1
|
Sirenko ST, Zahanich I, Li Y, Lukyanenko YO, Lyashkov AE, Ziman BD, Tarasov KV, Younes A, Riordon DR, Tarasova YS, Yang D, Vinogradova TM, Maltsev VA, Lakatta EG. Phosphoprotein Phosphatase 1 but Not 2A Activity Modulates Coupled-Clock Mechanisms to Impact on Intrinsic Automaticity of Sinoatrial Nodal Pacemaker Cells. Cells 2021; 10:cells10113106. [PMID: 34831329 PMCID: PMC8623309 DOI: 10.3390/cells10113106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 12/02/2022] Open
Abstract
Spontaneous AP (action potential) firing of sinoatrial nodal cells (SANC) is critically dependent on protein kinase A (PKA) and Ca2+/calmodulin-dependent protein kinase II (CaMKII)-dependent protein phosphorylation, which are required for the generation of spontaneous, diastolic local Ca2+ releases (LCRs). Although phosphoprotein phosphatases (PP) regulate protein phosphorylation, the expression level of PPs and phosphatase inhibitors in SANC and the impact of phosphatase inhibition on the spontaneous LCRs and other players of the oscillatory coupled-clock system is unknown. Here, we show that rabbit SANC express both PP1, PP2A, and endogenous PP inhibitors I-1 (PPI-1), dopamine and cyclic adenosine 3′,5′-monophosphate (cAMP)-regulated phosphoprotein (DARPP-32), kinase C-enhanced PP1 inhibitor (KEPI). Application of Calyculin A, (CyA), a PPs inhibitor, to intact, freshly isolated single SANC: (1) significantly increased phospholamban (PLB) phosphorylation (by 2–3-fold) at both CaMKII-dependent Thr17 and PKA-dependent Ser16 sites, in a time and concentration dependent manner; (2) increased ryanodine receptor (RyR) phosphorylation at the Ser2809 site; (3) substantially increased sarcoplasmic reticulum (SR) Ca2+ load; (4) augmented L-type Ca2+ current amplitude; (5) augmented LCR’s characteristics and decreased LCR period in intact and permeabilized SANC, and (6) increased the spontaneous basal AP firing rate. In contrast, the selective PP2A inhibitor okadaic acid (100 nmol/L) had no significant effect on spontaneous AP firing, LCR parameters, or PLB phosphorylation. Application of purified PP1 to permeabilized SANC suppressed LCR, whereas purified PP2A had no effect on LCR characteristics. Our numerical model simulations demonstrated that PP inhibition increases AP firing rate via a coupled-clock mechanism, including respective increases in the SR Ca2+ pumping rate, L-type Ca2+ current, and Na+/Ca2+-exchanger current. Thus, PP1 and its endogenous inhibitors modulate the basal spontaneous firing rate of cardiac pacemaker cells by suppressing SR Ca2+ cycling protein phosphorylation, the SR Ca2+ load and LCRs, and L-type Ca2+ current.
Collapse
|
2
|
Liu X, Zhao R, Ding Q, Yao X, Tsang SY. TRPC7 regulates the electrophysiological functions of embryonic stem cell-derived cardiomyocytes. Stem Cell Res Ther 2021; 12:262. [PMID: 33941260 PMCID: PMC8091699 DOI: 10.1186/s13287-021-02308-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/22/2021] [Indexed: 12/19/2022] Open
Abstract
Background Biological pacemakers consisting of pluripotent stem cell-derived cardiomyocytes are potentially useful for treating bradycardia. However, tachyarrhythmia caused by derived cardiomyocytes themselves is one of main barriers hampering their clinical translation. An in-depth understanding of the mechanisms underlying the spontaneous action potential (a.k.a. automaticity) might provide potential approaches to solve this problem. The aim of this project is to study the role of canonical transient receptor potential isoform 7 (TRPC7) channels in regulating the automaticity of embryonic stem cell-derived cardiomyocytes (ESC-CMs). Methods and results By Western blotting, the expression of TRPC7 was found to be increased during the differentiation of mouse ESC-CMs (mESC-CMs). Adenovirus-mediated TRPC7 knockdown decreased while overexpression increased the frequency of Ca2+ transients (CaTs), local Ca2+ releases (LCRs), and action potentials (APs) as detected by confocal microscopy and whole-cell patch-clamping. TRPC7 was found to be positively associated with the activity of ryanodine receptor 2 (RyR2), sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), and sodium-calcium exchanger (NCX) but not hyperpolarization-activated, cyclic nucleotide-gated channel (HCN), and inositol trisphosphate receptor (IP3R). Knockdown or overexpression of TRPC7 did not alter the expression of HCN4, Cav1.3, Cav3.1, Cav3.2, IP3R1, RyR2, and SERCA but positively regulated the phosphorylation of RyR2 at S2814 and phospholamban (PLN) at T17. Moreover, the positive regulation of APs by TRPC7 was Ca2+-dependent, as overexpression of N-terminus of TRPC7 (dominant negative of TRPC7) which diminished the Ca2+ permeability of TRPC7 decreased the AP frequency. Conclusions TRPC7 regulates the automaticity of mESC-CMs through two mechanisms. On the one hand, TRPC7 positively regulates the intracellular Ca2+ clock through the regulation of activities of both RyR2 and SERCA; on the other hand, TRPC7 also positively regulates the membrane clock via its influence on NCX activity. Altogether, our study reveals that TRPC7 is a potential drug target to manipulate the action potential firing rate of pluripotent stem cell-derived cardiomyocyte-based biological pacemakers to prevent tachyarrhythmia, a condition that might be encountered after transplantation.
