1
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Si M, Darvish A, Paulhus K, Kumar P, Hamilton KA, Glasscock E. Epilepsy-associated Kv1.1 channel subunits regulate intrinsic cardiac pacemaking in mice. J Gen Physiol 2024; 156:e202413578. [PMID: 39037413 PMCID: PMC11261506 DOI: 10.1085/jgp.202413578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/11/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
The heartbeat originates from spontaneous action potentials in specialized pacemaker cells within the sinoatrial node (SAN) of the right atrium. Voltage-gated potassium channels in SAN myocytes mediate outward K+ currents that regulate cardiac pacemaking by controlling action potential repolarization, influencing the time between heartbeats. Gene expression studies have identified transcripts for many types of voltage-gated potassium channels in the SAN, but most remain of unknown functional significance. One such gene is Kcna1, which encodes epilepsy-associated voltage-gated Kv1.1 K+ channel α-subunits that are important for regulating action potential firing in neurons and cardiomyocytes. Here, we investigated the functional contribution of Kv1.1 to cardiac pacemaking at the whole heart, SAN, and SAN myocyte levels by performing Langendorff-perfused isolated heart preparations, multielectrode array recordings, patch clamp electrophysiology, and immunocytochemistry using Kcna1 knockout (KO) and wild-type (WT) mice. Our results showed that either genetic or pharmacological ablation of Kv1.1 significantly decreased the SAN firing rate, primarily by impairing SAN myocyte action potential repolarization. Voltage-clamp electrophysiology and immunocytochemistry revealed that Kv1.1 exerts its effects despite contributing only a small outward K+ current component, which we term IKv1.1, and despite apparently being present in low abundance at the protein level in SAN myocytes. These findings establish Kv1.1 as the first identified member of the Kv1 channel family to play a role in sinoatrial function, thereby rendering it a potential candidate and therapeutic targeting of sinus node dysfunction. Furthermore, our results demonstrate that small currents generated via low-abundance channels can still have significant impacts on cardiac pacemaking.
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Affiliation(s)
- Man Si
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA
| | - Ahmad Darvish
- School of Biological and Physical Science, Northwestern State University, Natchitoches, LA, USA
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, Shreveport, LA, USA
| | - Kelsey Paulhus
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA
| | - Praveen Kumar
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA
| | - Kathryn A. Hamilton
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, Shreveport, LA, USA
| | - Edward Glasscock
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, Shreveport, Shreveport, LA, USA
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2
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Quigley KS, Gianaros PJ, Norman GJ, Jennings JR, Berntson GG, de Geus EJC. Publication guidelines for human heart rate and heart rate variability studies in psychophysiology-Part 1: Physiological underpinnings and foundations of measurement. Psychophysiology 2024; 61:e14604. [PMID: 38873876 DOI: 10.1111/psyp.14604] [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: 05/11/2022] [Revised: 12/22/2023] [Accepted: 04/04/2024] [Indexed: 06/15/2024]
Abstract
This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain-imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans.
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Affiliation(s)
- Karen S Quigley
- Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Peter J Gianaros
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Greg J Norman
- Department of Psychology, The University of Chicago, Chicago, Illinois, USA
| | - J Richard Jennings
- Department of Psychiatry & Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Gary G Berntson
- Department of Psychology & Psychiatry, The Ohio State University, Columbus, Ohio, USA
| | - Eco J C de Geus
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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3
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Lebedeva EA, Gonotkov MA, Furman AA, Velegzhaninov IO. VOLTAGE-GATED ION CHANNEL'S GENE EXPRESSION IN THE MYOCARDIUM OF EMBRYO AND ADULT CHICKENS. Dev Biol 2024:S0012-1606(24)00210-0. [PMID: 39127438 DOI: 10.1016/j.ydbio.2024.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 08/06/2024] [Accepted: 08/07/2024] [Indexed: 08/12/2024]
Abstract
The functioning of the cardiovascular system is critical for embryo survival. Cardiac contractions depend on the sequential activation of different classes of voltage-gated ion channels. Understanding the fundamental features of these interactions is important for identifying the mechanisms of pathologies development in the myocardium. However, at present there is no consensus on which ion channels are involved in the formation of automaticity in the early embryonic stages. The aim of this study was to elucidate the expression of genes encoding various types of ion channels that are involved in the generation of electrical activity chicken heart at different stages of ontogenesis. We analyzed the expression of 14 genes from different families of ion channels. It was revealed that the expression profiles of ion channel genes change depending on the stages of ontogenesis. The HCN4, CACNA1D, SCN1A, SCN5A, KCNA1 genes have maximum expression at the tubular heart stage. In adult, a switch occurs to the higher expression of CACNA1C, KCNH6, RYR and SLC8A1 genes. This data correlated with the results obtained by the microelectrode method. It can be assumed that the automaticity of the tubular heart is mainly due to the mechanism of the «membrane-clock» (hyperpolarization-activated current (If), Ca2+-current L-type (ICaL), Na+-current (INa) and the slow component of the delayed rectifier K+-current (IKs)). Whereas in adult birds, the mechanism for generating electrical impulses is determined by both «membrane- clock» and «Ca2+-clock».
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Affiliation(s)
- E A Lebedeva
- Institute of Physiology Komi Science Center, Ural Branch Russian Academy of SciencesGSP-2, 50 st. Pervomayskaya, 167982 Syktyvkar, Komi Republic, Russia.
| | - M A Gonotkov
- Institute of Physiology Komi Science Center, Ural Branch Russian Academy of SciencesGSP-2, 50 st. Pervomayskaya, 167982 Syktyvkar, Komi Republic, Russia
| | - A A Furman
- Institute of Physiology Komi Science Center, Ural Branch Russian Academy of SciencesGSP-2, 50 st. Pervomayskaya, 167982 Syktyvkar, Komi Republic, Russia
| | - I O Velegzhaninov
- Institute of Biology, Komi Science Center of Russian Academy of Sciences28 Kommunisticheskaya st., 167982 Syktyvkar, Komi Republic, Russia
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4
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Oh Y, Abid R, Dababneh S, Bakr M, Aslani T, Cook DP, Vanderhyden BC, Park JG, Munshi NV, Hui CC, Kim KH. Transcriptional regulation of the postnatal cardiac conduction system heterogeneity. Nat Commun 2024; 15:6550. [PMID: 39095365 PMCID: PMC11297185 DOI: 10.1038/s41467-024-50849-1] [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: 05/11/2023] [Accepted: 07/23/2024] [Indexed: 08/04/2024] Open
Abstract
The cardiac conduction system (CCS) is a network of specialized cardiomyocytes that coordinates electrical impulse generation and propagation for synchronized heart contractions. Although the components of the CCS, including the sinoatrial node, atrioventricular node, His bundle, bundle branches, and Purkinje fibers, were anatomically discovered more than 100 years ago, their molecular constituents and regulatory mechanisms remain incompletely understood. Here, we demonstrate the transcriptomic landscape of the postnatal mouse CCS at a single-cell resolution with spatial information. Integration of single-cell and spatial transcriptomics uncover region-specific markers and zonation patterns of expression. Network inference shows heterogeneous gene regulatory networks across the CCS. Notably, region-specific gene regulation is recapitulated in vitro using neonatal mouse atrial and ventricular myocytes overexpressing CCS-specific transcription factors, Tbx3 and/or Irx3. This finding is supported by ATAC-seq of different CCS regions, Tbx3 ChIP-seq, and Irx motifs. Overall, this study provides comprehensive molecular profiles of the postnatal CCS and elucidates gene regulatory mechanisms contributing to its heterogeneity.
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Affiliation(s)
- Yena Oh
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rimshah Abid
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Saif Dababneh
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Marwan Bakr
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Termeh Aslani
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - David P Cook
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Barbara C Vanderhyden
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Jin G Park
- Virginia G. Piper Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Nikhil V Munshi
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
- Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chi-Chung Hui
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Kyoung-Han Kim
- University of Ottawa Heart Institute, Ottawa, ON, Canada.
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
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5
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Rose RA, Howlett SE. Preclinical Studies on the Effects of Frailty in the Aging Heart. Can J Cardiol 2024; 40:1379-1393. [PMID: 38460611 DOI: 10.1016/j.cjca.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/11/2024] Open
Abstract
Age is a major risk factor for the development of cardiovascular diseases in men and in women. However, not all people age at the same rate and those who are aging rapidly are considered frail, compared with their fit counterparts. Frailty is an important clinical challenge because those who are frail are more likely to develop and die from illnesses, including cardiovascular diseases, than fit people of the same age. This increase in susceptibility to cardiovascular diseases in older individuals might occur as the cellular and molecular mechanisms involved in the aging process facilitate structural and functional damage in the heart. Consistent with this, recent studies in murine frailty models have provided strong evidence that maladaptive cardiac remodelling in older mice is the most pronounced in mice with a high level of frailty. For example, there is evidence that ventricular hypertrophy and contractile dysfunction increase as frailty increases in aging mice. Additionally, fibrosis and slowing of conduction in the sinoatrial node and atria are proportional to the level of frailty. These modifications could predispose frail older adults to diseases like heart failure and atrial fibrillation. This preclinical work also raises the possibility that emerging interventions designed to "treat frailty" might also treat or prevent cardiovascular diseases. These findings might help to explain why frail older people are most likely to develop these disorders as they age.
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Affiliation(s)
- Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
| | - Susan E Howlett
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medicine (Geriatric Medicine), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
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6
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Boulgakoff L, D'Amato G, Miquerol L. Molecular Regulation of Cardiac Conduction System Development. Curr Cardiol Rep 2024:10.1007/s11886-024-02094-7. [PMID: 38990492 DOI: 10.1007/s11886-024-02094-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/02/2024] [Indexed: 07/12/2024]
Abstract
PURPOSE OF REVIEW The cardiac conduction system, composed of pacemaker cells and conducting cardiomyocytes, orchestrates the propagation of electrical activity to synchronize heartbeats. The conduction system plays a crucial role in the development of cardiac arrhythmias. In the embryo, the cells of the conduction system derive from the same cardiac progenitors as the contractile cardiomyocytes and and the key question is how this choice is made during development. RECENT FINDINGS This review focuses on recent advances in developmental biology using the mouse as animal model to better understand the cellular origin and molecular regulations that control morphogenesis of the cardiac conduction system, including the latest findings in single-cell transcriptomics. The conducting cell fate is acquired during development starting with pacemaking activity and last with the formation of a complex fast-conducting network. Cardiac conduction system morphogenesis is controlled by complex transcriptional and gene regulatory networks that differ in the components of the cardiac conduction system.
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Affiliation(s)
| | - Gaetano D'Amato
- Aix-Marseille Université, CNRS IBDM UMR7288, Marseille, France
| | - Lucile Miquerol
- Aix-Marseille Université, CNRS IBDM UMR7288, Marseille, France.
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7
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Moghtadaei M, Tagirova S, Ahmet I, Moen J, Lakatta EG, Rose RA. Lifelong longitudinal assessment of the contribution of multi-fractal fluctuations to heart rate and heart rate variability in aging mice: role of the sinoatrial node and autonomic nervous system. GeroScience 2024:10.1007/s11357-024-01267-0. [PMID: 38967697 DOI: 10.1007/s11357-024-01267-0] [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: 05/14/2024] [Accepted: 06/25/2024] [Indexed: 07/06/2024] Open
Abstract
Aging is a major risk factor for sinoatrial node (SAN) dysfunction, which can impair heart rate (HR) control and heart rate variability (HRV). HR and HRV are determined by intrinsic SAN function and its regulation by the autonomic nervous system (ANS). The purpose of this study was to use multi-scale multi-fractal detrended fluctuation analysis (MSMFDFA; a complexity-based approach to analyze multi-fractal dynamics) to longitudinally assess changes in multi-fractal HRV properties and SAN function in ECG time series recorded repeatedly across the full adult lifespan in mice. ECGs were recorded in anesthetized mice in baseline conditions and after autonomic nervous system blockade every three months beginning at 6 months of age until the end of life. MSMFDFA was used to assess HRV and SAN function every three months between 6 and 27 months of age. Intrinsic HR (i.e. HR during ANS blockade) remained relatively stable until 15 months of age, and then progressively declined until study endpoint at 27 months of age. MSMFDFA revealed sudden and rapid changes in multi-fractal properties of the ECG RR interval time series in aging mice. In particular, multi-fractal spectrum width (MFSW, a measure of multi-fractality) was relatively stable between 6 months and 15 months of age and then progressively increased at 27 months of age. These changes in MFSW were evident in baseline conditions and during ANS blockade. Thus, intrinsic SAN function declines progressively during aging and is manifested by age-associated changes in multi-fractal HRV across the lifespan in mice, which can be accurately quantified by MSMFDFA.
