1
|
Yamaguchi Y, Nishiyama M, Kai H, Kaneko T, Kaihara K, Iribe G, Takai A, Naruse K, Morimatsu M. High hydrostatic pressure induces slow contraction in mouse cardiomyocytes. Biophys J 2022; 121:3286-3294. [PMID: 35841143 PMCID: PMC9463647 DOI: 10.1016/j.bpj.2022.07.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/26/2022] [Accepted: 07/11/2022] [Indexed: 11/28/2022] Open
Abstract
Cardiomyocytes are contractile cells that regulate heart contraction. Ca2+ flux via Ca2+ channels activates actomyosin interactions, leading to cardiomyocyte contraction, which is modulated by physical factors (e.g., stretch, shear stress, and hydrostatic pressure). We evaluated the mechanism triggering slow contractions using a high-pressure microscope to characterize changes in cell morphology and intracellular Ca2+ concentration ([Ca2+]i) in mouse cardiomyocytes exposed to high hydrostatic pressures. We found that cardiomyocytes contracted slowly without an acute transient increase in [Ca2+]i, while a myosin ATPase inhibitor interrupted pressure-induced slow contractions. Furthermore, transmission electron microscopy showed that, although the sarcomere length was shortened upon the application of 20 MPa, this pressure did not collapse cellular structures such as the sarcolemma and sarcomeres. Our results suggest that pressure-induced slow contractions in cardiomyocytes are driven by the activation of actomyosin interactions without an acute transient increase in [Ca2+]i.
Collapse
Affiliation(s)
- Yohei Yamaguchi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan; Department of Physiology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan.
| | - Masayoshi Nishiyama
- Department of Physics, Faculty of Science and Engineering, Kindai University, Higashiosaka, Osaka, Japan
| | - Hiroaki Kai
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Toshiyuki Kaneko
- Department of Physiology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Keiko Kaihara
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Gentaro Iribe
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan; Department of Physiology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Akira Takai
- Department of Physiology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Masatoshi Morimatsu
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
| |
Collapse
|
2
|
Jakob D, Klesen A, Allegrini B, Darkow E, Aria D, Emig R, Chica AS, Rog-Zielinska EA, Guth T, Beyersdorf F, Kari FA, Proksch S, Hatem SN, Karck M, Künzel SR, Guizouarn H, Schmidt C, Kohl P, Ravens U, Peyronnet R. Piezo1 and BK Ca channels in human atrial fibroblasts: Interplay and remodelling in atrial fibrillation. J Mol Cell Cardiol 2021; 158:49-62. [PMID: 33974928 DOI: 10.1016/j.yjmcc.2021.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 04/18/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
AIMS Atrial Fibrillation (AF) is an arrhythmia of increasing prevalence in the aging populations of developed countries. One of the important indicators of AF is sustained atrial dilatation, highlighting the importance of mechanical overload in the pathophysiology of AF. The mechanisms by which atrial cells, including fibroblasts, sense and react to changing mechanical forces, are not fully elucidated. Here, we characterise stretch-activated ion channels (SAC) in human atrial fibroblasts and changes in SAC- presence and activity associated with AF. METHODS AND RESULTS Using primary cultures of human atrial fibroblasts, isolated from patients in sinus rhythm or sustained AF, we combine electrophysiological, molecular and pharmacological tools to identify SAC. Two electrophysiological SAC- signatures were detected, indicative of cation-nonselective and potassium-selective channels. Using siRNA-mediated knockdown, we identified the cation-nonselective SAC as Piezo1. Biophysical properties of the potassium-selective channel, its sensitivity to calcium, paxilline or iberiotoxin (blockers), and NS11021 (activator), indicated presence of calcium-dependent 'big potassium channels' (BKCa). In cells from AF patients, Piezo1 activity and mRNA expression levels were higher than in cells from sinus rhythm patients, while BKCa activity (but not expression) was downregulated. Both Piezo1-knockdown and removal of extracellular calcium from the patch pipette resulted in a significant reduction of BKCa current during stretch. No co-immunoprecipitation of Piezo1 and BKCa was detected. CONCLUSIONS Human atrial fibroblasts contain at least two types of ion channels that are activated during stretch: Piezo1 and BKCa. While Piezo1 is directly stretch-activated, the increase in BKCa activity during mechanical stimulation appears to be mainly secondary to calcium influx via SAC such as Piezo1. During sustained AF, Piezo1 is increased, while BKCa activity is reduced, highlighting differential regulation of both channels. Our data support the presence and interplay of Piezo1 and BKCa in human atrial fibroblasts in the absence of physical links between the two channel proteins.
