparison to wild-type mice. Life-cell Ca2+ imaging was applied to monitor responses to pharmacological targeting of the elements of signaling cascades. Infection as a trigger of VOC was imitated by stimulation of RBCs with lysophosphatidic acid (LPA). These measurements were complemented with biochemical assays. (3) Results: Ca2+ entry into SCD RBCs in response to LPA stimulation exceeded that of healthy donors. LPA receptor 4 levels were increased in SCD RBCs. Their activation was followed by the activation of Gi protein, which in turn triggered opening of TRPC6 and CaV2.1 channels via a protein kinase Cα and a MAP kinase pathway, respectively. (4) Conclusions: We found a new Ca2+ signaling cascade that is increased in SCD patients and identified new pharmacological targets that might be promising in addressing the most severe symptom of SCD, the VOC.
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Affiliation(s)
- Jue Wang
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX 75708, USA;
| | - Laura Hertz
- Theoretical Medicine and Biosciences, Saarland University, 66421 Homburg, Germany;
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
| | - Sandra Ruppenthal
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
- Gynaecology, Obstetrics and Reproductive Medicine, Saarland University Hospital, 66421 Homburg, Germany
| | - Wassim El Nemer
- Etablissement Français du Sang PACA-Corse, Aix Marseille Université, EFS, CNRS, ADES, 13005 Marseille, France;
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France;
| | - Philippe Connes
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France;
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Teal, University Claude Bernard Lyon 1, 69008 Lyon, France
| | - Jeroen S. Goede
- Division of Oncology and Hematology, Kantonsspital Winterthur, CH-8401 Winterthur, Switzerland;
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, University of Zürich, CH-8057 Zürich, Switzerland;
| | - Lutz Birnbaumer
- Institute of Biomedical Research (BIOMED), Catholic University of Argentina, C1107AFF Buenos Aires, Argentina;
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, 66421 Homburg, Germany;
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
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8
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Gözen I, Dommersnes P. Biological lipid nanotubes and their potential role in evolution. THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS 2020; 229:2843-2862. [PMID: 33224439 PMCID: PMC7666715 DOI: 10.1140/epjst/e2020-000130-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The membrane of cells and organelles are highly deformable fluid interfaces, and can take on a multitude of shapes. One distinctive and particularly interesting property of biological membranes is their ability to from long and uniform nanotubes. These nanoconduits are surprisingly omnipresent in all domains of life, from archaea, bacteria, to plants and mammals. Some of these tubes have been known for a century, while others were only recently discovered. Their designations are different in different branches of biology, e.g. they are called stromule in plants and tunneling nanotubes in mammals. The mechanical transformation of flat membranes to tubes involves typically a combination of membrane anchoring and external forces, leading to a pulling action that results in very rapid membrane nanotube formation - micrometer long tubes can form in a matter of seconds. Their radius is set by a mechanical balance of tension and bending forces. There also exists a large class of membrane nanotubes that form due to curvature inducing molecules. It seems plausible that nanotube formation and functionality in plants and animals may have been inherited from their bacterial ancestors during endosymbiotic evolution. Here we attempt to connect observations of nanotubes in different branches of biology, and outline their similarities and differences with the aim of providing a perspective on their joint functions and evolutionary origin.
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Affiliation(s)
- Irep Gözen
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318 Norway
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0315 Norway
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, 412 96 Sweden
| | - Paul Dommersnes
- Department of Physics, Norwegian University of Science and Technology, Hoegskoleringen 5, 7491 Trondheim, Norway
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Nollet EE, Manders EM, Goebel M, Jansen V, Brockmann C, Osinga J, van der Velden J, Helmes M, Kuster DWD. Large-Scale Contractility Measurements Reveal Large Atrioventricular and Subtle Interventricular Differences in Cultured Unloaded Rat Cardiomyocytes. Front Physiol 2020; 11:815. [PMID: 32848817 PMCID: PMC7396550 DOI: 10.3389/fphys.2020.00815] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/18/2020] [Indexed: 01/22/2023] Open
Abstract
The chambers of the heart fulfill different hemodynamic functions, which are reflected in their structural and contractile properties. While the atria are highly elastic to allow filling from the venous system, the ventricles need to be able to produce sufficiently high pressures to eject blood into the circulation. The right ventricle (RV) pumps into the low pressure pulmonary circulation, while the left ventricle (LV) needs to overcome the high pressure of the systemic circulation. It is incompletely understood whether these differences can be explained by the contractile differences at the level of the individual cardiomyocytes of the chambers. We addressed this by isolating cardiomyocytes from atria, RV, LV, and interventricular septum (IVS) of five healthy wild-type rats. Using a high-throughput contractility set-up, we measured contractile function of 2,043 cells after overnight culture. Compared to ventricular cardiomyocytes, atrial cells showed a twofold lower contraction amplitude and 1.4- to 1.7-fold slower kinetics of contraction and relaxation. The interventricular differences in contractile function were much smaller; RV cells displayed 12–13% less fractional shortening and 5–9% slower contraction and 3–15% slower relaxation kinetics relative to their LV and IVS counterparts. Aided by a large dataset, we established relationships between contractile parameters and found contraction velocity, fractional shortening and relaxation velocity to be highly correlated. In conclusion, our findings are in line with contractile differences observed at the atrioventricular level, but can only partly explain the interventricular differences that exist at the organ level.
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Affiliation(s)
- Edgar E Nollet
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | | | - Max Goebel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Valentijn Jansen
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Cord Brockmann
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Jorrit Osinga
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Michiel Helmes
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,CytoCypher BV, Wageningen, Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
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10
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Kim JC, Le QA, Woo SH. Alterations of Ca 2+ signaling and Ca 2+ release sites in cultured ventricular myocytes with intact internal Ca 2+ storage. Biochem Biophys Res Commun 2020; 527:379-386. [PMID: 32321644 DOI: 10.1016/j.bbrc.2020.04.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
Although cultured adult cardiac myocytes in combination with cell-level genetic modifications have been adopted for the study of protein function, the cellular alterations caused by the culture conditions themselves need to be clarified before we can interpret the effects of genetically altered proteins. We systematically compared the cellular morphology, global Ca2+ signaling, elementary Ca2+ release (sparks), and arrangement of ryanodine receptor (RyR) clusters in short-term (2 days)-cultured adult rat ventricular myocytes with those of freshly isolated myocytes. The transverse (t)-tubules were remarkably decreased (to ∼25%) by culture, and whole-cell capacitance was reduced by ∼35%. The magnitude of depolarization-induced Ca2+ transients decreased to ∼50%, and Ca2+ transient decay was slowed by culture. The culture did not affect sarcoplasmic reticulum (SR) Ca2+ loading. Therefore, fractional Ca2+ release was attenuated by culture. In the cultured cells, the L-type Ca2+ current (ICa) was smaller (∼50% of controls) and its inactivation was slower. In cultured myocytes, there were significantly fewer (∼50% of control) Ca2+ sparks, the local Ca2+ releases through RyR clusters, compared with in freshly isolated cells. Amplitude and kinetics (duration and time-to-peak) of individual sparks were similar, but they showed greater width in cultured cells. Immunolocalization analysis revealed that the cross-striation of RyRs distribution became weaker and less organized, and that the density of RyR clusters decreased in cultured myocytes. Our data suggest that the loss of t-tubules and generation of compromised Ca2+ transients and ICa in short-term adult ventricular cell culture are independent of SR Ca2+ loading status. In addition, the deteriorated arrangement of the RyR-clusters and their decreased density after short-term culture may be partly responsible for fewer Ca2+ sparks and a decrease in global Ca2+ release.
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Affiliation(s)
- Joon-Chul Kim
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Qui Anh Le
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Sun-Hee Woo
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea.