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Affiliation(s)
- Motahareh Moghtadaei
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, GAC66, Health Research Innovation Centre, 3280 Hospital Drive N.W., Calgary, Alberta, T2N 4Z6, Canada
| | - Syevda Tagirova
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Ismayil Ahmet
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Jack Moen
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
| | - Robert A Rose
- Department of Cardiac Sciences, Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, GAC66, Health Research Innovation Centre, 3280 Hospital Drive N.W., Calgary, Alberta, T2N 4Z6, Canada.
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8
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Chelu A, Cartwright EJ, Dobrzynski H. Empowering artificial intelligence in characterizing the human primary pacemaker of the heart at single cell resolution. Sci Rep 2024; 14:14041. [PMID: 38890395 PMCID: PMC11189420 DOI: 10.1038/s41598-024-63542-6] [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: 05/14/2024] [Accepted: 05/29/2024] [Indexed: 06/20/2024] Open
Abstract
The sinus node (SN) serves as the primary pacemaker of the heart and is the first component of the cardiac conduction system. Due to its anatomical properties and sample scarcity, the cellular composition of the human SN has been historically challenging to study. Here, we employed a novel deep learning deconvolution method, namely Bulk2space, to characterise the cellular heterogeneity of the human SN using existing single-cell datasets of non-human species. As a proof of principle, we used Bulk2Space to profile the cells of the bulk human right atrium using publicly available mouse scRNA-Seq data as a reference. 18 human cell populations were identified, with cardiac myocytes being the most abundant. Each identified cell population correlated to its published experimental counterpart. Subsequently, we applied the deconvolution to the bulk transcriptome of the human SN and identified 11 cell populations, including a population of pacemaker cardiomyocytes expressing pacemaking ion channels (HCN1, HCN4, CACNA1D) and transcription factors (SHOX2 and TBX3). The connective tissue of the SN was characterised by adipocyte and fibroblast populations, as well as key immune cells. Our work unravelled the unique single cell composition of the human SN by leveraging the power of a novel machine learning method.
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Affiliation(s)
- Alexandru Chelu
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PL, UK.
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PL, UK
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PL, UK
- Department of Anatomy, Jagiellonian University Medical College, 31-008, Kraków, Poland
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9
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Belghazi M, Iborra C, Toutendji O, Lasserre M, Debanne D, Goaillard JM, Marquèze-Pouey B. High-Resolution Proteomics Unravel a Native Functional Complex of Cav1.3, SK3, and Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels in Midbrain Dopaminergic Neurons. Cells 2024; 13:944. [PMID: 38891076 PMCID: PMC11172389 DOI: 10.3390/cells13110944] [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: 03/04/2024] [Revised: 05/21/2024] [Accepted: 05/26/2024] [Indexed: 06/21/2024] Open
Abstract
Pacemaking activity in substantia nigra dopaminergic neurons is generated by the coordinated activity of a variety of distinct somatodendritic voltage- and calcium-gated ion channels. We investigated whether these functional interactions could arise from a common localization in macromolecular complexes where physical proximity would allow for efficient interaction and co-regulations. For that purpose, we immunopurified six ion channel proteins involved in substantia nigra neuron autonomous firing to identify their molecular interactions. The ion channels chosen as bait were Cav1.2, Cav1.3, HCN2, HCN4, Kv4.3, and SK3 channel proteins, and the methods chosen to determine interactions were co-immunoprecipitation analyzed through immunoblot and mass spectrometry as well as proximity ligation assay. A macromolecular complex composed of Cav1.3, HCN, and SK3 channels was unraveled. In addition, novel potential interactions between SK3 channels and sclerosis tuberous complex (Tsc) proteins, inhibitors of mTOR, and between HCN4 channels and the pro-degenerative protein Sarm1 were uncovered. In order to demonstrate the presence of these molecular interactions in situ, we used proximity ligation assay (PLA) imaging on midbrain slices containing the substantia nigra, and we could ascertain the presence of these protein complexes specifically in substantia nigra dopaminergic neurons. Based on the complementary functional role of the ion channels in the macromolecular complex identified, these results suggest that such tight interactions could partly underly the robustness of pacemaking in dopaminergic neurons.
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Affiliation(s)
- Maya Belghazi
- CRN2M Centre de Recherche Neurobiologie-Neurophysiologie, CNRS, UMR7286, Aix-Marseille Université, 13015 Marseille, France;
- Institut de Microbiologie de la Méditerranée (IMM), CNRS, Aix-Marseille Université, 13009 Marseille, France
| | - Cécile Iborra
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Ophélie Toutendji
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Manon Lasserre
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Dominique Debanne
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Jean-Marc Goaillard
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
- Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, 13005 Marseille, France
| | - Béatrice Marquèze-Pouey
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
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10
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Hennis K, Piantoni C, Biel M, Fenske S, Wahl-Schott C. Pacemaker Channels and the Chronotropic Response in Health and Disease. Circ Res 2024; 134:1348-1378. [PMID: 38723033 PMCID: PMC11081487 DOI: 10.1161/circresaha.123.323250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease-including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate-sensitive hyperpolarization-activated current (If) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate-dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.
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Affiliation(s)
- Konstantin Hennis
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Chiara Piantoni
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Stefanie Fenske
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Christian Wahl-Schott
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
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11
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Mesquita T, Miguel-Dos-Santos R, Cingolani E. Biological Pacemakers: Present and Future. Circ Res 2024; 134:837-841. [PMID: 38547251 DOI: 10.1161/circresaha.123.323180] [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] [Indexed: 04/02/2024]
Affiliation(s)
- Thassio Mesquita
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Eugenio Cingolani
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
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12
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Gandon-Renard M, Val-Blasco A, Oughlis C, Gerbaud P, Lefebvre F, Gomez S, Journé C, Courilleau D, Mercier-Nomé F, Pereira L, Benitah JP, Gómez AM, Mercadier JJ. Dual effect of cardiac FKBP12.6 overexpression on excitation-contraction coupling and the incidence of ventricular arrhythmia depending on its expression level. J Mol Cell Cardiol 2024; 188:15-29. [PMID: 38224852 DOI: 10.1016/j.yjmcc.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/17/2024]
Abstract
FKBP12.6, a binding protein to the immunosuppressant FK506, which also binds the ryanodine receptor (RyR2) in the heart, has been proposed to regulate RyR2 function and to have antiarrhythmic properties. However, the level of FKBP12.6 expression in normal hearts remains elusive and some controversies still persist regarding its effects, both in basal conditions and during β-adrenergic stimulation. We quantified FKBP12.6 in the left ventricles (LV) of WT (wild-type) mice and in two novel transgenic models expressing distinct levels of FKBP12.6, using a custom-made specific anti-FKBP12.6 antibody and a recombinant protein. FKBP12.6 level in WT LV was very low (0.16 ± 0.02 nmol/g of LV), indicating that <15% RyR2 monomers are bound to the protein. Mice with 14.1 ± 0.2 nmol of FKBP12.6 per g of LV (TG1) had mild cardiac hypertrophy and normal function and were protected against epinephrine/caffeine-evoked arrhythmias. The ventricular myocytes showed higher [Ca2+]i transient amplitudes than WT myocytes and normal SR-Ca2+ load, while fewer myocytes showed Ca2+ sparks. TG1 cardiomyocytes responded to 50 nM Isoproterenol increasing these [Ca2+]i parameters and producing RyR2-Ser2808 phosphorylation. Mice with more than twice the TG1 FKBP12.6 value (TG2) showed marked cardiac hypertrophy with calcineurin activation and more arrhythmias than WT mice during β-adrenergic stimulation, challenging the protective potential of high FKBP12.6. RyR2R420Q CPVT mice overexpressing FKBP12.6 showed fewer proarrhythmic events and decreased incidence and duration of stress-induced bidirectional ventricular tachycardia. Our study, therefore, quantifies for the first time endogenous FKBP12.6 in the mouse heart, questioning its physiological relevance, at least at rest due its low level. By contrast, our work demonstrates that with caution FKBP12.6 remains an interesting target for the development of new antiarrhythmic therapies.
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Affiliation(s)
- Marine Gandon-Renard
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Almudena Val-Blasco
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Célia Oughlis
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Pascale Gerbaud
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Florence Lefebvre
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Susana Gomez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Clément Journé
- Fédération de Recherche en Imagerie Multimodale (FRIM), Université Paris Cité, 75018 Paris, France
| | | | - Françoise Mercier-Nomé
- UMS-IPSIT, Université Paris-Saclay, 91400 Orsay, France; Inflammation, Microbiome and Immunosurveillance, Inserm UMR-996, Université Paris-Saclay, 92140 Clamart, France
| | - Laetitia Pereira
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Jean-Pierre Benitah
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Ana Maria Gómez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France.
| | - Jean-Jacques Mercadier
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France; Université Paris Cité, Paris, France.
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13
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Giles WR. The zebrafish atrioventricular canal: A model for mammalian AV node conduction and secondary or follower pacemaker activity. Acta Physiol (Oxf) 2024; 240:e14105. [PMID: 38270514 DOI: 10.1111/apha.14105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 01/26/2024]
Affiliation(s)
- W R Giles
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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14
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Dorey TW, McRae MD, Belke DD, Rose RA. PDE4D mediates impaired β-adrenergic receptor signalling in the sinoatrial node in mice with hypertensive heart disease. Cardiovasc Res 2023; 119:2697-2711. [PMID: 37643895 PMCID: PMC10757582 DOI: 10.1093/cvr/cvad138] [Citation(s) in RCA: 1] [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: 12/17/2022] [Revised: 06/06/2023] [Accepted: 07/18/2023] [Indexed: 08/31/2023] Open
Abstract
AIMS The sympathetic nervous system increases HR by activating β-adrenergic receptors (β-ARs) and increasing cAMP in sinoatrial node (SAN) myocytes while phosphodiesterases (PDEs) degrade cAMP. Chronotropic incompetence, the inability to regulate heart rate (HR) in response to sympathetic nervous system activation, is common in hypertensive heart disease; however, the basis for this is poorly understood. The objective of this study was to determine the mechanisms leading to chronotropic incompetence in mice with angiotensin II (AngII)-induced hypertensive heart disease. METHODS AND RESULTS C57BL/6 mice were infused with saline or AngII (2.5 mg/kg/day for 3 weeks) to induce hypertensive heart disease. HR and SAN function in response to the β-AR agonist isoproterenol (ISO) were studied in vivo using telemetry and electrocardiography, in isolated atrial preparations using optical mapping, in isolated SAN myocytes using patch-clamping, and using molecular biology. AngII-infused mice had smaller increases in HR in response to physical activity and during acute ISO injection. Optical mapping of the SAN in AngII-infused mice demonstrated impaired increases in conduction velocity and altered conduction patterns in response to ISO. Spontaneous AP firing responses to ISO in isolated SAN myocytes from AngII-infused mice were impaired due to smaller increases in diastolic depolarization (DD) slope, hyperpolarization-activated current (If), and L-type Ca2+ current (ICa,L). These changes were due to increased localization of PDE4D surrounding β1- and β2-ARs in the SAN, increased SAN PDE4 activity, and reduced cAMP generation in response to ISO. Knockdown of PDE4D using a virus-delivered shRNA or inhibition of PDE4 with rolipram normalized SAN sensitivity to β-AR stimulation in AngII-infused mice. CONCLUSIONS AngII-induced hypertensive heart disease results in impaired HR responses to β-AR stimulation due to up-regulation of PDE4D and reduced effects of cAMP on spontaneous AP firing in SAN myocytes.
