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Veron G, Maltsev VA, Stern MD, Maltsev AV. Elementary intracellular Ca signals approximated as a transition of release channel system from a metastable state. JOURNAL OF APPLIED PHYSICS 2023; 134:124701. [PMID: 37744735 PMCID: PMC10517864 DOI: 10.1063/5.0151255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Cardiac muscle contraction is initiated by an elementary Ca signal (called Ca spark) which is achieved by collective action of Ca release channels in a cluster. The mechanism of this synchronization remains uncertain. We approached Ca spark activation as an emergent phenomenon of an interactive system of release channels. We constructed a weakly lumped Markov chain that applies an Ising model formalism to such release channel clusters and probable open channel configurations and demonstrated that spark activation is described as a system transition from a metastable to an absorbing state, analogous to the pressure required to overcome surface tension in bubble formation. This yielded quantitative estimates of the spark generation probability as a function of various system parameters. We performed numerical simulations to find spark probabilities as a function of sarcoplasmic reticulum Ca concentration, obtaining similar values for spark activation threshold as our analytic model, as well as those reported in experimental studies. Our parametric sensitivity analyses also showed that the spark activation threshold decreased as Ca sensitivity of RyR activation and RyR cluster size increased.
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Affiliation(s)
- Guillermo Veron
- Cellular Biophysics Section, Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Victor A. Maltsev
- Cellular Biophysics Section, Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Michael D. Stern
- Cellular Biophysics Section, Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA
| | - Anna V. Maltsev
- School of Mathematical Sciences, Queen Mary University of London, London E14NS, United Kingdom
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2
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Grandi E, Navedo MF, Saucerman JJ, Bers DM, Chiamvimonvat N, Dixon RE, Dobrev D, Gomez AM, Harraz OF, Hegyi B, Jones DK, Krogh-Madsen T, Murfee WL, Nystoriak MA, Posnack NG, Ripplinger CM, Veeraraghavan R, Weinberg S. Diversity of cells and signals in the cardiovascular system. J Physiol 2023; 601:2547-2592. [PMID: 36744541 PMCID: PMC10313794 DOI: 10.1113/jp284011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/19/2023] [Indexed: 02/07/2023] Open
Abstract
This white paper is the outcome of the seventh UC Davis Cardiovascular Research Symposium on Systems Approach to Understanding Cardiovascular Disease and Arrhythmia. This biannual meeting aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The theme of the 2022 Symposium was 'Cell Diversity in the Cardiovascular System, cell-autonomous and cell-cell signalling'. Experts in the field contributed their experimental and mathematical modelling perspectives and discussed emerging questions, controversies, and challenges in examining cell and signal diversity, co-ordination and interrelationships involved in cardiovascular function. This paper originates from the topics of formal presentations and informal discussions from the Symposium, which aimed to develop a holistic view of how the multiple cell types in the cardiovascular system integrate to influence cardiovascular function, disease progression and therapeutic strategies. The first section describes the major cell types (e.g. cardiomyocytes, vascular smooth muscle and endothelial cells, fibroblasts, neurons, immune cells, etc.) and the signals involved in cardiovascular function. The second section emphasizes the complexity at the subcellular, cellular and system levels in the context of cardiovascular development, ageing and disease. Finally, the third section surveys the technological innovations that allow the interrogation of this diversity and advancing our understanding of the integrated cardiovascular function and dysfunction.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Jeffrey J. Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Department of Internal Medicine, University of California Davis, Davis, CA, USA
| | - Rose E. Dixon
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montréal, Canada
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Ana M. Gomez
- Signaling and Cardiovascular Pathophysiology-UMR-S 1180, INSERM, Université Paris-Saclay, Orsay, France
| | - Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, and Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, VT, USA
| | - Bence Hegyi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - David K. Jones
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Trine Krogh-Madsen
- Department of Physiology & Biophysics, Weill Cornell Medicine, New York, New York, USA
| | - Walter Lee Murfee
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Matthew A. Nystoriak
- Department of Medicine, Division of Environmental Medicine, Center for Cardiometabolic Science, University of Louisville, Louisville, KY, 40202, USA
| | - Nikki G. Posnack
- Department of Pediatrics, Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric and Surgical Innovation, Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
| | | | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University – Wexner Medical Center, Columbus, OH, USA
| | - Seth Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
- Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University – Wexner Medical Center, Columbus, OH, USA
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Zaveri S, Srivastava U, Qu YS, Chahine M, Boutjdir M. Pathophysiology of Ca v1.3 L-type calcium channels in the heart. Front Physiol 2023; 14:1144069. [PMID: 37025382 PMCID: PMC10070707 DOI: 10.3389/fphys.2023.1144069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/07/2023] [Indexed: 04/08/2023] Open
Abstract
Ca2+ plays a crucial role in excitation-contraction coupling in cardiac myocytes. Dysfunctional Ca2+ regulation alters the force of contraction and causes cardiac arrhythmias. Ca2+ entry into cardiomyocytes is mediated mainly through L-type Ca2+ channels, leading to the subsequent Ca2+ release from the sarcoplasmic reticulum. L-type Ca2+ channels are composed of the conventional Cav1.2, ubiquitously expressed in all heart chambers, and the developmentally regulated Cav1.3, exclusively expressed in the atria, sinoatrial node, and atrioventricular node in the adult heart. As such, Cav1.3 is implicated in the pathogenesis of sinoatrial and atrioventricular node dysfunction as well as atrial fibrillation. More recently, Cav1.3 de novo expression was suggested in heart failure. Here, we review the functional role, expression levels, and regulation of Cav1.3 in the heart, including in the context of cardiac diseases. We believe that the elucidation of the functional and molecular pathways regulating Cav1.3 in the heart will assist in developing novel targeted therapeutic interventions for the aforementioned arrhythmias.
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Affiliation(s)
- Sahil Zaveri
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, New York, NY, United States
| | - Ujala Srivastava
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
| | - Yongxia Sarah Qu
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, New York, NY, United States
- Department of Cardiology, New York Presbyterian Brooklyn Methodist Hospital, New York, NY, United States
| | - Mohamed Chahine
- CERVO Brain Research Center, Institut Universitaire en Santé Mentale de Québec, Québec, QC, Canada
- Department of Medicine, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, New York, NY, United States
- Division of Cardiology, Department of Medicine, NYU Grossman School of Medicine, New York, NY, United States
- *Correspondence: Mohamed Boutjdir,
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Fan W, Sun X, Yang C, Wan J, Luo H, Liao B. Pacemaker activity and ion channels in the sinoatrial node cells: MicroRNAs and arrhythmia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:151-167. [PMID: 36450332 DOI: 10.1016/j.pbiomolbio.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/13/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022]
Abstract
The primary pacemaking activity of the heart is determined by a spontaneous action potential (AP) within sinoatrial node (SAN) cells. This unique AP generation relies on two mechanisms: membrane clocks and calcium clocks. Nonhomologous arrhythmias are caused by several functional and structural changes in the myocardium. MicroRNAs (miRNAs) are essential regulators of gene expression in cardiomyocytes. These miRNAs play a vital role in regulating the stability of cardiac conduction and in the remodeling process that leads to arrhythmias. Although it remains unclear how miRNAs regulate the expression and function of ion channels in the heart, these regulatory mechanisms may support the development of emerging therapies. This study discusses the spread and generation of AP in the SAN as well as the regulation of miRNAs and individual ion channels. Arrhythmogenicity studies on ion channels will provide a research basis for miRNA modulation as a new therapeutic target.
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Affiliation(s)
- Wei Fan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Xuemei Sun
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Chao Yang
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Juyi Wan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Hongli Luo
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Bin Liao
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
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Ren L, Thai PN, Gopireddy RR, Timofeyev V, Ledford HA, Woltz RL, Park S, Puglisi JL, Moreno CM, Santana LF, Conti AC, Kotlikoff MI, Xiang YK, Yarov-Yarovoy V, Zaccolo M, Zhang XD, Yamoah EN, Navedo MF, Chiamvimonvat N. Adenylyl cyclase isoform 1 contributes to sinoatrial node automaticity via functional microdomains. JCI Insight 2022; 7:e162602. [PMID: 36509290 PMCID: PMC9746826 DOI: 10.1172/jci.insight.162602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/05/2022] [Indexed: 11/22/2022] Open
Abstract
Sinoatrial node (SAN) cells are the heart's primary pacemaker. Their activity is tightly regulated by β-adrenergic receptor (β-AR) signaling. Adenylyl cyclase (AC) is a key enzyme in the β-AR pathway that catalyzes the production of cAMP. There are current gaps in our knowledge regarding the dominant AC isoforms and the specific roles of Ca2+-activated ACs in the SAN. The current study tests the hypothesis that distinct AC isoforms are preferentially expressed in the SAN and compartmentalize within microdomains to orchestrate heart rate regulation during β-AR signaling. In contrast to atrial and ventricular myocytes, SAN cells express a diverse repertoire of ACs, with ACI as the predominant Ca2+-activated isoform. Although ACI-KO (ACI-/-) mice exhibit normal cardiac systolic or diastolic function, they experience SAN dysfunction. Similarly, SAN-specific CRISPR/Cas9-mediated gene silencing of ACI results in sinus node dysfunction. Mechanistically, hyperpolarization-activated cyclic nucleotide-gated 4 (HCN4) channels form functional microdomains almost exclusively with ACI, while ryanodine receptor and L-type Ca2+ channels likely compartmentalize with ACI and other AC isoforms. In contrast, there were no significant differences in T-type Ca2+ and Na+ currents at baseline or after β-AR stimulation between WT and ACI-/- SAN cells. Due to its central characteristic feature as a Ca2+-activated isoform, ACI plays a unique role in sustaining the rise of local cAMP and heart rates during β-AR stimulation. The findings provide insights into the critical roles of the Ca2+-activated isoform of AC in sustaining SAN automaticity that is distinct from contractile cardiomyocytes.