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11
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Miranda‐Silva D, Wüst RCI, Conceição G, Gonçalves‐Rodrigues P, Gonçalves N, Gonçalves A, Kuster DWD, Leite‐Moreira AF, Velden J, Sousa Beleza JM, Magalhães J, Stienen GJM, Falcão‐Pires I. Disturbed cardiac mitochondrial and cytosolic calcium handling in a metabolic risk-related rat model of heart failure with preserved ejection fraction. Acta Physiol (Oxf) 2020; 228:e13378. [PMID: 31520455 PMCID: PMC7064935 DOI: 10.1111/apha.13378] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 12/13/2022]
Abstract
AIM Calcium ions play a pivotal role in matching energy supply and demand in cardiac muscle. Mitochondrial calcium concentration is lower in animal models of heart failure with reduced ejection fraction (HFrEF), but limited information is available about mitochondrial calcium handling in heart failure with preserved ejection fraction (HFpEF). METHODS We assessed mitochondrial Ca2+ handling in intact cardiomyocytes from Zucker/fatty Spontaneously hypertensive F1 hybrid (ZSF1)-lean (control) and ZSF1-obese rats, a metabolic risk-related model of HFpEF. A mitochondrially targeted Ca2+ indicator (MitoCam) was expressed in cultured adult rat cardiomyocytes. Cytosolic and mitochondrial Ca2+ transients were measured at different stimulation frequencies. Mitochondrial respiration and swelling, and expression of key proteins were determined ex vivo. RESULTS At rest, mitochondrial Ca2+ concentration in ZSF1-obese was larger than in ZSF1-lean. The diastolic and systolic mitochondrial Ca2+ concentrations increased with stimulation frequency, but the steady-state levels were larger in ZSF1-obese. The half-widths of the contractile responses, the resting cytosolic Ca2+ concentration and the decay half-times of the cytosolic Ca2+ transients were higher in ZSF1-obese, likely because of a lower SERCA2a/phospholamban ratio. Mitochondrial respiration was lower, particularly with nicotinamide adenine dinucleotide (NADH) (complex I) substrates, and mitochondrial swelling was larger in ZSF1-obese. CONCLUSION The free mitochondrial calcium concentration is higher in HFpEF owing to alterations in mitochondrial and cytosolic Ca2+ handling. This coupling between cytosolic and mitochondrial Ca2+ levels may compensate for myocardial ATP supply in vivo under conditions of mild mitochondrial dysfunction. However, if mitochondrial Ca2+ concentration is sustainedly increased, it might trigger mitochondrial permeability transition pore opening.
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Affiliation(s)
- Daniela Miranda‐Silva
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Rob C. I. Wüst
- Department of Physiology Amsterdam UMC VUmc Amsterdam Cardiovascular Sciences Amsterdam the Netherlands
- Department of Human Movement Sciences Laboratory for Myology Faculty of Behavioural and Movement Sciences Amsterdam Movement Sciences Vrije Universiteit Amsterdam Amsterdam the Netherlands
| | - Glória Conceição
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Patrícia Gonçalves‐Rodrigues
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Nádia Gonçalves
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Alexandre Gonçalves
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Diederik W. D. Kuster
- Department of Physiology Amsterdam UMC VUmc Amsterdam Cardiovascular Sciences Amsterdam the Netherlands
| | - Adelino F. Leite‐Moreira
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
| | - Jolanda Velden
- Department of Physiology Amsterdam UMC VUmc Amsterdam Cardiovascular Sciences Amsterdam the Netherlands
- Netherlands Heart Institute Utrecht the Netherlands
| | - Jorge M. Sousa Beleza
- LaMetEx—Laboratory of Metabolism and Exercise Faculty of Sport Cardiovascular Research Center - UniC, University of Porto Porto Portugal
| | - José Magalhães
- LaMetEx—Laboratory of Metabolism and Exercise Faculty of Sport Cardiovascular Research Center - UniC, University of Porto Porto Portugal
| | - Ger J. M. Stienen
- Department of Physiology Amsterdam UMC VUmc Amsterdam Cardiovascular Sciences Amsterdam the Netherlands
| | - Inês Falcão‐Pires
- Department of Surgery and Physiology Cardiovascular R & D center Faculty of Medicine of the University of Porto Porto Portugal
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12
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Pires RH, Shree N, Manu E, Guzniczak E, Otto O. Cardiomyocyte mechanodynamics under conditions of actin remodelling. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190081. [PMID: 31587648 PMCID: PMC6792454 DOI: 10.1098/rstb.2019.0081] [Citation(s) in RCA: 10] [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] [Accepted: 06/10/2019] [Indexed: 01/26/2023] Open
Abstract
The mechanical performance of cardiomyocytes (CMs) is an important indicator of their maturation state and of primary importance for the development of therapies based on cardiac stem cells. As the mechanical analysis of adherent cells at high-throughput remains challenging, we explore the applicability of real-time deformability cytometry (RT-DC) to probe cardiomyocytes in suspension. RT-DC is a microfluidic technology allowing for real-time mechanical analysis of thousands of cells with a throughput exceeding 1000 cells per second. For CMs derived from human-induced pluripotent stem cells, we determined a Young's modulus of 1.25 ± 0.08 kPa which is in close range to previous reports. Upon challenging the cytoskeleton with cytochalasin D (CytoD) to induce filamentous actin depolymerization, we distinguish three different regimes in cellular elasticity. Transitions are observed below 10 nM and above 103 nM and are characterized by a decrease in Young's modulus. These regimes can be linked to cytoskeletal and sarcomeric actin contributions by CM contractility measurements at varying CytoD concentrations, where we observe a significant reduction in pulse duration only above 103 nM while no change is found for compound exposure at lower concentrations. Comparing our results to mechanical cell measurements using atomic force microscopy, we demonstrate for the first time to our knowledge, the feasibility of using a microfluidic technique to measure mechanical properties of large samples of adherent cells while linking our results to the composition of the cytoskeletal network. This article is part of a discussion meeting issue 'Single cell ecology'.
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Affiliation(s)
- Ricardo H. Pires
- Zentrum für Innovationskompetenz: Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Universität Greifswald, Fleischmannstrasse 42, 17489 Greifswald, Germany
| | - Nithya Shree
- Zentrum für Innovationskompetenz: Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Universität Greifswald, Fleischmannstrasse 42, 17489 Greifswald, Germany
| | - Emmanuel Manu
- Zentrum für Innovationskompetenz: Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Universität Greifswald, Fleischmannstrasse 42, 17489 Greifswald, Germany
| | - Ewa Guzniczak
- Heriot-Watt University School of Engineering and Physical Science, Institute of Biological Chemistry, Biophysics and Bioengineering, Edinburgh Campus, Edinburgh EH14 4AS, UK
| | - Oliver Otto
- Zentrum für Innovationskompetenz: Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Universität Greifswald, Fleischmannstrasse 42, 17489 Greifswald, Germany
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13
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Richards MA, Simon JN, Ma R, Loonat AA, Crabtree MJ, Paterson DJ, Fahlman RP, Casadei B, Fliegel L, Swietach P. Nitric oxide modulates cardiomyocyte pH control through a biphasic effect on sodium/hydrogen exchanger-1. Cardiovasc Res 2019; 116:1958-1971. [PMID: 31742355 PMCID: PMC7567331 DOI: 10.1093/cvr/cvz311] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/31/2019] [Accepted: 11/16/2019] [Indexed: 11/14/2022] Open
Abstract
AIMS When activated, Na+/H+ exchanger-1 (NHE1) produces some of the largest ionic fluxes in the heart. NHE1-dependent H+ extrusion and Na+ entry strongly modulate cardiac physiology through the direct effects of pH on proteins and by influencing intracellular Ca2+ handling. To attain an appropriate level of activation, cardiac NHE1 must respond to myocyte-derived cues. Among physiologically important cues is nitric oxide (NO), which regulates a myriad of cardiac functions, but its actions on NHE1 are unclear. METHODS AND RESULTS NHE1 activity was measured using pH-sensitive cSNARF1 fluorescence after acid-loading adult ventricular myocytes by an ammonium prepulse solution manoeuvre. NO signalling was manipulated by knockout of its major constitutive synthase nNOS, adenoviral nNOS gene delivery, nNOS inhibition, and application of NO-donors. NHE1 flux was found to be activated by low [NO], but inhibited at high [NO]. These responses involved cGMP-dependent signalling, rather than S-nitros(yl)ation. Stronger cGMP signals, that can inhibit phosphodiesterase enzymes, allowed [cAMP] to rise, as demonstrated by a FRET-based sensor. Inferring from the actions of membrane-permeant analogues, cGMP was determined to activate NHE1, whereas cAMP was inhibitory, which explains the biphasic regulation by NO. Activation of NHE1-dependent Na+ influx by low [NO] also increased the frequency of spontaneous Ca2+ waves, whereas high [NO] suppressed these aberrant forms of Ca2+ signalling. CONCLUSIONS Physiological levels of NO stimulation increase NHE1 activity, which boosts pH control during acid-disturbances and results in Na+-driven cellular Ca2+ loading. These responses are positively inotropic but also increase the likelihood of aberrant Ca2+ signals, and hence arrhythmia. Stronger NO signals inhibit NHE1, leading to a reversal of the aforementioned effects, ostensibly as a potential cardioprotective intervention to curtail NHE1 overdrive.