Collapse
Affiliation(s)
- Dorothee Jakob
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Alexander Klesen
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Benoit Allegrini
- CNRS University Cote d'Azur laboratory Institut Biology Valrose, Nice, France
| | - Elisa Darkow
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Diana Aria
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany; G.E.R.N. Tissue Replacement, Regeneration & Neogenesis, Department of Operative Dentistry and Periodontology, Medical Center - University of Freiburg, Germany
| | - Ramona Emig
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, Faculty of Biology, University of Freiburg, Germany
| | - Ana Simon Chica
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Tim Guth
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Friedhelm Beyersdorf
- Faculty of Medicine, University of Freiburg, Germany; Department of Cardiovascular Surgery, University Heart Center Freiburg Bad Krozingen, Medical Center - University of Freiburg, Germany
| | - Fabian A Kari
- Faculty of Medicine, University of Freiburg, Germany; Department of Cardiovascular Surgery, University Heart Center Freiburg Bad Krozingen, Medical Center - University of Freiburg, Germany
| | - Susanne Proksch
- Faculty of Medicine, University of Freiburg, Germany; G.E.R.N. Tissue Replacement, Regeneration & Neogenesis, Department of Operative Dentistry and Periodontology, Medical Center - University of Freiburg, Germany
| | - Stéphane N Hatem
- Sorbonne University, Assistance Publique-Hôpitaux de Paris, GH Pitié-Salpêtrière Hospital, INSERM UMR_S1166, Cardiology department, Institute of Cardiometabolism and Nutrition-ICAN, Paris, France
| | - Matthias Karck
- Department of Cardiac Surgery, University of Heidelberg, Germany
| | - Stephan R Künzel
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Hélène Guizouarn
- CNRS University Cote d'Azur laboratory Institut Biology Valrose, Nice, France
| | - Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research) partner site Heidelberg/Mannheim, University of Heidelberg, Germany
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, Faculty of Biology, University of Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Bad Krozingen, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany.
| |
Collapse
|
3
|
Stewart L, Turner NA. Channelling the Force to Reprogram the Matrix: Mechanosensitive Ion Channels in Cardiac Fibroblasts. Cells 2021; 10:990. [PMID: 33922466 PMCID: PMC8145896 DOI: 10.3390/cells10050990] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/13/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac fibroblasts (CF) play a pivotal role in preserving myocardial function and integrity of the heart tissue after injury, but also contribute to future susceptibility to heart failure. CF sense changes to the cardiac environment through chemical and mechanical cues that trigger changes in cellular function. In recent years, mechanosensitive ion channels have been implicated as key modulators of a range of CF functions that are important to fibrotic cardiac remodelling, including cell proliferation, myofibroblast differentiation, extracellular matrix turnover and paracrine signalling. To date, seven mechanosensitive ion channels are known to be functional in CF: the cation non-selective channels TRPC6, TRPM7, TRPV1, TRPV4 and Piezo1, and the potassium-selective channels TREK-1 and KATP. This review will outline current knowledge of these mechanosensitive ion channels in CF, discuss evidence of the mechanosensitivity of each channel, and detail the role that each channel plays in cardiac remodelling. By better understanding the role of mechanosensitive ion channels in CF, it is hoped that therapies may be developed for reducing pathological cardiac remodelling.
Collapse
Affiliation(s)
| | - Neil A. Turner
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds LS2 9JT, UK;
| |
Collapse
|
4
|
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: 61] [Impact Index Per Article: 15.3] [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.
