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Balderas E, Lee SHJ, Rai NK, Mollinedo DM, Duron HE, Chaudhuri D. Mitochondrial Calcium Regulation of Cardiac Metabolism in Health and Disease. Physiology (Bethesda) 2024; 39:0. [PMID: 38713090 DOI: 10.1152/physiol.00014.2024] [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: 02/29/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024] Open
Abstract
Oxidative phosphorylation is regulated by mitochondrial calcium (Ca2+) in health and disease. In physiological states, Ca2+ enters via the mitochondrial Ca2+ uniporter and rapidly enhances NADH and ATP production. However, maintaining Ca2+ homeostasis is critical: insufficient Ca2+ impairs stress adaptation, and Ca2+ overload can trigger cell death. In this review, we delve into recent insights further defining the relationship between mitochondrial Ca2+ dynamics and oxidative phosphorylation. Our focus is on how such regulation affects cardiac function in health and disease, including heart failure, ischemia-reperfusion, arrhythmias, catecholaminergic polymorphic ventricular tachycardia, mitochondrial cardiomyopathies, Barth syndrome, and Friedreich's ataxia. Several themes emerge from recent data. First, mitochondrial Ca2+ regulation is critical for fuel substrate selection, metabolite import, and matching of ATP supply to demand. Second, mitochondrial Ca2+ regulates both the production and response to reactive oxygen species (ROS), and the balance between its pro- and antioxidant effects is key to how it contributes to physiological and pathological states. Third, Ca2+ exerts localized effects on the electron transport chain (ETC), not through traditional allosteric mechanisms but rather indirectly. These effects hinge on specific transporters, such as the uniporter or the Na+/Ca2+ exchanger, and may not be noticeable acutely, contributing differently to phenotypes depending on whether Ca2+ transporters are acutely or chronically modified. Perturbations in these novel relationships during disease states may either serve as compensatory mechanisms or exacerbate impairments in oxidative phosphorylation. Consequently, targeting mitochondrial Ca2+ holds promise as a therapeutic strategy for a variety of cardiac diseases characterized by contractile failure or arrhythmias.
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Affiliation(s)
- Enrique Balderas
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Sandra H J Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Neeraj K Rai
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - David M Mollinedo
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Hannah E Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States
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Oropeza-Almazán Y, Blatter LA. Role of Mitochondrial ROS for Calcium Alternans in Atrial Myocytes. Biomolecules 2024; 14:144. [PMID: 38397381 PMCID: PMC10887423 DOI: 10.3390/biom14020144] [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: 12/16/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 02/25/2024] Open
Abstract
Atrial calcium transient (CaT) alternans is defined as beat-to-beat alternations in CaT amplitude and is causally linked to atrial fibrillation (AF). Mitochondria play a significant role in cardiac excitation-contraction coupling and Ca signaling through redox environment regulation. In isolated rabbit atrial myocytes, ROS production is enhanced during CaT alternans, measured by fluorescence microscopy. Exogenous ROS (tert-butyl hydroperoxide) enhanced CaT alternans, whereas ROS scavengers (dithiothreitol, MnTBAP, quercetin, tempol) alleviated CaT alternans. While the inhibition of cellular NADPH oxidases had no effect on CaT alternans, interference with mitochondrial ROS (ROSm) production had profound effects: (1) the superoxide dismutase mimetic MitoTempo diminished CaT alternans and shifted the pacing threshold to higher frequencies; (2) the inhibition of cyt c peroxidase by SS-31, and inhibitors of ROSm production by complexes of the electron transport chain S1QEL1.1 and S3QEL2, decreased the severity of CaT alternans; however (3) the impairment of mitochondrial antioxidant defense by the inhibition of nicotinamide nucleotide transhydrogenase with NBD-Cl and thioredoxin reductase-2 with auranofin enhanced CaT alternans. Our results suggest that intact mitochondrial antioxidant defense provides crucial protection against pro-arrhythmic CaT alternans. Thus, modulating the mitochondrial redox state represents a potential therapeutic approach for alternans-associated arrhythmias, including AF.