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Affiliation(s)
- Lu Ren
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, USA
| | - Phung N. Thai
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
- Department of Veteran Affairs, Northern California Health Care System, Sacramento, California, USA
| | | | - Valeriy Timofeyev
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
| | - Hannah A. Ledford
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
| | - Ryan L. Woltz
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
- Department of Veteran Affairs, Northern California Health Care System, Sacramento, California, USA
| | - Seojin Park
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, Nevada, USA
- Prestige Biopharma Korea, Myongjigukje 7-ro, Gangseo-gu, Busan, South Korea
| | - Jose L. Puglisi
- College of Medicine. California North State University, Sacramento, California, USA
| | - Claudia M. Moreno
- Department of Physiology and Membrane Biology, UCD, Davis, California, USA
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington, USA
| | | | - Alana C. Conti
- Research & Development Service, John D. Dingell VA Medical Center, and
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA
| | | | - Yang Kevin Xiang
- Department of Veteran Affairs, Northern California Health Care System, Sacramento, California, USA
- Department of Pharmacology, UCD, Davis, California, USA
| | | | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, United Kingdom
| | - Xiao-Dong Zhang
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
- Department of Veteran Affairs, Northern California Health Care System, Sacramento, California, USA
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, Nevada, USA
| | | | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Division of Cardiovascular Medicine, UCD, Davis, California, USA
- Department of Veteran Affairs, Northern California Health Care System, Sacramento, California, USA
- Department of Pharmacology, UCD, Davis, California, USA
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Frequency-Dependent Properties of the Hyperpolarization-Activated Cation Current, I f, in Adult Mouse Heart Primary Pacemaker Myocytes. Int J Mol Sci 2022; 23:ijms23084299. [PMID: 35457119 PMCID: PMC9024942 DOI: 10.3390/ijms23084299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
A number of distinct electrophysiological mechanisms that modulate the myogenic spontaneous pacemaker activity in the sinoatrial node (SAN) of the mammalian heart have been investigated extensively. There is agreement that several (3 or 4) different transmembrane ionic current changes (referred to as the voltage clock) are involved; and that the resulting net current interacts with direct and indirect effects of changes in intracellular Ca2+ (the calcium clock). However, significant uncertainties, and important knowledge gaps, remain concerning the functional roles in SAN spontaneous pacing of many of the individual ion channel- or exchanger-mediated transmembrane current changes. We report results from patch clamp studies and mathematical modeling of the hyperpolarization-activated current, If, in the generation/modulation of the diastolic depolarization, or pacemaker potential, produced by individual myocytes that were enzymatically isolated from the adult mouse sinoatrial node (SAN). Amphotericin-mediated patch microelectrode recordings at 35 °C were made under control conditions and in the presence of 5 or 10 nM isoproterenol (ISO). These sets of results were complemented and integrated with mathematical modeling of the current changes that take place in the range of membrane potentials (−70 to −50 mV), which corresponds to the ‘pacemaker depolarization’ in the adult mouse SAN. Our results reveal a very small, but functionally important, approximately steady-state or time-independent current generated by residual activation of If channels that are expressed in these pacemaker myocytes. Recordings of the pacemaker depolarization and action potential, combined with measurements of changes in If, and the well-known increases in the L-type Ca2+ current, ICaL, demonstrated that ICaL activation, is essential for myogenic pacing. Moreover, after being enhanced (approximately 3-fold) by 5 or 10 nM ISO, ICaL contributes significantly to the positive chronotropic effect. Our mathematical model has been developed in an attempt to better understand the underlying mechanisms for the pacemaker depolarization and action potential in adult mouse SAN myocytes. After being updated with our new experimental data describing If, our simulations reveal a novel functional component of If in adult mouse SAN. Computational work carried out with this model also confirms that in the presence of ISO the residual activation of If and opening of ICaL channels combine to generate a net current change during the slow diastolic depolarization phase that is essential for the observed accelerated pacemaking rate of these SAN myocytes.
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Reddy GR, Ren L, Thai PN, Caldwell JL, Zaccolo M, Bossuyt J, Ripplinger CM, Xiang YK, Nieves-Cintrón M, Chiamvimonvat N, Navedo MF. Deciphering cellular signals in adult mouse sinoatrial node cells. iScience 2022; 25:103693. [PMID: 35036877 PMCID: PMC8749457 DOI: 10.1016/j.isci.2021.103693] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/30/2021] [Accepted: 12/22/2021] [Indexed: 01/27/2023] Open
Abstract
Sinoatrial node (SAN) cells are the pacemakers of the heart. This study describes a method for culturing and infection of adult mouse SAN cells with FRET-based biosensors that can be exploited to examine signaling events. SAN cells cultured in media with blebbistatin or (S)-nitro-blebbistatin retain their morphology, protein distribution, action potential (AP) waveform, and cAMP dynamics for at least 40 h. SAN cells expressing targeted cAMP sensors show distinct β-adrenergic-mediated cAMP pools. Cyclic GMP, protein kinase A, Ca2+/CaM kinase II, and protein kinase D in SAN cells also show unique dynamics to different stimuli. Heart failure SAN cells show a decrease in cAMP and cGMP levels. In summary, a reliable method for maintaining adult mouse SAN cells in culture is presented, which facilitates studies of signaling networks and regulatory mechanisms during physiological and pathological conditions.
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Affiliation(s)
- Gopireddy R. Reddy
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
| | - Lu Ren
- Department of Internal Medicine, University of California Davis, 451 Health Science Drive, GBSF 6315, Davis, CA 95616, USA
| | - Phung N. Thai
- Department of Internal Medicine, University of California Davis, 451 Health Science Drive, GBSF 6315, Davis, CA 95616, USA
| | - Jessica L. Caldwell
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Julie Bossuyt
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
| | - Crystal M. Ripplinger
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
| | - Yang K. Xiang
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
- VA Northern California Healthcare System, 10535 Hospital Way, Mather, CA 95655, USA
| | - Madeline Nieves-Cintrón
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, University of California Davis, 451 Health Science Drive, GBSF 6315, Davis, CA 95616, USA
- VA Northern California Healthcare System, 10535 Hospital Way, Mather, CA 95655, USA
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, One Shields Avenue MED: PHARM Tupper 242, Davis, CA 95616, USA
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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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9
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Mesirca P, Nakao S, Nissen SD, Forte G, Anderson C, Trussell T, Li J, Cox C, Zi M, Logantha S, Yaar S, Cartensen H, Bidaud I, Stuart L, Soattin L, Morris GM, da Costa Martins PA, Cartwright EJ, Oceandy D, Mangoni ME, Jespersen T, Buhl R, Dobrzynski H, Boyett MR, D'Souza A. Intrinsic Electrical Remodeling Underlies Atrioventricular Block in Athletes. Circ Res 2021; 129:e1-e20. [PMID: 33849278 DOI: 10.1161/circresaha.119.316386] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [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
[Figure: see text].
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Affiliation(s)
- Pietro Mesirca
- IGF, Université de Montpellier, CNRS, INSERM, France (P.M., I.B., M.E.M.)
| | - Shu Nakao
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
- Department of Biomedical Sciences, Ritsumeikan University, Japan (S.N.)
| | - Sarah Dalgas Nissen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences (S.D.N., H.C., R.B.), University of Copenhagen, Denmark
| | - Gabriella Forte
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Cali Anderson
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Tariq Trussell
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Jue Li
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Charlotte Cox
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Min Zi
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Sunil Logantha
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
- Liverpool Centre for Cardiovascular Sciences, University of Liverpool, United Kingdom (S.L.)
| | - Sana Yaar
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Helena Cartensen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences (S.D.N., H.C., R.B.), University of Copenhagen, Denmark
| | - Isabelle Bidaud
- IGF, Université de Montpellier, CNRS, INSERM, France (P.M., I.B., M.E.M.)
| | - Luke Stuart
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | | | - Gwilym M Morris
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | | | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Delvac Oceandy
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
| | - Matteo E Mangoni
- IGF, Université de Montpellier, CNRS, INSERM, France (P.M., I.B., M.E.M.)
| | - Thomas Jespersen
- Department of Biomedical Sciences (T.J., M.R.B.), University of Copenhagen, Denmark
| | - Rikke Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences (S.D.N., H.C., R.B.), University of Copenhagen, Denmark
| | - Halina Dobrzynski
- Department of Anatomy, Jagiellonian University Medical College, Poland (H.D.)
| | - Mark R Boyett
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
- Department of Biomedical Sciences (T.J., M.R.B.), University of Copenhagen, Denmark
| | - Alicia D'Souza
- Division of Cardiovascular Sciences, University of Manchester, United Kingdom (S.N., G.F., C.A., T.T., J.L., C.C., M.Z., S.L., S.Y., L. Stuart, L. Soattin, G.M.M., E.J.C., D.O., H.D., M.R.B., A.D.)
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10
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Physiological Roles of the Rapidly Activated Delayed Rectifier K + Current in Adult Mouse Heart Primary Pacemaker Activity. Int J Mol Sci 2021; 22:ijms22094761. [PMID: 33946248 PMCID: PMC8124469 DOI: 10.3390/ijms22094761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 01/01/2023] Open
Abstract
Robust, spontaneous pacemaker activity originating in the sinoatrial node (SAN) of the heart is essential for cardiovascular function. Anatomical, electrophysiological, and molecular methods as well as mathematical modeling approaches have quite thoroughly characterized the transmembrane fluxes of Na+, K+ and Ca2+ that produce SAN action potentials (AP) and ‘pacemaker depolarizations’ in a number of different in vitro adult mammalian heart preparations. Possible ionic mechanisms that are responsible for SAN primary pacemaker activity are described in terms of: (i) a Ca2+-regulated mechanism based on a requirement for phasic release of Ca2+ from intracellular stores and activation of an inward current-mediated by Na+/Ca2+ exchange; (ii) time- and voltage-dependent activation of Na+ or Ca2+ currents, as well as a cyclic nucleotide-activated current, If; and/or (iii) a combination of (i) and (ii). Electrophysiological studies of single spontaneously active SAN myocytes in both adult mouse and rabbit hearts consistently reveal significant expression of a rapidly activating time- and voltage-dependent K+ current, often denoted IKr, that is selectively expressed in the leading or primary pacemaker region of the adult mouse SAN. The main goal of the present study was to examine by combined experimental and simulation approaches the functional or physiological roles of this K+ current in the pacemaker activity. Our patch clamp data of mouse SAN myocytes on the effects of a pharmacological blocker, E4031, revealed that a rapidly activating K+ current is essential for action potential (AP) repolarization, and its deactivation during the pacemaker potential contributes a small but significant component to the pacemaker depolarization. Mathematical simulations using a murine SAN AP model confirm that well known biophysical properties of a delayed rectifier K+ current can contribute to its role in generating spontaneous myogenic activity.
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11
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Wallace MJ, El Refaey M, Mesirca P, Hund TJ, Mangoni ME, Mohler PJ. Genetic Complexity of Sinoatrial Node Dysfunction. Front Genet 2021; 12:654925. [PMID: 33868385 PMCID: PMC8047474 DOI: 10.3389/fgene.2021.654925] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/01/2021] [Indexed: 12/13/2022] Open
Abstract
The pacemaker cells of the cardiac sinoatrial node (SAN) are essential for normal cardiac automaticity. Dysfunction in cardiac pacemaking results in human sinoatrial node dysfunction (SND). SND more generally occurs in the elderly population and is associated with impaired pacemaker function causing abnormal heart rhythm. Individuals with SND have a variety of symptoms including sinus bradycardia, sinus arrest, SAN block, bradycardia/tachycardia syndrome, and syncope. Importantly, individuals with SND report chronotropic incompetence in response to stress and/or exercise. SND may be genetic or secondary to systemic or cardiovascular conditions. Current management of patients with SND is limited to the relief of arrhythmia symptoms and pacemaker implantation if indicated. Lack of effective therapeutic measures that target the underlying causes of SND renders management of these patients challenging due to its progressive nature and has highlighted a critical need to improve our understanding of its underlying mechanistic basis of SND. This review focuses on current information on the genetics underlying SND, followed by future implications of this knowledge in the management of individuals with SND.
