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Shen S, Sewanan LR, Shao S, Halder SS, Stankey P, Li X, Campbell SG. Physiological calcium combined with electrical pacing accelerates maturation of human engineered heart tissue. Stem Cell Reports 2022; 17:2037-2049. [PMID: 35931080 PMCID: PMC9481907 DOI: 10.1016/j.stemcr.2022.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 12/24/2022] Open
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have wide potential application in basic research, drug discovery, and regenerative medicine, but functional maturation remains challenging. Here, we present a method whereby maturation of hiPSC-CMs can be accelerated by simultaneous application of physiological Ca2+ and frequency-ramped electrical pacing in culture. This combination produces positive force-frequency behavior, physiological twitch kinetics, robust β-adrenergic response, improved Ca2+ handling, and cardiac troponin I expression within 25 days. This study provides insights into the role of Ca2+ in hiPSC-CM maturation and offers a scalable platform for translational and clinical research.
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Affiliation(s)
- Shi Shen
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Lorenzo R Sewanan
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephanie Shao
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Saiti S Halder
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Paul Stankey
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xia Li
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA.
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2
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Kamkin AG, Kamkina OV, Shim AL, Bilichenko A, Mitrokhin VM, Kazansky VE, Filatova TS, Abramochkin D, Mladenov MI. The role of activation of two different sGC binding sites by NO-dependent and NO-independent mechanisms in the regulation of SACs in rat ventricular cardiomyocytes. Physiol Rep 2022; 10:e15246. [PMID: 35384354 PMCID: PMC8981922 DOI: 10.14814/phy2.15246] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 04/18/2023] Open
Abstract
The mechanoelectrical feedback (MEF) mechanism in the heart that plays a significant role in the occurrence of arrhythmias, involves cation flux through cation nonselective stretch-activated channels (SACs). It is well known that nitric oxide (NO) can act as a regulator of MEF. Here we addressed the possibility of SAC's regulation along NO-dependent and NO-independent pathways, as well as the possibility of S-nitrosylation of SACs. In freshly isolated rat ventricular cardiomyocytes, using the patch-clamp method in whole-cell configuration, inward nonselective stretch-activated cation current ISAC was recorded through SACs, which occurs during dosed cell stretching. NO donor SNAP, α1-subunit of sGC activator BAY41-2272, sGC blocker ODQ, PKG blocker KT5823, PKG activator 8Br-cGMP, and S-nitrosylation blocker ascorbic acid, were employed. We concluded that the physiological concentration of NO in the cell is a necessary condition for the functioning of SACs. An increase in NO due to SNAP in an unstretched cell causes the appearance of a Gd3+ -sensitive nonselective cation current, an analog of ISAC , while in a stretched cell it eliminates ISAC . The NO-independent pathway of sGC activation of α subunit, triggered by BAY41-2272, is also important for the regulation of SACs. Since S-nitrosylation inhibitor completely abolishes ISAC , this mechanism occurs. The application of BAY41-2272 cannot induce ISAC in a nonstretched cell; however, the addition of SNAP on its background activates SACs, rather due to S-nitrosylation. ODQ eliminates ISAC , but SNAP added on the background of stretch increases ISAC in addition to ODQ. This may be a result of the lack of NO as a result of inhibition of NOS by metabolically modified ODQ. KT5823 reduces PKG activity and reduces SACs phosphorylation, leading to an increase in ISAC . 8Br-cGMP reduces ISAC by activating PKG and its phosphorylation. These results demonstrate a significant contribution of S-nitrosylation to the regulation of SACs.