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Affiliation(s)
| | - Lothar A. Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 W. Harrison St., Chicago, IL 60612, USA;
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3
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Panel M, Fauconnier J. Restoring mitochondrial Ca 2+ uptake in metabolic cardiomyopathy: A new promising target to treat atrial fibrillation. Arch Cardiovasc Dis 2023; 116:539-541. [PMID: 37949780 DOI: 10.1016/j.acvd.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 11/12/2023]
Affiliation(s)
- Mathieu Panel
- PhyMedExp, Inserm, CNRS, University of Montpellier, Montpellier, France.
| | - Jérémy Fauconnier
- PhyMedExp, Inserm, CNRS, University of Montpellier, Montpellier, France
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Shen J, Liang J, Rejiepu M, Yuan P, Xiang J, Guo Y, Xiaokereti J, Zhang L, Tang B. Identification of a Novel Target Implicated in Chronic Obstructive Sleep Apnea-Related Atrial Fibrillation by Integrative Analysis of Transcriptome and Proteome. J Inflamm Res 2023; 16:5677-5695. [PMID: 38050561 PMCID: PMC10693830 DOI: 10.2147/jir.s438701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/21/2023] [Indexed: 12/06/2023] Open
Abstract
Objective This study aimed to identify a newly identified target involved in atrial fibrillation (AF) linked to chronic obstructive sleep apnea (COSA) through an integrative analysis of transcriptome and proteome. Methods Fifteen beagle canines were randomly assigned to three groups: control (CON), obstructive sleep apnea (OSA), and OSA with superior left ganglionated plexi ablation (OSA+GP). A COSA model was established by intermittently obstructing the endotracheal cannula during exhalation for 12 weeks. Left parasternal thoracotomy through the fourth intercostal space allowed for superior left ganglionated plexi (SLGP) ablation. In vivo open-chest electrophysiological programmed stimulation was performed to assess AF inducibility. Histological, transcriptomic, and proteomic analyses were conducted on atrial samples. Results After 12 weeks, the OSA group exhibited increased AF inducibility and longer AF durations compared to the CON group. Integrated transcriptomic and proteomic analyses identified 2422 differentially expressed genes (DEGs) and 1194 differentially expressed proteins (DEPs) between OSA and CON groups, as well as between OSA+GP and OSA groups (1850 DEGs and 1418 DEPs). The analysis revealed that differentially regulated DEGs were primarily enriched in mitochondrial biological processes in the CON-vs.-OSA and OSA-vs.-GP comparisons. Notably, the key regulatory molecule GSTZ1 was activated in OSA and inhibited by GP ablation. Conclusion These findings suggest that GSTZ1 may play a pivotal role in mitochondrial damage, triggering AF substrate formation, and increasing susceptibility to AF in the context of COSA.
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Affiliation(s)
- Jun Shen
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Junqing Liang
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Manzeremu Rejiepu
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Ping Yuan
- Department of Cardiology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People’s Republic of China
| | - Jie Xiang
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Yankai Guo
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Jiasuoer Xiaokereti
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Ling Zhang
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
| | - Baopeng Tang
- Xinjiang Key Laboratory of Cardiac Electrophysiology and Cardiac Remodeling, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China
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Li AL, Lian L, Chen XN, Cai WH, Fan XB, Fan YJ, Li TT, Xie YY, Zhang JP. The role of mitochondria in myocardial damage caused by energy metabolism disorders: From mechanisms to therapeutics. Free Radic Biol Med 2023; 208:236-251. [PMID: 37567516 DOI: 10.1016/j.freeradbiomed.2023.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023]
Abstract
Myocardial damage is the most serious pathological consequence of cardiovascular diseases and an important reason for their high mortality. In recent years, because of the high prevalence of systemic energy metabolism disorders (e.g., obesity, diabetes mellitus, and metabolic syndrome), complications of myocardial damage caused by these disorders have attracted widespread attention. Energy metabolism disorders are independent of traditional injury-related risk factors, such as ischemia, hypoxia, trauma, and infection. An imbalance of myocardial metabolic flexibility and myocardial energy depletion are usually the initial changes of myocardial injury caused by energy metabolism disorders, and abnormal morphology and functional destruction of the mitochondria are their important features. Specifically, mitochondria are the centers of energy metabolism, and recent evidence has shown that decreased mitochondrial function, caused by an imbalance in mitochondrial quality control, may play a key role in myocardial injury caused by energy metabolism disorders. Under chronic energy stress, mitochondria undergo pathological fission, while mitophagy, mitochondrial fusion, and biogenesis are inhibited, and mitochondrial protein balance and transfer are disturbed, resulting in the accumulation of nonfunctional and damaged mitochondria. Consequently, damaged mitochondria lead to myocardial energy depletion and the accumulation of large amounts of reactive oxygen species, further aggravating the imbalance in mitochondrial quality control and forming a vicious cycle. In addition, impaired mitochondria coordinate calcium homeostasis imbalance, and epigenetic alterations participate in the pathogenesis of myocardial damage. These pathological changes induce rapid progression of myocardial damage, eventually leading to heart failure or sudden cardiac death. To intervene more specifically in the myocardial damage caused by metabolic disorders, we need to understand the specific role of mitochondria in this context in detail. Accordingly, promising therapeutic strategies have been proposed. We also summarize the existing therapeutic strategies to provide a reference for clinical treatment and developing new therapies.