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Affiliation(s)
- Michael J. Wallace
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Mona El Refaey
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Pietro Mesirca
- CNRS, INSERM, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France
- Laboratory of Excellence ICST, Montpellier, France
| | - Thomas J. Hund
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - Matteo E. Mangoni
- CNRS, INSERM, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, France
- Laboratory of Excellence ICST, Montpellier, France
| | - Peter J. Mohler
- Frick Center for Heart Failure and Arrhythmia Research, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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12
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Mesirca P, Fedorov VV, Hund TJ, Torrente AG, Bidaud I, Mohler PJ, Mangoni ME. Pharmacologic Approach to Sinoatrial Node Dysfunction. Annu Rev Pharmacol Toxicol 2020; 61:757-778. [PMID: 33017571 DOI: 10.1146/annurev-pharmtox-031120-115815] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The spontaneous activity of the sinoatrial node initiates the heartbeat. Sino-atrial node dysfunction (SND) and sick sinoatrial (sick sinus) syndrome are caused by the heart's inability to generate a normal sinoatrial node action potential. In clinical practice, SND is generally considered an age-related pathology, secondary to degenerative fibrosis of the heart pacemaker tissue. However, other forms of SND exist, including idiopathic primary SND, which is genetic, and forms that are secondary to cardiovascular or systemic disease. The incidence of SND in the general population is expected to increase over the next half century, boosting the need to implant electronic pacemakers. During the last two decades, our knowledge of sino-atrial node physiology and of the pathophysiological mechanisms underlying SND has advanced considerably. This review summarizes the current knowledge about SND mechanisms and discusses the possibility of introducing new pharmacologic therapies for treating SND.
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Affiliation(s)
- Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Vadim V Fedorov
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Thomas J Hund
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Angelo G Torrente
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
| | - Peter J Mohler
- Frick Center for Heart Failure and Arrhythmia at the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Wexner Medical Center, Columbus, Ohio 43210, USA.,Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34096 Montpellier, France; .,LabEx Ion Channels Science and Therapeutics (ICST), 06560 Nice, France
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13
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Robinson RB, Dun W, Boyden PA. Autonomic modulation of sinoatrial node: Role of pacemaker current and calcium sensitive adenylyl cyclase isoforms. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 166:22-28. [PMID: 32853595 DOI: 10.1016/j.pbiomolbio.2020.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/08/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023]
Abstract
This article reviews work over the past three decades that is related to the contribution of the pacemaker current, If, to basal and autonomically regulated spontaneous rate in the sinoatrial node. It also addresses how the actions of the pacemaker current relate to those of Ca homeostasis with respect to basal and autonomically regulated rhythm. In this regard, it explores the relative contributions of Ca-sensitive and Ca-insensitive isoforms of adenylyl cyclase to sinoatrial node automaticity. The latter studies include previously unpublished work making use of mice in which both the type 1 and type 8 Ca-sensitive adenylyl cyclase isoforms were knocked out. These studies indicate that the pacemaker current and the L-type Ca current are distinctly influenced by Ca-sensitive and insensitive adenylyl cyclase isoforms.
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Affiliation(s)
- Richard B Robinson
- Department of Pharmacology, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Wen Dun
- Department of Pharmacology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Penelope A Boyden
- Department of Pharmacology, Columbia University Medical Center, New York, NY, 10032, USA
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14
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Ortner NJ, Kaserer T, Copeland JN, Striessnig J. De novo CACNA1D Ca 2+ channelopathies: clinical phenotypes and molecular mechanism. Pflugers Arch 2020; 472:755-773. [PMID: 32583268 PMCID: PMC7351864 DOI: 10.1007/s00424-020-02418-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/04/2020] [Accepted: 06/10/2020] [Indexed: 12/15/2022]
Abstract
The identification of rare disease-causing variants in humans by large-scale next-generation sequencing (NGS) studies has also provided us with new insights into the pathophysiological role of de novo missense variants in the CACNA1D gene that encodes the pore-forming α1-subunit of voltage-gated Cav1.3 L-type Ca2+ channels. These CACNA1D variants have been identified somatically in aldosterone-producing adenomas as well as germline in patients with neurodevelopmental and in some cases endocrine symptoms. In vitro studies in heterologous expression systems have revealed typical gating changes that indicate enhanced Ca2+ influx through Cav1.3 channels as the underlying disease-causing mechanism. Here we summarize the clinical findings of 12 well-characterized individuals with a total of 9 high-risk pathogenic CACNA1D variants. Moreover, we propose how information from somatic mutations in aldosterone-producing adenomas could be used to predict the potential pathogenicity of novel germline variants. Since these pathogenic de novo variants can cause a channel-gain-of function, we also discuss the use of L-type Ca2+ channel blockers as a potential therapeutic option.
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Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
| | - Teresa Kaserer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - J Nathan Copeland
- Duke Center for Autism and Brain Development, Duke Child and Family Mental Health and Developmental Neuroscience, Durham, USA
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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15
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Torrente AG, Mesirca P, Bidaud I, Mangoni ME. Channelopathies of voltage-gated L-type Cav1.3/α 1D and T-type Cav3.1/α 1G Ca 2+ channels in dysfunction of heart automaticity. Pflugers Arch 2020; 472:817-830. [PMID: 32601767 DOI: 10.1007/s00424-020-02421-1] [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: 04/08/2020] [Revised: 06/12/2020] [Accepted: 06/19/2020] [Indexed: 10/24/2022]
Abstract
The heart automaticity is a fundamental physiological function in vertebrates. The cardiac impulse is generated in the sinus node by a specialized population of spontaneously active myocytes known as "pacemaker cells." Failure in generating or conducting spontaneous activity induces dysfunction in cardiac automaticity. Several families of ion channels are involved in the generation and regulation of the heart automaticity. Among those, voltage-gated L-type Cav1.3 (α1D) and T-type Cav3.1 (α1G) Ca2+ channels play important roles in the spontaneous activity of pacemaker cells. Ca2+ channel channelopathies specifically affecting cardiac automaticity are considered rare. Recent research on familial disease has identified mutations in the Cav1.3-encoding CACNA1D gene that underlie congenital sinus node dysfunction and deafness (OMIM # 614896). In addition, both Cav1.3 and Cav3.1 channels have been identified as pathophysiological targets of sinus node dysfunction and heart block, caused by congenital autoimmune disease of the cardiac conduction system. The discovery of channelopathies linked to Cav1.3 and Cav3.1 channels underscores the importance of Ca2+ channels in the generation and regulation of heart's automaticity.
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Affiliation(s)
- Angelo G Torrente
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 141, rue de la cardonille, 34094, Montpellier, France.,LabEx Ion Channels Science and Therapeutics (ICST), Montpellier, France
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 141, rue de la cardonille, 34094, Montpellier, France.,LabEx Ion Channels Science and Therapeutics (ICST), Montpellier, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 141, rue de la cardonille, 34094, Montpellier, France.,LabEx Ion Channels Science and Therapeutics (ICST), Montpellier, France
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 141, rue de la cardonille, 34094, Montpellier, France. .,LabEx Ion Channels Science and Therapeutics (ICST), Montpellier, France.
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16
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Inhibition of G protein-gated K + channels by tertiapin-Q rescues sinus node dysfunction and atrioventricular conduction in mouse models of primary bradycardia. Sci Rep 2020; 10:9835. [PMID: 32555258 PMCID: PMC7300035 DOI: 10.1038/s41598-020-66673-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/21/2020] [Indexed: 02/06/2023] Open
Abstract
Sinus node (SAN) dysfunction (SND) manifests as low heart rate (HR) and is often accompanied by atrial tachycardia or atrioventricular (AV) block. The only currently available therapy for chronic SND is the implantation of an electronic pacemaker. Because of the growing burden of SND in the population, new pharmacological therapies of chronic SND and heart block are desirable. We developed a collection of genetically modified mouse strains recapitulating human primary SND associated with different degrees of AV block. These mice were generated with genetic ablation of L-type Cav1.3 (Cav1.3-/-), T-type Cav3.1 (Cav3.1-/-), or both (Cav1.3-/-/Cav3.1-/-). We also studied mice haplo-insufficient for the Na+ channel Nav1.5 (Nav1.5+/) and mice in which the cAMP-dependent regulation of hyperpolarization-activated f-(HCN4) channels has been abolished (HCN4-CNBD). We analysed, by telemetric ECG recording, whether pharmacological inhibition of the G-protein-activated K+ current (IKACh) by the peptide tertiapin-Q could improve HR and AV conduction in these mouse strains. Tertiapin-Q significantly improved the HR of Cav1.3-/- (19%), Cav1.3-/-/Cav3.1-/- (23%) and HCN4-CNBD (14%) mice. Tertiapin-Q also improved cardiac conduction of Nav1.5+/- mice by 24%. Our data suggest that the development of pharmacological IKACh inhibitors for the management of SND and conduction disease is a viable approach.
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17
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Long VP, Bonilla IM, Baine S, Glynn P, Kumar S, Schober K, Mowrey K, Weiss R, Lee NY, Mohler PJ, Györke S, Hund TJ, Fedorov VV, Carnes CA. Chronic heart failure increases negative chronotropic effects of adenosine in canine sinoatrial cells via A1R stimulation and GIRK-mediated I Kado. Life Sci 2019; 240:117068. [PMID: 31751583 DOI: 10.1016/j.lfs.2019.117068] [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: 09/06/2019] [Revised: 11/07/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
AIMS Bradycardia contributes to tachy-brady arrhythmias or sinus arrest during heart failure (HF). Sinoatrial node (SAN) adenosine A1 receptors (ADO A1Rs) are upregulated in HF, and adenosine is known to exert negative chronotropic effects on the SAN. Here, we investigated the role of A1R signaling at physiologically relevant ADO concentrations on HF SAN pacemaker cells. MAIN METHODS Dogs with tachypacing-induced chronic HF and normal controls (CTL) were studied. SAN tissue was collected for A1R and GIRK mRNA quantification. SAN cells were isolated for perforated patch clamp recordings and firing rate (bpm), slope of slow diastolic depolarization (SDD), and maximum diastolic potential (MDP) were measured. Action potentials (APs) and currents were recorded before and after addition of 1 and 10 μM ADO. To assess contributions of A1R and G protein-coupled Inward Rectifier Potassium Current (GIRK) to ADO effects, APs were measured after the addition of DPCPX (selective A1R antagonist) or TPQ (selective GIRK blocker). KEY FINDINGS A1R and GIRK mRNA expression were significantly increased in HF. In addition, ADO induced greater rate slowing and membrane hyperpolarization in HF vs CTL (p < 0.05). DPCPX prevented ADO-induced rate slowing in CTL and HF cells. The ADO-induced inward rectifying current, IKado, was observed significantly more frequently in HF than in CTL. TPQ prevented ADO-induced rate slowing in HF. SIGNIFICANCE An increase in A1R and GIRK expression enhances IKAdo, causing hyperpolarization, and subsequent negative chronotropic effects in canine chronic HF at relevant [ADO]. GIRK blockade may be a useful strategy to mitigate bradycardia in HF.