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Affiliation(s)
- Andre G. Kamkin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Olga V. Kamkina
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Andrey L. Shim
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Andrey Bilichenko
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Vadim M. Mitrokhin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Viktor E. Kazansky
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
| | - Tatiana S. Filatova
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Department of Human and Animal PhysiologyLomonosov Moscow State UniversityMoscowRussia
| | - Denis V. Abramochkin
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Department of Human and Animal PhysiologyLomonosov Moscow State UniversityMoscowRussia
| | - Mitko I. Mladenov
- Department of PhysiologyPirogov Russian National Research Medical UniversityMoscowRussia
- Faculty of Natural Sciences and MathematicsInstitute of Biology, “Ss. Cyril and Methodius” UniversitySkopjeMacedonia
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3
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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4
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Dowrick JM, Tran K, Loiselle DS, Nielsen PMF, Taberner AJ, Han J, Ward M. The slow force response to stretch: Controversy and contradictions. Acta Physiol (Oxf) 2019; 226:e13250. [PMID: 30614655 DOI: 10.1111/apha.13250] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/20/2018] [Accepted: 01/02/2019] [Indexed: 12/19/2022]
Abstract
When exposed to an abrupt stretch, cardiac muscle exhibits biphasic active force enhancement. The initial, instantaneous, force enhancement is well explained by the Frank-Starling mechanism. However, the cellular mechanisms associated with the second, slower phase remain contentious. This review explores hypotheses regarding this "slow force response" with the intention of clarifying some apparent contradictions in the literature. The review is partitioned into three sections. The first section considers pathways that modify the intracellular calcium handling to address the role of the sarcoplasmic reticulum in the mechanism underlying the slow force response. The second section focuses on extracellular calcium fluxes and explores the identity and contribution of the stretch-activated, non-specific, cation channels as well as signalling cascades associated with G-protein coupled receptors. The final section introduces promising candidates for the mechanosensor(s) responsible for detecting the stretch perturbation.
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Affiliation(s)
- Jarrah M. Dowrick
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Kenneth Tran
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Denis S. Loiselle
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Physiology University of Auckland Auckland New Zealand
| | - Poul M. F. Nielsen
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Engineering Science University of Auckland Auckland New Zealand
| | - Andrew J. Taberner
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
- Department of Engineering Science University of Auckland Auckland New Zealand
| | - June‐Chiew Han
- Auckland Bioengineering Institute University of Auckland Auckland New Zealand
| | - Marie‐Louise Ward
- Department of Physiology University of Auckland Auckland New Zealand
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5
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Quinn TA, Kohl P. Rabbit models of cardiac mechano-electric and mechano-mechanical coupling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:110-22. [PMID: 27208698 PMCID: PMC5067302 DOI: 10.1016/j.pbiomolbio.2016.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/01/2016] [Indexed: 12/11/2022]
Abstract
Cardiac auto-regulation involves integrated regulatory loops linking electrics and mechanics in the heart. Whereas mechanical activity is usually seen as 'the endpoint' of cardiac auto-regulation, it is important to appreciate that the heart would not function without feed-back from the mechanical environment to cardiac electrical (mechano-electric coupling, MEC) and mechanical (mechano-mechanical coupling, MMC) activity. MEC and MMC contribute to beat-by-beat adaption of cardiac output to physiological demand, and they are involved in various pathological settings, potentially aggravating cardiac dysfunction. Experimental and computational studies using rabbit as a model species have been integral to the development of our current understanding of MEC and MMC. In this paper we review this work, focusing on physiological and pathological implications for cardiac function.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada.
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany; National Heart and Lung Institute, Imperial College London, London, UK
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6
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Stams TR, Oosterhoff P, Heijdel A, Dunnink A, Beekman JD, van der Nagel R, van Rijen HV, van der Heyden MA, Vos MA. Beat-to-Beat Variability in Preload Unmasks Latent Risk of Torsade de Pointes in Anesthetized Chronic Atrioventricular Block Dogs. Circ J 2016; 80:1336-45. [PMID: 27151565 DOI: 10.1253/circj.cj-15-1335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Beat-to-beat variability in ventricular repolarization (BVR) associates with increased arrhythmic risk. Proarrhythmic remodeling in the dog with chronic AV-block (CAVB) compromises repolarization reserve and associates with increased BVR, which further increases upon dofetilide infusion and correlates with Torsade de Pointes (TdP) arrhythmias. It was hypothesized that these pro-arrhythmia-associated increases in BVR are induced by beat-to-beat variability in preload. METHODS AND RESULTS Left ventricular monophasic action potential duration (LVMAPD) was recorded in acute (AAVB) and CAVB dogs, before and after dofetilide infusion. BVR was quantified as short-term variability of LVMAPD. The PQ-interval was controlled by pacing: either a constant or an alternating preload pattern was established, verified by PV-loop. The effect of the stretch-activated channel blocker, streptomycin, on BVR was evaluated in a second CAVB group. At alternating preload only, BVR was increased after proarrhythmic remodeling (0.45±0.14 ms AAVB vs. 2.2±1.1 ms CAVB, P<0.01). At CAVB, but not at AAVB, dofetilide induced significant proarrhythmia. Preload variability augmented the dofetilide-induced BVR increase at CAVB (+1.5±0.8 ms vs. +0.9±0.9 ms, P=0.058). In the second group, the increase in baseline BVR by alternating preload (0.3±0.03 ms to 1.0±0.8 ms, P<0.01) was abolished by streptomycin (0.5±0.2 ms, P<0.05). CONCLUSIONS In CAVB dogs, the inverse relation between BVR and repolarization reserve originates from an augmented sensitivity of ventricular repolarization to beat-to-beat preload changes. Stretch-activated channels appear to be involved in the mechanism of BVR. (Circ J 2016; 80: 1336-1345).