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Affiliation(s)
- Ao-Lin Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Lu Lian
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Xin-Nong Chen
- Department of Traditional Chinese Medicine, Tianjin First Central Hospital, Tianjin, 300190, China
| | - Wen-Hui Cai
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Xin-Biao Fan
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Ya-Jie Fan
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Ting-Ting Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China; Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China
| | - Ying-Yu Xie
- College of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China.
| | - Jun-Ping Zhang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300183, China.
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Lozano O, Marcos P, Salazar-Ramirez FDJ, Lázaro-Alfaro AF, Sobrevia L, García-Rivas G. Targeting the mitochondrial Ca 2+ uniporter complex in cardiovascular disease. Acta Physiol (Oxf) 2023; 237:e13946. [PMID: 36751976 DOI: 10.1111/apha.13946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023]
Abstract
Cardiovascular diseases (CVDs), the leading cause of death worldwide, share in common mitochondrial dysfunction, in specific a dysregulation of Ca2+ uptake dynamics through the mitochondrial Ca2+ uniporter (MCU) complex. In particular, Ca2+ uptake regulates the mitochondrial ATP production, mitochondrial dynamics, oxidative stress, and cell death. Therefore, modulating the activity of the MCU complex to regulate Ca2+ uptake, has been suggested as a potential therapeutic approach for the treatment of CVDs. Here, the role and implications of the MCU complex in CVDs are presented, followed by a review of the evidence for MCU complex modulation, genetically and pharmacologically. While most approaches have aimed within the MCU complex for the modulation of the Ca2+ pore channel, the MCU subunit, its intra- and extra- mitochondrial implications, including Ca2+ dynamics, oxidative stress, post-translational modifications, and its repercussions in the cardiac function, highlight that targeting the MCU complex has the translational potential for novel CVDs therapeutics.
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Affiliation(s)
- Omar Lozano
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
- Biomedical Research Center, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
| | - Patricio Marcos
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Felipe de Jesús Salazar-Ramirez
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Anay F Lázaro-Alfaro
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
| | - Luis Sobrevia
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
- Cellular and Molecular Physiology Laboratory, Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville, Spain
- University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, Queensland, Australia
| | - Gerardo García-Rivas
- Cátedra de Cardiología y Medicina Vascular, School of Medicine and Health Sciences, Tecnologico de Monterrey, Monterrey, Mexico
- Biomedical Research Center, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
- The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Mexico
- Center of Functional Medicine, Hospital Zambrano-Hellion, TecSalud, Tecnologico de Monterrey, San Pedro Garza García, Mexico
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You T, Xie Y, Luo C, Zhang K, Zhang H. Mechanistic insights into spontaneous transition from cellular alternans to ventricular fibrillation. Physiol Rep 2023; 11:e15619. [PMID: 36863774 PMCID: PMC9981424 DOI: 10.14814/phy2.15619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/04/2023] [Accepted: 02/05/2023] [Indexed: 03/04/2023] Open
Abstract
T-wave alternans (TWA) has been used for predicting the risk of malignant cardiac arrhythmias and sudden cardiac death (SCD) in multiple clinical settings; however, possible mechanism(s) underlying the spontaneous transition from cellular alternans reflected by TWA to arrhythmias in impaired repolarization remains unclear. The healthy guinea pig ventricular myocytes under E-4031 blocking IKr (0.1 μM, N = 12; 0.3 μM, N = 10; 1 μM, N = 10) were evaluated using whole-cell patch-clamp. The electrophysiological properties of isolated perfused guinea pig hearts under E-4031 (0.1 μM, N = 5; 0.3 μM, N = 5; 1 μM, N = 5) were evaluated using dual- optical mapping. The amplitude/threshold/restitution curves of action potential duration (APD) alternans and potential mechanism(s) underlying the spontaneous transition of cellular alternans to ventricular