Collapse
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
| |
Collapse
|
5
|
Kaur S, Shen X, Power A, Ward ML. Stretch modulation of cardiac contractility: importance of myocyte calcium during the slow force response. Biophys Rev 2020; 12:135-142. [PMID: 31939110 DOI: 10.1007/s12551-020-00615-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanical response of the heart to myocardial stretch has been understood since the work of muscle physiologists more than 100 years ago, whereby an increase in ventricular chamber filling during diastole increases the subsequent force of contraction. The stretch-induced increase in contraction is biphasic. There is an abrupt increase in the force that coincides with the stretch (the rapid response), which is then followed by a slower response that develops over several minutes (the slow force response, or SFR). The SFR is associated with a progressive increase in the magnitude of the Ca2+ transient, the event that initiates myocyte cross-bridge cycling and force development. However, the mechanisms underlying the stretch-dependent increase in the Ca2+ transient are still debated. This review outlines recent literature on the SFR and summarizes the different stretch-activated Ca2+ entry pathways. The SFR might result from a combination of several different cellular mechanisms initiated in response to activation of different cellular stretch sensors.
Collapse
Affiliation(s)
- Sarbjot Kaur
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G.Jebsen Center for Cardiac Research, Oslo, Norway
| | - Amelia Power
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| |
Collapse
|
6
|
Del Canto I, Santamaría L, Genovés P, Such-Miquel L, Arias-Mutis O, Zarzoso M, Soler C, Parra G, Tormos Á, Alberola A, Such L, Chorro FJ. Effects of the Inhibition of Late Sodium Current by GS967 on Stretch-Induced Changes in Cardiac Electrophysiology. Cardiovasc Drugs Ther 2019; 32:413-425. [PMID: 30173392 DOI: 10.1007/s10557-018-6822-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE Mechanical stretch increases sodium and calcium entry into myocytes and activates the late sodium current. GS967, a triazolopyridine derivative, is a sodium channel blocker with preferential effects on the late sodium current. The present study evaluates whether GS967 inhibits or modulates the arrhythmogenic electrophysiological effects of myocardial stretch. METHODS Atrial and ventricular refractoriness and ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts (n = 28) using epicardial multiple electrodes and high-resolution mapping techniques under control conditions and during the perfusion of GS967 at different concentrations (0.03, 0.1, and 0.3 μM). RESULTS On comparing ventricular refractoriness, conduction velocity and wavelength obtained before stretch had no significant changes under each GS967 concentration while atrial refractoriness increased under GS967 0.3 μM. Under GS967, the stretch-induced changes were attenuated, and no significant differences were observed between before and during stretch. GS967 0.3 μM diminished the normal stretch-induced changes resulting in longer (less shortened) atrial refractoriness (138 ± 26 ms vs 95 ± 9 ms; p < 0.01), ventricular refractoriness (155 ± 18 ms vs 124 ± 16 ms; p < 0.01) and increments in spectral concentration (23 ± 5% vs 17 ± 2%; p < 0.01), the fifth percentile of ventricular activation intervals (46 ± 8 ms vs 31 ± 3 ms; p < 0.05), and wavelength of ventricular fibrillation (2.5 ±0.5 cm vs 1.7 ± 0.3 cm; p < 0.05) during stretch. The stretch-induced increments in dominant frequency during ventricular fibrillation (control = 38%, 0.03 μM = 33%, 0.1 μM = 33%, 0.3 μM = 14%; p < 0.01) and the stretch-induced increments in arrhythmia complexity index (control = 62%, 0.03μM = 41%, 0.1 μM = 32%, 0.3 μM = 16%; p < 0.05) progressively decreased on increasing the GS967 concentration. CONCLUSIONS GS967 attenuates stretch-induced changes in cardiac electrophysiology.
