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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.
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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.
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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).
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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.
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Ozawa M, Komatsu T, Sato Y, Kunugita F, Tachibana H, Tashiro A, Okabayashi H, Nakamura M. Comparison of the effects of bepridil and aprindine for the prevention of atrial fibrillation after cardiac and aortic surgery: A prospective randomized study. J Arrhythm 2015; 31:302-6. [PMID: 26550087 PMCID: PMC4600894 DOI: 10.1016/j.joa.2015.04.003] [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: 01/12/2015] [Revised: 04/01/2015] [Accepted: 04/05/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Approximately one-third of the patients undergoing cardiovascular surgery reportedly experience paroxysmal atrial fibrillation (AF) during the postoperative period. However, the usefulness of antiarrhythmic drugs for preventing postoperative AF recurrence in the Japanese population has not been extensively studied. METHODS From a total of 118 patients who developed postoperative paroxysmal AF between April 2009 and March 2011, 72 patients (45 men, mean age 68±8 years) requiring treatment for postoperative AF due to symptoms lasting ≥30 min were enrolled to prospectively investigate the efficacy of oral bepridil (100 mg/day, n=37) or aprindine (40 mg/day, n=35). RESULT The AF recurrence-free survival rates at 1, 3, 7, and 14 days were 100%, 94%, 57%, and 49%, respectively, in the aprindine group, and 100%, 97%, 86%, and 76%, respectively, in the bepridil group (P=0.028, aprindine vs. bepridil). CONCLUSION Bepridil, at a fixed dose of 100 mg/day, was considered to be more effective than a routine dose of aprindine for the prevention of postoperative AF recurrence.
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Affiliation(s)
- Mahito Ozawa
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Takashi Komatsu
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Yoshihiro Sato
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Fusanori Kunugita
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Hideaki Tachibana
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Atsushi Tashiro
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Hitoshi Okabayashi
- Department of Cardiovascular Surgery, Iwate Medical University School of Medicine, Morioka, Japan
| | - Motoyuki Nakamura
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
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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.
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Affiliation(s)
- Alistair Reed
- Medical Sciences Division, University of Oxford, United Kingdom
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Yang H, Li X, Ma J, Lv X, Zhao S, Lang W, Zhang Y. Blockade of the intermediate-conductance Ca(2+)-activated K+ channel inhibits the angiogenesis induced by epidermal growth factor in the treatment of corneal alkali burn. Exp Eye Res 2013; 110:76-87. [PMID: 23482085 DOI: 10.1016/j.exer.2013.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 02/17/2013] [Accepted: 02/21/2013] [Indexed: 12/29/2022]
Abstract
Epidermal growth factor (EGF) is used to treat alkali-burned corneas. However, EGF-induced corneal angiogenesis, which is currently untreatable, is a side effect of this therapy. We therefore explored the role of the intermediate-conductance Ca(2+)-activated K(+) channel (KCa3.1) in EGF-induced angiogenesis and tested whether KCa3.1 blockade can suppress EGF-induced corneal angiogenesis. The proliferation, migration and tube formation of HUVECs (human umbilical vein endothelial cells) in response to EGF, the MEK inhibitor PD98059 and the KCa3.1 inhibitor TRAM-34 were analyzed in vitro via MTT, cell counting, scratch and tube formation assays. The protein and mRNA levels of KCa3.1, phosphorylated-ERK (P-ERK), total-ERK (T-ERK), cyclin-dependent kinase 4 (CDK4), vimentin and MMP-2 were assessed via western blotting and RT-PCR. KCa3.1 and vimentin expression were also detected through immunofluorescence staining. Flow cytometry was performed to examine the cell cycle. Further, an in vivo murine alkali-burned cornea model was developed and treated with EGF and TRAM-34 eye drops to analyze the effect of these treatments on corneal healing and angiogenesis. The corneas were also analyzed by histological staining. The in vitro results showed that EGF induces the upregulation of KCa3.1 and P-ERK in HUVECs and that this upregulation is suppressed by PD98059. EGF stimulates proliferation, migration and tube formation in HUVECs, and this effect can be suppressed by TRAM-34. TRAM-34 also arrests HUVECs in the G1 phase of the cell cycle and downregulates CDK4, vimentin and MMP-2 in these cells. The in vivo results indicated that TRAM-34 suppresses EGF-induced corneal angiogenesis without affecting EGF-induced corneal wound healing. In summary, the upregulation of KCa3.1 may be crucial for EGF-induced angiogenesis through the MAPK/ERK signaling pathway. Thus, KCa3.1 may be a potential target for the treatment of EGF-induced corneal angiogenesis.
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Affiliation(s)
- Huike Yang
- Department of Anatomy, Harbin Medical University, Harbin 150081, China
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