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Affiliation(s)
- Tristan W Dorey
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Megan D McRae
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Darrell D Belke
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
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15
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Zawieja SD, Pea GA, Broyhill SE, Patro A, Bromert KH, Li M, Norton CE, Castorena-Gonzalez JA, Hancock EJ, Bertram CD, Davis MJ. IP3R1 underlies diastolic ANO1 activation and pressure-dependent chronotropy in lymphatic collecting vessels. J Gen Physiol 2023; 155:e202313358. [PMID: 37851027 PMCID: PMC10585095 DOI: 10.1085/jgp.202313358] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 08/11/2023] [Accepted: 09/22/2023] [Indexed: 10/19/2023] Open
Abstract
Pressure-dependent chronotropy of murine lymphatic collecting vessels relies on the activation of the Ca2+-activated chloride channel encoded by Anoctamin 1 (Ano1) in lymphatic muscle cells. Genetic ablation or pharmacological inhibition of ANO1 results in a significant reduction in basal contraction frequency and essentially complete loss of pressure-dependent frequency modulation by decreasing the rate of the diastolic depolarization phase of the ionic pacemaker in lymphatic muscle cells (LMCs). Oscillating Ca2+ release from sarcoendoplasmic reticulum Ca2+ channels has been hypothesized to drive ANO1 activity during diastole, but the source of Ca2+ for ANO1 activation in smooth muscle remains unclear. Here, we investigated the role of the inositol triphosphate receptor 1 (Itpr1; Ip3r1) in this process using pressure myography, Ca2+ imaging, and membrane potential recordings in LMCs of ex vivo pressurized inguinal-axillary lymphatic vessels from control or Myh11CreERT2;Ip3r1fl/fl (Ip3r1ismKO) mice. Ip3r1ismKO vessels had significant reductions in contraction frequency and tone but an increased contraction amplitude. Membrane potential recordings from LMCs of Ip3r1ismKO vessels revealed a depressed diastolic depolarization rate and an elongation of the plateau phase of the action potential (AP). Ca2+ imaging of LMCs using the genetically encoded Ca2+ sensor GCaMP6f demonstrated an elongation of the Ca2+ flash associated with an AP-driven contraction. Critically, diastolic subcellular Ca2+ transients were absent in LMCs of Ip3r1ismKO mice, demonstrating the necessity of IP3R1 activity in controlling ANO1-mediated diastolic depolarization. These findings indicate a critical role for IP3R1 in lymphatic vessel pressure-dependent chronotropy and contractile regulation.
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Affiliation(s)
- Scott D. Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Grace A. Pea
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Sarah E. Broyhill
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Advaya Patro
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Karen H. Bromert
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Charles E. Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | | | - Edward J. Hancock
- School of Mathematics and Statistics, University of Sydney, Sydney, Australia
| | | | - Michael J. Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
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16
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Leemann S, Schneider-Warme F, Kleinlogel S. Cardiac optogenetics: shining light on signaling pathways. Pflugers Arch 2023; 475:1421-1437. [PMID: 38097805 PMCID: PMC10730638 DOI: 10.1007/s00424-023-02892-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023]
Abstract
In the early 2000s, the field of neuroscience experienced a groundbreaking transformation with the advent of optogenetics. This innovative technique harnesses the properties of naturally occurring and genetically engineered rhodopsins to confer light sensitivity upon target cells. The remarkable spatiotemporal precision offered by optogenetics has provided researchers with unprecedented opportunities to dissect cellular physiology, leading to an entirely new level of investigation. Initially revolutionizing neuroscience, optogenetics quickly piqued the interest of the wider scientific community, and optogenetic applications were expanded to cardiovascular research. Over the past decade, researchers have employed various optical tools to observe, regulate, and steer the membrane potential of excitable cells in the heart. Despite these advancements, achieving control over specific signaling pathways within the heart has remained an elusive goal. Here, we review the optogenetic tools suitable to control cardiac signaling pathways with a focus on GPCR signaling, and delineate potential applications for studying these pathways, both in healthy and diseased hearts. By shedding light on these exciting developments, we hope to contribute to the ongoing progress in basic cardiac research to facilitate the discovery of novel therapeutic possibilities for treating cardiovascular pathologies.
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Affiliation(s)
- Siri Leemann
- Institute of Physiology, University of Bern, Bern, Switzerland.
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Sonja Kleinlogel
- Institute of Physiology, University of Bern, Bern, Switzerland
- F. Hoffmann-La Roche, Translational Medicine Neuroscience, Basel, Switzerland
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17
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Mesirca P. Nfix: a transcription factor with an important functional role in cardiac automaticity. Acta Physiol (Oxf) 2023; 239:e14034. [PMID: 37596765 DOI: 10.1111/apha.14034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/20/2023]
Affiliation(s)
- Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, Inserm, Montpellier, France
- LabEx, Ion ChannelsScience and Therapeutics, Montpellier, France
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18
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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19
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Engel JL, Zhang X, Lu DR, Vila OF, Arias V, Lee J, Hale C, Hsu YH, Li CM, Wu RS, Vedantham V, Ang YS. Single Cell Multi-Omics of an iPSC Model of Human Sinoatrial Node Development Reveals Genetic Determinants of Heart Rate and Arrhythmia Susceptibility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.01.547335. [PMID: 37425707 PMCID: PMC10327193 DOI: 10.1101/2023.07.01.547335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cellular heterogeneity within the sinoatrial node (SAN) is functionally important but has been difficult to model in vitro , presenting a major obstacle to studies of heart rate regulation and arrhythmias. Here we describe a scalable method to derive sinoatrial node pacemaker cardiomyocytes (PCs) from human induced pluripotent stem cells that recapitulates differentiation into distinct PC subtypes, including SAN Head, SAN Tail, transitional zone cells, and sinus venosus myocardium. Single cell (sc) RNA-sequencing, sc-ATAC-sequencing, and trajectory analyses were used to define epigenetic and transcriptomic signatures of each cell type, and to identify novel transcriptional pathways important for PC subtype differentiation. Integration of our multi-omics datasets with genome wide association studies uncovered cell type-specific regulatory elements that associated with heart rate regulation and susceptibility to atrial fibrillation. Taken together, these datasets validate a novel, robust, and realistic in vitro platform that will enable deeper mechanistic exploration of human cardiac automaticity and arrhythmia.
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20
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El Gameel D, Sharif AF, Shoeib O, Elgebally EI, Fayed MM. Development and validation of a risk prediction nomogram for serious arrhythmias in acute digoxin toxicity among pediatrics: A multicenter study. Toxicon 2023; 233:107241. [PMID: 37558139 DOI: 10.1016/j.toxicon.2023.107241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/24/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023]
Abstract
Digoxin is a cardiac glycoside obtained from the leaves of the foxglove plant, Digitalis lanata. Several studies have described the safety of digoxin including various life-threatening events, notably cardiac arrhythmias. Early identification of high-risk patients and subsequent initiation of the utmost medical care are associated with a better prognosis. The assessment of serum digoxin levels, which is not always convenient, is the only tool used to evaluate the severity of digoxin exposure. However, the feasibility of this tool, particularly in resource-restricted countries, remains unclear. Therefore, the current study aimed to establish and validate a feasible alternative tool, a bedside nomogram, to identify pediatric patients diagnosed with acute digoxin intoxication who are at risk of developing serious arrhythmias. This was a two-phase, multicenter, retrospective study. The prevalence of serious arrhythmias was approximately 17%. Patients diagnosed with serious arrhythmias showed significantly higher serum digoxin, random blood glucose, and potassium levels but lower sodium, magnesium, and hemoglobin levels. Serious arrhythmias were associated with significantly lower P-R intervals, shorter QTc intervals, and more frequent digoxin effects (p < 0.05). The proposed nomogram showed that combining age and initial random blood glucose, sodium, and potassium levels could predict the future incidence of serious arrhythmia with an accuracy of 96.2% (sensitivity = 94.4%, specificity = 96.5%), an area under the curve (AUC) of 0.977, and p < 0.001. Validation of the proposed nomogram yielded an AUC for the nomogram probability of approximately 81%, and the AUC for the predicted probability using the developed model was 98.3%, indicating that both the validated model and the developed nomogram were significant predictors of serious arrhythmia. The utility of using the four-factor nomogram to determine the risk of serious arrhythmia in children exposed to an overdose of digoxin is comparable, if not superior, to the serum digoxin level.
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Affiliation(s)
- Dina El Gameel
- Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; Poison Control Center, Aseer, Saudi Arabia
| | - Asmaa Fady Sharif
- Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; Clinical Medical Sciences Department, College of Medicine, Dar Al-Uloom University, Riyadh, Saudi Arabia.
| | - Osama Shoeib
- Cardiology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Elsayed Ibrahim Elgebally
- Department of Pediatrics, Menoufia University, Shebeen Al-kom, Egypt; Paediatric Department, Saudi German Hospital, Aseer, Saudi Arabia
| | - Manar Maher Fayed
- Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
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21
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Li N, Li YJ, Guo XJ, Wu SH, Jiang WF, Zhang DL, Wang KW, Li L, Sun YM, Xu YJ, Yang YQ, Qiu XB. Discovery of TBX20 as a Novel Gene Underlying Atrial Fibrillation. BIOLOGY 2023; 12:1186. [PMID: 37759586 PMCID: PMC10525918 DOI: 10.3390/biology12091186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/29/2023]
Abstract
Atrial fibrillation (AF), the most prevalent type of sustained cardiac dysrhythmia globally, confers strikingly enhanced risks for cognitive dysfunction, stroke, chronic cardiac failure, and sudden cardiovascular demise. Aggregating studies underscore the crucial roles of inherited determinants in the occurrence and perpetuation of AF. However, due to conspicuous genetic heterogeneity, the inherited defects accounting for AF remain largely indefinite. Here, via whole-genome genotyping with genetic markers and a linkage assay in a family suffering from AF, a new AF-causative locus was located at human chromosome 7p14.2-p14.3, a ~4.89 cM (~4.43-Mb) interval between the markers D7S526 and D7S2250. An exome-wide sequencing assay unveiled that, at the defined locus, the mutation in the TBX20 gene, NM_001077653.2: c.695A>G; p.(His232Arg), was solely co-segregated with AF in the family. Additionally, a Sanger sequencing assay of TBX20 in another family suffering from AF uncovered a novel mutation, NM_001077653.2: c.862G>C; p.(Asp288His). Neither of the two mutations were observed in 600 unrelated control individuals. Functional investigations demonstrated that the two mutations both significantly reduced the transactivation of the target gene KCNH2 (a well-established AF-causing gene) and the ability to bind the promoter of KCNH2, while they had no effect on the nuclear distribution of TBX20. Conclusively, these findings reveal a new AF-causative locus at human chromosome 7p14.2-p14.3 and strongly indicate TBX20 as a novel AF-predisposing gene, shedding light on the mechanism underlying AF and suggesting clinical significance for the allele-specific treatment of AF patients.
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Affiliation(s)
- Ning Li
- Department of Cardiology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China;
| | - Yan-Jie Li
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China; (Y.-J.L.); (S.-H.W.); (W.-F.J.)
| | - Xiao-Juan Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China; (X.-J.G.); (Y.-J.X.)