Collapse
Affiliation(s)
- Irene Del Canto
- CIBER CV. Carlos III Health Institute, Madrid, Spain.,Department of Electronics, Universitat Politècnica de València, Valencia, Spain
| | - Laura Santamaría
- Department of Physiology, Valencia University - Estudi General, Valencia, Spain
| | | | - Luis Such-Miquel
- CIBER CV. Carlos III Health Institute, Madrid, Spain.,Department of Physiotherapy, Valencia University - Estudi General, Valencia, Spain
| | | | - Manuel Zarzoso
- Department of Physiotherapy, Valencia University - Estudi General, Valencia, Spain
| | - Carlos Soler
- Department of Physiology, Valencia University - Estudi General, Valencia, Spain
| | - Germán Parra
- Department of Physiology, Valencia University - Estudi General, Valencia, Spain
| | - Álvaro Tormos
- CIBER CV. Carlos III Health Institute, Madrid, Spain.,Department of Electronics, Universitat Politècnica de València, Valencia, Spain
| | - Antonio Alberola
- CIBER CV. Carlos III Health Institute, Madrid, Spain.,Department of Physiology, Valencia University - Estudi General, Valencia, Spain
| | - Luis Such
- CIBER CV. Carlos III Health Institute, Madrid, Spain.,Department of Physiology, Valencia University - Estudi General, Valencia, Spain
| | - Francisco J Chorro
- CIBER CV. Carlos III Health Institute, Madrid, Spain. .,Service of Cardiology, Valencia University Clinic Hospital, INCLIVA, Valencia, Spain. .,Department of Medicine, Valencia University - Estudi General, Valencia, Spain. .,Servicio de Cardiología, Hospital Clínico Universitario, Avda. Blasco Ibañez 17, 46010, Valencia, Spain.
| |
Collapse
|
7
|
Schmidt C, Peyronnet R. Voltage-gated and stretch-activated potassium channels in the human heart : Pathophysiological and clinical significance. Herzschrittmacherther Elektrophysiol 2018; 29:36-42. [PMID: 29305705 DOI: 10.1007/s00399-017-0541-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/14/2017] [Indexed: 12/14/2022]
Abstract
Ion channels are essential for electrical signaling and contractility in cardiomyocytes. Detailed knowledge about the molecular function and regulation of cardiac ion channels is crucial for understanding cardiac physiology and pathophysiology especially in the field of arrhythmias. This review aims at providing a general overview on the identity, functional characteristics, and roles of voltage-gated as well as stretch-activated potassium selective channels in the heart. In particular, we will highlight potential therapeutic targets as well as the emerging fields of future investigations.
Collapse
Affiliation(s)
- Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center, Medical Center - University of Freiburg, and Faculty of Medicine, University of Freiburg, Elsässer Straße 2q, 79110, Freiburg, Germany.
| |
Collapse
|
8
|
Decher N, Kiper AK, Rinné S. Stretch-activated potassium currents in the heart: Focus on TREK-1 and arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:223-232. [PMID: 28526352 DOI: 10.1016/j.pbiomolbio.2017.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 12/26/2022]
Abstract
This review focuses on the role and the molecular candidates of the cardiac stretch-activated potassium current (SAK). The functional properties of the two-pore domain potassium (K2P) channel TREK-1, a major candidate for the cardiac SAK, are analyzed and the molecular mechanism of stretch-activation in K2P potassium channels is discussed. Furthermore, the functional modulation of TREK-1 by different cardiac interaction partners, as well as evidence for the functional role of the stretch-dependent TREK-1 and its putative subunits in the heart is reviewed. In addition, we summarize the recent evidence that TREK-1 is involved in the pathogenesis of human cardiac arrhythmias.
Collapse
Affiliation(s)
- Niels Decher
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany.