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Affiliation(s)
- Victor P Long
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Ingrid M Bonilla
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Stephen Baine
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Patric Glynn
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Sanjay Kumar
- Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Karsten Schober
- College of Veterinary Medicine, The Ohio State University, Columbus, OH
| | | | - Raul Weiss
- Division of Cardiovascular Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Nam Y Lee
- Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Peter J Mohler
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Sandor Györke
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Thomas J Hund
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Vadim V Fedorov
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Cynthia A Carnes
- College of Pharmacy, The Ohio State University, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.
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18
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Natriuretic Peptide Receptor-C Protects Against Angiotensin II-Mediated Sinoatrial Node Disease in Mice. JACC Basic Transl Sci 2018; 3:824-843. [PMID: 30623142 PMCID: PMC6314975 DOI: 10.1016/j.jacbts.2018.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 12/19/2022]
Abstract
SAN disease is prevalent in hypertension and heart failure and can be induced by chronic Ang II treatment in mice. Ang II caused SAN disease in mice in association with impaired electrical conduction, reduction in the hyperpolarization-activated current (If) in SAN myocytes, and increased SAN fibrosis. Ang II-induced SAN disease was worsened in mice lacking NPR-C in association with enhanced SAN fibrosis. Mice co-treated with Ang II and an NPR-C agonist (cANF) were protected from SAN disease. NPR-C may represent a new target to protect against Ang II-induced SAN disease.
Sinoatrial node (SAN) disease mechanisms are poorly understood, and therapeutic options are limited. Natriuretic peptide(s) (NP) are cardioprotective hormones whose effects can be mediated partly by the NP receptor C (NPR-C). We investigated the role of NPR-C in angiotensin II (Ang II)-mediated SAN disease in mice. Ang II caused SAN disease due to impaired electrical activity in SAN myocytes and increased SAN fibrosis. Strikingly, Ang II treatment in NPR-C−/− mice worsened SAN disease, whereas co-treatment of wild-type mice with Ang II and a selective NPR-C agonist (cANF) prevented SAN dysfunction. NPR-C may represent a new target to protect against the development of Ang II-induced SAN disease.
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Key Words
- AP, action potential
- Ang II, angiotensin II
- CV, conduction velocity
- DD, diastolic depolarization
- Gmax, maximum conductance
- HR, heart rate
- ICa,L, L-type calcium current
- ICa,T, T-type calcium current
- INCX, sodium–calcium exchanger current
- IV, current voltage relationship
- If, hyperpolarization-activated current
- NP, natriuretic peptide
- NPR, natriuretic peptide receptor
- NPR-C, natriuretic peptide receptor C
- SAN, sinoatrial node
- SBP, systolic blood pressure
- V1/2(act), voltage for 50% channel activation
- cSNRT, corrected sinoatrial node recovery time
- fibrosis
- hypertension
- ion currents
- natriuretic peptide
- sinoatrial node
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19
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Lang D, Glukhov AV. Functional Microdomains in Heart's Pacemaker: A Step Beyond Classical Electrophysiology and Remodeling. Front Physiol 2018; 9:1686. [PMID: 30538641 PMCID: PMC6277479 DOI: 10.3389/fphys.2018.01686] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Spontaneous beating of the sinoatrial node (SAN), the primary pacemaker of the heart, is initiated, sustained, and regulated by a complex system that integrates ion channels and transporters on the cell membrane surface (often referred to as "membrane clock") with subcellular calcium handling machinery (by parity of reasoning referred to as an intracellular "Ca2+ clock"). Stable, rhythmic beating of the SAN is ensured by a rigorous synchronization between these two clocks highlighted in the coupled-clock system concept of SAN timekeeping. The emerging results demonstrate that such synchronization of the complex pacemaking machinery at the cellular level depends on tightly regulated spatiotemporal signals which are restricted to precise sub-cellular microdomains and associated with discrete clusters of different ion channels, transporters, and regulatory receptors. It has recently become evident that within the microdomains, various proteins form an interacting network and work together as a part of a macromolecular signaling complex. These protein-protein interactions are tightly controlled and regulated by a variety of neurohormonal signaling pathways and the diversity of cellular responses achieved with a limited pool of second messengers is made possible through the organization of essential signal components in particular microdomains. In this review, we highlight the emerging understanding of the functionality of distinct subcellular microdomains in SAN myocytes and their functional role in the accumulation and neurohormonal regulation of proteins involved in cardiac pacemaking. We also demonstrate how changes in scaffolding proteins may lead to microdomain-targeted remodeling and regulation of pacemaker proteins contributing to SAN dysfunction.
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Affiliation(s)
- Di Lang
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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Siri-Angkul N, Xie LH, Chattipakorn SC, Chattipakorn N. Cellular Electrophysiology of Iron-Overloaded Cardiomyocytes. Front Physiol 2018; 9:1615. [PMID: 30498456 PMCID: PMC6249272 DOI: 10.3389/fphys.2018.01615] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/25/2018] [Indexed: 01/07/2023] Open
Abstract
Iron, the most abundant transition metal element in the human body, plays an essential role in many physiological processes. However, without a physiologically active excretory pathway, iron is subject to strict homeostatic processes acting upon its absorption, storage, mobilization, and utilization. These intricate controls are perturbed in primary and secondary hemochromatoses, leading to a deposition of excess iron in multiple vital organs including the heart. Iron overload cardiomyopathy is the leading cause of mortality in patients with iron overload conditions. Apart from mechanical deterioration of the siderotic myocardium, arrhythmias reportedly contribute to a substantial portion of cardiac death associated with iron overload. Despite this significant impact, the cellular mechanisms of electrical disturbances in an iron-overloaded heart are still incompletely characterized. This review article focuses on cellular electrophysiological studies that directly investigate the effects of iron overload on the function of cardiac ion channels, including trans-sarcolemmal and sarcoplasmic reticulum Ca2+ fluxes, as well as cardiac action potential morphology. Our ultimate aim is to provide a comprehensive summary of the currently available information that will encourage and facilitate further mechanistic elucidation of iron-induced pathoelectrophysiological changes in the heart.
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Affiliation(s)
- Natthaphat Siri-Angkul
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.,Department of Cell Biology and Molecular Medicine, Rutgers University - New Jersey Medical School, Newark, NJ, United States.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers University - New Jersey Medical School, Newark, NJ, United States
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.,Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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van Opbergen CJ, van der Voorn SM, Vos MA, de Boer TP, van Veen TA. Cardiac Ca2+ signalling in zebrafish: Translation of findings to man. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:45-58. [DOI: 10.1016/j.pbiomolbio.2018.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023]
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Altered function of neuronal L-type calcium channels in ageing and neuroinflammation: Implications in age-related synaptic dysfunction and cognitive decline. Ageing Res Rev 2018; 42:86-99. [PMID: 29339150 DOI: 10.1016/j.arr.2018.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 12/29/2022]
Abstract
The rapid developments in science have led to an increase in human life expectancy and thus, ageing and age-related disorders/diseases have become one of the greatest concerns in the 21st century. Cognitive abilities tend to decline as we get older. This age-related cognitive decline is mainly attributed to aberrant changes in synaptic plasticity and neuronal connections. Recent studies show that alterations in Ca2+ homeostasis underlie the increased vulnerability of neurons to age-related processes like cognitive decline and synaptic dysfunctions. Dysregulation of Ca2+ can lead to dramatic changes in neuronal functions. We discuss in this review, the recent advances on the potential role of dysregulated Ca2+ homeostasis through altered function of L-type voltage gated Ca2+ channels (LTCC) in ageing, with an emphasis on cognitive decline. This review therefore focuses on age-related changes mainly in the hippocampus, and with mention of other brain areas, that are important for learning and memory. This review also highlights age-related memory deficits via synaptic alterations and neuroinflammation. An understanding of these mechanisms will help us formulate strategies to reverse or ameliorate age-related disorders like cognitive decline.
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Zhang Q, Chen J, Qin Y, Wang J, Zhou L. Mutations in voltage-gated L-type calcium channel: implications in cardiac arrhythmia. Channels (Austin) 2018; 12:201-218. [PMID: 30027834 PMCID: PMC6104696 DOI: 10.1080/19336950.2018.1499368] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/08/2018] [Accepted: 07/05/2018] [Indexed: 02/06/2023] Open
Abstract
The voltage-gated L-type calcium channel (LTCC) is essential for multiple cellular processes. In the heart, calcium influx through LTCC plays an important role in cardiac electrical excitation. Mutations in LTCC genes, including CACNA1C, CACNA1D, CACNB2 and CACNA2D, will induce the dysfunctions of calcium channels, which result in the abnormal excitations of cardiomyocytes, and finally lead to cardiac arrhythmias. Nevertheless, the newly found mutations in LTCC and their functions are continuously being elucidated. This review summarizes recent findings on the mutations of LTCC, which are associated with long QT syndromes, Timothy syndromes, Brugada syndromes, short QT syndromes, and some other cardiac arrhythmias. Indeed, we describe the gain/loss-of-functions of these mutations in LTCC, which can give an explanation for the phenotypes of cardiac arrhythmias. Moreover, we present several challenges in the field at present, and propose some diagnostic or therapeutic approaches to these mutation-associated cardiac diseases in the future.
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Affiliation(s)
- Qing Zhang
- Department of Cardiology, the Second Affiliated Hospital of Nantong University, Nantong First Hospital, Nantong, Jiangsu, China
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Junjie Chen
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yao Qin
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Juejin Wang
- Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Lei Zhou
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
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Brown K, Legros S, Ortega FA, Dai Y, Doss MX, Christini DJ, Robinson RB, Foley AC. Overexpression of Map3k7 activates sinoatrial node-like differentiation in mouse ES-derived cardiomyocytes. PLoS One 2017; 12:e0189818. [PMID: 29281682 PMCID: PMC5744947 DOI: 10.1371/journal.pone.0189818] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 12/02/2017] [Indexed: 12/12/2022] Open
Abstract
In vivo, cardiomyocytes comprise a heterogeneous population of contractile cells defined by unique electrophysiologies, molecular markers and morphologies. The mechanisms directing myocardial cells to specific sub-lineages remain poorly understood. Here we report that overexpression of TGFβ-Activated Kinase (TAK1/Map3k7) in mouse embryonic stem (ES) cells faithfully directs myocardial differentiation of embryoid body (EB)-derived cardiac cells toward the sinoatrial node (SAN) lineage. Most cardiac cells in Map3k7-overexpressing EBs adopt markers, cellular morphologies, and electrophysiological behaviors characteristic of the SAN. These data, in addition to the fact that Map3k7 is upregulated in the sinus venous—the source of cells for the SAN—suggest that Map3k7 may be an endogenous regulator of the SAN fate.