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Affiliation(s)
- Mark A Richards
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre for Research Excellence, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Ruichong Ma
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Aminah A Loonat
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Mark J Crabtree
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre for Research Excellence, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - David J Paterson
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre for Research Excellence, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Pawel Swietach
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
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14
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Glucocorticoids preserve the t-tubular system in ventricular cardiomyocytes by upregulation of autophagic flux. Basic Res Cardiol 2019; 114:47. [PMID: 31673803 DOI: 10.1007/s00395-019-0758-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022]
Abstract
A major contributor to contractile dysfunction in heart failure is remodelling and loss of the cardiomyocyte transverse tubular system (t-system), but underlying mechanisms and signalling pathways remain elusive. It has been shown that dexamethasone promotes t-tubule development in stem cell-derived cardiomyocytes and that cardiomyocyte-specific glucocorticoid receptor (GR) knockout (GRKO) leads to heart failure. Here, we studied if the t-system is altered in GRKO hearts and if GR signalling is required for t-system preservation in adult cardiomyocytes. Confocal and 3D STED microscopy of myocardium from cardiomyocyte-specific GRKO mice revealed decreased t-system density and increased distances between ryanodine receptors (RyR) and L-type Ca2+ channels (LTCC). Because t-system remodelling and heart failure are intertwined, we investigated the underlying mechanisms in vitro. Ventricular cardiomyocytes from failing human and healthy adult rat hearts cultured in the absence of glucocorticoids (CTRL) showed distinctively lower t-system density than cells treated with dexamethasone (EC50 1.1 nM) or corticosterone. The GR antagonist mifepristone abrogated the effect of dexamethasone. Dexamethasone improved RyR-LTCC coupling and synchrony of intracellular Ca2+ release, but did not alter expression levels of t-system-associated proteins junctophilin-2 (JPH2), bridging integrator-1 (BIN1) or caveolin-3 (CAV3). Rather, dexamethasone upregulated LC3B and increased autophagic flux. The broad-spectrum protein kinase inhibitor staurosporine prevented dexamethasone-induced upregulation of autophagy and t-system preservation, and autophagy inhibitors bafilomycin A and chloroquine accelerated t-system loss. Conversely, induction of autophagy by rapamycin or amino acid starvation preserved the t-system. These findings suggest that GR signalling and autophagy are critically involved in t-system preservation and remodelling in the heart.
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15
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Moshal KS, Roder K, Kabakov AY, Werdich AA, Yi-Eng Chiang D, Turan NN, Xie A, Kim TY, Cooper LL, Lu Y, Zhong M, Li W, Terentyev D, Choi BR, Karma A, MacRae CA, Koren G. LITAF (Lipopolysaccharide-Induced Tumor Necrosis Factor) Regulates Cardiac L-Type Calcium Channels by Modulating NEDD (Neural Precursor Cell Expressed Developmentally Downregulated Protein) 4-1 Ubiquitin Ligase. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2019; 12:407-420. [PMID: 31462068 PMCID: PMC6750970 DOI: 10.1161/circgen.119.002641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/19/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND The turnover of cardiac ion channels underlying action potential duration is regulated by ubiquitination. Genome-wide association studies of QT interval identified several single-nucleotide polymorphisms located in or near genes involved in protein ubiquitination. A genetic variant upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor) gene prompted us to determine its role in modulating cardiac excitation. METHODS Optical mapping was performed in zebrafish hearts to determine Ca2+ transients. Live-cell confocal calcium imaging was performed on adult rabbit cardiomyocytes to determine intracellular Ca2+handling. L-type calcium channel (LTCC) current (ICa,L) was measured using whole-cell recording. To study the effect of LITAF on Cav1.2 (L-type voltage-gated calcium channel 1.2) channel expression, surface biotinylation, and Westerns were performed. LITAF interactions were studied using coimmunoprecipitation and in situ proximity ligation assay. RESULTS LITAF knockdown in zebrafish resulted in a robust increase in calcium transients. Overexpressed LITAF in 3-week-old rabbit cardiomyocytes resulted in a decrease in ICa,L and Cavα1c abundance, whereas LITAF knockdown increased ICa,L and Cavα1c protein. LITAF-overexpressing decreases calcium transients in adult rabbit cardiomyocytes, which was associated with lower Cavα1c levels. In tsA201 cells, overexpressed LITAF downregulated total and surface pools of Cavα1c via increased Cavα1c ubiquitination and its subsequent lysosomal degradation. We observed colocalization between LITAF and LTCC in tsA201 and cardiomyocytes. In tsA201, NEDD (neural precursor cell expressed developmentally downregulated protein) 4-1, but not its catalytically inactive form NEDD4-1-C867A, increased Cavα1c ubiquitination. Cavα1c ubiquitination was further increased by coexpressed LITAF and NEDD4-1 but not NEDD4-1-C867A. NEDD4-1 knockdown abolished the negative effect of LITAF on ICa,L and Cavα1c levels in 3-week-old rabbit cardiomyocytes. Computer simulations demonstrated that a decrease of ICa,L current associated with LITAF overexpression simultaneously shortened action potential duration and decreased calcium transients in rabbit cardiomyocytes. CONCLUSIONS LITAF acts as an adaptor protein promoting NEDD4-1-mediated ubiquitination and subsequent degradation of LTCC, thereby controlling LTCC membrane levels and function and thus cardiac excitation.
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Affiliation(s)
- Karni S. Moshal
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Karim Roder
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Anatoli Y. Kabakov
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Andreas A. Werdich
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - David Yi-Eng Chiang
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Nilüfer N. Turan
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - An Xie
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Tae Yun Kim
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | | | - Yichun Lu
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Mingwang Zhong
- Physics Dept & Center for Interdisciplinary Research in Complex Systems, Northeastern Univ, Boston, MA
| | - Weiyan Li
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Dmitry Terentyev
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Bum-Rak Choi
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Alain Karma
- Physics Dept & Center for Interdisciplinary Research in Complex Systems, Northeastern Univ, Boston, MA
| | - Calum A. MacRae
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
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16
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Segal S, Kirschner Peretz N, Arbel-Ganon L, Liang J, Li L, Marbach D, Yang D, Wang SQ, Yaniv Y. Eliminating contraction during culture maintains global and local Ca 2+ dynamics in cultured rabbit pacemaker cells. Cell Calcium 2018; 78:35-47. [PMID: 30594820 DOI: 10.1016/j.ceca.2018.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 12/12/2022]
Abstract
Pacemaker cells residing in the sinoatrial node generate the regular heartbeat. Ca2+ signaling controls the heartbeat rate-directly, through the effect on membrane molecules (NCX exchange, K+ channel), and indirectly, through activation of calmodulin-AC-cAMP-PKA signaling. Thus, the physiological role of signaling in pacemaker cells can only be assessed if the Ca2+ dynamics are in the physiological range. Cultured cells that can be genetically manipulated and/or virally infected with probes are required for this purpose. Because rabbit pacemaker cells in culture experience a decrease in their spontaneous action potential (AP) firing rate below the physiological range, Ca2+ dynamics are expected to be affected. However, Ca2+ dynamics in cultured pacemaker cells have not been reported before. We aim to a develop a modified culture method that sustains the global and local Ca2+ kinetics along with the AP firing rate of rabbit pacemaker cells. We used experimental and computational tools to test the viability of rabbit pacemaker cells in culture under various conditions. We tested the effect of culture dish coating, pH, phosphorylation, and energy balance on cultured rabbit pacemaker cells function. The cells were maintained in culture for 48 h in two types of culture media: one without the addition of a contraction uncoupler and one enriched with either 10 mM BDM (2,3-Butanedione 2-monoxime) or 25 μM blebbistatin. The uncoupler was washed out from the medium prior to the experiments. Cells were successfully infected with a GFP adenovirus cultured with either BDM or blebbistatin. Using either uncoupler during culture led to the cell surface area being maintained at the same level as fresh cells. Moreover, the phospholamban and ryanodine receptor densities and their phosphorylation level remained intact in culture when either blebbistatin or BDM were present. Spontaneous AP firing rate, spontaneous Ca2+ kinetics, and spontaneous local Ca2+ release parameters were similar in the cultured cells with blebbistatin as in fresh cells. However, BDM affects these parameters. Using experimental and a computational model, we showed that by eliminating contraction, phosphorylation activity is preserved and energy is reduced. However, the side-effects of BDM render it less effective than blebbistatin.