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Affiliation(s)
- Thom Rg Stams
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center
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Aguettaz E, Lopez JJ, Krzesiak A, Lipskaia L, Adnot S, Hajjar RJ, Cognard C, Constantin B, Sebille S. Axial stretch-dependent cation entry in dystrophic cardiomyopathy: Involvement of several TRPs channels. Cell Calcium 2016; 59:145-155. [PMID: 26803937 DOI: 10.1016/j.ceca.2016.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/14/2015] [Accepted: 01/02/2016] [Indexed: 02/07/2023]
Abstract
In Duchenne muscular dystrophy (DMD), deficiency of the cytoskeletal protein dystrophin leads to well-described defects in skeletal muscle but also to dilated cardiomyopathy (DCM). In cardiac cells, the subsarcolemmal localization of dystrophin is thought to protect the membrane from mechanical stress. The dystrophin deficiency leads to membrane instability and a high stress-induced Ca(2+) influx due to dysregulation of sarcolemmal channels such as stretch-activated channels (SACs). In this work divalent cation entry has been explored in isolated ventricular Wild Type (WT) and mdx cardiomyocytes in two different conditions: at rest and during the application of an axial stretch. At rest, our results suggest that activation of TRPV2 channels participates to a constitutive basal cation entry in mdx cardiomyocytes.Using microcarbon fibres technique, an axial stretchwas applied to mimic effects of physiological conditions of ventricular filling and study on cation influx bythe Mn(2+)-quenching techniquedemonstrated a high stretch-dependentcationic influx in dystrophic cells, partially due to SACs. Involvement of TRPs channels in this excessive Ca(2+) influx has been investigated using specific modulators and demonstratedboth sarcolemmal localization and an abnormal activity of TRPV2 channels. In conclusion, TRPV2 channels are demonstrated here to play a key role in cation influx and dysregulation in dystrophin deficient cardiomyocytes, enhanced in stretching conditions.