fibrillation (VF) were examined. There were longer APD80 and increased amplitude and threshold of APD alternans in E-4031 group compared with baseline group, which was reflected by more pronounced arrhythmogenesis at the tissue level, and were associated with steep restitution curves of the APD and the conduction velocity (CV). Conduction of AP alternans augmented tissue's functional spatiotemporal heterogeneity of regional AP/Ca alternans, as well as the AP/Ca dispersion, leading to localized uni-directional conduction block that spontaneous facilitated the formation of reentrant excitation waves without the need for additional premature stimulus. Our results provide a possible mechanism for the spontaneous transition from cardiac electrical alternans in cellular action potentials and intercellular conduction without the involvement of premature excitations, and explain the increased susceptibility to ventricular arrhythmias in impaired repolarization. In this study, we implemented voltage-clamp and dual-optical mapping approaches to investigate the underlying mechanism(s) for the arrhythmogenesis of cardiac alternans in the guinea pig heart at cellular and tissue levels. Our results demonstrated a spontaneous development of reentry from cellular alternans, arising from a combined actions of restitution properties of action potential duration, conduction velocity of excitation wave and interplay between alternants of action potential and the intracellular Ca handling. We believe this study provides new insights into underlying the mechanism, by which cellular cardiac alternans spontaneously evolves into cardiac arrhythmias.
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Affiliation(s)
- Tingting You
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, (Collaborative Innovation Center for Prevention of Cardiovascular Diseases)Institute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
- Department of NeurosurgeryXinqiao Hospital, Army Medical UniversityChongqingChina
| | - Yulong Xie
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, (Collaborative Innovation Center for Prevention of Cardiovascular Diseases)Institute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
| | - Cunjin Luo
- School of Computer Science and Electronic EngineeringUniversity of EssexColchesterUK
| | - Kevin Zhang
- School of MedicineImperial College of LondonLondonUK
| | - Henggui Zhang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, (Collaborative Innovation Center for Prevention of Cardiovascular Diseases)Institute of Cardiovascular Research, Southwest Medical UniversityLuzhouChina
- Department of Physics and AstronomyUniversity of ManchesterManchesterUK
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8
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Voigt N, Maack C, Pronto JRD. Targeting Mitochondrial Calcium Handling to Treat Atrial Fibrillation. J Am Coll Cardiol 2022; 80:2220-2223. [DOI: 10.1016/j.jacc.2022.09.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 09/26/2022] [Indexed: 11/29/2022]
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Mikhryakova PP, Butova XA, Myachina TA, Simonova RA, Khokhlova AD. A Study of Mechanical Alternans in Single Rat Cardiomyocytes in Acetylcholine-CaCl2 Induced Atrial Fibrillation. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s002209302207002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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10
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Fossier L, Panel M, Butruille L, Colombani S, Azria L, Woitrain E, Decoin R, Torrente AG, Thireau J, Lacampagne A, Montaigne D, Fauconnier J. Enhanced Mitochondrial Calcium Uptake Suppresses Atrial Fibrillation Associated With Metabolic Syndrome. J Am Coll Cardiol 2022; 80:2205-2219. [DOI: 10.1016/j.jacc.2022.09.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 09/12/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
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Voglhuber J, Holzer M, Radulović S, Thai PN, Djalinac N, Matzer I, Wallner M, Bugger H, Zirlik A, Leitinger G, Dedkova EN, Bers DM, Ljubojevic-Holzer S. Functional remodelling of perinuclear mitochondria alters nucleoplasmic Ca 2+ signalling in heart failure. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210320. [PMID: 36189813 PMCID: PMC9527904 DOI: 10.1098/rstb.2021.0320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 01/23/2022] [Indexed: 11/12/2022] Open
Abstract