Collapse
Affiliation(s)
- Xianji Liu
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Rui Zhao
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Qianqian Ding
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Xiaoqiang Yao
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Suk Ying Tsang
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China. .,State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong SAR, China. .,Key Laboratory for Regenerative Medicine, Ministry of Education, The Chinese University of Hong Kong, Hong Kong SAR, China. .,Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| |
Collapse
|
3
|
Tsutsui K, Florio MC, Yang A, Wirth AN, Yang D, Kim MS, Ziman BD, Bychkov R, Monfredi OJ, Maltsev VA, Lakatta EG. cAMP-Dependent Signaling Restores AP Firing in Dormant SA Node Cells via Enhancement of Surface Membrane Currents and Calcium Coupling. Front Physiol 2021; 12:596832. [PMID: 33897445 PMCID: PMC8063038 DOI: 10.3389/fphys.2021.596832] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 03/09/2021] [Indexed: 11/24/2022] Open
Abstract
Action potential (AP) firing rate and rhythm of sinoatrial nodal cells (SANC) are controlled by synergy between intracellular rhythmic local Ca2+ releases (LCRs) ("Ca2+ clock") and sarcolemmal electrogenic mechanisms ("membrane clock"). However, some SANC do not fire APs (dormant SANC). Prior studies have shown that β-adrenoceptor stimulation can restore AP firing in these cells. Here we tested whether this relates to improvement of synchronization of clock coupling. We characterized membrane potential, ion currents, Ca2+ dynamics, and phospholamban (PLB) phosphorylation, regulating Ca2+ pump in enzymatically isolated single guinea pig SANC prior to, during, and following β-adrenoceptor stimulation (isoproterenol) or application of cell-permeant cAMP (CPT-cAMP). Phosphorylation of PLB (Serine 16) was quantified in the same cells following Ca2+ measurement. In dormant SANC LCRs were small and disorganized at baseline, membrane potential was depolarized (-38 ± 1 mV, n = 46), and ICaL, If, and IK densities were smaller vs SANC firing APs. β-adrenoceptor stimulation or application of CPT-cAMP led to de novo spontaneous AP generation in 44 and 46% of dormant SANC, respectively. The initial response was an increase in size, rhythmicity and synchronization of LCRs, paralleled with membrane hyperpolarization and small amplitude APs (rate ∼1 Hz). During the transition to steady-state AP firing, LCR size further increased, while LCR period shortened. LCRs became more synchronized resulting in the growth of an ensemble LCR signal peaked in late diastole, culminating in AP ignition; the rate of diastolic depolarization, AP amplitude, and AP firing rate increased. ICaL, IK, and If amplitudes in dormant SANC increased in response to β-adrenoceptor stimulation. During washout, all changes reversed in order. Total PLB was higher, but the ratio of phosphorylated PLB (Serine 16) to total PLB was lower in dormant SANC. β-adrenoceptor stimulation increased this ratio in AP-firing cells. Thus, transition of dormant SANC to AP firing is linked to the increased functional coupling of membrane and Ca2+ clock proteins. The transition occurs via (i) an increase in cAMP-mediated phosphorylation of PLB accelerating Ca2+ pumping, (ii) increased spatiotemporal LCR synchronization, yielding a larger diastolic LCR ensemble signal resulting in an earlier increase in diastolic INCX; and (iii) increased current densities of If, ICaL, and IK.
Collapse
Affiliation(s)
- Kenta Tsutsui
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
- Department of Cardiovascular Medicine, Faculty of Medicine, Saitama Medical University International Medical Center, Saitama, Japan
| | - Maria Cristina Florio
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Annie Yang
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Ashley N. Wirth
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Dongmei Yang
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Mary S. Kim
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Bruce D. Ziman
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Rostislav Bychkov
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Oliver J. Monfredi
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
- Heart and Vascular Center, University of Virginia, Charlottesville, VA, United States
| | - Victor A. Maltsev
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Edward G. Lakatta
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States
| |
Collapse
|
4
|
Li Y, Wang K, Li Q, Hancox JC, Zhang H. Reciprocal interaction between IK1 and If in biological pacemakers: A simulation study. PLoS Comput Biol 2021; 17:e1008177. [PMID: 33690622 PMCID: PMC7984617 DOI: 10.1371/journal.pcbi.1008177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/22/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022] Open
Abstract
Pacemaking dysfunction (PD) may result in heart rhythm disorders, syncope or even death. Current treatment of PD using implanted electronic pacemakers has some limitations, such as finite battery life and the risk of repeated surgery. As such, the biological pacemaker has been proposed as a potential alternative to the electronic pacemaker for PD treatment. Experimentally and computationally, it has been shown that bio-engineered pacemaker cells can be generated from non-rhythmic ventricular myocytes (VMs) by knocking out genes related to the inward rectifier potassium channel current (IK1) or by overexpressing hyperpolarization-activated cyclic nucleotide gated channel genes responsible for the "funny" current (If). However, it is unclear if a bio-engineered pacemaker based on the modification of IK1- and If-related channels simultaneously would enhance the ability and stability of bio-engineered pacemaking action potentials. In this study, the possible mechanism(s) responsible for VMs to generate spontaneous pacemaking activity by regulating IK1 and If density were investigated by a computational approach. Our results showed that there was a reciprocal interaction between IK1 and If in ventricular pacemaker model. The effect of IK1 depression on generating ventricular pacemaker was mono-phasic while that of If augmentation was bi-phasic. A moderate increase of If promoted pacemaking activity but excessive increase of If resulted in a slowdown in the pacemaking rate and even an unstable pacemaking state. The dedicated interplay between IK1 and If in generating stable pacemaking and dysrhythmias was evaluated. Finally, a theoretical analysis in the IK1/If parameter space for generating pacemaking action potentials in different states was provided. In conclusion, to the best of our knowledge, this study provides a wide theoretical insight into understandings for generating stable and robust pacemaker cells from non-pacemaking VMs by the interplay of IK1 and If, which may be helpful in designing engineered biological pacemakers for application purposes.