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Affiliation(s)
- E Aguettaz
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - J J Lopez
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Calcium et Microenvironnement des Cellules Souches (CMCS), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - A Krzesiak
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - L Lipskaia
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, AP-HP, Université Paris-Est Créteil (UPEC), 94010 Créteil, France.,Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - S Adnot
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, AP-HP, Université Paris-Est Créteil (UPEC), 94010 Créteil, France
| | - R J Hajjar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - C Cognard
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - B Constantin
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Calcium et Microenvironnement des Cellules Souches (CMCS), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - S Sebille
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
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8
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Khodabukus A, Baar K. Streptomycin Decreases the Functional Shift to a Slow Phenotype Induced by Electrical Stimulation in Engineered Muscle. Tissue Eng Part A 2015; 21:1003-12. [DOI: 10.1089/ten.tea.2014.0462] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Alastair Khodabukus
- Division of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
| | - Keith Baar
- Division of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
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9
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Arrhythmogenic effects by local left ventricular stretch: effects of flecainide and streptomycin. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:763-75. [DOI: 10.1007/s00210-014-0988-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/29/2014] [Indexed: 12/20/2022]
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10
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Li N, Jia N, Dai DZ, Hu C, Dai Y. Role of endothelin in the effects of isoprenaline on potassium currents and calsequestrin 2 expression in the heart. Clin Exp Pharmacol Physiol 2010. [DOI: 10.1111/j.1440-1681.2010.05349.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Iribe G, Ward CW, Camelliti P, Bollensdorff C, Mason F, Burton RAB, Garny A, Morphew MK, Hoenger A, Lederer WJ, Kohl P. Axial stretch of rat single ventricular cardiomyocytes causes an acute and transient increase in Ca2+ spark rate. Circ Res 2009; 104:787-95. [PMID: 19197074 PMCID: PMC3522525 DOI: 10.1161/circresaha.108.193334] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigate acute effects of axial stretch, applied by carbon fibers (CFs), on diastolic Ca2+ spark rate in rat isolated cardiomyocytes. CFs were attached either to both cell ends (to maximize the stretched region), or to the center and one end of the cell (to compare responses in stretched and nonstretched half-cells). Sarcomere length was increased by 8.01+/-0.94% in the stretched cell fraction, and time series of XY confocal images were recorded to monitor diastolic Ca2+ spark frequency and dynamics. Whole-cell stretch causes an acute increase of Ca2+ spark rate (to 130.7+/-6.4%) within 5 seconds, followed by a return to near background levels (to 104.4+/-5.1%) within 1 minute of sustained distension. Spark rate increased only in the stretched cell region, without significant differences in spark amplitude, time to peak, and decay time constants of sparks in stretched and nonstretched areas. Block of stretch-activated ion channels (2 micromol/L GsMTx-4), perfusion with Na+/Ca2+-free solution, and block of nitric oxide synthesis (1 mmol/L L-NAME) all had no effect on the stretch-induced acute increase in Ca2+ spark rate. Conversely, interference with cytoskeletal integrity (2 hours of 10 micromol/L colchicine) abolished the response. Subsequent electron microscopic tomography confirmed the close approximation of microtubules with the T-tubular-sarcoplasmic reticulum complex (to within approximately 10(-8)m). In conclusion, axial stretch of rat cardiomyocytes acutely and transiently increases sarcoplasmic reticulum Ca2+ spark rate via a mechanism that is independent of sarcolemmal stretch-activated ion channels, nitric oxide synthesis, or availability of extracellular calcium but that requires cytoskeletal integrity. The potential of microtubule-mediated modulation of ryanodine receptor function warrants further investigation.
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Affiliation(s)
- Gentaro Iribe
- University of Oxford, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
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12
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Dyachenko V, Husse B, Rueckschloss U, Isenberg G. Mechanical deformation of ventricular myocytes modulates both TRPC6 and Kir2.3 channels. Cell Calcium 2008; 45:38-54. [PMID: 18635261 DOI: 10.1016/j.ceca.2008.06.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 05/30/2008] [Accepted: 06/03/2008] [Indexed: 10/21/2022]
Abstract
Cardiomyocytes respond to mechanical stretch with an increase [Ca2+]i. Here, we analyzed which ion channels could mediate this effect. Murine ventricular myocytes were attached to a glass coverslip and a cell-attached glass stylus sheared the upper cell part versus the attached cell bottom. At negative clamp potentials, stretch induced inward currents that increased with the extent of stretch and reversed within 2 min after relaxation from stretch. Stretch activated a nearly voltage-independent GsMTx-4-sensitive non-selective cation conductance Gns, antibodies against TRPC6 prevented Gns activation. In addition, stretch deactivated a Cs+-sensitive inwardly rectifying potassium conductance GK1, antibodies against Kir2.3 inhibited this effect. Immunolabeling localized TRPC6 and Kir2.3 in T-tubular membranes, and stretch-induced changes in membrane currents were absent in cells whose T-tubules had been removed. In absence of stretch, we could activate Gns and deactivate GK1 by 1-oleoyl-2-acetyl-sn-glycerol (OAG) and other amphipaths. We interpret that the function of TRPC6 and Kir2.3 channels is controlled by both tension and curvature of the surrounding lipid bilayer that are changed by incorporation of amphipaths. Stretch-activation of TRPC6 channels may increase Ca2+ influx directly and indirectly, by membrane depolarization (activation of voltage-gated Ca2+ channels) and by elevated [Na+]i (augmented Na+,Ca2+-exchange).