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Affiliation(s)
- Sofia Segal
- Biomedical Engineering Faculty, Technion-IIT, Haifa, Israel
| | | | | | - Jinghui Liang
- College of Life Sciences, Peking University, Beijing, China
| | - Linlin Li
- College of Life Sciences, Peking University, Beijing, China
| | - Daphna Marbach
- Biomedical Engineering Faculty, Technion-IIT, Haifa, Israel
| | - Dongmei Yang
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Shi-Qiang Wang
- College of Life Sciences, Peking University, Beijing, China
| | - Yael Yaniv
- Biomedical Engineering Faculty, Technion-IIT, Haifa, Israel.
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17
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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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18
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Basheer WA, Shaw RM. Connexin 43 and CaV1.2 Ion Channel Trafficking in Healthy and Diseased Myocardium. Circ Arrhythm Electrophysiol 2018; 9:e001357. [PMID: 27266274 DOI: 10.1161/circep.115.001357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/29/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Wassim A Basheer
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.).
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19
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Abstract
During the past few decades, gene delivery using recombinant virus has made tremendous progress. With a higher than 80 % transduction efficiency, even in non-dividing cells, viral transduction has become the method of choice for efficient gene transfer into cardiomyocytes. However, in vitro gene delivery is dependent on a robust cell isolation protocol, as prolonged cultivation is needed to initiate gene expression and target specific cellular processes. This chapter describes some of the important steps that need to be considered for successful in vitro gene transfer into adult cardiomyocytes. Included are detailed protocols for isolating cells, maintaining rod shaped cardiomyocytes in culture over several days, and employing adenovirus for gene transduction.
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Affiliation(s)
- Kjetil Hodne
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - David B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Ullevål, Kirkeveien 166, 0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Ullevål, Kirkeveien 166, 0407, Oslo, Norway.
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway.
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20
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Guo A, Chen R, Wang Y, Huang CK, Chen B, Kutschke W, Hong J, Song LS. Transient activation of PKC results in long-lasting detrimental effects on systolic [Ca 2+] i in cardiomyocytes by altering actin cytoskeletal dynamics and T-tubule integrity. J Mol Cell Cardiol 2018; 115:104-114. [PMID: 29307535 DOI: 10.1016/j.yjmcc.2018.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 11/25/2022]
Abstract
AIMS Protein kinase C (PKC) isozymes contribute to the development of heart failure through dysregulation of Ca2+ handling properties and disruption of contractile function in cardiomyocytes. However, the mechanisms by which PKC activation leads to Ca2+ dysfunction are incompletely understood. METHODS AND RESULTS Shortly upon ventricular pressure overload in mice, we detected transient PKC activation that was associated with pulsed actin cytoskeletal rearrangement. In cultured cardiomyocytes, transient activation of PKC promoted long-term deleterious effects on the integrity of the transverse (T)- tubule system, resulting in a significant decrease in the amplitude and increase in the rising kinetics of Ca2+ transients. Treatment with a PKCα/β inhibitor restored the synchronization of Ca2+ transients and maintained T-tubule integrity in cultured cardiomyocytes. Supporting these data, PKCα/β inhibition protected against T-tubule remodeling and cardiac dysfunction in a mouse model of pressure overload-induced heart failure. Mechanistically, transient activation of PKC resulted in biphasic actin cytoskeletal rearrangement, consistent with in vivo observations in the pressure overloaded mouse model. Transient inhibition of actin polymerization or depolymerization resulted in severe T-tubule damage, recapitulating the T-tubule damage induced by PKC activation. Moreover, inhibition of stretch activated channels (SAC) protected against T-tubule remodeling and E-C coupling dysfunction induced by transient PKC activation and actin cytoskeletal rearrangement. CONCLUSIONS These data identify a key mechanistic link between transient PKC activation and long-term Ca2+ handling defects through PKC-induced actin cytoskeletal rearrangement and resultant T-tubule damage.
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Affiliation(s)
- Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Rong Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Yihui Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Chun-Kai Huang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA.
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21
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Tian Q, Kaestner L, Schröder L, Guo J, Lipp P. An adaptation of astronomical image processing enables characterization and functional 3D mapping of individual sites of excitation-contraction coupling in rat cardiac muscle. eLife 2017; 6:30425. [PMID: 29135437 PMCID: PMC5703646 DOI: 10.7554/elife.30425] [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: 07/14/2017] [Accepted: 11/03/2017] [Indexed: 01/06/2023] Open
Abstract
In beating cardiomyocytes, synchronized localized Ca2+ transients from thousands of active excitation-contraction coupling sites (ECC couplons) comprising plasma and sarcoplasmic reticulum membrane calcium channels are important determinants of the heart's performance. Nevertheless, our knowledge about the properties of ECC couplons is limited by the lack of appropriate experimental and analysis strategies. We designed CaCLEAN to untangle the fundamental characteristics of ECC couplons by combining the astronomer's CLEAN algorithm with known properties of calcium diffusion. CaCLEAN empowers the investigation of fundamental properties of ECC couplons in beating cardiomyocytes without pharmacological interventions. Upon examining individual ECC couplons at the nanoscopic level, we reveal their roles in the negative amplitude-frequency relationship and in β-adrenergic stimulation, including decreasing and increasing firing reliability, respectively. CaCLEAN combined with 3D confocal imaging of beating cardiomyocytes provides a functional 3D map of active ECC couplons (on average, 17,000 per myocyte). CaCLEAN will further enlighten the ECC-couplon-remodelling processes that underlie cardiac diseases.
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Affiliation(s)
- Qinghai Tian
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Lars Kaestner
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Laura Schröder
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Jia Guo
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
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22
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Peter AK, Bjerke MA, Leinwand LA. Biology of the cardiac myocyte in heart disease. Mol Biol Cell 2017; 27:2149-60. [PMID: 27418636 PMCID: PMC4945135 DOI: 10.1091/mbc.e16-01-0038] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/23/2016] [Indexed: 12/21/2022] Open
Abstract
Cardiac hypertrophy is a major risk factor for heart failure, and it has been shown that this increase in size occurs at the level of the cardiac myocyte. Cardiac myocyte model systems have been developed to study this process. Here we focus on cell culture tools, including primary cells, immortalized cell lines, human stem cells, and their morphological and molecular responses to pathological stimuli. For each cell type, we discuss commonly used methods for inducing hypertrophy, markers of pathological hypertrophy, advantages for each model, and disadvantages to using a particular cell type over other in vitro model systems. Where applicable, we discuss how each system is used to model human disease and how these models may be applicable to current drug therapeutic strategies. Finally, we discuss the increasing use of biomaterials to mimic healthy and diseased hearts and how these matrices can contribute to in vitro model systems of cardiac cell biology.