- Center for Complex Cardiac Arrhythmias of Minhang District, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Shao-Hui Wu
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China; (Y.-J.L.); (S.-H.W.); (W.-F.J.)
| | - Wei-Feng Jiang
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China; (Y.-J.L.); (S.-H.W.); (W.-F.J.)
| | - Dao-Liang Zhang
- Cardiac Arrhythmia Center, Fuwai Hospital, Chinese Academy of Medical Sciences, Shenzhen 518057, China;
| | - Kun-Wei Wang
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China;
| | - Li Li
- Key Laboratory of Arrhythmias, Ministry of Education of China, Tongji University School of Medicine, Shanghai 200092, China;
| | - Yu-Min Sun
- Department of Cardiology, Shanghai Jing’an District Central Hospital, Fudan University, Shanghai 200040, China;
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China; (X.-J.G.); (Y.-J.X.)
- Center for Complex Cardiac Arrhythmias of Minhang District, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China; (X.-J.G.); (Y.-J.X.)
- Center for Complex Cardiac Arrhythmias of Minhang District, Shanghai Fifth People′s Hospital, Fudan University, Shanghai 200240, China
- Cardiovascular Research Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
- Central Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China; (Y.-J.L.); (S.-H.W.); (W.-F.J.)
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22
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Liu CM, Chen YC, Hu YF. Harnessing cell reprogramming for cardiac biological pacing. J Biomed Sci 2023; 30:74. [PMID: 37633890 PMCID: PMC10463311 DOI: 10.1186/s12929-023-00970-y] [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: 05/06/2023] [Accepted: 08/22/2023] [Indexed: 08/28/2023] Open
Abstract
Electrical impulses from cardiac pacemaker cardiomyocytes initiate cardiac contraction and blood pumping and maintain life. Abnormal electrical impulses bring patients with low heart rates to cardiac arrest. The current therapy is to implant electronic devices to generate backup electricity. However, complications inherent to electronic devices remain unbearable suffering. Therefore, cardiac biological pacing has been developed as a hardware-free alternative. The approaches to generating biological pacing have evolved recently using cell reprogramming technology to generate pacemaker cardiomyocytes in-vivo or in-vitro. Different from conventional methods by electrical re-engineering, reprogramming-based biological pacing recapitulates various phenotypes of de novo pacemaker cardiomyocytes and is more physiological, efficient, and easy for clinical implementation. This article reviews the present state of the art in reprogramming-based biological pacing. We begin with the rationale for this new approach and review its advances in creating a biological pacemaker to treat bradyarrhythmia.
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Affiliation(s)
- Chih-Min Liu
- Division of Cardiology, Department of Medicine, Heart Rhythm Center, Taipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine and Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chun Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Institute of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yu-Feng Hu
- Division of Cardiology, Department of Medicine, Heart Rhythm Center, Taipei Veterans General Hospital, Taipei, Taiwan.
- Faculty of Medicine and Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
- Institute of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan.
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23
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Delgado-Betancourt V, Chinda K, Mesirca P, Barrère C, Covinhes A, Gallot L, Vincent A, Bidaud I, Kumphune S, Nargeot J, Piot C, Wickman K, Mangoni ME, Barrère-Lemaire S. Heart rate reduction after genetic ablation of L-type Ca v1.3 channels induces cardioprotection against ischemia-reperfusion injury. Front Cardiovasc Med 2023; 10:1134503. [PMID: 37593151 PMCID: PMC10429177 DOI: 10.3389/fcvm.2023.1134503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 06/21/2023] [Indexed: 08/19/2023] Open
Abstract
Background Acute myocardial infarction (AMI) is the major cause of cardiovascular mortality worldwide. Most ischemic episodes are triggered by an increase in heart rate, which induces an imbalance between myocardial oxygen delivery and consumption. Developing drugs that selectively reduce heart rate by inhibiting ion channels involved in heart rate control could provide more clinical benefits. The Cav1.3-mediated L-type Ca2+ current (ICav1.3) play important roles in the generation of heart rate. Therefore, they can constitute relevant targets for selective control of heart rate and cardioprotection during AMI. Objective We aimed to investigate the relationship between heart rate and infarct size using mouse strains knockout for Cav1.3 (Cav1.3-/-) L-type calcium channel and of the cardiac G protein gated potassium channel (Girk4-/-) in association with the funny (f)-channel inhibitor ivabradine. Methods Wild-type (WT), Cav1.3+/-, Cav1.3-/- and Girk4-/- mice were used as models of respectively normal heart rate, moderate heart rate reduction, bradycardia, and mild tachycardia, respectively. Mice underwent a surgical protocol of myocardial IR (40 min ischemia and 60 min reperfusion). Heart rate was recorded by one-lead surface ECG recording, and infarct size measured by triphenyl tetrazolium chloride staining. In addition, Cav1.3-/- and WT hearts perfused on a Langendorff system were subjected to the same ischemia-reperfusion protocol ex vivo, without or with atrial pacing, and the coronary flow was recorded. Results Cav1.3-/- mice presented reduced infarct size (-29%), while Girk4-/- displayed increased infarct size (+30%) compared to WT mice. Consistently, heart rate reduction in Cav1.3+/- or by the f-channel blocker ivabradine was associated with significant decrease in infarct size (-27% and -32%, respectively) in comparison to WT mice. Conclusion Our results show that decreasing heart rate allows to protect the myocardium against IR injury in vivo and reveal a close relationship between basal heart rate and IR injury. In addition, this study suggests that targeting Cav1.3 channels could constitute a relevant target for reducing infarct size, since maximal heart rate dependent cardioprotective effect is already observed in Cav1.3+/- mice.
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Affiliation(s)
- Viviana Delgado-Betancourt
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Kroekkiat Chinda
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Christian Barrère
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Aurélie Covinhes
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Laura Gallot
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Anne Vincent
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Sarawut Kumphune
- Biomedical Engineering Institute (BMEi), Chiang Mai University, Chiang Mai, Thailand
| | - Joël Nargeot
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Christophe Piot
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
- Département de Cardiologie Interventionnelle, Clinique du Millénaire, Montpellier, France
| | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
| | - Matteo Elia Mangoni
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
| | - Stéphanie Barrère-Lemaire
- Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France
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24
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Kanemaru K, Cranley J, Muraro D, Miranda AMA, Ho SY, Wilbrey-Clark A, Patrick Pett J, Polanski K, Richardson L, Litvinukova M, Kumasaka N, Qin Y, Jablonska Z, Semprich CI, Mach L, Dabrowska M, Richoz N, Bolt L, Mamanova L, Kapuge R, Barnett SN, Perera S, Talavera-López C, Mulas I, Mahbubani KT, Tuck L, Wang L, Huang MM, Prete M, Pritchard S, Dark J, Saeb-Parsy K, Patel M, Clatworthy MR, Hübner N, Chowdhury RA, Noseda M, Teichmann SA. Spatially resolved multiomics of human cardiac niches. Nature 2023; 619:801-810. [PMID: 37438528 PMCID: PMC10371870 DOI: 10.1038/s41586-023-06311-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 06/12/2023] [Indexed: 07/14/2023]
Abstract
The function of a cell is defined by its intrinsic characteristics and its niche: the tissue microenvironment in which it dwells. Here we combine single-cell and spatial transcriptomics data to discover cellular niches within eight regions of the human heart. We map cells to microanatomical locations and integrate knowledge-based and unsupervised structural annotations. We also profile the cells of the human cardiac conduction system1. The results revealed their distinctive repertoire of ion channels, G-protein-coupled receptors (GPCRs) and regulatory networks, and implicated FOXP2 in the pacemaker phenotype. We show that the sinoatrial node is compartmentalized, with a core of pacemaker cells, fibroblasts and glial cells supporting glutamatergic signalling. Using a custom CellPhoneDB.org module, we identify trans-synaptic pacemaker cell interactions with glia. We introduce a druggable target prediction tool, drug2cell, which leverages single-cell profiles and drug-target interactions to provide mechanistic insights into the chronotropic effects of drugs, including GLP-1 analogues. In the epicardium, we show enrichment of both IgG+ and IgA+ plasma cells forming immune niches that may contribute to infection defence. Overall, we provide new clarity to cardiac electro-anatomy and immunology, and our suite of computational approaches can be applied to other tissues and organs.
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Affiliation(s)
- Kazumasa Kanemaru
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - James Cranley
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Daniele Muraro
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | | | - Siew Yen Ho
- Cardiac Morphology Unit, Royal Brompton Hospital and Imperial College London, London, UK
| | - Anna Wilbrey-Clark
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Jan Patrick Pett
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Krzysztof Polanski
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Laura Richardson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Monika Litvinukova
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Natsuhiko Kumasaka
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Yue Qin
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Zuzanna Jablonska
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Claudia I Semprich
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Lukas Mach
- National Heart and Lung Institute, Imperial College London, London, UK
- Royal Brompton Hospital, London, UK
| | - Monika Dabrowska
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Nathan Richoz
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Liam Bolt
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Lira Mamanova
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Rakeshlal Kapuge
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Sam N Barnett
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Shani Perera
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Carlos Talavera-López
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
- Würzburg Institute for Systems Immunology, Max Planck Research Group, Julius-Maximilian-Universität, Würzburg, Germany
| | - Ilaria Mulas
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Krishnaa T Mahbubani
- Department of Surgery, University of Cambridge, and Cambridge Biorepository for Translational Medicine, NIHR Cambridge Biomedical Centre, Cambridge, UK
| | - Liz Tuck
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Lu Wang
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Margaret M Huang
- Department of Surgery, University of Cambridge, and Cambridge Biorepository for Translational Medicine, NIHR Cambridge Biomedical Centre, Cambridge, UK
| | - Martin Prete
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Sophie Pritchard
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - John Dark
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Kourosh Saeb-Parsy
- Department of Surgery, University of Cambridge, and Cambridge Biorepository for Translational Medicine, NIHR Cambridge Biomedical Centre, Cambridge, UK
| | - Minal Patel
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Menna R Clatworthy
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Norbert Hübner
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Charité-Universitätsmedizin, Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | | | - Michela Noseda
- National Heart and Lung Institute, Imperial College London, London, UK.
| | - Sarah A Teichmann
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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25
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Kyle Martin W, Schladweiler MC, Oshiro W, Smoot J, Fisher A, Williams W, Valdez M, Miller CN, Jackson TW, Freeborn D, Kim YH, Davies D, Ian Gilmour M, Kodavanti U, Kodavanti P, Hazari MS, Farraj AK. Wildfire-related smoke inhalation worsens cardiovascular risk in sleep disrupted rats. FRONTIERS IN ENVIRONMENTAL HEALTH 2023; 2:1166918. [PMID: 38116203 PMCID: PMC10726696 DOI: 10.3389/fenvh.2023.1166918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Introduction As a lifestyle factor, poor sleep status is associated with increased cardiovascular morbidity and mortality and may be influenced by environmental stressors, including air pollution. Methods To determine whether exposure to air pollution modified cardiovascular effects of sleep disruption, we evaluated the effects of single or repeated (twice/wk for 4 wks) inhalation exposure to eucalyptus wood smoke (ES; 964 μg/m3 for 1 h), a key wildland fire air pollution source, on mild sleep loss in the form of gentle handling in rats. Blood pressure (BP) radiotelemetry and echocardiography were evaluated along with assessments of lung and systemic inflammation, cardiac and hypothalamic gene expression, and heart rate variability (HRV), a measure of cardiac autonomic tone. Results and Discussion GH alone disrupted sleep, as evidenced by active period-like locomotor activity, and increases in BP, heart rate (HR), and hypothalamic expression of the circadian gene Per2. A single bout of sleep disruption and ES, but neither alone, increased HR and BP as rats transitioned into their active period, a period aligned with a critical early morning window for stroke risk in humans. These responses were immediately preceded by reduced HRV, indicating increased cardiac sympathetic tone. In addition, only sleep disrupted rats exposed to ES had increased HR and BP during the final sleep disruption period. These rats also had increased cardiac output and cardiac expression of genes related to adrenergic function, and regulation of vasoconstriction and systemic blood pressure one day after final ES exposure. There was little evidence of lung or systemic inflammation, except for increases in serum LDL cholesterol and alanine aminotransferase. These results suggest that inhaled air pollution increases sleep perturbation-related cardiovascular risk, potentially in part by increased sympathetic activity.