Collapse
Affiliation(s)
- Yacong Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- * E-mail: (KW); (HZ)
| | - Qince Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- Peng Cheng Laboratory, Shenzhen, China
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Henggui Zhang
- Peng Cheng Laboratory, Shenzhen, China
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- * E-mail: (KW); (HZ)
| |
Collapse
|
5
|
Cohen O, Nitsan I, Tzlil S, Safran SA. Long-Time Phase Correlations Reveal Regulation of Beating Cardiomyocytes. PHYSICAL REVIEW LETTERS 2020; 125:258101. [PMID: 33416366 DOI: 10.1103/physrevlett.125.258101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Spontaneous contractions of cardiomyocytes are driven by calcium oscillations due to the activity of ionic calcium channels and pumps. The beating phase is related to the time-dependent deviation of the oscillations from their average frequency, due to noise and the resulting cellular response. Here, we demonstrate experimentally that, in addition to the short-time (1-2 Hz), beat-to-beat variability, there are long-time correlations (tens of minutes) in the beating phase dynamics of isolated cardiomyocytes. Our theoretical model relates these long-time correlations to cellular regulation that restores the frequency to its average, homeostatic value in response to stochastic perturbations.
Collapse
Affiliation(s)
- Ohad Cohen
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ido Nitsan
- Faculty of Mechanical Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
| | - Shelly Tzlil
- Faculty of Mechanical Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
6
|
Chia LY, Evans BA, Mukaida S, Bengtsson T, Hutchinson DS, Sato M. Adrenoceptor regulation of the mechanistic target of rapamycin in muscle and adipose tissue. Br J Pharmacol 2019; 176:2433-2448. [PMID: 30740664 PMCID: PMC6592864 DOI: 10.1111/bph.14616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 01/21/2019] [Indexed: 12/16/2022] Open
Abstract
A vital role of adrenoceptors in metabolism and energy balance has been well documented in the heart, skeletal muscle, and adipose tissue. It has been only recently demonstrated, however, that activation of the mechanistic target of rapamycin (mTOR) makes a significant contribution to various metabolic and physiological responses to adrenoceptor agonists. mTOR exists as two distinct complexes named mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) and has been shown to play a critical role in protein synthesis, cell proliferation, hypertrophy, mitochondrial function, and glucose uptake. This review will describe the physiological significance of mTORC1 and 2 as a novel paradigm of adrenoceptor signalling in the heart, skeletal muscle, and adipose tissue. Understanding the detailed signalling cascades of adrenoceptors and how they regulate physiological responses is important for identifying new therapeutic targets and identifying novel therapeutic interventions. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
Collapse
Affiliation(s)
- Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Bronwyn A. Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Dana S. Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| |
Collapse
|
7
|
Gamu D, Juracic ES, Hall KJ, Tupling AR. The sarcoplasmic reticulum and SERCA: a nexus for muscular adaptive thermogenesis. Appl Physiol Nutr Metab 2019; 45:1-10. [PMID: 31116956 DOI: 10.1139/apnm-2019-0067] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We are currently facing an "obesity epidemic" worldwide. Promoting inefficient metabolism in muscle represents a potential treatment for obesity and its complications. Sarco(endo)plasmic reticulum (SR) Ca2+-ATPase (SERCA) pumps in muscle are responsible for maintaining low cytosolic Ca2+ concentration through the ATP-dependent pumping of Ca2+ from the cytosol into the SR lumen. SERCA activity has the potential to be a critical regulator of body mass and adiposity given that it is estimated to contribute upwards of 20% of daily energy expenditure. More interestingly, this fraction can be modified physiologically in the face of stressors, such as ambient temperature and diet, through its physical interaction with several regulators known to inhibit Ca2+ uptake and muscle function. In this review, we discuss advances in our understanding of Ca2+-cycling thermogenesis within skeletal muscle, focusing on SERCA and its protein regulators, which were thought previously to only modulate muscular contractility. Novelty ATP consumption by SERCA pumps comprises a large proportion of resting energy expenditure in muscle and is dynamically regulated through interactions with small SERCA regulatory proteins. SERCA efficiency correlates significantly with resting metabolism, such that individuals with a higher resting metabolic rate have less energetically efficient SERCA Ca2+ pumping in muscle (i.e., lower coupling ratio). Futile Ca2+ cycling is a versatile heat generating mechanism utilized by both skeletal muscle and beige fat.