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Affiliation(s)
- V Dyachenko
- Department of Physiology, Martin-Luther-University Halle, 06097 Halle, Germany
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13
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Stretch-activated channels in the heart: Contributions to length-dependence and to cardiomyopathy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 97:232-49. [DOI: 10.1016/j.pbiomolbio.2008.02.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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Ninio DM, Saint DA. The role of stretch-activated channels in atrial fibrillation and the impact of intracellular acidosis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 97:401-16. [PMID: 18367236 DOI: 10.1016/j.pbiomolbio.2008.02.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The incidence of atrial fibrillation correlates with increasing atrial size. The electrical consequences of atrial stretch contribute to both the initiation and maintenance of atrial fibrillation. It is suggested that altered calcium handling and stretch-activated channel activity could explain the experimental findings of stretch-induced depolarisation, shortened refractoriness, slowed conduction and increased heterogeneity of refractoriness and conduction. Stretch-activated channel blocking agents protect against these pro-arrhythmic effects. Gadolinium, GsMTx-4 toxin and streptomycin prevent the stretch-related vulnerability to atrial fibrillation without altering the drop in refractory period associated with stretch. Changes the activity of two-pore K+ channels, which are sensitive to stretch and pH but not gadolinium, could underlie the drop in refractoriness. Intracellular acidosis induced with propionate amplified the change in refractoriness with stretch in the isolated rabbit heart model in keeping with the clinical observation of increased propensity to atrial fibrillation with acidosis. We propose that activation of non-specific cation stretch-activated channels provides the triggers for acute atrial fibrillation with high atrial pressure while activation of atrial two-pore K+ channels shortens atrial refractory period and increases heterogeneity of refractoriness, providing the substrate for atrial fibrillation to be sustained. Stretch-activated channel blockade represents an exciting target for future antiarrhythmic drugs.
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Affiliation(s)
- Daniel M Ninio
- Discipline of Physiology, School of Molecular & Biomedical Science, University of Adelaide, SA 5005, Australia
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15
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Li N, Yang L, Dai DZ, Wang QJ, Dai Y. Chiral separation of racemate CPU86017, an anti-arrhythmic agent, produces stereoisomers possessing favourable ion channel blockade and less alpha-adrenoceptor antagonism. Clin Exp Pharmacol Physiol 2007; 35:643-50. [PMID: 18177475 DOI: 10.1111/j.1440-1681.2007.04854.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. CPU86017 is an effective anti-arrhythmic agent of the Class III complex that has two chiral centres, 7N and 13aC. As a promising anti-arrhythmic agent, the blockade on I(Kr), I(Ks) and calcium influx may be modulated to be mild, moderate and potent, with less a-adrenoceptor blockade. In order to improve activity at ion channels, four stereoisomers, namely SS ((+)-7S,13aS-CPU86017), SR ((-)-7S,13aR-CPU86017), RR ((-)-7R,13aR-CPU86017) and RS ((+)-7R,13aS-CPU86017), have been separated. In the present study, the effects of these four isomers on I(Kr) and I(Ks), calcium channels and a-adrenoceptors were compared with the effects of the racemate CPU86017. 2. In the present study, I(Kr) and I(Ks) were measured as tail currents (I(Kr.tail) and I(Ks.tail), respectively) using the whole-cell patch-clamp technique. Antagonism of receptor-operated calcium channels and voltage-dependent calcium channels (VDC) in vascular smooth muscle by CPU86017 and the four isomers were tested as suppression of phenylephrine- or KCl-induced contractions of aortic rings, respectively. 3. For I(Kr.tail) inhibition, the IC(50) of SS, SR, RR, RS and CPU86017 was 2.86 +/- 1.20, 39.4 +/- 8.5, 3.48 +/- 0.80, 7.65 +/- 1.50 and 12.5 +/- 7.8 x 10(-9) mol/L, respectively; for I(Ks.tail) inhibition IC(50) values were 16.9 +/- 4.0, 20.0 +/- 2.1, 99.1 +/- 5.9, 160 +/- 81 and 65.0 +/- 4.7 x 10(-9) mol/L, respectively. The SR isomer showed balanced blockade of I(Kr) and I(Ks) that was associated with a loss of a-adrenoceptor antagonism but enhanced VDC blockade. 4. Configuration of 13aC critically determines I(Kr) blockade and the Ca(2+) antagonism of the isomers of CPU86017. The SR isomer exhibits mild blockade of I(Kr), moderately enhanced blockade of I(Ks) and Ca(2+) influx and less a-adrenoceptor antagonism compared with the racemate and may be promising as an anti-arrhythmic.