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Affiliation(s)
- W. Kyle Martin
- Curriculum in Toxicology and Environmental Medicine, UNC, Chapel Hill, NC, United States
| | - M. C. Schladweiler
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - W. Oshiro
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - J. Smoot
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - A. Fisher
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - W. Williams
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - M. Valdez
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - C. N. Miller
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - T. W. Jackson
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - D. Freeborn
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - Y. H. Kim
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - D. Davies
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - M. Ian Gilmour
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - U. Kodavanti
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - P. Kodavanti
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - M. S. Hazari
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
| | - A. K. Farraj
- Public Health & Integrated Toxicology Division, US EPA, Research Triangle Park, NC, United States
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26
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Martin KE, Ravisankar P, Beerens M, MacRae CA, Waxman JS. Nr2f1a maintains atrial nkx2.5 expression to repress pacemaker identity within venous atrial cardiomyocytes of zebrafish. eLife 2023; 12:e77408. [PMID: 37184369 PMCID: PMC10185342 DOI: 10.7554/elife.77408] [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: 01/27/2022] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Maintenance of cardiomyocyte identity is vital for normal heart development and function. However, our understanding of cardiomyocyte plasticity remains incomplete. Here, we show that sustained expression of the zebrafish transcription factor Nr2f1a prevents the progressive acquisition of ventricular cardiomyocyte (VC) and pacemaker cardiomyocyte (PC) identities within distinct regions of the atrium. Transcriptomic analysis of flow-sorted atrial cardiomyocytes (ACs) from nr2f1a mutant zebrafish embryos showed increased VC marker gene expression and altered expression of core PC regulatory genes, including decreased expression of nkx2.5, a critical repressor of PC differentiation. At the arterial (outflow) pole of the atrium in nr2f1a mutants, cardiomyocytes resolve to VC identity within the expanded atrioventricular canal. However, at the venous (inflow) pole of the atrium, there is a progressive wave of AC transdifferentiation into PCs across the atrium toward the arterial pole. Restoring Nkx2.5 is sufficient to repress PC marker identity in nr2f1a mutant atria and analysis of chromatin accessibility identified an Nr2f1a-dependent nkx2.5 enhancer expressed in the atrial myocardium directly adjacent to PCs. CRISPR/Cas9-mediated deletion of the putative nkx2.5 enhancer leads to a loss of Nkx2.5-expressing ACs and expansion of a PC reporter, supporting that Nr2f1a limits PC differentiation within venous ACs via maintaining nkx2.5 expression. The Nr2f-dependent maintenance of AC identity within discrete atrial compartments may provide insights into the molecular etiology of concurrent structural congenital heart defects and associated arrhythmias.
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Affiliation(s)
- Kendall E Martin
- Molecular Genetics, Biochemistry, and Microbiology Graduate Program, University of Cincinnati College of MedicineCincinnatiUnited States
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Padmapriyadarshini Ravisankar
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Manu Beerens
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Calum A MacRae
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Joshua S Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Department of Pediatrics, University of Cincinnati College of MedicineCincinnatiUnited States
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27
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Manoj P, Kim JA, Kim S, Li T, Sewani M, Chelu MG, Li N. Sinus node dysfunction: current understanding and future directions. Am J Physiol Heart Circ Physiol 2023; 324:H259-H278. [PMID: 36563014 PMCID: PMC9886352 DOI: 10.1152/ajpheart.00618.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
The sinoatrial node (SAN) is the primary pacemaker of the heart. Normal SAN function is crucial in maintaining proper cardiac rhythm and contraction. Sinus node dysfunction (SND) is due to abnormalities within the SAN, which can affect the heartbeat frequency, regularity, and the propagation of electrical pulses through the cardiac conduction system. As a result, SND often increases the risk of cardiac arrhythmias. SND is most commonly seen as a disease of the elderly given the role of degenerative fibrosis as well as other age-dependent changes in its pathogenesis. Despite the prevalence of SND, current treatment is limited to pacemaker implantation, which is associated with substantial medical costs and complications. Emerging evidence has identified various genetic abnormalities that can cause SND, shedding light on the molecular underpinnings of SND. Identification of these molecular mechanisms and pathways implicated in the pathogenesis of SND is hoped to identify novel therapeutic targets for the development of more effective therapies for this disease. In this review article, we examine the anatomy of the SAN and the pathophysiology and epidemiology of SND. We then discuss in detail the most common genetic mutations correlated with SND and provide our perspectives on future research and therapeutic opportunities in this field.
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Affiliation(s)
- Pavan Manoj
- School of Public Health, Texas A&M University, College Station, Texas
| | - Jitae A Kim
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Stephanie Kim
- Department of BioSciences, Rice University, Houston, Texas
| | - Tingting Li
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Maham Sewani
- Department of BioSciences, Rice University, Houston, Texas
| | - Mihail G Chelu
- Division of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Na Li
- Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas
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28
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Characterization of sinoatrial automaticity in Microcebus murinus to study the effect of aging on cardiac activity and the correlation with longevity. Sci Rep 2023; 13:3054. [PMID: 36810863 PMCID: PMC9944915 DOI: 10.1038/s41598-023-29723-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
Microcebus murinus, or gray mouse lemur (GML), is one of the smallest primates known, with a size in between mice and rats. The small size, genetic proximity to humans and prolonged senescence, make this lemur an emerging model for neurodegenerative diseases. For the same reasons, it could help understand how aging affects cardiac activity. Here, we provide the first characterization of sinoatrial (SAN) pacemaker activity and of the effect of aging on GML heart rate (HR). According to GML size, its heartbeat and intrinsic pacemaker frequencies lie in between those of mice and rats. To sustain this fast automaticity the GML SAN expresses funny and Ca2+ currents (If, ICa,L and ICa,T) at densities similar to that of small rodents. SAN automaticity was also responsive to β-adrenergic and cholinergic pharmacological stimulation, showing a consequent shift in the localization of the origin of pacemaker activity. We found that aging causes decrease of basal HR and atrial remodeling in GML. We also estimated that, over 12 years of a lifetime, GML generates about 3 billion heartbeats, thus, as many as humans and three times more than rodents of equivalent size. In addition, we estimated that the high number of heartbeats per lifetime is a characteristic that distinguishes primates from rodents or other eutherian mammals, independently from body size. Thus, cardiac endurance could contribute to the exceptional longevity of GML and other primates, suggesting that GML's heart sustains a workload comparable to that of humans in a lifetime. In conclusion, despite the fast HR, GML replicates some of the cardiac deficiencies reported in old people, providing a suitable model to study heart rhythm impairment in aging. Moreover, we estimated that, along with humans and other primates, GML presents a remarkable cardiac longevity, enabling longer life span than other mammals of equivalent size.
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Zalas D, Bobkowski W, Piskorski J, Guzik P. Heart Rate Asymmetry in Healthy Children. J Clin Med 2023; 12:jcm12031194. [PMID: 36769841 PMCID: PMC9918166 DOI: 10.3390/jcm12031194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Heart rate asymmetry (HRA) is a physiological phenomenon characterized by an unequal contribution of heart rate decelerations and accelerations to different heart rate variability (HRV) features. While HRA has been demonstrated in adults' ECGs of different duration, a similar investigation in healthy children has not been conducted. This study investigated the variance- and number-based HRA features in 96 healthy children (50 girls and 46 boys, aged 3-18 years) using 24-h ECGs. Additionally, we studied sex differences in HRA. To quantify HRA, variance-based and relative contributions of heart rate decelerations to short-term (C1d), long-term (C2d), and total (CTd) HRV, and the number of all heartbeats (Nd) were computed. Heart rate decelerations contributed more to C1d, but less to C2d and CTd, and were less frequent than heart rate accelerations. Short-term HRA was better expressed in boys. The majority of children (93.7%) had short-term HRA, 88.5% had long-term HRA, 88.5% had total HRA, and 99.0% had more accelerations than decelerations. No sex differences were observed for the rate of various HRA features. Heart rate asymmetry is a common phenomenon in healthy children, as observed in 24-h ECGs. Our findings can be used as reference data for future clinical studies on HRA in children.
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Affiliation(s)
- Dominika Zalas
- Department of Pediatric Cardiology, Poznan University of Medical Sciences, 61-701 Poznań, Poland
| | - Waldemar Bobkowski
- Department of Pediatric Cardiology, Poznan University of Medical Sciences, 61-701 Poznań, Poland
| | - Jarosław Piskorski
- Institute of Physics, University of Zielona Gora, 65-516 Zielona Góra, Poland
| | - Przemysław Guzik
- Department of Cardiology-Intensive Therapy, Poznan University of Medical Sciences, 61-701 Poznań, Poland
- Correspondence:
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Landstrom AP, Yang Q, Sun B, Perelli RM, Bidzimou MT, Zhang Z, Aguilar-Sanchez Y, Alsina KM, Cao S, Reynolds JO, Word TA, van der Sangen NM, Wells Q, Kannankeril PJ, Ludwig A, Kim JJ, Wehrens XH. Reduction in Junctophilin 2 Expression in Cardiac Nodal Tissue Results in Intracellular Calcium-Driven Increase in Nodal Cell Automaticity. Circ Arrhythm Electrophysiol 2023; 16:e010858. [PMID: 36706317 PMCID: PMC9974897 DOI: 10.1161/circep.122.010858] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 01/06/2023] [Indexed: 01/29/2023]
Abstract
BACKGROUND Spontaneously depolarizing nodal cells comprise the pacemaker of the heart. Intracellular calcium (Ca2+) plays a critical role in mediating nodal cell automaticity and understanding this so-called Ca2+ clock is critical to understanding nodal arrhythmias. We previously demonstrated a role for Jph2 (junctophilin 2) in regulating Ca2+-signaling through inhibition of RyR2 (ryanodine receptor 2) Ca2+ leak in cardiac myocytes; however, its role in pacemaker function and nodal arrhythmias remains unknown. We sought to determine whether nodal Jph2 expression silencing causes increased sinoatrial and atrioventricular nodal cell automaticity due to aberrant RyR2 Ca2+ leak. METHODS A tamoxifen-inducible, nodal tissue-specific, knockdown mouse of Jph2 was achieved using a Cre-recombinase-triggered short RNA hairpin directed against Jph2 (Hcn4:shJph2). In vivo cardiac rhythm was monitored by surface ECG, implantable cardiac telemetry, and intracardiac electrophysiology studies. Intracellular Ca2+ imaging was performed using confocal-based line scans of isolated nodal cells loaded with fluorescent Ca2+ reporter Cal-520. Whole cell patch clamp was conducted on isolated nodal cells to determine action potential kinetics and sodium-calcium exchanger function. RESULTS Hcn4:shJph2 mice demonstrated a 40% reduction in nodal Jph2 expression, resting sinus tachycardia, and impaired heart rate response to pharmacologic stress. In vivo intracardiac electrophysiology studies and ex vivo optical mapping demonstrated accelerated junctional rhythm originating from the atrioventricular node. Hcn4:shJph2 nodal cells demonstrated increased and irregular Ca2+ transient generation with increased Ca2+ spark frequency and Ca2+ leak from the sarcoplasmic reticulum. This was associated with increased nodal cell AP firing rate, faster diastolic repolarization rate, and reduced sodium-calcium exchanger activity during repolarized states compared to control. Phenome-wide association studies of the JPH2 locus identified an association with sinoatrial nodal disease and atrioventricular nodal block. CONCLUSIONS Nodal-specific Jph2 knockdown causes increased nodal automaticity through increased Ca2+ leak from intracellular stores. Dysregulated intracellular Ca2+ underlies nodal arrhythmogenesis in this mouse model.