Collapse
Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Emma Sara Juracic
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Karlee J Hall
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| |
Collapse
|
8
|
Vinogradova TM, Tagirova Sirenko S, Lakatta EG. Unique Ca 2+-Cycling Protein Abundance and Regulation Sustains Local Ca 2+ Releases and Spontaneous Firing of Rabbit Sinoatrial Node Cells. Int J Mol Sci 2018; 19:ijms19082173. [PMID: 30044420 PMCID: PMC6121616 DOI: 10.3390/ijms19082173] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 11/16/2022] Open
Abstract
Spontaneous beating of the heart pacemaker, the sinoatrial node, is generated by sinoatrial node cells (SANC) and caused by gradual change of the membrane potential called diastolic depolarization (DD). Submembrane local Ca2+ releases (LCR) from sarcoplasmic reticulum (SR) occur during late DD and activate an inward Na+/Ca2+ exchange current, which accelerates the DD rate leading to earlier occurrence of an action potential. A comparison of intrinsic SR Ca2+ cycling revealed that, at similar physiological Ca2+ concentrations, LCRs are large and rhythmic in permeabilized SANC, but small and random in permeabilized ventricular myocytes (VM). Permeabilized SANC spontaneously released more Ca2+ from SR than VM, despite comparable SR Ca2+ content in both cell types. In this review we discuss specific patterns of expression and distribution of SR Ca2+ cycling proteins (SR Ca2+ ATPase (SERCA2), phospholamban (PLB) and ryanodine receptors (RyR)) in SANC and ventricular myocytes. We link ability of SANC to generate larger and rhythmic LCRs with increased abundance of SERCA2, reduced abundance of the SERCA inhibitor PLB. In addition, an increase in intracellular [Ca2+] increases phosphorylation of both PLB and RyR exclusively in SANC. The differences in SR Ca2+ cycling protein expression between SANC and VM provide insights into diverse regulation of intrinsic SR Ca2+ cycling that drives automaticity of SANC.
Collapse
Affiliation(s)
- Tatiana M Vinogradova
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
| | - Syevda Tagirova Sirenko
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
| |
Collapse
|
9
|
Tsutsui K, Monfredi OJ, Sirenko-Tagirova SG, Maltseva LA, Bychkov R, Kim MS, Ziman BD, Tarasov KV, Tarasova YS, Zhang J, Wang M, Maltsev AV, Brennan JA, Efimov IR, Stern MD, Maltsev VA, Lakatta EG. A coupled-clock system drives the automaticity of human sinoatrial nodal pacemaker cells. Sci Signal 2018; 11:eaap7608. [PMID: 29895616 PMCID: PMC6138244 DOI: 10.1126/scisignal.aap7608] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The spontaneous rhythmic action potentials generated by the sinoatrial node (SAN), the primary pacemaker in the heart, dictate the regular and optimal cardiac contractions that pump blood around the body. Although the heart rate of humans is substantially slower than that of smaller experimental animals, current perspectives on the biophysical mechanisms underlying the automaticity of sinoatrial nodal pacemaker cells (SANCs) have been gleaned largely from studies of animal hearts. Using human SANCs, we demonstrated that spontaneous rhythmic local Ca2+ releases generated by a Ca2+ clock were coupled to electrogenic surface membrane molecules (the M clock) to trigger rhythmic action potentials, and that Ca2+-cAMP-protein kinase A (PKA) signaling regulated clock coupling. When these clocks became uncoupled, SANCs failed to generate spontaneous action potentials, showing a depolarized membrane potential and disorganized local Ca2+ releases that failed to activate the M clock. β-Adrenergic receptor (β-AR) stimulation, which increases cAMP concentrations and clock coupling in other species, restored spontaneous, rhythmic action potentials in some nonbeating "arrested" human SANCs by increasing intracellular Ca2+ concentrations and synchronizing diastolic local Ca2+ releases. When β-AR stimulation was withdrawn, the clocks again became uncoupled, and SANCs reverted to a nonbeating arrested state. Thus, automaticity of human pacemaker cells is driven by a coupled-clock system driven by Ca2+-cAMP-PKA signaling. Extreme clock uncoupling led to failure of spontaneous action potential generation, which was restored by recoupling of the clocks. Clock coupling and action potential firing in some of these arrested cells can be restored by β-AR stimulation-induced augmentation of Ca2+-cAMP-PKA signaling.
Collapse
Affiliation(s)
- Kenta Tsutsui
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Oliver J Monfredi
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
- Institute of Cardiovascular Sciences, University of Manchester, Manchester M13 9NT, UK
- Department of Cardiovascular Electrophysiology, Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD 21287, USA
| | | | - Larissa A Maltseva
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Rostislav Bychkov
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Mary S Kim
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Bruce D Ziman
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Kirill V Tarasov
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Yelena S Tarasova
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Jing Zhang
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Mingyi Wang
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Alexander V Maltsev
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Jaclyn A Brennan
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
| | - Michael D Stern
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Victor A Maltsev
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, Baltimore, MD 21224, USA.