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Affiliation(s)
- Kemar Brown
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Stephanie Legros
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Francis A. Ortega
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Yunkai Dai
- Department of Bioengineering, Clemson University, Charleston, SC, United States of America
| | - Michael Xavier Doss
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - David J. Christini
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Richard B. Robinson
- Department of Pharmacology, Columbia University Medical Center, New York, NY, United States of America
| | - Ann C. Foley
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, New York, United States of America
- Department of Bioengineering, Clemson University, Charleston, SC, United States of America
- * E-mail:
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Toyoda F, Ding WG, Matsuura H. Heterogeneous functional expression of the sustained inward Na + current in guinea pig sinoatrial node cells. Pflugers Arch 2017; 470:481-490. [PMID: 29197941 DOI: 10.1007/s00424-017-2091-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/08/2017] [Accepted: 11/21/2017] [Indexed: 11/26/2022]
Abstract
The sustained inward Na+ current (I st) identified in the sinoatrial node (SAN) cell has been suggested to play a pivotal role in cardiac pacemaking. However, the composition of cells in the SAN is heterogeneous and cell-to-cell variability in the magnitude of I st remains to be fully characterized. The present study investigated the current density of I st in morphologically different types of pacemaker cells dissociated from guinea pig SAN. I st was preferentially detected in spontaneously active spindle or spider-shaped cells, but was less well expressed in larger-sized elongated spindle-type cells and practically absent in clearly striated atrial-like cells, despite clear expression of the funny current (I f). The current density of I st in spindle and spider cells varied from 0.7 to 1.6 pA pF-1 and was significantly reduced in non-beating cells with similar morphologies. By linear regression analysis, we identified a positive correlation between the current densities of I st and the L-type Ca2+ current (I Ca,L), which was specifically observed in spindle and spider cells. These cells exhibited a more negative voltage for half maximal I Ca,L activation than atrial-like cells, suggesting a variable ratio between CaV1.2- and CaV1.3-mediated I Ca,L in SAN cells. Consistent single-cell transcript measurements confirmed a higher relative expression of CaV1.3, which activates at more negative potentials, in spindle cells than in atrial-like cells. Taken together, these results can be interpreted as indicating that I st plays a specific role in primary pacemaker cells and that its presence is closely correlated with functional levels of CaV1.3-mediated I Ca,L.
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Affiliation(s)
- Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Seta Tsukinowa, Otsu, Shiga, 520-2192, Japan.
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Seta Tsukinowa, Otsu, Shiga, 520-2192, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Seta Tsukinowa, Otsu, Shiga, 520-2192, Japan
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Ionic mechanisms of the action of anaesthetics on sinoatrial node automaticity. Eur J Pharmacol 2017; 814:63-72. [DOI: 10.1016/j.ejphar.2017.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/06/2017] [Accepted: 08/07/2017] [Indexed: 12/11/2022]
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Ca V1.3 L-type Ca 2+ channel contributes to the heartbeat by generating a dihydropyridine-sensitive persistent Na + current. Sci Rep 2017; 7:7869. [PMID: 28801600 PMCID: PMC5554211 DOI: 10.1038/s41598-017-08191-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/07/2017] [Indexed: 11/22/2022] Open
Abstract
The spontaneous activity of sinoatrial node (SAN) pacemaker cells is generated by a functional interplay between the activity of ionic currents of the plasma membrane and intracellular Ca2+ dynamics. The molecular correlate of a dihydropyridine (DHP)-sensitive sustained inward Na+ current (Ist), a key player in SAN automaticity, is still unknown. Here we show that Ist and the L-type Ca2+ current (ICa,L) share CaV1.3 as a common molecular determinant. Patch-clamp recordings of mouse SAN cells showed that Ist is activated in the diastolic depolarization range, and displays Na+ permeability and minimal inactivation and sensitivity to ICa,L activators and blockers. Both CaV1.3-mediated ICa,L and Ist were abolished in CaV1.3-deficient (CaV1.3−/−) SAN cells but the CaV1.2-mediated ICa,L current component was preserved. In SAN cells isolated from mice expressing DHP-insensitive CaV1.2 channels (CaV1.2DHP−/−), Ist and CaV1.3-mediated ICa,L displayed overlapping sensitivity and concentration–response relationships to the DHP blocker nifedipine. Consistent with the hypothesis that CaV1.3 rather than CaV1.2 underlies Ist, a considerable fraction of ICa,L was resistant to nifedipine inhibition in CaV1.2DHP−/− SAN cells. These findings identify CaV1.3 channels as essential molecular components of the voltage-dependent, DHP-sensitive Ist Na+ current in the SAN.
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28
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Guo Y, Cui L, Jiang S, Zhang A, Jiang S. Proteomics of acute heart failure in a rat post-myocardial infarction model. Mol Med Rep 2017; 16:1946-1956. [PMID: 28656274 PMCID: PMC5561871 DOI: 10.3892/mmr.2017.6820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 04/07/2017] [Indexed: 12/28/2022] Open
Abstract
The aim of the present study was to identify the mechanisms underlying the development of post-myocardial infarction (post-MI) heart failure. The left anterior descending coronary artery of rats was occluded to mimic human ischemic heart disease. Linear Trap Quadropole OrbiTrap mass spectrometry was used to profile the expressions of energy metabolism‑associated and calcium‑binding proteins in the post‑MI and control groups. Using the online Protein Analysis Through Evolutionary Relationships classification system, 78 differentially expressed proteins were identified, including 50 downregulated proteins and 28 upregulated proteins in post‑MI group when compared with the control group. The differentially expressed proteins were closely associated with energy metabolism, contractile function, calcium handling, pathological hypertrophy and cardiac remodeling. These results were further validated using western blotting. At different postoperative time points (1st and 14th day following surgery) during the progression of advanced heart failure post‑MI, dynamic alterations in differential protein expression were identified. The expression of the vitamin D protein was significantly upregulated on the 1st day post‑MI however, was then downregulated with progression of the disease on the 14th day post‑MI. These results identified various target proteins associated with the disease, which may be used as diagnostic markers.
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Affiliation(s)
- Yichen Guo
- Department of Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Lianqun Cui
- Department of Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shiliang Jiang
- Department of Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Airong Zhang
- Department of Cardiology, Shandong Zhongqi Hospital, Jinan, Shandong 250021, P.R. China
| | - Shu Jiang
- Department of Surgery, Huaiyin People's Hospital, Jinan, Shandong 250021, P.R. China
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29
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Novel function of α 1D L-type calcium channel in the atria. Biochem Biophys Res Commun 2017; 482:771-776. [DOI: 10.1016/j.bbrc.2016.11.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 11/18/2016] [Indexed: 11/24/2022]
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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Sun XL, Yuan JF, Jin T, Cheng XQ, Wang Q, Guo J, Zhang W, Zhang Y, Lu L, Zhang Z. Physical and functional interaction of Snapin with Cav1.3 calcium channel impacts channel protein trafficking in atrial myocytes. Cell Signal 2016; 30:118-129. [PMID: 27915047 DOI: 10.1016/j.cellsig.2016.11.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/10/2016] [Accepted: 11/27/2016] [Indexed: 10/20/2022]
Abstract
The L-type Ca2+ channel (LTCC) Cav1.3 plays a critical role in generating electrical activity in atrial myocytes and cardiac pacemaker cells. However, the molecular and functional basis of Cav1.3 modulation in atrial myocytes has not yet been fully understood. By using the yeast two-hybrid system (Y2H), a Cav1.3-associated protein was screened, which was identified as Snapin. Physical interaction and co-localization between Snapin and Cav1.3 were then confirmed in both the heterologous expression system and mouse atrial myocytes. Direct interaction between them was additionally addressed in a GST pull down assay. Furthermore, both total and membrane expressions of Cav1.3 were significantly impaired by Snapin overexpression, resulting in the ubiquitin-proteasomal degradation of Cav1.3 and a consequent reduction of the densities of whole-cell ICa-L. Snapin-induced down-regulation of Cav1.3 was reversed by SNAP-23 competitively. What is more important is that the depressed-expression of Cav1.3 paralleled with enhanced-expression of Snapin was documented in atrial samples from atrial fibrillation (AF) patients. Our results provide the evidence of a direct regulatory role of Snapin on Cav1.3 channels in atrial myocytes, and highlight a potential role of Snapin in the regulation of Cav1.3 in atrial arrhythmogenesis.
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Affiliation(s)
- Xiao-Li Sun
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Ju-Fang Yuan
- Anesthesia Department of The Affiliated People's Hospital, Jiangsu University, Zhenjiang 212002, China
| | - Tao Jin
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Xiao-Qing Cheng
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Qiang Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Jia Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China; Department of Nephrology at the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, China
| | - Wei Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Yin Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Zhao Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China.
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32
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McKinnon D, Rosati B. Transmural gradients in ion channel and auxiliary subunit expression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:165-186. [PMID: 27702655 DOI: 10.1016/j.pbiomolbio.2016.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.
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Affiliation(s)
- David McKinnon
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Barbara Rosati
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
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Mesirca P, Bidaud I, Mangoni ME. Rescuing cardiac automaticity in L-type Cav1.3 channelopathies and beyond. J Physiol 2016; 594:5869-5879. [PMID: 27374078 DOI: 10.1113/jp270678] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 06/24/2016] [Indexed: 11/08/2022] Open
Abstract
Pacemaker activity of the sino-atrial node generates the heart rate. Disease of the sinus node and impairment of atrioventricular conduction induce an excessively low ventricular rate (bradycardia), which cannot meet the needs of the organism. Bradycardia accounts for about half of the total workload of clinical cardiologists. The 'sick sinus' syndrome (SSS) is characterized by sinus bradycardia and periods of intermittent atrial fibrillation. Several genetic or acquired risk factors or pathologies can lead to SSS. Implantation of an electronic pacemaker constitutes the only available therapy for SSS. The incidence of SSS is forecast to double over the next 50 years, with ageing of the general population thus urging the development of complementary or alternative therapeutic strategies. In recent years an increasing number of mutations affecting ion channels involved in sino-atrial automaticity have been reported to underlie inheritable SSS. L-type Cav 1.3 channels play a major role in the generation and regulation of sino-atrial pacemaker activity and atrioventricular conduction. Mutation in the CACNA1D gene encoding Cav 1.3 channels induces loss-of-function in channel activity and underlies the sino-atrial node dysfunction and deafness syndrome (SANDD). Mice lacking Cav 1.3 channels (Cav 1.3-/- ) fairly recapitulate SSS and constitute a precious model to test new therapeutic approaches to handle this disease. Work in our laboratory shows that targeting G protein-gated K+ (IKACh ) channels effectively rescues SSS of Cav 1.3-/- mice. This new concept of 'compensatory' ion channel targeting shines new light on the principles underlying the pacemaker mechanism and may open the way to new therapies for SSS.