Mitochondrial dysfunction in cardiomyocytes is a hallmark of heart failure development. Although initial studies recognized the importance of different mitochondrial subpopulations, there is a striking lack of direct comparison of intrafibrillar (IF) versus perinuclear (PN) mitochondria during the development of HF. Here, we use multiple approaches to examine the morphology and functional properties of IF versus PN mitochondria in pressure overload-induced cardiac remodelling in mice, and in non-failing and failing human cardiomyocytes. We demonstrate that PN mitochondria from failing cardiomyocytes are more susceptible to depolarization of mitochondrial membrane potential, reactive oxygen species generation and impairment in Ca2+ uptake compared with IF mitochondria at baseline and under physiological stress protocol. We also demonstrate, for the first time to our knowledge, that under normal conditions PN mitochondrial Ca2+ uptake shapes nucleoplasmic Ca2+ transients (CaTs) and limits nucleoplasmic Ca2+ loading. The loss of PN mitochondrial Ca2+ buffering capacity translates into increased nucleoplasmic CaTs and may explain disproportionate rise in nucleoplasmic [Ca2+] in failing cardiomyocytes at increased stimulation frequencies. Therefore, a previously unidentified benefit of restoring the mitochondrial Ca2+ uptake may be normalization of nuclear Ca2+ signalling and alleviation of altered excitation-transcription, which could be an important therapeutic approach to prevent adverse cardiac remodelling. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Julia Voglhuber
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Michael Holzer
- BioTechMed-Graz, Graz, Austria
- Division of Pharmacology, Otto-Loewi Research Centre, Medical University of Graz, Graz, Austria
| | - Snježana Radulović
- Research Unit Electron Microscopic Techniques, Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Phung N. Thai
- Department of Internal Medicine, Cardiovascular Medicine, University of California Davis, Davis, CA, USA
| | - Natasa Djalinac
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Ingrid Matzer
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Markus Wallner
- Department of Cardiology, Medical University of Graz, Graz, Austria
- Lewis Katz School of Medicine, Temple University, Cardiovascular Research Center, Philadelphia, PA, USA
| | - Heiko Bugger
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Andreas Zirlik
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Gerd Leitinger
- Research Unit Electron Microscopic Techniques, Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Elena N. Dedkova
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Senka Ljubojevic-Holzer
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
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12
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Elezaby A, Dexheimer R, Sallam K. Cardiovascular effects of immunosuppression agents. Front Cardiovasc Med 2022; 9:981838. [PMID: 36211586 PMCID: PMC9534182 DOI: 10.3389/fcvm.2022.981838] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/30/2022] [Indexed: 11/26/2022] Open
Abstract
Immunosuppressive medications are widely used to treat patients with neoplasms, autoimmune conditions and solid organ transplants. Key drug classes, namely calcineurin inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and purine synthesis inhibitors, have direct effects on the structure and function of the heart and vascular system. In the heart, immunosuppressive agents modulate cardiac hypertrophy, mitochondrial function, and arrhythmia risk, while in vasculature, they influence vessel remodeling, circulating lipids, and blood pressure. The aim of this review is to present the preclinical and clinical literature examining the cardiovascular effects of immunosuppressive agents, with a specific focus on cyclosporine, tacrolimus, sirolimus, everolimus, mycophenolate, and azathioprine.
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Affiliation(s)
- Aly Elezaby
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Ryan Dexheimer
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
| | - Karim Sallam
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- *Correspondence: Karim Sallam
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13
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Krstic AM, Power AS, Ward ML. Visualization of Dynamic Mitochondrial Calcium Fluxes in Isolated Cardiomyocytes. Front Physiol 2022; 12:808798. [PMID: 35140632 PMCID: PMC8818789 DOI: 10.3389/fphys.2021.808798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/30/2021] [Indexed: 01/19/2023] Open
Abstract