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Affiliation(s)
- Andrew P. Landstrom
- Dept of Pediatrics, Division of Cardiology, Duke Univ School of Medicine, Durham, NC
- Dept of Cell Biology, Duke Univ School of Medicine, Durham, NC
| | - Qixin Yang
- Dept of Pediatrics, Division of Cardiology, Duke Univ School of Medicine, Durham, NC
- Dept of Cardiology, The First Affiliated Hospital, College of Medicine, Zhejiang Univ, Hangzhou, China
| | - Bo Sun
- Dept of Pediatrics, Division of Cardiology, Duke Univ School of Medicine, Durham, NC
| | | | | | - Zhushan Zhang
- Dept of Cell Biology, Duke Univ School of Medicine, Durham, NC
| | - Yuriana Aguilar-Sanchez
- Integrative Molecular & Biomedical Sciences Program, Baylor College of Medicine, Houston, TX
| | - Katherina M. Alsina
- Integrative Molecular & Biomedical Sciences Program, Baylor College of Medicine, Houston, TX
| | - Shuyi Cao
- Dept of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX
| | - Julia O. Reynolds
- Dept of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX
| | - Tarah A. Word
- Dept of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX
| | | | - Quinn Wells
- Depts of Medicine, Pharmacology, and Biomedical Informatics, Vanderbilt Univ School of Medicine, Nashville, TN
| | - Prince J. Kannankeril
- Center for Pediatric Precision Medicine, Dept of Pediatrics, Vanderbilt Univ School of Medicine, Nashville, TN
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jeffrey J. Kim
- Dept of Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, TX
| | - Xander H.T. Wehrens
- Dept of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX
- Dept of Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, TX
- Depts of Neuroscience & Center for Space Medicine and the Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
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Ricci E, Bartolucci C, Severi S. The virtual sinoatrial node: What did computational models tell us about cardiac pacemaking? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:55-79. [PMID: 36374743 DOI: 10.1016/j.pbiomolbio.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/17/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
Abstract
Since its discovery, the sinoatrial node (SAN) has represented a fascinating and complex matter of research. Despite over a century of discoveries, a full comprehension of pacemaking has still to be achieved. Experiments often produced conflicting evidence that was used either in support or against alternative theories, originating intense debates. In this context, mathematical descriptions of the phenomena underlying the heartbeat have grown in importance in the last decades since they helped in gaining insights where experimental evaluation could not reach. This review presents the most updated SAN computational models and discusses their contribution to our understanding of cardiac pacemaking. Electrophysiological, structural and pathological aspects - as well as the autonomic control over the SAN - are taken into consideration to reach a holistic view of SAN activity.
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Affiliation(s)
- Eugenio Ricci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy
| | - Chiara Bartolucci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy
| | - Stefano Severi
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena (FC), Italy.
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32
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Fan W, Sun X, Yang C, Wan J, Luo H, Liao B. Pacemaker activity and ion channels in the sinoatrial node cells: MicroRNAs and arrhythmia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:151-167. [PMID: 36450332 DOI: 10.1016/j.pbiomolbio.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/13/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022]
Abstract
The primary pacemaking activity of the heart is determined by a spontaneous action potential (AP) within sinoatrial node (SAN) cells. This unique AP generation relies on two mechanisms: membrane clocks and calcium clocks. Nonhomologous arrhythmias are caused by several functional and structural changes in the myocardium. MicroRNAs (miRNAs) are essential regulators of gene expression in cardiomyocytes. These miRNAs play a vital role in regulating the stability of cardiac conduction and in the remodeling process that leads to arrhythmias. Although it remains unclear how miRNAs regulate the expression and function of ion channels in the heart, these regulatory mechanisms may support the development of emerging therapies. This study discusses the spread and generation of AP in the SAN as well as the regulation of miRNAs and individual ion channels. Arrhythmogenicity studies on ion channels will provide a research basis for miRNA modulation as a new therapeutic target.
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Affiliation(s)
- Wei Fan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Xuemei Sun
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Chao Yang
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China
| | - Juyi Wan
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Hongli Luo
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
| | - Bin Liao
- Department of Cardiovascular Surgery, Affiliated Hospital of Southwest Medical University, 25 Taiping Street, Jiangyang District, Luzhou, Sichuan Province, 646000, China.
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33
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Armstrong R, Wheen P, Brandon L, Maree A, Kenny RA. Heart rate: control mechanisms, pathophysiology and assessment of the neurocardiac system in health and disease. QJM 2022; 115:806-812. [PMID: 33486521 DOI: 10.1093/qjmed/hcab016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/02/2021] [Accepted: 01/10/2021] [Indexed: 12/15/2022] Open
Abstract
The monitoring of physiological function and dysfunction is an important principle in modern medicine. Heart rate is a basic example of this type of observation, particularly assessing the neurocardiac system, which entails the autonomic nervous system and intracardiac processes. The neurocardiac axis is an underappreciated and often overlooked system which, if measured appropriately in the clinical setting, may allow identification of patients at risk of disease progression and even mortality. While heart rate itself is a simplistic tool, more information may be gathered through assessing heart rate variability and heart rate recovery time. Studies have demonstrated an association of slow heart rate recovery and lower heart rate variability as markers of elevated sympathetic and lower parasympathetic tone. These parameters have additionally been shown to relate to development of arrhythmia, heart failure, systemic inflammatory processes, ischaemic heart disease and an increased rate of mortality. The aim of this review is to detail how heart rate is homeostatically controlled by the autonomic nervous system, how heart rate can impact on pathophysiological processes, and how heart rate variability and heart rate recovery time may be used in the clinical setting to allow the neurocardiac system to be assessed.
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Affiliation(s)
- R Armstrong
- From the Department of Cardiology, St James's Hospital, James's Street, Dublin 8
- Department of Medicine, Trinity College Medical School, Trinity College, College Green, Dublin 2
| | - P Wheen
- From the Department of Cardiology, St James's Hospital, James's Street, Dublin 8
- Department of Medicine, Trinity College Medical School, Trinity College, College Green, Dublin 2
| | - L Brandon
- From the Department of Cardiology, St James's Hospital, James's Street, Dublin 8
| | - A Maree
- From the Department of Cardiology, St James's Hospital, James's Street, Dublin 8
- Department of Medicine, Trinity College Medical School, Trinity College, College Green, Dublin 2
| | - R-A Kenny
- Department of Medicine, Trinity College Medical School, Trinity College, College Green, Dublin 2
- Department of Medical Gerontology, Mercers Institute for Successful Ageing, St James's Hospital, James's Street Dublin 8, Ireland
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Wild Watermelon-Extracted Juice Ingestion Reduces Peripheral Arterial Stiffness with an Increase in Nitric Oxide Production: A Randomized Crossover Pilot Study. Nutrients 2022; 14:nu14245199. [PMID: 36558358 PMCID: PMC9780996 DOI: 10.3390/nu14245199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Wild watermelon contains various nutrients, but the effect of its acute ingestion on arterial stiffness is unclear. This study aimed to investigate whether a single bout of acute ingestion of wild watermelon-extracted juice decreased arterial stiffness concomitant with an increase in nitric oxide (NO) production. Twelve healthy young female participants were tested under two conditions in a randomized, double-blind crossover study: (1) a beverage containing 90 g of wild watermelon extract and (2) a control beverage: a placebo. Pulse wave velocity (PWV), an index of arterial stiffness, blood flow, and plasma nitrate/nitrite (NOx) levels were measured in the supine position at 30, 60, and 90 min after the intake of each beverage. The changes in femoral-ankle PWV were significantly reduced after wild watermelon-extracted juice intake compared to those in the placebo group. Additionally, the changes in blood flow in the posterior tibial artery and plasma NOx levels after intake of wild watermelon-extracted juice were significantly increased compared to those in the placebo group. These data show that acute ingestion of wild watermelon-extracted juice reduces peripheral (lower limb) arterial stiffness and increases NO bioavailability. To confirm these associations, more detailed investigations of the nutrients that influence these effects should be conducted.
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35
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Zheng M, Li RG, Song J, Zhao X, Tang L, Erhardt S, Chen W, Nguyen BH, Li X, Li M, Wang J, Evans SM, Christoffels VM, Li N, Wang J. Hippo-Yap Signaling Maintains Sinoatrial Node Homeostasis. Circulation 2022; 146:1694-1711. [PMID: 36317529 PMCID: PMC9897204 DOI: 10.1161/circulationaha.121.058777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 09/20/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND The sinoatrial node (SAN) functions as the pacemaker of the heart, initiating rhythmic heartbeats. Despite its importance, the SAN is one of the most poorly understood cardiac entities because of its small size and complex composition and function. The Hippo signaling pathway is a molecular signaling pathway fundamental to heart development and regeneration. Although abnormalities of the Hippo pathway are associated with cardiac arrhythmias in human patients, the role of this pathway in the SAN is unknown. METHODS We investigated key regulators of the Hippo pathway in SAN pacemaker cells by conditionally inactivating the Hippo signaling kinases Lats1 and Lats2 using the tamoxifen-inducible, cardiac conduction system-specific Cre driver Hcn4CreERT2 with Lats1 and Lats2 conditional knockout alleles. In addition, the Hippo-signaling effectors Yap and Taz were conditionally inactivated in the SAN. To determine the function of Hippo signaling in the SAN and other cardiac conduction system components, we conducted a series of physiological and molecular experiments, including telemetry ECG recording, echocardiography, Masson Trichrome staining, calcium imaging, immunostaining, RNAscope, cleavage under targets and tagmentation sequencing using antibodies against Yap1 or H3K4me3, quantitative real-time polymerase chain reaction, and Western blotting. We also performed comprehensive bioinformatics analyses of various datasets. RESULTS We found that Lats1/2 inactivation caused severe sinus node dysfunction. Compared with the controls, Lats1/2 conditional knockout mutants exhibited dysregulated calcium handling and increased fibrosis in the SAN, indicating that Lats1/2 function through both cell-autonomous and non-cell-autonomous mechanisms. It is notable that the Lats1/2 conditional knockout phenotype was rescued by genetic deletion of Yap and Taz in the cardiac conduction system. These rescued mice had normal sinus rhythm and reduced fibrosis of the SAN, indicating that Lats1/2 function through Yap and Taz. Cleavage Under Targets and Tagmentation sequencing data showed that Yap potentially regulates genes critical for calcium homeostasis such as Ryr2 and genes encoding paracrine factors important in intercellular communication and fibrosis induction such as Tgfb1 and Tgfb3. Consistent with this, Lats1/2 conditional knockout mutants had decreased Ryr2 expression and increased Tgfb1 and Tgfb3 expression compared with control mice. CONCLUSIONS We reveal, for the first time to our knowledge, that the canonical Hippo-Yap pathway plays a pivotal role in maintaining SAN homeostasis.