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, AG Vegetative Physiology, Deutschhausstrasse 1-2, 35037 Marburg, Germany
| |
Collapse
|
9
|
Jin H, Iribe G, Naruse K. Effects of bepridil on stretch-activated BKca channels and stretch-induced extrasystoles in isolated chick hearts. Physiol Res 2017; 66:459-465. [PMID: 28248537 DOI: 10.33549/physiolres.933315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Various types of mechanosensitive ion channels, including cationic stretch-activated channels (SAC(NS)) and stretch-activated BKca (SAKca) channels, modulate heart rhythm. Bepridil has been used as an antiarrhythmic drug with multiple pharmacological effects; however, whether it is effective for mechanically induced arrhythmia has not been well investigated. To test the effects of Bepridil on SAKca channels activity, cultured chick embryonic ventricular myocytes were used for single-channel recordings. Bepridil significantly reduced the open probability of the SAKca channel (P(O)). Next, to test the effects of bepridil on stretch-induced extrasystoles (SIE), we used an isolated 2-week-old Langendorff-perfused chick heart. The left ventricle (LV) volume was rapidly changed, and the probability of SIE was calculated in the presence and absence of bepridil, and the effect of the drug was compared with that of Gadolinium (Gd(3+)). Bepridil decreased the probability of SIE despite its suppressive effects on SAKca channel activity. The effects of Gd(3+), which blocks both SAKca and SAC(NS), on the probability of SIE were the same as those of bepridil. Our results suggest that bepridil blocks not only SAKca channels but possible also blocks SAC(NS), and thus decreases the stretch-induced cation influx (stabilizing membrane potential) to compensate and override the effects of the decrease in outward SAKca current (destabilizing membrane potential).
Collapse
Affiliation(s)
- H Jin
- Department of Pharmacy, The Affiliated Hospital of YanBian University, YanJi City, JiLin Province, China. ; Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Kita-ku, Okayama, Japan.
| | | | | |
Collapse
|
10
|
Abstract
Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret, and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, is exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intracardially and are, thus, maintained even in heart transplant recipients. Although mechanosensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechanotransduction have started to emerge. Mechano-gated ion channels are cardiac mechanoreceptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them.
Collapse
Affiliation(s)
- Rémi Peyronnet
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Jeanne M Nerbonne
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.)
| | - Peter Kohl
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (R.P., P.K.); Departments of Developmental Biology and Internal Medicine, Center for Cardiovascular Research, Washington University School of Medicine, St. Louis, MO (J.M.N.); Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Freiburg, Germany (R.P., P.K.).
| |
Collapse
|
11
|
Latrunculin B modulates electrophysiological characteristics and arrhythmogenesis in pulmonary vein cardiomyocytes. Clin Sci (Lond) 2016; 130:721-32. [PMID: 26839418 DOI: 10.1042/cs20150593] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 02/02/2016] [Indexed: 01/28/2023]
Abstract
AF (atrial fibrillation) is the most common sustained arrhythmia, and the PVs (pulmonary veins) play a critical role in triggering AF. Stretch causes structural remodelling, including cytoskeleton rearrangement, which may play a role in the genesis of AF. Lat-B (latrunculin B), an inhibitor of actin polymerization, is involved in Ca(2+) regulation. However, it is unclear whether Lat-B directly modulates the electrophysiological characteristics and Ca(2+) homoeostasis of the PVs. Conventional microelectrodes, whole-cell patch-clamp, and the fluo-3 fluorimetric ratio technique were used to record ionic currents and intracellular Ca(2+) within isolated rabbit PV preparations, or within isolated single PV cardiomyocytes, before and after administration of Lat-B (100 nM). Langendorff-perfused rabbit hearts were exposed to acute and continuous atrial stretch, and we studied PV electrical activity. Lat-B (100 nM) decreased the spontaneous electrical activity by 16±4% in PV preparations. Lat-B (100 nM) decreased the late Na(+) current, L-type Ca(2+) current, Na(+)/Ca(2+) exchanger current, and stretch-activated BKCa current, but did not affect the Na(+) current in PV cardiomyocytes. Lat-B reduced the transient outward K(+) current and ultra-rapid delayed rectifier K(+) current, but increased the delayed rectifier K(+) current in isolated PV cardiomyocytes. In addition, Lat-B (100 nM) decreased intracellular Ca(2+) transient and sarcoplasmic reticulum Ca(2+) content in PV cardiomyocytes. Moreover, Lat-B attenuated stretch-induced increased spontaneous electrical activity and trigger activity. The effects of Lat-B on the PV spontaneous electrical activity were attenuated in the presence of Y-27632 [10 μM, a ROCK (Rho-associated kinase) inhibitor] and cytochalasin D (10 μM, an actin polymerization inhibitor). In conclusion, Lat-B regulates PV electrophysiological characteristics and attenuates stretch-induced arrhythmogenesis.