BackgroundCardiomyocyte contraction requires a constant supply of ATP, which varies depending on work rate. Maintaining ATP supply is particularly important during excitation-contraction coupling, where cytosolic Ca2+ fluxes drive repeated cycles of contraction and relaxation. Ca2+ is one of the key regulators of ATP production, and its uptake into the mitochondrial matrix occurs via the mitochondrial calcium uniporter. Fluorescent indicators are commonly used for detecting cytosolic Ca2+ changes. However, visualizing mitochondrial Ca2+ fluxes using similar methods is more difficult, as the fluorophore must be permeable to both the sarcolemma and the inner mitochondrial membrane. Our aim was therefore to optimize a method using the fluorescent Ca2+ indicator Rhod-2 to visualize beat-to-beat mitochondrial calcium fluxes in rat cardiomyocytes.MethodsHealthy, adult male Wistar rat hearts were isolated and enzymatically digested to yield rod-shaped, quiescent ventricular cardiomyocytes. The fluorescent Ca2+ indicator Rhod-2 was reduced to di-hydroRhod-2 and confocal microscopy was used to validate mitochondrial compartmentalization. Cardiomyocytes were subjected to various pharmacological interventions, including caffeine and β-adrenergic stimulation. Upon confirmation of mitochondrial Rhod-2 localization, loaded myocytes were then super-fused with 1.5 mM Ca2+ Tyrodes containing 1 μM isoproterenol and 150 μM spermine. Myocytes were externally stimulated at 0.1, 0.5 and 1 Hz and whole cell recordings of both cytosolic ([Ca2+]cyto) and mitochondrial calcium ([Ca2+]mito) transients were made.ResultsMyocytes loaded with di-hydroRhod-2 revealed a distinct mitochondrial pattern when visualized by confocal microscopy. Application of 20 mM caffeine revealed no change in fluorescence, confirming no sarcoplasmic reticulum compartmentalization. Myocytes loaded with di-hydroRhod-2 also showed a large increase in fluorescence within the mitochondria in response to β-adrenergic stimulation (P < 0.05). Beat-to-beat mitochondrial Ca2+ transients were smaller in amplitude and had a slower time to peak and maximum rate of rise relative to cytosolic calcium transients at all stimulation frequencies (P < 0.001).ConclusionMyocytes loaded with di-hydroRhod-2 revealed mitochondrial specific compartmentalization. Mitochondrial Ca2+ transients recorded from di-hydroRhod-2 loaded myocytes were distinct in comparison to the large and rapid Rhod-2 cytosolic transients, indicating different kinetics between [Ca2+]cyto and [Ca2+]mito transients. Overall, our results showed that di-hydroRhod-2 loading is a quick and suitable method for measuring beat-to-beat [Ca2+]mito transients in intact myocytes.
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Affiliation(s)
- Anna Maria Krstic
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Amelia Sally Power
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- *Correspondence: Marie-Louise Ward,
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14
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Swift LM, Kay MW, Ripplinger CM, Posnack NG. Stop the beat to see the rhythm: excitation-contraction uncoupling in cardiac research. Am J Physiol Heart Circ Physiol 2021; 321:H1005-H1013. [PMID: 34623183 DOI: 10.1152/ajpheart.00477.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Optical mapping is an imaging technique that is extensively used in cardiovascular research, wherein parameter-sensitive fluorescent indicators are used to study the electrophysiology and excitation-contraction coupling of cardiac tissues. Despite many benefits of optical mapping, eliminating motion artifacts within the optical signals is a major challenge, as myocardial contraction interferes with the faithful acquisition of action potentials and intracellular calcium transients. As such, excitation-contraction uncoupling agents are frequently used to reduce signal distortion by suppressing contraction. When compared with other uncoupling agents, blebbistatin is the most frequently used, as it offers increased potency with minimal direct effects on cardiac electrophysiology. Nevertheless, blebbistatin may exert secondary effects on electrical activity, metabolism, and coronary flow, and the incorrect administration of blebbistatin to cardiac tissue can prove detrimental, resulting in erroneous interpretation of optical mapping results. In this "Getting It Right" perspective, we briefly review the literature regarding the use of blebbistatin in cardiac optical mapping experiments, highlight potential secondary effects of blebbistatin on cardiac electrical activity and metabolic demand, and conclude with the consensus of the authors on best practices for effectively using blebbistatin in optical mapping studies of cardiac tissue.