| |
Collapse
|
10
|
Yavari A, Bellahcene M, Bucchi A, Sirenko S, Pinter K, Herring N, Jung JJ, Tarasov KV, Sharpe EJ, Wolfien M, Czibik G, Steeples V, Ghaffari S, Nguyen C, Stockenhuber A, Clair JRS, Rimmbach C, Okamoto Y, Yang D, Wang M, Ziman BD, Moen JM, Riordon DR, Ramirez C, Paina M, Lee J, Zhang J, Ahmet I, Matt MG, Tarasova YS, Baban D, Sahgal N, Lockstone H, Puliyadi R, de Bono J, Siggs OM, Gomes J, Muskett H, Maguire ML, Beglov Y, Kelly M, Dos Santos PPN, Bright NJ, Woods A, Gehmlich K, Isackson H, Douglas G, Ferguson DJP, Schneider JE, Tinker A, Wolkenhauer O, Channon KM, Cornall RJ, Sternick EB, Paterson DJ, Redwood CS, Carling D, Proenza C, David R, Baruscotti M, DiFrancesco D, Lakatta EG, Watkins H, Ashrafian H. Mammalian γ2 AMPK regulates intrinsic heart rate. Nat Commun 2017; 8:1258. [PMID: 29097735 PMCID: PMC5668267 DOI: 10.1038/s41467-017-01342-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/08/2017] [Indexed: 11/22/2022] Open
Abstract
AMPK is a conserved serine/threonine kinase whose activity maintains cellular energy homeostasis. Eukaryotic AMPK exists as αβγ complexes, whose regulatory γ subunit confers energy sensor function by binding adenine nucleotides. Humans bearing activating mutations in the γ2 subunit exhibit a phenotype including unexplained slowing of heart rate (bradycardia). Here, we show that γ2 AMPK activation downregulates fundamental sinoatrial cell pacemaker mechanisms to lower heart rate, including sarcolemmal hyperpolarization-activated current (I f) and ryanodine receptor-derived diastolic local subsarcolemmal Ca2+ release. In contrast, loss of γ2 AMPK induces a reciprocal phenotype of increased heart rate, and prevents the adaptive intrinsic bradycardia of endurance training. Our results reveal that in mammals, for which heart rate is a key determinant of cardiac energy demand, AMPK functions in an organ-specific manner to maintain cardiac energy homeostasis and determines cardiac physiological adaptation to exercise by modulating intrinsic sinoatrial cell behavior.
Collapse
Affiliation(s)
- Arash Yavari
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK.
| | - Mohamed Bellahcene
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Annalisa Bucchi
- Department of Biosciences, Università degli Studi di Milano, Milan, 20133, Italy
- Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, Milan, 20133, Italy
| | - Syevda Sirenko
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Katalin Pinter
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Julia J Jung
- Department of Cardiac Surgery, Rostock University Medical Centre, 18057, Rostock, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany
| | - Kirill V Tarasov
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Emily J Sharpe
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Markus Wolfien
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, 18051, Germany
| | - Gabor Czibik
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Sahar Ghaffari
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Chinh Nguyen
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Alexander Stockenhuber
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Joshua R St Clair
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Christian Rimmbach
- Department of Cardiac Surgery, Rostock University Medical Centre, 18057, Rostock, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany
| | - Yosuke Okamoto
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Dongmei Yang
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Mingyi Wang
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Bruce D Ziman
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Jack M Moen
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Daniel R Riordon
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Christopher Ramirez
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Manuel Paina
- Department of Biosciences, Università degli Studi di Milano, Milan, 20133, Italy
- Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, Milan, 20133, Italy
| | - Joonho Lee
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Jing Zhang
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Ismayil Ahmet
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Michael G Matt
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Yelena S Tarasova
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Dilair Baban
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Natasha Sahgal
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Helen Lockstone
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Rathi Puliyadi
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Joseph de Bono
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Owen M Siggs
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - John Gomes
- Department of Medicine, BHF Laboratories, The Rayne Institute, University College London, London, WC1E 6JJ, UK
| | - Hannah Muskett
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Mahon L Maguire
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Youlia Beglov
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Matthew Kelly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Pedro P N Dos Santos
- Instituto de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, 30.130-110, Brazil
| | - Nicola J Bright
- Cellular Stress Group, MRC London Institute of Medical Sciences, Imperial College London, London, W12 0NN, UK
| | - Angela Woods
- Cellular Stress Group, MRC London Institute of Medical Sciences, Imperial College London, London, W12 0NN, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Henrik Isackson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Gillian Douglas
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - David J P Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, Oxford, OX3 9DU, UK
| | - Jürgen E Schneider
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Andrew Tinker
- Department of Medicine, BHF Laboratories, The Rayne Institute, University College London, London, WC1E 6JJ, UK
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, EC1M 6BQ, UK
| | - Olaf Wolkenhauer
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, 18051, Germany
- Stellenbosch Institute of Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, 7602, South Africa
| | - Keith M Channon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Richard J Cornall
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Eduardo B Sternick
- Instituto de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, 30.130-110, Brazil
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Charles S Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - David Carling
- Cellular Stress Group, MRC London Institute of Medical Sciences, Imperial College London, London, W12 0NN, UK
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Robert David
- Department of Cardiac Surgery, Rostock University Medical Centre, 18057, Rostock, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany
| | - Mirko Baruscotti
- Department of Biosciences, Università degli Studi di Milano, Milan, 20133, Italy
- Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, Milan, 20133, Italy
| | - Dario DiFrancesco
- Department of Biosciences, Università degli Studi di Milano, Milan, 20133, Italy
- Centro Interuniversitario di Medicina Molecolare e Biofisica Applicata, University of Milano, Milan, 20133, Italy
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, 21224, USA
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Houman Ashrafian
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
- The Wellcome Trust Centre for Human Genetics, Oxford, OX3 7BN, UK.