Collapse
|
12
|
Seo K, Inagaki M, Hidaka I, Fukano H, Sugimachi M, Hisada T, Nishimura S, Sugiura S. Relevance of cardiomyocyte mechano-electric coupling to stretch-induced arrhythmias: optical voltage/calcium measurement in mechanically stimulated cells, tissues and organs. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:129-39. [PMID: 25084395 DOI: 10.1016/j.pbiomolbio.2014.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/19/2014] [Indexed: 12/27/2022]
Abstract
Stretch-induced arrhythmias are multi-scale phenomena in which alterations in channel activities and/or calcium handling lead to the organ level derangement of the heart rhythm. To understand how cellular mechano-electric coupling (MEC) leads to stretch-induced arrhythmias at the organ level, we developed stretching devices and optical voltage/calcium measurement techniques optimized to each cardiac level. This review introduces these experimental techniques of (1) optical voltage measurement coupled with a carbon-fiber technique for single isolated cardiomyocytes, (2) optical voltage mapping combined with motion tracking technique for myocardial tissue/whole heart preparations and (3) real-time calcium imaging coupled with a laser optical trap technique for cardiomyocytes. Following the overview of each methodology, results are presented. We conclude that individual MEC in cardiomyocytes can be heterogeneous at the ventricular level, especially when moderate amplitude mechanical stretches are applied to the heart, and that this heterogeneous MEC can evoke focal excitation that develops into re-entrant arrhythmias.
Collapse
Affiliation(s)
- Kinya Seo
- Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
| | - Masashi Inagaki
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center Research Institute, Osaka 565-0873, Japan.
| | - Ichiro Hidaka
- Division of Physical and Health Education, Graduate School of Education, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Hana Fukano
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan.
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center Research Institute, Osaka 565-0873, Japan.
| | - Toshiaki Hisada
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan.
| | - Satoshi Nishimura
- Research Division of Cell and Molecular Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan; Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, The University of Tokyo, Tokyo 113-8655, Japan.
| | - Seiryo Sugiura
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan.
| |
Collapse
|
13
|
Reed A, Kohl P, Peyronnet R. Molecular candidates for cardiac stretch-activated ion channels. Glob Cardiol Sci Pract 2014; 2014:9-25. [PMID: 25405172 PMCID: PMC4220428 DOI: 10.5339/gcsp.2014.19] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 06/08/2014] [Indexed: 01/20/2023] Open
Abstract
The heart is a mechanically-active organ that dynamically senses its own mechanical environment. This environment is constantly changing, on a beat-by-beat basis, with additional modulation by respiratory activity and changes in posture or physical activity, and further overlaid with more slowly occurring physiological (e.g. pregnancy, endurance training) or pathological challenges (e.g. pressure or volume overload). Far from being a simple pump, the heart detects changes in mechanical demand and adjusts its performance accordingly, both via heart rate and stroke volume alteration. Many of the underlying regulatory processes are encoded intracardially, and are thus maintained even in heart transplant recipients. Over the last three decades, molecular substrates of cardiac mechanosensitivity have gained increasing recognition in the scientific and clinical communities. Nonetheless, the processes underlying this phenomenon are still poorly understood. Stretch-activated ion channels (SAC) have been identified as one contributor to mechanosensitive autoregulation of the heartbeat. They also appear to play important roles in the development of cardiac pathologies – most notably stretch-induced arrhythmias. As recently discovered, some established cardiac drugs act, in part at least, via mechanotransduction pathways suggesting SAC as potential therapeutic targets. Clearly, identification of the molecular substrate of cardiac SAC is of clinical importance and a number of candidate proteins have been identified. At the same time, experimental studies have revealed variable–and at times contrasting–results regarding their function. Further complication arises from the fact that many ion channels that are not classically defined as SAC, including voltage and ligand-gated ion channels, can respond to mechanical stimulation. Here, we summarise what is known about the molecular substrate of the main candidates for cardiac SAC, before identifying potential further developments in this area of translational research.