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Affiliation(s)
- Na Li
- Research Division of Pharmacology, China Pharmaceutical University, Nanjing, China
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Martínez-Salgado C, López-Hernández FJ, López-Novoa JM. Glomerular nephrotoxicity of aminoglycosides. Toxicol Appl Pharmacol 2007; 223:86-98. [PMID: 17602717 DOI: 10.1016/j.taap.2007.05.004] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/17/2007] [Accepted: 05/10/2007] [Indexed: 11/23/2022]
Abstract
Aminoglycoside antibiotics are the most commonly used antibiotics worldwide in the treatment of Gram-negative bacterial infections. However, aminoglycosides induce nephrotoxicity in 10-20% of therapeutic courses. Aminoglycoside-induced nephrotoxicity is characterized by slow rises in serum creatinine, tubular necrosis and marked decreases in glomerular filtration rate and in the ultrafiltration coefficient. Regulation of the ultrafiltration coefficient depends on the activity of intraglomerular mesangial cells. The mechanisms responsible for tubular nephrotoxicity of aminoglycosides have been intensively reviewed previously, but glomerular toxicity has received less attention. The purpose of this review is to critically assess the published literature regarding the toxic mechanisms of action of aminoglycosides on renal glomeruli and mesangial cells. The main goal of this review is to provide an actualized and mechanistic vision of pathways involved in glomerular toxic effects of aminoglycosides.
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Affiliation(s)
- Carlos Martínez-Salgado
- Unidad de Investigación, Hospital Universitario de Salamanca, Paseo San Vicente 58-182, 37007 Salamanca, Spain.
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Kohl P, Bollensdorff C, Garny A. Effects of mechanosensitive ion channels on ventricular electrophysiology: experimental and theoretical models. Exp Physiol 2006; 91:307-21. [PMID: 16407474 DOI: 10.1113/expphysiol.2005.031062] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The heart is an electrically driven mechanical pump, somewhat like an electric motor. Interestingly, like an electric motor in 'dynamo mode', the heart can also convert mechanical stimuli into electrical signals. This feedback from cardiac mechanics to electrical activity involves mechanosensitive ion channels, whose properties and pathophysiological relevance are reviewed in the context of experimental and theoretical modelling of ventricular beat-by-beat electromechanical function.
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Affiliation(s)
- Peter Kohl
- The Cardiac Mechano-Electric Feedback Group, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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Cooper PJ, Kohl P. Species- and preparation-dependence of stretch effects on sino-atrial node pacemaking. Ann N Y Acad Sci 2005; 1047:324-35. [PMID: 16093508 DOI: 10.1196/annals.1341.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Acute dilation of the right atrium (e.g., via increased venous return) raises spontaneous beating rate (BR) of the heart in many species. Neural mechanisms contribute to this behavior in vivo, but a positive chronotropic response to stretch can also be observed in isolated right atrial tissue preparations and even at the level of single sino-atrial node (SAN) cells. The underlying mechanism has previously been reported to be compatible with stretch-activation of cation nonselective ion channels (SAC). This review reports species peculiarities in the chronotropic response of isolated SAN tissue strips to stretch: in contrast to guinea pig, murine SAN preparations respond to distension with a reduction in spontaneous BR. This differential response need not necessarily involve disparate (sub-)cellular mechanisms, as SAC activation would occur against the background of very different SAN electrophysiology in the two species. On the basis of single SAN cell action potential recordings, this review illustrates how this may give rise to potentially opposing effects on spontaneous BR. Interestingly, streptomycin (a useful SAC blocker in isolated cells) has no effect on stretch-induced chronotropy in situ, and this is interpreted as an indication of protection of SAC, in native tissue, from interaction with the drug.