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Affiliation(s)
- Angela K Peter
- Biofrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Maureen A Bjerke
- Biofrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Leslie A Leinwand
- Biofrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
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23
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Abstract
Unique to striated muscle cells, transverse tubules (t-tubules) are membrane organelles that consist of sarcolemma penetrating into the myocyte interior, forming a highly branched and interconnected network. Mature t-tubule networks are found in mammalian ventricular cardiomyocytes, with the transverse components of t-tubules occurring near sarcomeric z-discs. Cardiac t-tubules contain membrane microdomains enriched with ion channels and signaling molecules. The microdomains serve as key signaling hubs in regulation of cardiomyocyte function. Dyad microdomains formed at the junctional contact between t-tubule membrane and neighboring sarcoplasmic reticulum are critical in calcium signaling and excitation-contraction coupling necessary for beat-to-beat heart contraction. In this review, we provide an overview of the current knowledge in gross morphology and structure, membrane and protein composition, and function of the cardiac t-tubule network. We also review in detail current knowledge on the formation of functional membrane subdomains within t-tubules, with a particular focus on the cardiac dyad microdomain. Lastly, we discuss the dynamic nature of t-tubules including membrane turnover, trafficking of transmembrane proteins, and the life cycles of membrane subdomains such as the cardiac BIN1-microdomain, as well as t-tubule remodeling and alteration in diseased hearts. Understanding cardiac t-tubule biology in normal and failing hearts is providing novel diagnostic and therapeutic opportunities to better treat patients with failing hearts.
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Affiliation(s)
- TingTing Hong
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California; and Department of Medicine, University of California Los Angeles, Los Angeles, California
| | - Robin M Shaw
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California; and Department of Medicine, University of California Los Angeles, Los Angeles, California
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24
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Affiliation(s)
- Hans Blom
- Royal Institute of Technology (KTH), Dept Applied Physics, SciLifeLab, 17165 Solna, Sweden
| | - Jerker Widengren
- Royal Institute of Technology (KTH), Dept Applied Physics, Albanova Univ Center, 10691 Stockholm, Sweden
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25
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Wüst RCI, Helmes M, Martin JL, van der Wardt TJT, Musters RJP, van der Velden J, Stienen GJM. Rapid frequency-dependent changes in free mitochondrial calcium concentration in rat cardiac myocytes. J Physiol 2017; 595:2001-2019. [PMID: 28028811 DOI: 10.1113/jp273589] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/16/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Calcium ions regulate mitochondrial ATP production and contractile activity and thus play a pivotal role in matching energy supply and demand in cardiac muscle. The magnitude and kinetics of the changes in free mitochondrial calcium concentration in cardiac myocytes are largely unknown. Rapid stimulation frequency-dependent increases but relatively slow decreases in free mitochondrial calcium concentration were observed in rat cardiac myocytes. This asymmetry caused a rise in the mitochondrial calcium concentration with stimulation frequency. These results provide insight into the mechanisms of mitochondrial calcium uptake and release that are important in healthy and diseased myocardium. ABSTRACT Calcium ions regulate mitochondrial ATP production and contractile activity and thus play a pivotal role in matching energy supply and demand in cardiac muscle. Little is known about the magnitude and kinetics of the changes in free mitochondrial calcium concentration in cardiomyocytes. Using adenoviral infection, a ratiometric mitochondrially targeted Förster resonance energy transfer (FRET)-based calcium indicator (4mtD3cpv, MitoCam) was expressed in cultured adult rat cardiomyocytes and the free mitochondrial calcium concentration ([Ca2+ ]m ) was measured at different stimulation frequencies (0.1-4 Hz) and external calcium concentrations (1.8-3.6 mm) at 37°C. Cytosolic calcium concentrations were assessed under the same experimental conditions in separate experiments using Fura-4AM. The increases in [Ca2+ ]m during electrical stimulation at 0.1 Hz were rapid (rise time = 49 ± 2 ms), while the decreases in [Ca2+ ]m occurred more slowly (decay half time = 1.17 ± 0.07 s). Model calculations confirmed that this asymmetry caused the rise in [Ca2+ ]m during diastole observed at elevated stimulation frequencies. Inhibition of the mitochondrial sodium-calcium exchanger (mNCE) resulted in a rise in [Ca2+ ]m at baseline and, paradoxically, in an acceleration of Ca2+ release. IN CONCLUSION rapid increases in [Ca2+ ]m allow for fast adjustment of mitochondrial ATP production to increases in myocardial demand on a beat-to-beat basis and mitochondrial calcium release depends on mNCE activity and mitochondrial calcium buffering.
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Affiliation(s)
- Rob C I Wüst
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Michiel Helmes
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands.,IonOptix LLC, Milton, MA, USA
| | - Jody L Martin
- Cell and Molecular Physiology, Loyola University, Chicago, IL, USA
| | - Thomas J T van der Wardt
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - René J P Musters
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Ger J M Stienen
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands.,Faculty of Science, Department of Physics and Astronomy, VU University, Amsterdam, the Netherlands
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26
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Ackers-Johnson M, Li PY, Holmes AP, O'Brien SM, Pavlovic D, Foo RS. A Simplified, Langendorff-Free Method for Concomitant Isolation of Viable Cardiac Myocytes and Nonmyocytes From the Adult Mouse Heart. Circ Res 2016; 119:909-20. [PMID: 27502479 DOI: 10.1161/circresaha.116.309202] [Citation(s) in RCA: 315] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 08/05/2016] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardiovascular disease represents a global pandemic. The advent of and recent advances in mouse genomics, epigenomics, and transgenics offer ever-greater potential for powerful avenues of research. However, progress is often constrained by unique complexities associated with the isolation of viable myocytes from the adult mouse heart. Current protocols rely on retrograde aortic perfusion using specialized Langendorff apparatus, which poses considerable logistical and technical barriers to researchers and demands extensive training investment. OBJECTIVE To identify and optimize a convenient, alternative approach, allowing the robust isolation and culture of adult mouse cardiac myocytes using only common surgical and laboratory equipment. METHODS AND RESULTS Cardiac myocytes were isolated with yields comparable to those in published Langendorff-based methods, using direct needle perfusion of the LV ex vivo and without requirement for heparin injection. Isolated myocytes can be cultured antibiotic free, with retained organized contractile and mitochondrial morphology, transcriptional signatures, calcium handling, responses to hypoxia, neurohormonal stimulation, and electric pacing, and are amenable to patch clamp and adenoviral gene transfer techniques. Furthermore, the methodology permits concurrent isolation, separation, and coculture of myocyte and nonmyocyte cardiac populations. CONCLUSIONS We present a novel, simplified method, demonstrating concomitant isolation of viable cardiac myocytes and nonmyocytes from the same adult mouse heart. We anticipate that this new approach will expand and accelerate innovative research in the field of cardiac biology.
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Affiliation(s)
- Matthew Ackers-Johnson
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Peter Yiqing Li
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Andrew P Holmes
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Sian-Marie O'Brien
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Davor Pavlovic
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Roger S Foo
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.).
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27
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Richards M, Lomas O, Jalink K, Ford KL, Vaughan-Jones RD, Lefkimmiatis K, Swietach P. Intracellular tortuosity underlies slow cAMP diffusion in adult ventricular myocytes. Cardiovasc Res 2016; 110:395-407. [PMID: 27089919 PMCID: PMC4872880 DOI: 10.1093/cvr/cvw080] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 04/11/2016] [Indexed: 12/20/2022] Open
Abstract
Aims 3′,5′-Cyclic adenosine monophosphate (cAMP) signals in the heart are often confined to concentration microdomains shaped by cAMP diffusion and enzymatic degradation. While the importance of phosphodiesterases (degradative enzymes) in sculpting cAMP microdomains is well established in cardiomyocytes, less is known about cAMP diffusivity (DcAMP) and factors affecting it. Many earlier studies have reported fast diffusivity, which argues against sharply defined microdomains. Methods and results [cAMP] dynamics in the cytoplasm of adult rat ventricular myocytes were imaged using a fourth generation genetically encoded FRET-based sensor. The [cAMP]-response to the addition and removal of isoproterenol (β-adrenoceptor agonist) quantified the rates of cAMP synthesis and degradation. To obtain a read out of DcAMP, a stable [cAMP] gradient was generated using a microfluidic device which delivered agonist to one half of the myocyte only. After accounting for phosphodiesterase activity, DcAMP was calculated to be 32 µm2/s; an order of magnitude lower than in water. Diffusivity was independent of the amount of cAMP produced. Saturating cAMP-binding sites with the analogue 6-Bnz-cAMP did not accelerate DcAMP, arguing against a role of buffering in restricting cAMP mobility. cAMP diffused at a comparable rate to chemically unrelated but similar sized molecules, arguing for a common physical cause of restricted diffusivity. Lower mitochondrial density and order in neonatal cardiac myocytes allowed for faster diffusion, demonstrating the importance of mitochondria as physical barriers to cAMP mobility. Conclusion In adult cardiac myocytes, tortuosity due to physical barriers, notably mitochondria, restricts cAMP diffusion to levels that are more compatible with microdomain signalling.