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Affiliation(s)
- Pietro Mesirca
- Département de Physiologie, Institut de Genomique Fonctionnelle, LabEx ICST, UMR-5203, Centre national de la recherche scientifique, F-34094, Montpellier, France. .,INSERM U1191, F-34094, Montpellier, France. .,Université de Montpellier, F-34094, Montpellier, France.
| | - Isabelle Bidaud
- Département de Physiologie, Institut de Genomique Fonctionnelle, LabEx ICST, UMR-5203, Centre national de la recherche scientifique, F-34094, Montpellier, France.,INSERM U1191, F-34094, Montpellier, France.,Université de Montpellier, F-34094, Montpellier, France
| | - Matteo E Mangoni
- Département de Physiologie, Institut de Genomique Fonctionnelle, LabEx ICST, UMR-5203, Centre national de la recherche scientifique, F-34094, Montpellier, France. .,INSERM U1191, F-34094, Montpellier, France. .,Université de Montpellier, F-34094, Montpellier, France.
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Striessnig J, Ortner NJ, Pinggera A. Pharmacology of L-type Calcium Channels: Novel Drugs for Old Targets? Curr Mol Pharmacol 2016; 8:110-22. [PMID: 25966690 PMCID: PMC5384371 DOI: 10.2174/1874467208666150507105845] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/10/2015] [Accepted: 04/20/2015] [Indexed: 11/22/2022]
Abstract
Inhibition of voltage-gated L-type calcium channels by organic calcium channel blockers is a well-established pharmacodynamic concept for the treatment of hypertension and cardiac ischemia. Since decades these antihypertensives (such as the dihydropyridines amlodipine, felodipine or nifedipine) belong to the most widely prescribed drugs
world-wide. Their tolerability is excellent because at therapeutic doses their pharmacological effects in humans are limited to the cardiovascular system. During the last years substantial progress has been made to reveal the physiological role of different L-type calcium channel isoforms in many other tissues, including the brain, endocrine and sensory cells.
Moreover, there is accumulating evidence about their involvement in various human diseases, such as Parkinson's disease, neuropsychiatric disorders and hyperaldosteronism. In this review we discuss the pathogenetic role of L-type calcium channels, potential new indications for existing or isoform-selective compounds and strategies to minimize potential side effects.
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Affiliation(s)
- Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, A-6020 Innsbruck, Austria.
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Cardiac sodium channel regulator MOG1 regulates cardiac morphogenesis and rhythm. Sci Rep 2016; 6:21538. [PMID: 26903377 PMCID: PMC4763225 DOI: 10.1038/srep21538] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/26/2016] [Indexed: 01/09/2023] Open
Abstract
MOG1 was initially identified as a protein that interacts with the small GTPase Ran involved in transport of macromolecules into and out of the nucleus. In addition, we have established that MOG1 interacts with the cardiac sodium channel Nav1.5 and regulates cell surface trafficking of Nav1.5. Here we used zebrafish as a model system to study the in vivo physiological role of MOG1. Knockdown of mog1 expression in zebrafish embryos significantly decreased the heart rate (HR). Consistently, the HR increases in embryos with over-expression of human MOG1. Compared with wild type MOG1 or control EGFP, mutant MOG1 with mutation E83D associated with Brugada syndrome significantly decreases the HR. Interestingly, knockdown of mog1 resulted in abnormal cardiac looping during embryogenesis. Mechanistically, knockdown of mog1 decreases expression of hcn4 involved in the regulation of the HR, and reduces expression of nkx2.5, gata4 and hand2 involved in cardiac morphogenesis. These data for the first time revealed a novel role that MOG1, a nucleocytoplasmic transport protein, plays in cardiac physiology and development.
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G protein-gated IKACh channels as therapeutic targets for treatment of sick sinus syndrome and heart block. Proc Natl Acad Sci U S A 2016; 113:E932-41. [PMID: 26831068 DOI: 10.1073/pnas.1517181113] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dysfunction of pacemaker activity in the sinoatrial node (SAN) underlies "sick sinus" syndrome (SSS), a common clinical condition characterized by abnormally low heart rate (bradycardia). If untreated, SSS carries potentially life-threatening symptoms, such as syncope and end-stage organ hypoperfusion. The only currently available therapy for SSS consists of electronic pacemaker implantation. Mice lacking L-type Cav1.3 Ca(2+) channels (Cav1.3(-/-)) recapitulate several symptoms of SSS in humans, including bradycardia and atrioventricular (AV) dysfunction (heart block). Here, we tested whether genetic ablation or pharmacological inhibition of the muscarinic-gated K(+) channel (IKACh) could rescue SSS and heart block in Cav1.3(-/-) mice. We found that genetic inactivation of IKACh abolished SSS symptoms in Cav1.3(-/-) mice without reducing the relative degree of heart rate regulation. Rescuing of SAN and AV dysfunction could be obtained also by pharmacological inhibition of IKACh either in Cav1.3(-/-) mice or following selective inhibition of Cav1.3-mediated L-type Ca(2+) (ICa,L) current in vivo. Ablation of IKACh prevented dysfunction of SAN pacemaker activity by allowing net inward current to flow during the diastolic depolarization phase under cholinergic activation. Our data suggest that patients affected by SSS and heart block may benefit from IKACh suppression achieved by gene therapy or selective pharmacological inhibition.
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Banciu DD, Banciu A, Radu BM. Electrophysiological Features of Telocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 913:287-302. [PMID: 27796895 DOI: 10.1007/978-981-10-1061-3_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Telocytes (TCs) are interstitial cells described in multiple structures, including the gastrointestinal tract, respiratory tract, urinary tract, uterus, and heart. Several studies have indicated the possibility that TCs are involved in the pacemaker potential in these organs. It is supposed that TCs are interacting with the neighboring muscular cells and their network contributes to the initiation and propagation of the electrical potentials. In order to understand the contribution of TCs to various excitability mechanisms, it is necessary to analyze the plasma membrane proteins (e.g., ion channels) functionally expressed in these cells. So far, potassium, calcium, and chloride currents, but not sodium currents, have been described in TCs in primary cell culture from different tissues. Moreover, TCs have been described as sensors for mechanical stimuli (e.g., contraction, extension, etc.). In conclusion, TCs might play an essential role in gastrointestinal peristalsis, in respiration, in pregnant uterus contraction, or in miction, but further highlighting studies are necessary to understand the molecular mechanisms and the cell-cell interactions by which TCs contribute to the tissue excitability and pacemaker potentials initiation/propagation.
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Affiliation(s)
- Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest, 050095, Romania
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest, 050095, Romania
| | - Beatrice Mihaela Radu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest, 050095, Romania. .,Department of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona, 37134, Italy.
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Weisbrod D, Khun SH, Bueno H, Peretz A, Attali B. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels. Acta Pharmacol Sin 2016; 37:82-97. [PMID: 26725737 PMCID: PMC4722971 DOI: 10.1038/aps.2015.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/25/2015] [Indexed: 12/25/2022] Open
Abstract
The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.
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Affiliation(s)
- David Weisbrod
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shiraz Haron Khun
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hanna Bueno
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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Husse B, Franz WM. Generation of cardiac pacemaker cells by programming and differentiation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1948-52. [PMID: 26681531 DOI: 10.1016/j.bbamcr.2015.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/30/2015] [Accepted: 12/07/2015] [Indexed: 12/22/2022]
Abstract
A number of diseases are caused by faulty function of the cardiac pacemaker and described as "sick sinus syndrome". The medical treatment of sick sinus syndrome with electrical pacemaker implants in the diseased heart includes risks. These problems may be overcome via "biological pacemaker" derived from different adult cardiac cells or pluripotent stem cells. The generation of cardiac pacemaker cells requires the understanding of the pacing automaticity. Two characteristic phenomena the "membrane-clock" and the "Ca(2+)-clock" are responsible for the modulation of the pacemaker activity. Processes in the "membrane-clock" generating the spontaneous pacemaker firing are based on the voltage-sensitive membrane ion channel activity starting with slow diastolic depolarization and discharging in the action potential. The influence of the intracellular Ca(2+) modulating the pacemaker activity is characterized by the "Ca(2+)-clock". The generation of pacemaker cells started with the reprogramming of adult cardiac cells by targeted induction of one pacemaker function like HCN1-4 overexpression and enclosed in an activation of single pacemaker specific transcription factors. Reprogramming of adult cardiac cells with the transcription factor Tbx18 created cardiac cells with characteristic features of cardiac pacemaker cells. Another key transcription factor is Tbx3 specifically expressed in the cardiac conduction system including the sinoatrial node and sufficient for the induction of the cardiac pacemaker gene program. For a successful cell therapeutic practice, the generated cells should have all regulating mechanisms of cardiac pacemaker cells. Otherwise, the generated pacemaker cells serve only as investigating model for the fundamental research or as drug testing model for new antiarrhythmics. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Britta Husse
- Medical University Innsbruck, Department of Internal Medicine III, Cardiology and Angiology, Anichstr. 35, A-6020 Innsbruck, Austria.
| | - Wolfgang-Michael Franz
- Medical University Innsbruck, Department of Internal Medicine III, Cardiology and Angiology, Anichstr. 35, A-6020 Innsbruck, Austria.
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Zamponi GW, Striessnig J, Koschak A, Dolphin AC. The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential. Pharmacol Rev 2015; 67:821-70. [PMID: 26362469 PMCID: PMC4630564 DOI: 10.1124/pr.114.009654] [Citation(s) in RCA: 704] [Impact Index Per Article: 78.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Ca(V)1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension. T-type (Ca(V)3) channels are a target of ethosuximide, widely used in absence epilepsy. The auxiliary subunit α2δ-1 is the therapeutic target of the gabapentinoid drugs, which are of value in certain epilepsies and chronic neuropathic pain. The limited use of intrathecal ziconotide, a peptide blocker of N-type (Ca(V)2.2) calcium channels, as a treatment of intractable pain, gives an indication that these channels represent excellent drug targets for various pain conditions. We describe how selectivity for different subtypes of calcium channels (e.g., Ca(V)1.2 and Ca(V)1.3 L-type channels) may be achieved in the future by exploiting differences between channel isoforms in terms of sequence and biophysical properties, variation in splicing in different target tissues, and differences in the properties of the target tissues themselves in terms of membrane potential or firing frequency. Thus, use-dependent blockers of the different isoforms could selectively block calcium channels in particular pathologies, such as nociceptive neurons in pain states or in epileptic brain circuits. Of important future potential are selective Ca(V)1.3 blockers for neuropsychiatric diseases, neuroprotection in Parkinson's disease, and resistant hypertension. In addition, selective or nonselective T-type channel blockers are considered potential therapeutic targets in epilepsy, pain, obesity, sleep, and anxiety. Use-dependent N-type calcium channel blockers are likely to be of therapeutic use in chronic pain conditions. Thus, more selective calcium channel blockers hold promise for therapeutic intervention.