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Affiliation(s)
- Mingjie Zheng
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston (M.Z., X.Z., S.E., W.C., Jun Wang)
| | - Rich G Li
- Texas Heart Institute, Houston (R.G.L., X.L.)
| | - Jia Song
- Department of Medicine (Section of Cardiovascular Research), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX (J.S., N.L.)
| | - Xiaolei Zhao
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston (M.Z., X.Z., S.E., W.C., Jun Wang)
| | - Li Tang
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha, Hunan, China (L.T., M.L., Jianxin Wang)
| | - Shannon Erhardt
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston (M.Z., X.Z., S.E., W.C., Jun Wang)
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston (S.E., Jun Wang)
| | - Wen Chen
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston (M.Z., X.Z., S.E., W.C., Jun Wang)
| | - Bao H Nguyen
- Department of Molecular Physiology and Biophysics (B.H.N.)
| | - Xiao Li
- Texas Heart Institute, Houston (R.G.L., X.L.)
| | - Min Li
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha, Hunan, China (L.T., M.L., Jianxin Wang)
| | - Jianxin Wang
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha, Hunan, China (L.T., M.L., Jianxin Wang)
| | - Sylvia M Evans
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Departments of Pharmacology and Medicine, University of California at San Diego, La Jolla (S.M.E.)
| | - Vincent M Christoffels
- Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, The Netherlands (V.M.C.)
| | - Na Li
- Department of Medicine (Section of Cardiovascular Research), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX (J.S., N.L.)
| | - Jun Wang
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston (M.Z., X.Z., S.E., W.C., Jun Wang)
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston (S.E., Jun Wang)
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Sebastian S, Weinstein LS, Ludwig A, Munroe P, Tinker A. Slowing Heart Rate Protects Against Pathological Cardiac Hypertrophy. FUNCTION 2022; 4:zqac055. [PMID: 36540889 PMCID: PMC9761894 DOI: 10.1093/function/zqac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 10/27/2022] [Indexed: 12/23/2022] Open
Abstract
We aimed to determine the pathophysiological impact of heart rate (HR) slowing on cardiac function. We have recently developed a murine model in which it is possible to conditionally delete the stimulatory heterotrimeric G-protein (Gαs) in the sinoatrial (SA) node after the addition of tamoxifen using cre-loxP technology. The addition of tamoxifen leads to bradycardia. We used this approach to examine the physiological and pathophysiological effects of HR slowing. We first looked at the impact on exercise performance by running the mice on a treadmill. After the addition of tamoxifen, mice with conditional deletion of Gαs in the SA node ran a shorter distance at a slower speed. Littermate controls preserved their exercise capacity after tamoxifen. Results consistent with impaired cardiac capacity in the mutants were also obtained with a dobutamine echocardiographic stress test. We then examined if HR reduction influenced pathological cardiac hypertrophy using two models: ligation of the left anterior descending coronary artery for myocardial infarction and abdominal aortic banding for hypertensive heart disease. In littermate controls, both procedures resulted in cardiac hypertrophy. However, induction of HR reduction prior to surgical intervention significantly ameliorated the hypertrophy. In order to assess potential protein kinase pathways that may be activated in the left ventricle by relative bradycardia, we used a phospho-antibody array and this revealed selective activation of phosphoinositide-3 kinase. In conclusion, HR reduction protects against pathological cardiac hypertrophy but limits physiological exercise capacity.
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Affiliation(s)
- Sonia Sebastian
- William Harvey Heart Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Lee S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases/National Institutes of Health, Building 10, Room 8C101, Bethesda, MD 20892-1752, USA
| | - Andreas Ludwig
- Institut fuer Experimentelle und Klinische Pharmakologie und Toxikologie, Universitaet Erlangen-Nuernberg, Fahrstr. 17, 91054 Erlangen, Germany
| | - Patricia Munroe
- William Harvey Heart Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
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Moghtadaei M, Dorey TW, Rose RA. Evaluation of non-linear heart rate variability using multi-scale multi-fractal detrended fluctuation analysis in mice: Roles of the autonomic nervous system and sinoatrial node. Front Physiol 2022; 13:970393. [PMID: 36237525 PMCID: PMC9552224 DOI: 10.3389/fphys.2022.970393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Nonlinear analyses of heart rate variability (HRV) can be used to quantify the unpredictability, fractal properties and complexity of heart rate. Fractality and its analysis provides valuable information about cardiovascular health. Multi-Scale Multi-Fractal Detrended Fluctuation Analysis (MSMFDFA) is a complexity-based algorithm that can be used to quantify the multi-fractal dynamics of the HRV time series through investigating characteristic exponents at different time scales. This method is applicable to short time series and it is robust to noise and nonstationarity. We have used MSMFDFA, which enables assessment of HRV in the frequency ranges encompassing the very-low frequency and ultra-low frequency bands, to jointly assess multi-scale and multi-fractal dynamics of HRV signals obtained from telemetric ECG recordings in wildtype mice at baseline and after autonomic nervous system (ANS) blockade, from electrograms recorded from isolated atrial preparations and from spontaneous action potential recordings in isolated sinoatrial node myocytes. Data demonstrate that the fractal profile of the intrinsic heart rate is significantly different from the baseline heart rate in vivo, and it is also altered after ANS blockade at specific scales and fractal order domains. For beating rate in isolated atrial preparations and intrinsic heart rate in vivo, the average fractal structure of the HRV increased and multi-fractality strength decreased. These data demonstrate that fractal properties of the HRV depend on both ANS activity and intrinsic sinoatrial node function and that assessing multi-fractality at different time scales is an effective approach for HRV assessment.
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Affiliation(s)
- Motahareh Moghtadaei
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Tristan W. Dorey
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Robert A. Rose
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Robert A. Rose,
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Abstract
The global burden caused by cardiovascular disease is substantial, with heart disease representing the most common cause of death around the world. There remains a need to develop better mechanistic models of cardiac function in order to combat this health concern. Heart rhythm disorders, or arrhythmias, are one particular type of disease which has been amenable to quantitative investigation. Here we review the application of quantitative methodologies to explore dynamical questions pertaining to arrhythmias. We begin by describing single-cell models of cardiac myocytes, from which two and three dimensional models can be constructed. Special focus is placed on results relating to pattern formation across these spatially-distributed systems, especially the formation of spiral waves of activation. Next, we discuss mechanisms which can lead to the initiation of arrhythmias, focusing on the dynamical state of spatially discordant alternans, and outline proposed mechanisms perpetuating arrhythmias such as fibrillation. We then review experimental and clinical results related to the spatio-temporal mapping of heart rhythm disorders. Finally, we describe treatment options for heart rhythm disorders and demonstrate how statistical physics tools can provide insights into the dynamics of heart rhythm disorders.
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Affiliation(s)
- Wouter-Jan Rappel
- Department of Physics, University of California San Diego, La Jolla, CA 92037
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39
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Ren L, Gopireddy RR, Perkins G, Zhang H, Timofeyev V, Lyu Y, Diloretto DA, Trinh P, Sirish P, Overton JL, Xu W, Grainger N, Xiang YK, Dedkova EN, Zhang XD, Yamoah EN, Navedo MF, Thai PN, Chiamvimonvat N. Disruption of mitochondria-sarcoplasmic reticulum microdomain connectomics contributes to sinus node dysfunction in heart failure. Proc Natl Acad Sci U S A 2022; 119:e2206708119. [PMID: 36044551 PMCID: PMC9456763 DOI: 10.1073/pnas.2206708119] [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: 04/20/2022] [Accepted: 08/01/2022] [Indexed: 11/18/2022] Open
Abstract
The sinoatrial node (SAN), the leading pacemaker region, generates electrical impulses that propagate throughout the heart. SAN dysfunction with bradyarrhythmia is well documented in heart failure (HF). However, the underlying mechanisms are not completely understood. Mitochondria are critical to cellular processes that determine the life or death of the cell. The release of Ca2+ from the ryanodine receptors 2 (RyR2) on the sarcoplasmic reticulum (SR) at mitochondria-SR microdomains serves as the critical communication to match energy production to meet metabolic demands. Therefore, we tested the hypothesis that alterations in the mitochondria-SR connectomics contribute to SAN dysfunction in HF. We took advantage of a mouse model of chronic pressure overload-induced HF by transverse aortic constriction (TAC) and a SAN-specific CRISPR-Cas9-mediated knockdown of mitofusin-2 (Mfn2), the mitochondria-SR tethering GTPase protein. TAC mice exhibited impaired cardiac function with HF, cardiac fibrosis, and profound SAN dysfunction. Ultrastructural imaging using electron microscope (EM) tomography revealed abnormal mitochondrial structure with increased mitochondria-SR distance. The expression of Mfn2 was significantly down-regulated and showed reduced colocalization with RyR2 in HF SAN cells. Indeed, SAN-specific Mfn2 knockdown led to alterations in the mitochondria-SR microdomains and SAN dysfunction. Finally, disruptions in the mitochondria-SR microdomains resulted in abnormal mitochondrial Ca2+ handling, alterations in localized protein kinase A (PKA) activity, and impaired mitochondrial function in HF SAN cells. The current study provides insights into the role of mitochondria-SR microdomains in SAN automaticity and possible therapeutic targets for SAN dysfunction in HF patients.
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Affiliation(s)
- Lu Ren
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | | | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA 92093
| | - Hao Zhang
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Valeriy Timofeyev
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Yankun Lyu
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Daphne A. Diloretto
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Pauline Trinh
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - James L. Overton
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Wilson Xu
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Nathan Grainger
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616
| | - Yang K. Xiang
- Department of Pharmacology, University of California, Davis, CA 95616
| | - Elena N. Dedkova
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616
| | - Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV 89557
| | - Manuel F. Navedo
- Department of Pharmacology, University of California, Davis, CA 95616
| | - Phung N. Thai
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV 89557
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA 95616
- Department of Pharmacology, University of California, Davis, CA 95616
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655
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Kuznetsov SV, Kuznetsova NN. Effects of Ni2+ on Heart and Respiratory Rhythms in Newborn Rats. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022050088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Grainger N, Shonnard CC, Quiggle SK, Fox EB, Presley H, Daugherty R, Shonnard MC, Drumm BT, Sanders KM. Propagation of Pacemaker Activity and Peristaltic Contractions in the Mouse Renal Pelvis Rely on Ca 2+-activated Cl - Channels and T-Type Ca 2+ Channels. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqac041. [PMID: 36325511 PMCID: PMC9614935 DOI: 10.1093/function/zqac041] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 01/07/2023]
Abstract
The process of urine removal from the kidney occurs via the renal pelvis (RP). The RP demarcates the beginning of the upper urinary tract and is endowed with smooth muscle cells. Along the RP, organized contraction of smooth muscle cells generates the force required to move urine boluses toward the ureters and bladder. This process is mediated by specialized pacemaker cells that are highly expressed in the proximal RP that generate spontaneous rhythmic electrical activity to drive smooth muscle depolarization. The mechanisms by which peristaltic contractions propagate from the proximal to distal RP are not fully understood. In this study, we utilized a transgenic mouse that expresses the genetically encoded Ca2+ indicator, GCaMP3, under a myosin heavy chain promotor to visualize spreading peristaltic contractions in high spatial detail. Using this approach, we discovered variable effects of L-type Ca2+ channel antagonists on contraction parameters. Inhibition of T-type Ca2+ channels reduced the frequency and propagation distance of contractions. Similarly, antagonizing Ca2+-activated Cl- channels or altering the transmembrane Cl- gradient decreased contractile frequency and significantly inhibited peristaltic propagation. These data suggest that voltage-gated Ca2+ channels are important determinants of contraction initiation and maintain the fidelity of peristalsis as the spreading contraction moves further toward the ureter. Recruitment of Ca2+-activated Cl- channels, likely Anoctamin-1, and T-type Ca2+ channels are required for efficiently conducting the depolarizing current throughout the length of the RP. These mechanisms are necessary for the efficient removal of urine from the kidney.