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Affiliation(s)
- Mark Richards
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Oliver Lomas
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Kees Jalink
- Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Kerrie L Ford
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Richard D Vaughan-Jones
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Konstantinos Lefkimmiatis
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK BHF Centre of Research Excellence, Oxford
| | - Pawel Swietach
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
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28
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Lomas O, Brescia M, Carnicer R, Monterisi S, Surdo NC, Zaccolo M. Adenoviral transduction of FRET-based biosensors for cAMP in primary adult mouse cardiomyocytes. Methods Mol Biol 2015; 1294:103-15. [PMID: 25783880 DOI: 10.1007/978-1-4939-2537-7_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genetically encoded biosensors that make use of fluorescence resonance energy transfer (FRET) are important tools for the study of compartmentalized cyclic nucleotide signaling in living cells. With the advent of germ line and tissue-specific transgenic technologies, the adult mouse represents a useful tool for the study of cardiovascular pathophysiology. The use of FRET-based genetically encoded biosensors coupled with this animal model represents a powerful combination for the study of cAMP signaling in live primary cardiomyocytes. In this chapter, we describe the steps required during the isolation, viral transduction, and culture of cardiomyocytes from an adult mouse to obtain reliable expression of genetically encoded FRET biosensors for the study of cAMP signaling in living cells.
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Affiliation(s)
- Oliver Lomas
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
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BIN1 regulates dynamic t-tubule membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1839-47. [PMID: 26578114 DOI: 10.1016/j.bbamcr.2015.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/31/2015] [Accepted: 11/09/2015] [Indexed: 11/23/2022]
Abstract
Cardiac transverse tubules (t-tubules) are specific membrane organelles critical in calcium signaling and excitation-contraction coupling required for beat-to-beat heart contraction. T-tubules are highly branched and form an interconnected network that penetrates the myocyte interior to form junctions with the sarcoplasmic reticulum. T-tubules are selectively enriched with specific ion channels and proteins crucial in calcium transient development necessary in excitation-contraction coupling, thus t-tubules are a key component of cardiac myocyte function. In this review, we focus primarily on two proteins concentrated within the t-tubular network, the L-type calcium channel (LTCC) and associated membrane anchor protein, bridging integrator 1 (BIN1). Here, we provide an overview of current knowledge in t-tubule morphology, composition, microdomains, as well as the dynamics of the t-tubule network. Secondly, we highlight multiple aspects of BIN1-dependent t-tubule function, which includes forward trafficking of LTCCs to t-tubules, LTCC clustering at t-tubule surface, microdomain organization and regulation at t-tubule membrane, and the formation of a slow diffusion barrier within t-tubules. Lastly, we describe progress in characterizing how acquired human heart failure can be attributed to abnormal BIN1 transcription and associated t-tubule remodeling. Understanding BIN1-regulated cardiac t-tubule biology in human heart failure management has the dual benefit of promoting progress in both biomarker development and therapeutic target identification. 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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Lorin C, Vögeli I, Niggli E. Dystrophic cardiomyopathy: role of TRPV2 channels in stretch-induced cell damage. Cardiovasc Res 2015; 106:153-62. [PMID: 25616416 DOI: 10.1093/cvr/cvv021] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
AIMS Duchenne muscular dystrophy (DMD), a degenerative pathology of skeletal muscle, also induces cardiac failure and arrhythmias due to a mutation leading to the lack of the protein dystrophin. In cardiac cells, the subsarcolemmal localization of dystrophin is thought to protect the membrane from mechanical stress. The absence of dystrophin results in an elevated stress-induced Ca2+ influx due to the inadequate functioning of several proteins, such as stretch-activated channels (SACs). Our aim was to investigate whether transient receptor potential vanilloid channels type 2 (TRPV2) form subunits of the dysregulated SACs in cardiac dystrophy. METHODS AND RESULTS We defined the role of TRPV2 channels in the abnormal Ca2+ influx of cardiomyocytes isolated from dystrophic mdx mice, an established animal model for DMD. In dystrophic cells, western blotting showed that TRPV2 was two-fold overexpressed. While normally localized intracellularly, in myocytes from mdx mice TRPV2 channels were translocated to the sarcolemma and were prominent along the T-tubules, as indicated by immunocytochemistry. Membrane localization was confirmed by biotinylation assays. Furthermore, in mdx myocytes pharmacological modulators suggested an abnormal activity of TRPV2, which has a unique pharmacological profile among TRP channels. Confocal imaging showed that these compounds protected the cells from stress-induced abnormal Ca2+ signals. The involvement of TRPV2 in these signals was confirmed by specific pore-blocking antibodies and by small-interfering RNA ablation of TRPV2. CONCLUSION Together, these results establish the involvement of TRPV2 in a stretch-activated calcium influx pathway in dystrophic cardiomyopathy, contributing to the defective cellular Ca2+ handling in this disease.
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Affiliation(s)
- Charlotte Lorin
- Department of Physiology, University of Bern, Buehlplatz 5, 3012 Bern, Switzerland
| | - Isabelle Vögeli
- Department of Physiology, University of Bern, Buehlplatz 5, 3012 Bern, Switzerland
| | - Ernst Niggli
- Department of Physiology, University of Bern, Buehlplatz 5, 3012 Bern, Switzerland
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31
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Bossuyt J, Bers DM. Assessing GPCR and G protein signaling to the nucleus in live cells using fluorescent biosensors. Methods Mol Biol 2015; 1234:149-159. [PMID: 25304355 DOI: 10.1007/978-1-4939-1755-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
G protein-coupled receptor (GPCR) signaling cascades regulate a wide variety of cellular processes and feature prominently in many cardiovascular pathologies. As such they represent major drug targets and discovering novel aspects of GPCR signaling provide important opportunities to identify additional potential therapeutic approaches to reverse or prevent cardiac remodeling and failure. Monitoring cellular trafficking of signaling components and specific protein kinase activities using fluorescent biosensors has provided key insight into stress/GPCR-induced kinase signaling networks and their effect on cardiac gene expression. Herein we describe the protocols for the expression, visualization (by confocal microscopy), and interpretation of data obtained with such biosensors expressed in adult cardiomyocytes. Our focus is on the cellular trafficking of class II histone deacetylases (i.e., HDAC5) and on the FRET sensor (Camui) for calmodulin-dependent protein kinase II (CaMKII).
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Affiliation(s)
- Julie Bossuyt
- Department of Pharmacology, University of California, Davis, CA, 95616-8636, USA
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32
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Xiao S, Shaw RM. Cardiomyocyte protein trafficking: Relevance to heart disease and opportunities for therapeutic intervention. Trends Cardiovasc Med 2014; 25:379-89. [PMID: 25649302 DOI: 10.1016/j.tcm.2014.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 11/30/2022]
Abstract
Cardiomyocytes, the individual contractile units of heart muscle, are long-lived and robust. Given the longevity of these cells, it can be easy to overlook their dynamic intracellular environment that contain rapid protein movements and frequent protein turnover. Critical gene transcription and protein translation occur continuously, as well as trafficking and localization of proteins to specific functional zones of cell membrane. As heart failure becomes an increasingly important clinical entity, growing numbers of investigative teams are examining the cell biology of healthy and diseased cardiomyocytes. In this review, we introduce the major architectural structures and types of protein movements within cardiac cells, and then review recent studies that explore the regulation of such movements. We conclude by introducing current translational directions of the basic studies with a focus on novel areas of therapeutic development.