| |
Collapse
|
11
|
Computer algorithms for automated detection and analysis of local Ca2+ releases in spontaneously beating cardiac pacemaker cells. PLoS One 2017; 12:e0179419. [PMID: 28683095 PMCID: PMC5500000 DOI: 10.1371/journal.pone.0179419] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 05/29/2017] [Indexed: 11/25/2022] Open
Abstract
Local Ca2+ Releases (LCRs) are crucial events involved in cardiac pacemaker cell function. However, specific algorithms for automatic LCR detection and analysis have not been developed in live, spontaneously beating pacemaker cells. In the present study we measured LCRs using a high-speed 2D-camera in spontaneously contracting sinoatrial (SA) node cells isolated from rabbit and guinea pig and developed a new algorithm capable of detecting and analyzing the LCRs spatially in two-dimensions, and in time. Our algorithm tracks points along the midline of the contracting cell. It uses these points as a coordinate system for affine transform, producing a transformed image series where the cell does not contract. Action potential-induced Ca2+ transients and LCRs were thereafter isolated from recording noise by applying a series of spatial filters. The LCR birth and death events were detected by a differential (frame-to-frame) sensitivity algorithm applied to each pixel (cell location). An LCR was detected when its signal changes sufficiently quickly within a sufficiently large area. The LCR is considered to have died when its amplitude decays substantially, or when it merges into the rising whole cell Ca2+ transient. Ultimately, our algorithm provides major LCR parameters such as period, signal mass, duration, and propagation path area. As the LCRs propagate within live cells, the algorithm identifies splitting and merging behaviors, indicating the importance of locally propagating Ca2+-induced-Ca2+-release for the fate of LCRs and for generating a powerful ensemble Ca2+ signal. Thus, our new computer algorithms eliminate motion artifacts and detect 2D local spatiotemporal events from recording noise and global signals. While the algorithms were developed to detect LCRs in sinoatrial nodal cells, they have the potential to be used in other applications in biophysics and cell physiology, for example, to detect Ca2+ wavelets (abortive waves), sparks and embers in muscle cells and Ca2+ puffs and syntillas in neurons.
Collapse
|
12
|
Qian F, Huang C, Lin YD, Ivanovskaya AN, O'Hara TJ, Booth RH, Creek CJ, Enright HA, Soscia DA, Belle AM, Liao R, Lightstone FC, Kulp KS, Wheeler EK. Simultaneous electrical recording of cardiac electrophysiology and contraction on chip. LAB ON A CHIP 2017; 17:1732-1739. [PMID: 28448074 DOI: 10.1039/c7lc00210f] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Prevailing commercialized cardiac platforms for in vitro drug development utilize planar microelectrode arrays to map action potentials, or impedance sensing to record contraction in real time, but cannot record both functions on the same chip with high spatial resolution. Here we report a novel cardiac platform that can record cardiac tissue adhesion, electrophysiology, and contractility on the same chip. The platform integrates two independent yet interpenetrating sensor arrays: a microelectrode array for field potential readouts and an interdigitated electrode array for impedance readouts. Together, these arrays provide real-time, non-invasive data acquisition of both cardiac electrophysiology and contractility under physiological conditions and under drug stimuli. Human induced pluripotent stem cell-derived cardiomyocytes were cultured as a model system, and used to validate the platform with an excitation-contraction decoupling chemical. Preliminary data using the platform to investigate the effect of the drug norepinephrine are combined with computational efforts. This platform provides a quantitative and predictive assay system that can potentially be used for comprehensive assessment of cardiac toxicity earlier in the drug discovery process.
Collapse
Affiliation(s)
- Fang Qian
- Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Chao Huang
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Yi-Dong Lin
- Department of Medicine, Harvard Medical School/Brigham Women's Hospital, Boston, Massachusetts 02115, USA
| | - Anna N Ivanovskaya
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Thomas J O'Hara
- Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Ross H Booth
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Cameron J Creek
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Heather A Enright
- Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - David A Soscia
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Anna M Belle
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Ronglih Liao
- Department of Medicine, Harvard Medical School/Brigham Women's Hospital, Boston, Massachusetts 02115, USA
| | - Felice C Lightstone
- Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Kristen S Kulp
- Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| | - Elizabeth K Wheeler
- Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
| |
Collapse
|
13
|
Modification of distinct ion channels differentially modulates Ca 2+ dynamics in primary cultured rat ventricular cardiomyocytes. Sci Rep 2017; 7:40952. [PMID: 28102360 PMCID: PMC5244425 DOI: 10.1038/srep40952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/12/2016] [Indexed: 01/03/2023] Open
Abstract
Primary cultured cardiomyocytes show spontaneous Ca2+ oscillations (SCOs) which not only govern contractile events, but undergo derangements that promote arrhythmogenesis through Ca2+ -dependent mechanism. We systematically examined influence on SCOs of an array of ion channel modifiers by recording intracellular Ca2+ dynamics in rat ventricular cardiomyocytes using Ca2+ specific fluorescence dye, Fluo-8/AM. Voltage-gated sodium channels (VGSCs) activation elongates SCO duration and reduces SCO frequency while inhibition of VGSCs decreases SCO frequency without affecting amplitude and duration. Inhibition of voltage-gated potassium channel increases SCO duration. Direct activation of L-type Ca2+ channels (LTCCs) induces SCO bursts while suppressing LTCCs decreases SCO amplitude and slightly increases SCO frequency. Activation of ryanodine receptors (RyRs) increases SCO duration and decreases both SCO amplitude and frequency while inhibiting RyRs decreases SCO frequency without affecting amplitude and duration. The potencies of these ion channel modifiers on SCO responses are generally consistent with their affinities in respective targets demonstrating that modification of distinct targets produces different SCO profiles. We further demonstrate that clinically-used drugs that produce Long-QT syndrome including cisapride, dofetilide, sotalol, and quinidine all induce SCO bursts while verapamil has no effect. Therefore, occurrence of SCO bursts may have a translational value to predict cardiotoxicants causing Long-QT syndrome.