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Kong CR, Bursac N, Tung L. Mechanoelectrical excitation by fluid jets in monolayers of cultured cardiac myocytes. J Appl Physiol (1985) 2005; 98:2328-36; discussion 2320. [PMID: 15731396 DOI: 10.1152/japplphysiol.01084.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the prevailing view of mechanoelectric feedback (MEF) in the heart is in terms of longitudinal cell stretch, other mechanical forces are considerable during the cardiac cycle, including intramyocardial pressure and shear stress. Their contribution to MEF is largely unknown. In this study, mechanical stimuli in the form of localized fluid jet pulses were applied to neonatal rat ventricular cells cultured as confluent monolayers. Such pulses result in pressure and shear stresses (but not longitudinal stretch) in the monolayer at the point of impingement. The goal was to determine whether these mechanical stimuli can trigger excitation, initiate a propagated wave, and induce reentry. Cells were stained with the voltage-sensitive dye RH237, and multi-site optical mapping was used to record the spread of electrical activity in isotropic and anisotropic monolayers. Pulses (10 ms) with velocities ranging from 0.3 to 1.8 m/s were applied from a 0.4-mm diameter nozzle located 1 mm above the cell monolayer. Fluid jet pulses resulted in circular wavefronts that propagated radially from the stimulus site. The likelihood for mechanical stimulation was quantified as an average stimulus success rate (ASSR). ASSR increased with jet amplitude and time waited between stimuli and decreased with the application of gadolinium and streptomycin, blockers of stretch-activated channels, but not with nifedipine, a blocker of the L-type Ca channel. Absence of cellular injury was confirmed by smooth propagation maps and propidium iodide stains. In rare instances, the mechanical pulse resulted in the induction of reentrant activity. We conclude that mechanical stimuli other than stretch can evoke action potentials, propagated activity, and reentrant arrhythmia in two-dimensional sheets of cardiac cells.
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Affiliation(s)
- Chae-Ryon Kong
- Dept. of Biomedical Engineering, The Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD 21205, USA
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Calaghan SC, Belus A, White E. Do stretch-induced changes in intracellular calcium modify the electrical activity of cardiac muscle? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2003; 82:81-95. [PMID: 12732270 DOI: 10.1016/s0079-6107(03)00007-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stretch of the myocardium influences the shape and amplitude of the intracellular Ca(2+)([Ca(2+)](i)) transient. Under isometric conditions stretch immediately increases myofilament Ca(2+) sensitivity, increasing force production and abbreviating the time course of the [Ca(2+)](i) transient (the rapid response). Conversely, muscle shortening can prolong the Ca(2+) transient by decreasing myofilament Ca(2+) sensitivity. During the cardiac cycle, increased ventricular dilation may increase myofilament Ca(2+) sensitivity during diastolic filling and the isovolumic phase of systole, but enhance the decrease in myofilament Ca(2+) sensitivity during the systolic shortening of the ejection phase. If stretch is maintained there is a gradual increase in the amplitude of the Ca(2+) transient and force production, which takes several minutes to develop fully (the slow response). The rapid and slow responses have been reported in whole hearts and single myocytes. Here we review stretch-induced changes in [Ca(2+)](i) and the underlying mechanisms. Myocardial stretch also modifies electrical activity and the opening of stretch-activated channels (SACs) is often used to explain this effect. However, the myocardium has many ionic currents that are regulated by [Ca(2+)](i) and in this review we discuss how stretch-induced changes in [Ca(2+)](i) can influence electrical activity via the modulation of these Ca(2+)-dependent currents. Our recent work in single ventricular myocytes has shown that axial stretch prolongs the action potential. This effect is sensitive to either SAC blockade by streptomycin or the buffering of [Ca(2+)](i) with BAPTA, suggesting that both SACs and [Ca(2+)](i) are important for the full effects of axial stretch on electrical activity to develop.
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Affiliation(s)
- S C Calaghan
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK
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