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Affiliation(s)
- Shaohua Xiao
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA; Department of Medicine, University of California Los Angeles, Los Angeles, CA.
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33
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Nothdurft FP, Fontana D, Ruppenthal S, May A, Aktas C, Mehraein Y, Lipp P, Kaestner L. Differential Behavior of Fibroblasts and Epithelial Cells on Structured Implant Abutment Materials: A Comparison of Materials and Surface Topographies. Clin Implant Dent Relat Res 2014; 17:1237-49. [PMID: 25066589 DOI: 10.1111/cid.12253] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of this study was to compare the proliferation and attachment behavior of fibroblasts and epithelial cells on differently structured abutment materials. MATERIALS AND METHODS Three different surface topographies were prepared on zirconia and titanium alloy specimens and defined as follows: machined (as delivered without further surface modification), smooth (polished), and rough (sandblasted). Energy-dispersive X-ray spectroscopy, topographical analysis, and water contact angle measurements were used to analyze the surface properties. Fibroblasts (HGF1) and epithelial cells (HNEpC) grown on the specimens were investigated 24 hours and 72 hours after seeding and counted using fluorescence imaging. To investigate adhesion, the abundance and arrangement of the focal adhesion protein vinculin were evaluated by immunocytochemistry. RESULTS Similar surface topographies were created on both materials. Fibroblasts exhibited significant higher proliferation rates on comparable surface topographies of zirconia compared with the titanium alloy. The proliferation of fibroblasts and epithelial cells was optimal on different substrate/topography combinations. Cell spreading was generally higher on polished and machined surfaces than on sandblasted surfaces. Rough surfaces provided favorable properties in terms of cellular adhesion of fibroblasts but not of epithelial cells. CONCLUSIONS Our data support complex soft tissue cell-substrate interactions: the fibroblast and epithelial cell response is influenced by both the material and surface topography.
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Affiliation(s)
- Frank P Nothdurft
- Department of Prosthetic Dentistry and Dental Materials Sciences, Saarland University, Homburg/Saar, Germany
| | - Dorothee Fontana
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Sandra Ruppenthal
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Alexander May
- CVD/Biosurfaces, Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Cenk Aktas
- Division CVD/Biosurfaces, Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Yasmin Mehraein
- Institute of Human Genetics, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Lars Kaestner
- Research Center for Molecular Imaging and Screening, Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
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34
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Kaestner L, Scholz A, Tian Q, Ruppenthal S, Tabellion W, Wiesen K, Katus HA, Müller OJ, Kotlikoff MI, Lipp P. Genetically encoded Ca2+ indicators in cardiac myocytes. Circ Res 2014; 114:1623-39. [PMID: 24812351 DOI: 10.1161/circresaha.114.303475] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genetically encoded Ca(2+) indicators constitute a powerful set of tools to investigate functional aspects of Ca(2+) signaling in isolated cardiomyocytes, cardiac tissue, and whole hearts. Here, we provide an overview of the concepts, experiences, state of the art, and ongoing developments in the use of genetically encoded Ca(2+) indicators for cardiac cells and heart tissue. This review is supplemented with in vivo viral gene transfer experiments and comparisons of available genetically encoded Ca(2+) indicators with each other and with the small molecule dye Fura-2. In the context of cardiac myocytes, we provide guidelines for selecting a genetically encoded Ca(2+) indicator. For future developments, we discuss improvements of a broad range of properties, including photophysical properties such as spectral spread and biocompatibility, as well as cellular and in vivo applications.
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Affiliation(s)
- Lars Kaestner
- From the Institute for Molecular Cell Biology and Research Center for Molecular Imaging and Screening, School of Medicine, Saarland University, Homburg-Saar, Germany (L.K., A.S., Q.T., S.R., W.T., K.W., P.L.); Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany (H.A.K., O.J.M.); DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Germany (H.A.K., O.J.M.); and Biomedical Sciences Department, College of Veterinary Medicine, Cornell University, Ithaca, NY (M.I.K.)
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35
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Hong T, Yang H, Zhang SS, Cho HC, Kalashnikova M, Sun B, Zhang H, Bhargava A, Grabe M, Olgin J, Gorelik J, Marbán E, Jan LY, Shaw RM. Cardiac BIN1 folds T-tubule membrane, controlling ion flux and limiting arrhythmia. Nat Med 2014; 20:624-32. [PMID: 24836577 PMCID: PMC4048325 DOI: 10.1038/nm.3543] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/24/2014] [Indexed: 11/08/2022]
Abstract
Cardiomyocyte T tubules are important for regulating ion flux. Bridging integrator 1 (BIN1) is a T-tubule protein associated with calcium channel trafficking that is downregulated in failing hearts. Here we find that cardiac T tubules normally contain dense protective inner membrane folds that are formed by a cardiac isoform of BIN1. In mice with cardiac Bin1 deletion, T-tubule folding is decreased, which does not change overall cardiomyocyte morphology but leads to free diffusion of local extracellular calcium and potassium ions, prolonging action-potential duration and increasing susceptibility to ventricular arrhythmias. We also found that T-tubule inner folds are rescued by expression of the BIN1 isoform BIN1+13+17, which promotes N-WASP-dependent actin polymerization to stabilize the T-tubule membrane at cardiac Z discs. BIN1+13+17 recruits actin to fold the T-tubule membrane, creating a 'fuzzy space' that protectively restricts ion flux. When the amount of the BIN1+13+17 isoform is decreased, as occurs in acquired cardiomyopathy, T-tubule morphology is altered, and arrhythmia can result.
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Affiliation(s)
- TingTing Hong
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Huanghe Yang
- Departments of Physiology, Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Shan-Shan Zhang
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hee Cheol Cho
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Mariya Kalashnikova
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Baiming Sun
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hao Zhang
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Anamika Bhargava
- Imperial Center for Translational and Experimental Medicine, Imperial College, London, UK
| | - Michael Grabe
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Jeffrey Olgin
- Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Julia Gorelik
- Imperial Center for Translational and Experimental Medicine, Imperial College, London, UK
| | - Eduardo Marbán
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lily Y. Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, USA
| | - Robin M. Shaw
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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36
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McDade JR, Archambeau A, Michele DE. Rapid actin-cytoskeleton-dependent recruitment of plasma membrane-derived dysferlin at wounds is critical for muscle membrane repair. FASEB J 2014; 28:3660-70. [PMID: 24784578 DOI: 10.1096/fj.14-250191] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Deficits in membrane repair may contribute to disease progression in dysferlin-deficient muscular dystrophy. Dysferlin, a type-II transmembrane phospholipid-binding protein, is hypothesized to regulate fusion of repair vesicles with the sarcolemma to facilitate membrane repair, but the dysferlin-containing compartments involved in membrane repair and the mechanism by which these compartments contribute to resealing are unclear. A dysferlin-pHluorin [dysf-pH-sensitive green fluorescent protein (pHGFP)] muscle-specific transgenic mouse was developed to examine the dynamic behavior and subcellular localization of dysferlin during membrane repair in adult skeletal muscle fibers. Live-cell confocal microscopy of uninjured adult dysf-pHGFP muscle fibers revealed that dysferlin is highly enriched in the sarcolemma and transverse tubules. Laser-wounding induced rapid recruitment of ∼30 μm of local dysferlin-containing sarcolemma, leading to formation of stable dysferlin accumulations surrounding lesions, endocytosis of dysferlin, and formation of large cytoplasmic vesicles from distal regions of the fiber. Disruption of the actin cytoskeleton decreased recruitment of sarcolemma-derived dysferlin to lesions in dysf-pHGFP fibers without affecting endocytosis and impaired membrane resealing in wild-type fibers, similar to findings in dysferlin deficiency (a 2-fold increase in FM1-43 uptake). Our data support a new mechanism whereby recruitment of sarcolemma-derived dysferlin creates an active zone of high lipid-binding activity at wounds to interact with repair vesicles and facilitate membrane resealing in skeletal muscle.