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Affiliation(s)
- Luther M Swift
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia.,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
| | - Matthew W Kay
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
| | | | - Nikki Gillum Posnack
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia.,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia.,Department of Pediatrics, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
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15
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Pfenniger A, Yoo S, Arora R. Nucleoplasmic Ca 2+: The 'Mastermind' Behind Pathological Atrial Remodeling? Circ Res 2021; 128:636-638. [PMID: 34314193 PMCID: PMC9278521 DOI: 10.1161/circresaha.121.318800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Anna Pfenniger
- Department of Medicine, Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, IL
| | - Shin Yoo
- Department of Medicine, Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, IL
| | - Rishi Arora
- Department of Medicine, Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, IL
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16
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You T, Luo C, Zhang K, Zhang H. Electrophysiological Mechanisms Underlying T-Wave Alternans and Their Role in Arrhythmogenesis. Front Physiol 2021; 12:614946. [PMID: 33746768 PMCID: PMC7969788 DOI: 10.3389/fphys.2021.614946] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 02/10/2021] [Indexed: 12/18/2022] Open
Abstract
T-wave alternans (TWA) reflects every-other-beat alterations in the morphology of the electrocardiogram ST segment or T wave in the setting of a constant heart rate, hence, in the absence of heart rate variability. It is believed to be associated with the dispersion of repolarization and has been used as a non-invasive marker for predicting the risk of malignant cardiac arrhythmias and sudden cardiac death as numerous studies have shown. This review aims to provide up-to-date review on both experimental and simulation studies in elucidating possible mechanisms underlying the genesis of TWA at the cellular level, as well as the genesis of spatially concordant/discordant alternans at the tissue level, and their transition to cardiac arrhythmia. Recent progress and future perspectives in antiarrhythmic therapies associated with TWA are also discussed.
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Affiliation(s)
- Tingting You
- Key Lab of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Cunjin Luo
- School of Computer Science and Electronic Engineering, University of Essex, Colchester, United Kingdom
| | - Kevin Zhang
- School of Medicine, Imperial College of London, London, United Kingdom
| | - Henggui Zhang
- Key Lab of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.,Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
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17
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Saadeh K, Fazmin IT. Mitochondrial Dysfunction Increases Arrhythmic Triggers and Substrates; Potential Anti-arrhythmic Pharmacological Targets. Front Cardiovasc Med 2021; 8:646932. [PMID: 33659284 PMCID: PMC7917191 DOI: 10.3389/fcvm.2021.646932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/26/2021] [Indexed: 12/31/2022] Open
Abstract
Incidence of cardiac arrhythmias increases significantly with age. In order to effectively stratify arrhythmic risk in the aging population it is crucial to elucidate the relevant underlying molecular mechanisms. The changes underlying age-related electrophysiological disruption appear to be closely associated with mitochondrial dysfunction. Thus, the present review examines the mechanisms by which age-related mitochondrial dysfunction promotes arrhythmic triggers and substrate. Namely, via alterations in plasmalemmal ionic currents (both sodium and potassium), gap junctions, cellular Ca2+ homeostasis, and cardiac fibrosis. Stratification of patients' mitochondrial function status permits application of appropriate anti-arrhythmic therapies. Here, we discuss novel potential anti-arrhythmic pharmacological interventions that specifically target upstream mitochondrial function and hence ameliorates the need for therapies targeting downstream changes which have constituted traditional antiarrhythmic therapy.
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Affiliation(s)
- Khalil Saadeh
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ibrahim Talal Fazmin
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
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18
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Salazar-Ramírez F, Ramos-Mondragón R, García-Rivas G. Mitochondrial and Sarcoplasmic Reticulum Interconnection in Cardiac Arrhythmia. Front Cell Dev Biol 2021; 8:623381. [PMID: 33585462 PMCID: PMC7876262 DOI: 10.3389/fcell.2020.623381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/30/2020] [Indexed: 12/31/2022] Open
Abstract
Ca2+ plays a pivotal role in mitochondrial energy production, contraction, and apoptosis. Mitochondrial Ca2+-targeted fluorescent probes have demonstrated that mitochondria Ca2+ transients are synchronized with Ca2+ fluxes occurring in the sarcoplasmic reticulum (SR). The presence of specialized proteins tethering SR to mitochondria ensures the local Ca2+ flux between these organelles. Furthermore, communication between SR and mitochondria impacts their functionality in a bidirectional manner. Mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniplex is essential for ATP production and controlled reactive oxygen species levels for proper cellular signaling. Conversely, mitochondrial ATP ensures the proper functioning of SR Ca2+-handling proteins, which ensures that mitochondria receive an adequate supply of Ca2+. Recent evidence suggests that altered SR Ca2+ proteins, such as ryanodine receptors and the sarco/endoplasmic reticulum Ca2+ ATPase pump, play an important role in maintaining proper cardiac membrane excitability, which may be initiated and potentiated when mitochondria are dysfunctional. This recognized mitochondrial role offers the opportunity to develop new therapeutic approaches aimed at preventing cardiac arrhythmias in cardiac disease.