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Affiliation(s)
- Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Joerg Striessnig
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Alexandra Koschak
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Annette C Dolphin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
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Myers R, Timofeyev V, Li N, Kim C, Ledford HA, Sirish P, Lau V, Zhang Y, Fayyaz K, Singapuri A, Lopez JE, Knowlton AA, Zhang XD, Chiamvimonvat N. Feedback mechanisms for cardiac-specific microRNAs and cAMP signaling in electrical remodeling. Circ Arrhythm Electrophysiol 2015; 8:942-50. [PMID: 25995211 DOI: 10.1161/circep.114.002162] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 05/08/2015] [Indexed: 12/25/2022]
Abstract
BACKGROUND Loss of transient outward K(+) current (Ito) is well documented in cardiac hypertrophy and failure both in animal models and in humans. Electrical remodeling contributes to prolonged action potential duration and increased incidence of arrhythmias. Furthermore, there is a growing body of evidence linking microRNA (miR) dysregulation to the progression of both conditions. In this study, we examined the mechanistic basis underlying miR dysregulation in electrical remodeling and revealed a novel interaction with the adrenergic signaling pathway. METHODS AND RESULTS We first used a tissue-specific knockout model of Dicer1 in cardiomyocytes to reveal the overall regulatory effect of miRs on the ionic currents and action potentials. We then validated the inducible cAMP early repressor as a target of miR-1 and took advantage of a clinically relevant model of post myocardial infarction and miR delivery to probe the mechanistic basis of miR dysregulation in electrical remodeling. These experiments revealed the role of inducible cAMP early repressor as a repressor of miR-1 and Ito, leading to prolonged action potential duration post myocardial infarction. In addition, delivery of miR-1 and miR-133a suppressed inducible cAMP early repressor expression and prevented both electrical remodeling and hypertrophy. CONCLUSIONS Taken together, our results illuminate the mechanistic links between miRs, adrenergic signaling, and electrical remodeling. They also serve as a proof-of-concept for the therapeutic potential of miR delivery post myocardial infarction.
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Affiliation(s)
- Richard Myers
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Valeriy Timofeyev
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Ning Li
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Catherine Kim
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Hannah A Ledford
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Padmini Sirish
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Victor Lau
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Yinuo Zhang
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Kiran Fayyaz
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Anil Singapuri
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Javier E Lopez
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Anne A Knowlton
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.)
| | - Xiao-Dong Zhang
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.).
| | - Nipavan Chiamvimonvat
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis (R.M., V.T.,N.L., C.K., H.A.L., P.S., V.L., Y.Z., K.F., A.S., J.E.L., A.A.K., X.-D.Z., N.C.); and Department of Veterans Affairs, Northern California Health Care System, Mather (A.A.K., N.C.).
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Brodarac A, Šarić T, Oberwallner B, Mahmoodzadeh S, Neef K, Albrecht J, Burkert K, Oliverio M, Nguemo F, Choi YH, Neiss WF, Morano I, Hescheler J, Stamm C. Susceptibility of murine induced pluripotent stem cell-derived cardiomyocytes to hypoxia and nutrient deprivation. Stem Cell Res Ther 2015; 6:83. [PMID: 25900017 PMCID: PMC4445302 DOI: 10.1186/s13287-015-0057-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 05/23/2014] [Accepted: 03/19/2015] [Indexed: 01/06/2023] Open
Abstract
Introduction Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) may be suitable for myocardial repair. While their functional and structural properties have been extensively investigated, their response to ischemia-like conditions has not yet been clearly defined. Methods iPS-CMs were differentiated and enriched from murine induced pluripotent stem cells expressing enhanced green fluorescent protein (eGFP) and puromycin resistance genes under the control of an α-myosin heavy chain (α-MHC) promoter. iPS-CMs maturity and function were characterized by microscopy, real-time PCR, calcium transient recordings, electrophysiology, and mitochondrial function assays, and compared to those from neonatal murine cardiomyocytes. iPS-CMs as well as neonatal murine cardiomyocytes were exposed for 3 hours to hypoxia (1% O2) and glucose/serum deprivation, and viability, apoptosis markers, reactive oxygen species, mitochondrial membrane potential and intracellular stress signaling cascades were investigated. Then, the iPS-CMs response to mesenchymal stromal cell-conditioned medium was determined. Results iPS-CMs displayed key morphological and functional properties that were comparable to those of neonatal cardiomyocytes, but several parameters indicated an earlier iPS-CMs maturation stage. During hypoxia and glucose/serum deprivation, iPS-CMs exhibited a significantly higher proportion of poly-caspase-active, 7-aminoactinomycin D-positive and TUNEL-positive cells than neonatal cardiomyocytes. The average mitochondrial membrane potential was reduced in “ischemic” iPS-CMs but remained unchanged in neonatal cardiomyocytes; reactive oxygen species production was only increased in “ischemic” iPS-CMs, and oxidoreductase activity in iPS-CMs dropped more rapidly than in neonatal cardiomyocytes. In iPS-CMs, hypoxia and glucose/serum deprivation led to upregulation of Hsp70 transcripts and decreased STAT3 phosphorylation and total PKCε protein expression. Treatment with mesenchymal stromal cell-conditioned medium preserved oxidoreductase activity and restored pSTAT3 and PKCε levels. Conclusion iPS-CMs appear to be particularly sensitive to hypoxia and nutrient deprivation. Counteracting the ischemic susceptibility of iPS-CMs with mesenchymal stromal cell-conditioned medium may help enhance their survival and efficacy in cell-based approaches for myocardial repair.
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Affiliation(s)
- Andreja Brodarac
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany.
| | - Tomo Šarić
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Barbara Oberwallner
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany.
| | | | - Klaus Neef
- Department of Cardiothoracic Surgery, Heart Center, University Hospital Cologne, Cologne, Germany.
| | - Julie Albrecht
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Karsten Burkert
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Matteo Oliverio
- Max-Planck-Institute for Metabolism Research, Cologne, Germany.
| | - Filomain Nguemo
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Yeong-Hoon Choi
- Department of Cardiothoracic Surgery, Heart Center, University Hospital Cologne, Cologne, Germany.
| | - Wolfram F Neiss
- Department of Anatomy I, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Ingo Morano
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
| | - Jürgen Hescheler
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Christof Stamm
- Berlin-Brandenburg Center for Regenerative Therapies, Föhrer Str.15, Berlin, 13353, Germany. .,Deutsches Herzzentrum Berlin, Berlin, Germany.
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Capel RA, Terrar DA. The importance of Ca(2+)-dependent mechanisms for the initiation of the heartbeat. Front Physiol 2015; 6:80. [PMID: 25859219 PMCID: PMC4373508 DOI: 10.3389/fphys.2015.00080] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/02/2015] [Indexed: 01/01/2023] Open
Abstract
Mechanisms underlying pacemaker activity in the sinus node remain controversial, with some ascribing a dominant role to timing events in the surface membrane (“membrane clock”) and others to uptake and release of calcium from the sarcoplasmic reticulum (SR) (“calcium clock”). Here we discuss recent evidence on mechanisms underlying pacemaker activity with a particular emphasis on the many roles of calcium. There are particular areas of controversy concerning the contribution of calcium spark-like events and the importance of I(f) to spontaneous diastolic depolarisation, though it will be suggested that neither of these is essential for pacemaking. Sodium-calcium exchange (NCX) is most often considered in the context of mediating membrane depolarisation after spark-like events. We present evidence for a broader role of this electrogenic exchanger which need not always depend upon these spark-like events. Short (milliseconds or seconds) and long (minutes) term influences of calcium are discussed including direct regulation of ion channels and NCX, and control of the activity of calcium-dependent enzymes (including CaMKII, AC1, and AC8). The balance between the many contributory factors to pacemaker activity may well alter with experimental and clinical conditions, and potentially redundant mechanisms are desirable to ensure the regular spontaneous heart rate that is essential for life. This review presents evidence that calcium is central to the normal control of pacemaking across a range of temporal scales and seeks to broaden the accepted description of the “calcium clock” to cover these important influences.
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Affiliation(s)
- Rebecca A Capel
- British Heart Foundation Centre of Research Excellence, Department of Pharmacology, University of Oxford Oxford, UK
| | - Derek A Terrar
- British Heart Foundation Centre of Research Excellence, Department of Pharmacology, University of Oxford Oxford, UK
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Motonaga KS, Punn R, Axelrod DM, Ceresnak SR, Hanisch D, Kazmucha JA, Dubin AM. Diminished exercise capacity and chronotropic incompetence in pediatric patients with congenital complete heart block and chronic right ventricular pacing. Heart Rhythm 2015; 12:560-565. [DOI: 10.1016/j.hrthm.2014.11.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Indexed: 12/29/2022]
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Mesirca P, Torrente AG, Mangoni ME. Functional role of voltage gated Ca(2+) channels in heart automaticity. Front Physiol 2015; 6:19. [PMID: 25698974 PMCID: PMC4313592 DOI: 10.3389/fphys.2015.00019] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/12/2015] [Indexed: 01/08/2023] Open
Abstract
Pacemaker activity of automatic cardiac myocytes controls the heartbeat in everyday life. Cardiac automaticity is under the control of several neurotransmitters and hormones and is constantly regulated by the autonomic nervous system to match the physiological needs of the organism. Several classes of ion channels and proteins involved in intracellular Ca(2+) dynamics contribute to pacemaker activity. The functional role of voltage-gated calcium channels (VGCCs) in heart automaticity and impulse conduction has been matter of debate for 30 years. However, growing evidence shows that VGCCs are important regulators of the pacemaker mechanisms and play also a major role in atrio-ventricular impulse conduction. Incidentally, studies performed in genetically modified mice lacking L-type Cav1.3 (Cav1.3(-/-)) or T-type Cav3.1 (Cav3.1(-/-)) channels show that genetic inactivation of these channels strongly impacts pacemaking. In cardiac pacemaker cells, VGCCs activate at negative voltages at the beginning of the diastolic depolarization and importantly contribute to this phase by supplying inward current. Loss-of-function of these channels also impairs atrio-ventricular conduction. Furthermore, inactivation of Cav1.3 channels promotes also atrial fibrillation and flutter in knockout mice suggesting that these channels can play a role in stabilizing atrial rhythm. Genomic analysis demonstrated that Cav1.3 and Cav3.1 channels are widely expressed in pacemaker tissue of mice, rabbits and humans. Importantly, human diseases of pacemaker activity such as congenital bradycardia and heart block have been attributed to loss-of-function of Cav1.3 and Cav3.1 channels. In this article, we will review the current knowledge on the role of VGCCs in the generation and regulation of heart rate and rhythm. We will discuss also how loss of Ca(2+) entry through VGCCs could influence intracellular Ca(2+) handling and promote atrial arrhythmias.