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Affiliation(s)
- Joel R McDade
- Department of Molecular and Integrative Physiology and
| | | | - Daniel E Michele
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, Michigan, USA
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37
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Preservation of cardiomyocytes from the adult heart. J Mol Cell Cardiol 2013; 64:108-19. [PMID: 24051370 DOI: 10.1016/j.yjmcc.2013.09.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 08/08/2013] [Accepted: 09/05/2013] [Indexed: 11/21/2022]
Abstract
Cardiomyocytes represent one of the most useful models to conduct cardiac research. A single adult heart yields millions of cardiomyocytes, but these cells do not survive for long after isolation. We aimed to determine whether inhibition of myosin II ATPase that is essential for muscle contraction may preserve fully differentiated adult cardiomyocytes. Using inhibitors of the myosin II ATPase, blebbistatin and N-benzyl-p-toluene sulphonamide (BTS), we preserved freshly isolated fully differentiated adult primary cardiomyocytes that were stored at a refrigerated temperature. Specifically, preserved cardiomyocytes stayed viable for a 2-week period with a stable expression of cardiac genes and retained the expression of key markers characteristic of cardiomyocytes. Furthermore, voltage-clamp, action potential, calcium transient and contractility studies confirmed that the preserved cardiomyocytes are comparable to freshly isolated cells. Long-term exposure of preserved cardiomyocytes to four tyrosine kinase inhibitors, sunitinib malate, dasatinib, sorafenib tosylate and imatinib mesylate, revealed their potential to induce cardiac toxicity that was manifested with a decrease in contractility and induction of cell death, but this toxicity was not observed in acute experiments conducted over the time course amenable to freshly prepared cardiomyocytes. This study introduces the concept that the inhibition of myosin II ATPase safeguards the structure and function of fully differentiated adult cardiomyocytes. The fact that these preserved cardiomyocytes can be used for numerous days after preparation makes them a robust and versatile tool in cardiac research and allows the investigation of long-term exposure to novel drugs on cardiomyocyte function.
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Manipulating L-type calcium channels in cardiomyocytes using split-intein protein transsplicing. Proc Natl Acad Sci U S A 2013; 110:15461-6. [PMID: 24003157 DOI: 10.1073/pnas.1308161110] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Manipulating expression of large genes (>6 kb) in adult cardiomyocytes is challenging because these cells are only efficiently transduced by viral vectors with a 4-7 kb packaging capacity. This limitation impedes understanding structure-function mechanisms of important proteins in heart. L-type calcium channels (LTCCs) regulate diverse facets of cardiac physiology including excitation-contraction coupling, excitability, and gene expression. Many important questions about how LTCCs mediate such multidimensional signaling are best resolved by manipulating expression of the 6.6 kb pore-forming α1C-subunit in adult cardiomyocytes. Here, we use split-intein-mediated protein transsplicing to reconstitute LTCC α1C-subunit from two distinct halves, overcoming the difficulty of expressing full-length α1C in cardiomyocytes. Split-intein-tagged α1C fragments encoding dihydropyridine-resistant channels were incorporated into adenovirus and reconstituted in cardiomyocytes. Similar to endogenous LTCCs, recombinant channels targeted to dyads, triggered Ca(2+) transients, associated with caveolin-3, and supported β-adrenergic regulation of excitation-contraction coupling. This approach lowers a longstanding technical hurdle to manipulating large proteins in cardiomyocytes.
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39
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Oberhofer M, Tian Q, Ruppenthal S, Wegener S, Reil JC, Körbel C, Hammer K, Menger M, Neuberger HR, Kaestner L, Lipp P. Calcium dysregulation in ventricular myocytes from mice expressing constitutively active Rac1. Cell Calcium 2013; 54:26-36. [DOI: 10.1016/j.ceca.2013.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/20/2013] [Accepted: 03/30/2013] [Indexed: 10/26/2022]
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40
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Shaw RM, Colecraft HM. L-type calcium channel targeting and local signalling in cardiac myocytes. Cardiovasc Res 2013; 98:177-86. [PMID: 23417040 DOI: 10.1093/cvr/cvt021] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the heart, Ca(2+) influx via Ca(V)1.2 L-type calcium channels (LTCCs) is a multi-functional signal that triggers muscle contraction, controls action potential duration, and regulates gene expression. The use of LTCC Ca(2+) as a multi-dimensional signalling molecule in the heart is complicated by several aspects of cardiac physiology. Cytosolic Ca(2+) continuously cycles between ~100 nM and ~1 μM with each heartbeat due to Ca(2+) linked signalling from LTCCs to ryanodine receptors. This rapid cycling raises the question as to how cardiac myocytes distinguish the Ca(2+) fluxes originating through L-type channels that are dedicated to contraction from Ca(2+) fluxes originating from other L-type channels that are used for non-contraction-related signalling. In general, disparate Ca(2+) sources in cardiac myocytes such as current through differently localized LTCCs as well as from IP3 receptors can signal selectively to Ca(2+)-dependent effectors in local microdomains that can be impervious to the cytoplasmic Ca(2+) transients that drive contraction. A particular challenge for diversified signalling via cardiac LTCCs is that they are voltage-gated and, therefore, open and presumably flood their microdomains with Ca(2+) with each action potential. Thus spatial localization of Cav1.2 channels to different types of microdomains of the ventricular cardiomyocyte membrane as well as the existence of particular macromolecular complexes in each Cav1.2 microdomain are important to effect different types of Cav1.2 signalling. In this review we examine aspects of Cav1.2 structure, targeting and signalling in two specialized membrane microdomains--transverse tubules and caveolae.
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Affiliation(s)
- Robin M Shaw
- Cardiovascular Research Institute and Department of Medicine, University of California, San Francisco, CA 94143, USA
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Balse E, Steele DF, Abriel H, Coulombe A, Fedida D, Hatem SN. Dynamic of Ion Channel Expression at the Plasma Membrane of Cardiomyocytes. Physiol Rev 2012; 92:1317-58. [DOI: 10.1152/physrev.00041.2011] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiac myocytes are characterized by distinct structural and functional entities involved in the generation and transmission of the action potential and the excitation-contraction coupling process. Key to their function is the specific organization of ion channels and transporters to and within distinct membrane domains, which supports the anisotropic propagation of the depolarization wave. This review addresses the current knowledge on the molecular actors regulating the distinct trafficking and targeting mechanisms of ion channels in the highly polarized cardiac myocyte. In addition to ubiquitous mechanisms shared by other excitable cells, cardiac myocytes show unique specialization, illustrated by the molecular organization of myocyte-myocyte contacts, e.g., the intercalated disc and the gap junction. Many factors contribute to the specialization of the cardiac sarcolemma and the functional expression of cardiac ion channels, including various anchoring proteins, motors, small GTPases, membrane lipids, and cholesterol. The discovery of genetic defects in some of these actors, leading to complex cardiac disorders, emphasizes the importance of trafficking and targeting of ion channels to cardiac function. A major challenge in the field is to understand how these and other actors work together in intact myocytes to fine-tune ion channel expression and control cardiac excitability.
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Affiliation(s)
- Elise Balse
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David F. Steele
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Hugues Abriel
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Alain Coulombe
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David Fedida
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Stéphane N. Hatem
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
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Mesoscopic analysis of motion and conformation of cross-bridges. Biophys Rev 2012; 4:299-311. [PMID: 28510208 DOI: 10.1007/s12551-012-0074-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 03/15/2012] [Indexed: 01/03/2023] Open
Abstract
The orientation of a cross-bridge is widely used as a parameter in determining the state of muscle. The conventional measurements of orientation, such as that made by wide-field fluorescence microscopy, electron paramagnetic resonance (EPR) or X-ray diffraction or scattering, report the average orientation of 1012-109 myosin cross-bridges. Under conditions where all the cross-bridges are immobile and assume the same orientation, for example in normal skeletal muscle in rigor, it is possible to determine the average orientation from such global measurements. But in actively contracting muscle, where a parameter indicating orientation fluctuates in time, the measurements of the average value provide no information about cross-bridge kinetics. To avoid problems associated with averaging information from trillions of cross-bridges, it is necessary to decrease the number of observed cross-bridges to a mesoscopic value (i.e. the value affected by fluctuations around the average). In such mesoscopic regimes, the averaging of the signal is minimal and dynamic behavior can be examined in great detail. Examples of mesoscopic analysis on skeletal and cardiac muscle are provided.
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