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Affiliation(s)
- Felipe Salazar-Ramírez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Cátedra de Cardiología y Medicina Cardiovascular, Monterrey, Mexico
| | - Roberto Ramos-Mondragón
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Gerardo García-Rivas
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Cátedra de Cardiología y Medicina Cardiovascular, Monterrey, Mexico.,TecSalud, Centro de Investigación Biomédica, Hospital Zambrano-Hellion, San Pedro Garza García, Mexico.,TecSalud, Centro de Medicina Funcional, Hospital Zambrano-Hellion, San Pedro Garza García, Mexico
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19
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Atrial fibrillation rhythm is associated with marked changes in metabolic and myofibrillar protein expression in left atrial appendage. Pflugers Arch 2021; 473:461-475. [PMID: 33454842 DOI: 10.1007/s00424-021-02514-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/26/2020] [Accepted: 01/04/2021] [Indexed: 12/15/2022]
Abstract
Atrial fibrillation (AF) is strongly associated with risk of stroke and heart failure. AF promotes atrial remodeling that increases risk of stroke due to left atrial thrombogenesis, and increases energy demand to support high rate electrical activity and muscle contraction. While many transcriptomic studies have assessed AF-related changes in mRNA abundance, fewer studies have assessed proteomic changes. We performed a proteomic analysis on left atrial appendage (LAA) tissues from 12 patients with a history of AF undergoing elective surgery; atrial rhythm was documented at time of surgery. Proteomic analysis was performed using liquid chromatography with mass spectrometry (LC/MS-MS). Data-dependent analysis identified 3090 unique proteins, with 408 differentially expressed between sinus rhythm and AF. Ingenuity Pathway Analysis of differentially expressed proteins identified mitochondrial dysfunction, oxidative phosphorylation, and sirtuin signaling among the most affected pathways. Increased abundance of electron transport chain (ETC) proteins in AF was accompanied by decreased expression of ETC complex assembly factors, tricarboxylic acid cycle proteins, and other key metabolic modulators. Discordant changes were also evident in the contractile unit with both up and downregulation of key components. Similar pathways were affected in a comparison of patients with a history of persistent vs. paroxysmal AF, presenting for surgery in sinus rhythm. Together, these data suggest that while the LAA attempts to meet the energetic demands of AF, an uncoordinated response may reduce ATP availability, contribute to tissue contractile and electrophysiologic heterogeneity, and promote a progression of AF from paroxysmal episodes to development of a substrate amenable to persistent arrhythmia.
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20
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Blatter LA, Kanaporis G, Martinez-Hernandez E, Oropeza-Almazan Y, Banach K. Excitation-contraction coupling and calcium release in atrial muscle. Pflugers Arch 2021; 473:317-329. [PMID: 33398498 DOI: 10.1007/s00424-020-02506-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/16/2020] [Indexed: 01/02/2023]
Abstract
In cardiac muscle, the process of excitation-contraction coupling (ECC) describes the chain of events that links action potential induced myocyte membrane depolarization, surface membrane ion channel activation, triggering of Ca2+ induced Ca2+ release from the sarcoplasmic reticulum (SR) Ca2+ store to activation of the contractile machinery that is ultimately responsible for the pump function of the heart. Here we review similarities and differences of structural and functional attributes of ECC between atrial and ventricular tissue. We explore a novel "fire-diffuse-uptake-fire" paradigm of atrial ECC and Ca2+ release that assigns a novel role to the SR SERCA pump and involves a concerted "tandem" activation of the ryanodine receptor Ca2+ release channel by cytosolic and luminal Ca2+. We discuss the contribution of the inositol 1,4,5-trisphosphate (IP3) receptor Ca2+ release channel as an auxiliary pathway to Ca2+ signaling, and we review IP3 receptor-induced Ca2+ release involvement in beat-to-beat ECC, nuclear Ca2+ signaling, and arrhythmogenesis. Finally, we explore the topic of electromechanical and Ca2+ alternans and its ramifications for atrial arrhythmia.
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Affiliation(s)
- L A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA.
| | - G Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - E Martinez-Hernandez
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - Y Oropeza-Almazan
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - K Banach
- Department of Internal Medicine/Cardiology, Rush University Medical Center, Chicago, IL, 60612, USA
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