Collapse
|
14
|
Li Y, Wang X, Lou C. Gastrodin Pretreatment Impact on Sarcoplasmic Reticulum Calcium Transport ATPase (SERCA) and Calcium Phosphate (PLB) Expression in Rats with Myocardial Ischemia Reperfusion. Med Sci Monit 2016; 22:3309-15. [PMID: 27641420 PMCID: PMC5031171 DOI: 10.12659/msm.896835] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background Calcium overload, inflammation, and apoptosis play important roles in myocardial ischemia-reperfusion injury (MIRI). Gastrodin pretreatment can alleviate MIRI. This study observed sarcoplasmic reticulum calcium transport ATPase (Ca2+-ATPase, SERCA) and calcium phosphate (PLB) protein expression in the ventricular remodeling process after myocardial infarction to explore the effect of gastrodin pretreatment on MIRI. Material/Methods Healthy 7-week-old male SD rats were randomly divided into a sham group (A), a model group (B), and gastrodin pretreatment groups C, D, and E (100, 200, and 400 mg/kg, respectively) with 20 in each group. Anterior descending coronary artery ligation method was used to establish a rat MIRI model with 30-min ischemia and 120-min reperfusion. Cardiac electrophysiological activity was recorded. Serum IL-6 and IL10 levels were determined by ELISA. SERCA activity was tested by colorimetric phosphorus method. SERCA, PLB, and pSer-PLB protein expression were detected by Western blot. Results Compared with the sham group, IL-6 and IL-10 levels were elevated, SERCA2a expression was downregulated, and PLB protein was elevated in the model group (P<0.05). pSer16-PLB showed no significant difference among groups, and the ratio of pSer16-PLB/PLB obviously decreased (P<0.05). IL-6 level gradually declined and IL-10 increased in the gastrodin group following concentration elevation. SERCA 2a expression rose in the gastrodin group in a dose-dependent manner (P<0.05). Elevated PLB protein expression showed no significant difference, while pSer16-PLB protein increased (P<0.05), leading to elevated pSer16 PLB/PLB ratio (P<0.05). Conclusions Gastrodin pretreatment alleviates MIRI and inflammation injury by regulating SERCA and PLB expression to decrease calcium overload.
Collapse
Affiliation(s)
- Yufen Li
- Department of ENT, Linyi City People's Hospital, Linyi, Shandong, China (mainland)
| | - Xiaomei Wang
- Genetics Laboratory, Women and Children's Hospital of Linyi City, Linyi, Shandong, China (mainland)
| | - Changli Lou
- Department of ENT, Linyi City People's Hospital, Linyi, Shandong, China (mainland)
| |
Collapse
|
15
|
Garg V, Taylor T, Warren M, Venable P, Sciuto K, Shibayama J, Zaitsev A. β-Adrenergic stimulation and rapid pacing mutually promote heterogeneous electrical failure and ventricular fibrillation in the globally ischemic heart. Am J Physiol Heart Circ Physiol 2015; 308:H1155-70. [PMID: 25713306 PMCID: PMC4551128 DOI: 10.1152/ajpheart.00768.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/16/2015] [Indexed: 01/09/2023]
Abstract
Global ischemia, catecholamine surge, and rapid heart rhythm (RHR) due to ventricular tachycardia or ventricular fibrillation (VF) are the three major factors of sudden cardiac arrest (SCA). Loss of excitability culminating in global electrical failure (asystole) is the major adverse outcome of SCA with increasing prevalence worldwide. The roles of catecholamines and RHR in the electrical failure during SCA remain unclear. We hypothesized that both β-adrenergic stimulation (βAS) and RHR accelerate electrical failure in the globally ischemic heart. We performed optical mapping of the action potential (OAP) in the right ventricular (RV) and left (LV) ventricular epicardium of isolated rabbit hearts subjected to 30-min global ischemia. Hearts were paced at a cycle length of either 300 or 200 ms, and either in the presence or in the absence of β-agonist isoproterenol (30 nM). 2,3-Butanedione monoxime (20 mM) was used to reduce motion artifact. We found that RHR and βAS synergistically accelerated the decline of the OAP upstroke velocity and the progressive expansion of inexcitable regions. Under all conditions, inexcitability developed faster in the LV than in the RV. At the same time, both RHR and βAS shortened the time to VF (TVF) during ischemia. Moreover, the time at which 10% of the mapped LV area became inexcitable strongly correlated with TVF (R(2) = 0 .72, P < 0.0001). We conclude that both βAS and RHR are major factors of electrical depression and failure in the globally ischemic heart and may contribute to adverse outcomes of SCA such as asystole and recurrent/persistent VF.