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Affiliation(s)
- Pietro Mesirca
- Laboratory of Excellence in Ion Channel Science and Therapeutics, Département de Physiologie, Institut de Génomique Fonctionnelle Montpellier, France ; UMR-5203, Centre National de la Recherche Scientifique, Universités de Montpellier 1 and 2 Montpellier, France ; INSERM U 1191, Département de Physiologie, Universités de Montpellier 1 and 2 Montpellier, France
| | - Angelo G Torrente
- Laboratory of Excellence in Ion Channel Science and Therapeutics, Département de Physiologie, Institut de Génomique Fonctionnelle Montpellier, France ; UMR-5203, Centre National de la Recherche Scientifique, Universités de Montpellier 1 and 2 Montpellier, France ; INSERM U 1191, Département de Physiologie, Universités de Montpellier 1 and 2 Montpellier, France
| | - Matteo E Mangoni
- Laboratory of Excellence in Ion Channel Science and Therapeutics, Département de Physiologie, Institut de Génomique Fonctionnelle Montpellier, France ; UMR-5203, Centre National de la Recherche Scientifique, Universités de Montpellier 1 and 2 Montpellier, France ; INSERM U 1191, Département de Physiologie, Universités de Montpellier 1 and 2 Montpellier, France
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Abstract
One of the main strategies for cancer therapy is to use tyrosine kinase inhibitors for inhibiting tumor proliferation. Increasing evidence has demonstrated the potential risks of cardiac arrhythmias (such as prolonged QT interval) of these drugs. We report here that a widely used selective inhibitor of Src tyrosine kinases, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), can inhibit and prevent β-adrenergic stimulation of cardiac pacemaker activity. First, in dissected rat sinus node, PP2 inhibited and prevented the isoproterenol-induced increase of spontaneous beating rate. Second, in isolated rat sinus node myocytes, PP2 suppressed the hyperpolarization-activated "funny" current (traditionally called cardiac pacemaker current, I(f)) by negatively shifting the activation curve and decelerating activation kinetics. Third, in isolated rat sinus node myocytes, PP2 decreased the Src kinase activity, the cell surface expression, and tyrosine phosphorylation of hyperpolarization-activated, cyclic nucleotide-modulated channel 4 (HCN4) channel proteins. Finally, in human embryonic kidney 293 cells overexpressing recombinant human HCN4 channels, PP2 reversed the enhancement of HCN4 channels by isoproterenol and inhibited 573x, a cyclic adenosine momophosphate-insensitive human HCN4 mutant. These results demonstrated that inhibition of Src kinase activity in heart by PP2 decreased and prevented β-adrenergic stimulation of cardiac pacemaker activity. These effects are mediated, at least partially, by a cAMP-independent attenuation of channel activity and cell surface expression of HCN4, the main channel protein that controls the heart rate.
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Lu L, Sirish P, Zhang Z, Woltz RL, Li N, Timofeyev V, Knowlton AA, Zhang XD, Yamoah EN, Chiamvimonvat N. Regulation of gene transcription by voltage-gated L-type calcium channel, Cav1.3. J Biol Chem 2014; 290:4663-4676. [PMID: 25538241 DOI: 10.1074/jbc.m114.586883] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cav1.3 L-type Ca(2+) channel is known to be highly expressed in neurons and neuroendocrine cells. However, we have previously demonstrated that the Cav1.3 channel is also expressed in atria and pacemaking cells in the heart. The significance of the tissue-specific expression of the channel is underpinned by our previous demonstration of atrial fibrillation in a Cav1.3 null mutant mouse model. Indeed, a recent study has confirmed the critical roles of Cav1.3 in the human heart (Baig, S. M., Koschak, A., Lieb, A., Gebhart, M., Dafinger, C., Nürnberg, G., Ali, A., Ahmad, I., Sinnegger-Brauns, M. J., Brandt, N., Engel, J., Mangoni, M. E., Farooq, M., Khan, H. U., Nürnberg, P., Striessnig, J., and Bolz, H. J. (2011) Nat. Neurosci. 14, 77-84). These studies suggest that detailed knowledge of Cav1.3 may have broad therapeutic ramifications in the treatment of cardiac arrhythmias. Here, we tested the hypothesis that there is a functional cross-talk between the Cav1.3 channel and a small conductance Ca(2+)-activated K(+) channel (SK2), which we have documented to be highly expressed in human and mouse atrial myocytes. Specifically, we tested the hypothesis that the C terminus of Cav1.3 may translocate to the nucleus where it functions as a transcriptional factor. Here, we reported for the first time that the C terminus of Cav1.3 translocates to the nucleus where it functions as a transcriptional regulator to modulate the function of Ca(2+)-activated K(+) channels in atrial myocytes. Nuclear translocation of the C-terminal domain of Cav1.3 is directly regulated by intracellular Ca(2+). Utilizing a Cav1.3 null mutant mouse model, we demonstrate that ablation of Cav1.3 results in a decrease in the protein expression of myosin light chain 2, which interacts and increases the membrane localization of SK2 channels.
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Affiliation(s)
- Ling Lu
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616,; the College of Life Sciences, Nanjing Normal University, Nanjing 210046, China.
| | - Padmini Sirish
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Zheng Zhang
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Ryan L Woltz
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Ning Li
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Valeriy Timofeyev
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Anne A Knowlton
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616,; the Department of Veterans Affairs, Northern California Health Care System, Mather, California 95655
| | - Xiao-Dong Zhang
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616
| | - Ebenezer N Yamoah
- the Department of Physiology, School of Medicine, University of Nevada, Reno, Nevada 89557, and.
| | - Nipavan Chiamvimonvat
- From the Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, California 95616,; the Department of Veterans Affairs, Northern California Health Care System, Mather, California 95655,.
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Sano M, Kamitsuji S, Kamatani N, Hong KW, Han BG, Kim Y, Kim JW, Aizawa Y, Fukuda K. Genome-wide association study of electrocardiographic parameters identifies a new association for PR interval and confirms previously reported associations. Hum Mol Genet 2014; 23:6668-76. [PMID: 25055868 DOI: 10.1093/hmg/ddu375] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Previous reports have described several associations of PR, QRS, QT and heart rate with genomic variations by genome-wide association studies (GWASs). In the present study, we examined the association of ∼2.5 million SNPs from 2994 Japanese healthy volunteers obtained from the JPDSC database with electrocardiographic parameters. We confirmed associations of PR interval, QRS duration and QT interval in individuals of Japanese ancestry with 11 of the 45 SNPs (6 of 20 for QT, 5 of 19 for PR and 0 of 6 for QRS) observed among individuals of European, African and Asian (Indian and Korean) ancestries. Those results indicate that many of the electrocardiographic associations with genes are shared by different ethnic groups including Japanese. Possible novel associations found in this study were validated by Korean data. As a result, we identified a novel association of SNP rs4952632[G] (maps near SLC8A1, sodium-calcium exchanger) (P = 7.595 × 10(-6)) with PR interval in Japanese individuals, and replication testing among Koreans confirmed the association of the same SNP with prolonged PR interval. Meta-analysis of the Japanese and Korean datasets demonstrated highly significant associations of SNP rs4952632[G] with a 2.325-ms (95% CI, 1.693-2.957 ms) longer PR interval per minor allele copy (P = 5.598 × 10(-13)). Cell-type-specific SLC8A1 knockout mice have demonstrated a regulatory role of sodium-calcium exchanger in automaticity and conduction in sinoatrial node, atrium and atrioventricular node. Our findings support a functional role of sodium-calcium exchanger in human atrial and atrioventricular nodal conduction as suggested by genetically modified mouse models.
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Affiliation(s)
- Motoaki Sano
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan,
| | | | | | - Kyung-Won Hong
- Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon 363-951, Korea and
| | - Bok-Ghee Han
- Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon 363-951, Korea and
| | - Yeonjung Kim
- Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon 363-951, Korea and
| | - Jong Wook Kim
- Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea
| | - Yoshiyasu Aizawa
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Keiichi Fukuda
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
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Genetic, cellular, and functional evidence for Ca2+ inflow through Cav1.2 and Cav1.3 channels in murine spiral ganglion neurons. J Neurosci 2014; 34:7383-93. [PMID: 24849370 DOI: 10.1523/jneurosci.5416-13.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Spiral ganglion neurons (SGNs) of the eighth nerve serve as the bridge between hair cells and the cochlear nucleus. Hair cells use Cav1.3 as the primary channel for Ca(2+) inflow to mediate transmitter release. In contrast, SGNs are equipped with multiple Ca(2+) channels to mediate Ca(2+)-dependent functions. We examined directly the role of Cav1.3 channels in SGNs using Cav1.3-deficient mice (Cav1.3(-/-)). We revealed a surprising finding that SGNs functionally express the cardiac-specific Cav1.2, as well as neuronal Cav1.3 channels. We show that evoked action potentials recorded from SGNs show a significant decrease in the frequency of firing in Cav1.3(-/-) mice compared with wild-type (Cav1.3(+/+)) littermates. Although Cav1.3 is the designated L-type channel in neurons, whole-cell currents recorded in isolated SGNs from Cav1.3(-/-) mice showed a surprising remnant current with sensitivity toward the dihydropyridine (DHP) agonist and antagonist, and a depolarization shift in the voltage-dependent activation compared with that in the Cav1.3(+/+) mice. Indeed, direct measurement of the elementary properties of Ca(2+) channels, in Cav1.3(+/+) neurons, confirmed the existence of two DHP-sensitive single-channel currents, with distinct open probabilities and conductances. We demonstrate that the DHP-sensitive current in Cav1.3(-/-) mice is derived from Cav1.2 channel activity, providing for the first time, to our knowledge, functional data for the expression of Cav1.2 currents in neurons. Finally, using shRNA gene knockdown methodology, and histological analyses of SGNs from Cav1.2(+/-) and Cav1.3(+/-) mice, we were able to establish the differential roles of Cav1.2 and Cav1.3 in SGNs.
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Schmitt N, Grunnet M, Olesen SP. Cardiac potassium channel subtypes: new roles in repolarization and arrhythmia. Physiol Rev 2014; 94:609-53. [PMID: 24692356 DOI: 10.1152/physrev.00022.2013] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K+ channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K+ channels drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K+ channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure. The underlying posttranscriptional and posttranslational remodeling of the individual K+ channels changes their activity and significance relative to each other, and they must be viewed together to understand their role in keeping a stable heart rhythm, also under menacing conditions like attacks of reentry arrhythmia.
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