Collapse
Affiliation(s)
- Alistair Reed
- Medical Sciences Division, University of Oxford, United Kingdom
| | | | | |
Collapse
|
14
|
Takahashi K, Naruse K. Stretch-activated BK channel and heart function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 110:239-44. [PMID: 23281538 DOI: 10.1016/j.pbiomolbio.2012.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The heart is an organ that is exposed to extreme dynamic mechanical stimuli. From birth till death, the heart indefinitely repeats periodic contraction and dilation, i.e., shortening and elongation of cardiomyocytes. Mechanical stretch elicits a change in heart rate and may cause arrhythmia if it is excessive. Thus, mechanosensitivity is crucial to heart function. The molecule that is substantially involved in mechanosensitivity is a stretch-activated ion channel. Among several ion channels believed to be activated by stretch in the heart, the stretch-activated KCa (SAKCA) channel, a member of the group of large conductance (Big Potassium, BK) channels, shows a mechanosensitive (MS) response to membrane stretch. As BK channels respond to voltage and intracellular calcium concentration with large conductance, they are considered to be involved in repolarization after depolarization. Some BK channels are known to be activated by stretch and are expressed in a number of cells, including human osteoblasts and guinea pig intestinal neurons. The SAKCA channel was found to be sensitive to stretch in the chick heart. Given that the cardiomyocyte is unremittingly exposed to contraction and dilation and that it generates action potential and its contractility is modulated by intracellular calcium concentration, the SAKCA channel, which is dependent voltage and calcium, may be involved in action potential generation. It was recently reported that a BK channel is involved in the modulation of heart rate in the mouse. Further studies regarding the role of MS BK channels, including SAKCA, in the modulation of heart rate and contractility are expected.
Collapse
Affiliation(s)
- Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
| | | |
Collapse
|
15
|
Abstract
Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation.
Collapse
Affiliation(s)
- Nitin T Aggarwal
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI 53792, USA
| | | |
Collapse
|
16
|
Iribe G, Jin H, Naruse K. Role of sarcolemmal BK(Ca) channels in stretch-induced extrasystoles in isolated chick hearts. Circ J 2011; 75:2552-8. [PMID: 21914957 DOI: 10.1253/circj.cj-11-0486] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND It remains unclear whether sarcolemmal BK(Ca) channels in post-hatch chick ventricular myocytes contribute to stretch-induced extrasystoles (SIE), and whether they are stretch-activated BK(Ca) (SAK(Ca)) channels or a non-stretch-sensitive BK(Ca) variant. METHODS AND RESULTS To determine the role of sarcolemmal BK(Ca) channels in SIE and their stretch sensitivity, an isolated 2-week-old Langendorff-perfused chick heart and mathematical simulation were used. The ventricular wall was rapidly stretched by application of a volume change pulse. As the speed of the stretch increased, the probability of SIE also significantly increased, significantly shortening the delay between SIE and the initiation of the stretch. Application of 100 nmol/L of Grammostola spatulata mechanotoxin 4, a cation-selective stretch-activated channel (SAC) blocker, significantly decreased the probability of SIE. The application of Iberiotoxin, however, a BK(Ca) channel blocker, significantly increased the probability of SIE, suggesting that a K(+) efflux via a sarcolemmal BK(Ca) channel reduces SIE by balancing out stretch-induced cation influx via SACs. The simulation using a cardiomyocyte model combined with a new stretch sensitivity model that considers viscoelastic intracellular force transmission showed that stretch sensitivity in BK(Ca) channels is required to reproduce the present wet experimental results. CONCLUSIONS Sarcolemmal BK(Ca) channels in post-hatch chick ventricular myocytes are SAK(Ca) channels, and they have a suppressive effect on SIE.
Collapse
Affiliation(s)
- Gentaro Iribe
- Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | | | | |
Collapse
|