Collapse
Affiliation(s)
- Vivek Garg
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Tyson Taylor
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah; and
| | - Mark Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah; and
| | - Paul Venable
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah; and
| | - Katie Sciuto
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah; and
| | - Junko Shibayama
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, School of Medicine, University of Utah, Salt Lake City, Utah
| | - Alexey Zaitsev
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah; and
| |
Collapse
|
16
|
Chan YH, Tsai WC, Song Z, Ko CY, Qu Z, Weiss JN, Lin SF, Chen PS, Jones LR, Chen Z. Acute reversal of phospholamban inhibition facilitates the rhythmic whole-cell propagating calcium waves in isolated ventricular myocytes. J Mol Cell Cardiol 2015; 80:126-35. [PMID: 25596331 DOI: 10.1016/j.yjmcc.2014.12.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/08/2014] [Accepted: 12/30/2014] [Indexed: 02/01/2023]
Abstract
Phospholamban (PLB) inhibits the activity of cardiac sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a). Phosphorylation of PLB during sympathetic activation reverses SERCA2a inhibition, increasing SR Ca(2+) uptake. However, sympathetic activation also modulates multiple other intracellular targets in ventricular myocytes (VMs), making it impossible to determine the specific effects of the reversal of PLB inhibition on the spontaneous SR Ca(2+) release. Therefore, it remains unclear how PLB regulates rhythmic activity in VMs. Here, we used the Fab fragment of 2D12, a monoclonal anti-PLB antibody, to test how acute reversal of PLB inhibition affects the spontaneous SR Ca(2+) release in normal VMs. Ca(2+) sparks and spontaneous Ca(2+) waves (SCWs) were recorded in the line-scan mode of confocal microscopy using the Ca(2+) fluorescent dye Fluo-4 in isolated permeabilized mouse VMs. Fab, which reverses PLB inhibition, significantly increased the frequency, amplitude, and spatial/temporal spread of Ca(2+) sparks in VMs exposed to 50 nM free [Ca(2+)]. At physiological diastolic free [Ca(2+)] (100-200 nM), Fab facilitated the formation of whole-cell propagating SCWs. At higher free [Ca(2+)], Fab increased the frequency and velocity, but decreased the decay time of the SCWs. cAMP had little additional effect on the frequency or morphology of Ca(2+) sparks or SCWs after Fab addition. These findings were complemented by computer simulations. In conclusion, acute reversal of PLB inhibition alone significantly increased the spontaneous SR Ca(2+) release, leading to the facilitation and organization of whole-cell propagating SCWs in normal VMs. PLB thus plays a key role in subcellular Ca(2+) dynamics and rhythmic activity of VMs.
Collapse
Affiliation(s)
- Yi-Hsin Chan
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan
| | - Wei-Chung Tsai
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Kaohsiung, Taiwan
| | - Zhen Song
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, CA, USA
| | - Christopher Y Ko
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, CA, USA
| | - Zhilin Qu
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, CA, USA
| | - James N Weiss
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, CA, USA
| | - Shien-Fong Lin
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Larry R Jones
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Zhenhui Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
| |
Collapse
|
17
|
Maltsev VA, Yaniv Y, Maltsev AV, Stern MD, Lakatta EG. Modern perspectives on numerical modeling of cardiac pacemaker cell. J Pharmacol Sci 2014; 125:6-38. [PMID: 24748434 DOI: 10.1254/jphs.13r04cr] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent "coupled-clock" theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age.
Collapse
Affiliation(s)
- Victor A Maltsev
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, USA
| | | | | | | | | |
Collapse
|
18
|
Yaniv Y, Maltsev VA. Numerical Modeling Calcium and CaMKII Effects in the SA Node. Front Pharmacol 2014; 5:58. [PMID: 24744732 PMCID: PMC3978345 DOI: 10.3389/fphar.2014.00058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/16/2014] [Indexed: 11/13/2022] Open
Abstract
Sinoatrial node (SAN) is the primary heart pacemaker which initiates each heartbeat under normal conditions. Numerous experimental data have demonstrated that Ca(2+-) and CaMKII-dependent processes are crucially important for regulation of SAN cells. However, specific mechanisms of this regulation and their relative contribution to pacemaker function remain mainly unknown. Our review summarizes available data and existing numerical modeling approaches to understand Ca(2+) and CaMKII effects on the SAN. Data interpretation and future directions to address the problem are given within the coupled-clock theory, i.e., a modern view on the cardiac pacemaker cell function generated by a system of sarcolemmal and intracellular proteins.
Collapse
Affiliation(s)
- Yael Yaniv
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging - National Institutes of Health Baltimore, MD, USA ; Department of Biomedical Engineering, Technion - Israel Institute of Technology Haifa, Israel
| | - Victor A Maltsev
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging - National Institutes of Health Baltimore, MD, USA
| |
Collapse
|