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Affiliation(s)
| | - Cameron C Shonnard
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Sage K Quiggle
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Emily B Fox
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Hannah Presley
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Robbie Daugherty
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Matthew C Shonnard
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA,Department of Life and Health Science, Dundalk Institute of Technology, Dublin Road, Dundalk, Co. Louth, A91 K584, Ireland
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
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Glutamate drives 'local Ca 2+ release' in cardiac pacemaker cells. Cell Res 2022; 32:843-854. [PMID: 35840807 PMCID: PMC9437105 DOI: 10.1038/s41422-022-00693-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 06/27/2022] [Indexed: 11/30/2022] Open
Abstract
The sinoatrial node (SAN) is the origin of the electrical signals for rhythmic heartbeats in mammals. The spontaneous firing of SAN pacemaker cells (SANPCs) triggers cardiac contraction. ‘Local Ca2+ release’ (LCR), a unique cellular activity, acts as the ‘engine’ of the spontaneous firing of SANPCs. However, the mechanism of LCR initiation remains unclear. Here, we report that endogenous glutamate drives LCRs in SANPCs. Using a glutamate sensor, we unraveled a tight correlation between glutamate accumulation and LCR occurrence, indicating a potential relationship between glutamate and LCRs. Intracellular application of glutamate significantly enhanced the LCRs in both intact and permeabilized SANPCs. Mechanistically, we revealed that mitochondrial excitatory amino acid transporter 1 (EAAT1)-dependent mitochondrial glutamate import promoted ROS generation, which in turn led to the oxidation of Ca2+-handling proteins, ultimately resulting in enhanced LCRs. Importantly, EAAT1 depletion reduced both the spontaneous firing rates of isolated SANPCs and the heart rate in vitro and in vivo, suggesting the central role of EAAT1 as a glutamate transporter in the regulation of cardiac autonomic rhythm. In conclusion, our results indicate that glutamate serves as an LCR igniter in SANPCs, adding a potentially important element to the coupled-clock theory that explains the origin of spontaneous firing. These findings shed new light on the future prevention and treatment of cardiac pacemaker cell-related arrhythmias.
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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Paradigm shift: new concepts for HCN4 function in cardiac pacemaking. Pflugers Arch 2022; 474:649-663. [PMID: 35556164 PMCID: PMC9192375 DOI: 10.1007/s00424-022-02698-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 11/05/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide–gated (HCN) channels are the molecular correlate of the If current and are critically involved in controlling neuronal excitability and the autonomous rhythm of the heart. The HCN4 isoform is the main HCN channel subtype expressed in the sinoatrial node (SAN), a tissue composed of specialized pacemaker cells responsible for generating the intrinsic heartbeat. More than 40 years ago, the If current was first discovered in rabbit SAN tissue. Along with this discovery, a theory was proposed that cyclic adenosine monophosphate–dependent modulation of If mediates heart rate regulation by the autonomic nervous system—a process called chronotropic effect. However, up to the present day, this classical theory could not be reliably validated. Recently, new concepts emerged confirming that HCN4 channels indeed play an important role in heart rate regulation. However, the cellular mechanism by which HCN4 controls heart rate turned out to be completely different than originally postulated. Here, we review the latest findings regarding the physiological role of HCN4 in the SAN. We describe a newly discovered mechanism underlying heart rate regulation by HCN4 at the tissue and single cell levels, and we discuss these observations in the context of results from previously studied HCN4 mouse models.
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Choi S, Vivas O, Baudot M, Moreno CM. Aging Alters the Formation and Functionality of Signaling Microdomains Between L-type Calcium Channels and β2-Adrenergic Receptors in Cardiac Pacemaker Cells. Front Physiol 2022; 13:805909. [PMID: 35514336 PMCID: PMC9065441 DOI: 10.3389/fphys.2022.805909] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/03/2022] [Indexed: 12/19/2022] Open
Abstract
Heart rate is accelerated to match physiological demands through the action of noradrenaline on the cardiac pacemaker. Noradrenaline is released from sympathetic terminals and activates β1-and β2-adrenergic receptors (ΑRs) located at the plasma membrane of pacemaker cells. L-type calcium channels are one of the main downstream targets potentiated by the activation of β-ARs. For this signaling to occur, L-type calcium channels need to be located in close proximity to β-ARs inside caveolae. Although it is known that aging causes a slowdown of the pacemaker rate and a reduction in the response of pacemaker cells to noradrenaline, there is a lack of in-depth mechanistic insights into these age-associated changes. Here, we show that aging affects the formation and function of adrenergic signaling microdomains inside caveolae. By evaluating the β1 and β2 components of the adrenergic regulation of the L-type calcium current, we show that aging does not alter the regulation mediated by β1-ARs but drastically impairs that mediated by β2-ARs. We studied the integrity of the signaling microdomains formed between L-type calcium channels and β-ARs by combining high-resolution microscopy and proximity ligation assays. We show that consistent with the electrophysiological data, aging decreases the physical association between β2-ARs and L-type calcium channels. Interestingly, this reduction is associated with a decrease in the association of L-type calcium channels with the scaffolding protein AKAP150. Old pacemaker cells also have a reduction in caveolae density and in the association of L-type calcium channels with caveolin-3. Together the age-dependent alterations in caveolar formation and the nano-organization of β2-ARs and L-type calcium channels result in a reduced sensitivity of the channels to β2 adrenergic modulation. Our results highlight the importance of these signaling microdomains in maintaining the chronotropic modulation of the heart and also pinpoint the direct impact that aging has on their function.
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Affiliation(s)
- Sabrina Choi
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Matthias Baudot
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Claudia M Moreno
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
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Maltsev AV, Stern MD, Lakatta EG, Maltsev VA. Functional Heterogeneity of Cell Populations Increases Robustness of Pacemaker Function in a Numerical Model of the Sinoatrial Node Tissue. Front Physiol 2022; 13:845634. [PMID: 35574456 PMCID: PMC9091312 DOI: 10.3389/fphys.2022.845634] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/15/2022] [Indexed: 11/19/2022] Open
Abstract
Each heartbeat is initiated by specialized pacemaker cells operating within the sinoatrial node (SAN). While individual cells within SAN tissue exhibit substantial heterogeneity of their electrophysiological parameters and Ca cycling, the role of this heterogeneity for cardiac pacemaker function remains mainly unknown. Here we investigated the problem numerically in a 25 × 25 square grid of connected coupled-clock Maltsev-Lakatta cell models. The tissue models were populated by cells with different degree of heterogeneity of the two key model parameters, maximum L-type Ca current conductance (gCaL) and sarcoplasmic reticulum Ca pumping rate (Pup). Our simulations showed that in the areas of Pup-gCaL parametric space at the edge of the system stability, where action potential (AP) firing is absent or dysrhythmic in SAN tissue models populated with identical cells, rhythmic AP firing can be rescued by populating the tissues with heterogeneous cells. This robust SAN function is synergistic with respect to heterogeneity in gCaL and Pup and can be further strengthened by clustering of cells with similar properties. The effect of cell heterogeneity is not due to a simple summation of activity of intrinsically firing cells naturally present in heterogeneous SAN; rather AP firing cells locally and critically interact with non-firing/dormant cells. When firing cells prevail, they recruit many dormant cells to fire, strongly enhancing overall SAN function; and vice versa, prevailing dormant cells suppress AP firing in cells with intrinsic automaticity and halt SAN function. The transitions between firing and non-firing states of the system are sharp, resembling phase transitions in statistical physics. Furthermore, robust function of heterogeneous SAN tissue requires weak cell coupling, a known property of the central area of SAN where cardiac impulse emerges; stronger cell coupling reduces AP firing rate and ultimately halts SAN automaticity at the edge of stability.
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Frequency-Dependent Properties of the Hyperpolarization-Activated Cation Current, I f, in Adult Mouse Heart Primary Pacemaker Myocytes. Int J Mol Sci 2022; 23:ijms23084299. [PMID: 35457119 PMCID: PMC9024942 DOI: 10.3390/ijms23084299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
A number of distinct electrophysiological mechanisms that modulate the myogenic spontaneous pacemaker activity in the sinoatrial node (SAN) of the mammalian heart have been investigated extensively. There is agreement that several (3 or 4) different transmembrane ionic current changes (referred to as the voltage clock) are involved; and that the resulting net current interacts with direct and indirect effects of changes in intracellular Ca2+ (the calcium clock). However, significant uncertainties, and important knowledge gaps, remain concerning the functional roles in SAN spontaneous pacing of many of the individual ion channel- or exchanger-mediated transmembrane current changes. We report results from patch clamp studies and mathematical modeling of the hyperpolarization-activated current, If, in the generation/modulation of the diastolic depolarization, or pacemaker potential, produced by individual myocytes that were enzymatically isolated from the adult mouse sinoatrial node (SAN). Amphotericin-mediated patch microelectrode recordings at 35 °C were made under control conditions and in the presence of 5 or 10 nM isoproterenol (ISO). These sets of results were complemented and integrated with mathematical modeling of the current changes that take place in the range of membrane potentials (−70 to −50 mV), which corresponds to the ‘pacemaker depolarization’ in the adult mouse SAN. Our results reveal a very small, but functionally important, approximately steady-state or time-independent current generated by residual activation of If channels that are expressed in these pacemaker myocytes. Recordings of the pacemaker depolarization and action potential, combined with measurements of changes in If, and the well-known increases in the L-type Ca2+ current, ICaL, demonstrated that ICaL activation, is essential for myogenic pacing. Moreover, after being enhanced (approximately 3-fold) by 5 or 10 nM ISO, ICaL contributes significantly to the positive chronotropic effect. Our mathematical model has been developed in an attempt to better understand the underlying mechanisms for the pacemaker depolarization and action potential in adult mouse SAN myocytes. After being updated with our new experimental data describing If, our simulations reveal a novel functional component of If in adult mouse SAN. Computational work carried out with this model also confirms that in the presence of ISO the residual activation of If and opening of ICaL channels combine to generate a net current change during the slow diastolic depolarization phase that is essential for the observed accelerated pacemaking rate of these SAN myocytes.
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Remme CA. Getting to the heart of rhythm: A century of progress. Physiol Rev 2022; 102:1553-1567. [PMID: 35343827 DOI: 10.1152/physrev.00043.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The human heart beats over eighty thousand times a day, and the average person's heart may have beaten up to 3 billion times by the age of 80. During the early stages of pregnancy, the heart beat provides the first visual and auditory sign of life of the foetus. Conversely, the first audible sound that the foetus is likely to hear is the heart beat of the mother. How fitting then, that at the "birth" Physiological Reviews the very first article published in 1921 written by Eyster and Meek addressed "The origin and conduction of the heart beat".1 In their insightful review, the authors discussed the landmark discoveries made from the mid-19th century on the electrical function of the heart. Now, a hundred years later, at the start of the next century of Physiological Reviews, an update on the huge progress made in the "exciting" field of cardiac electrophysiology is warranted. Guided by a number of excellent reviews published in Physiological Reviews since 1921 as well as a large body of literature, an overview of the important advancements made on the topic is provided here.
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Affiliation(s)
- Carol Ann Remme
- Amsterdam UMC, location University of Amsterdam, Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
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Louradour J, Bortolotti O, Torre E, Bidaud I, Lamb N, Fernandez A, Le Guennec JY, Mangoni ME, Mesirca P. L-Type Cav1.3 Calcium Channels Are Required for Beta-Adrenergic Triggered Automaticity in Dormant Mouse Sinoatrial Pacemaker Cells. Cells 2022; 11:cells11071114. [PMID: 35406677 PMCID: PMC8997967 DOI: 10.3390/cells11071114] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/18/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Sinoatrial node cells (SANC) automaticity is generated by functional association between the activity of plasmalemmal ion channels and local diastolic intracellular Ca2+ release (LCR) from ryanodine receptors. Strikingly, most isolated SANC exhibit a “dormant” state, whereas only a fraction shows regular firing as observed in intact SAN. Recent studies showed that β-adrenergic stimulation can initiate spontaneous firing in dormant SANC, though this mechanism is not entirely understood. Methods: To investigate the role of L-type Cav1.3 Ca2+ channels in the adrenergic regulation of automaticity in dormant SANC, we used a knock-in mouse strain in which the sensitivity of L-type Cav1.2 α1 subunits to dihydropyridines (DHPs) was inactivated (Cav1.2DHP−/−), enabling the selective pharmacological inhibition of Cav1.3 by DHPs. Results: In dormant SANC, β-adrenergic stimulation with isoproterenol (ISO) induced spontaneous action potentials (AP) and Ca2+ transients, which were completely arrested with concomitant perfusion of the DHP nifedipine. In spontaneously firing SANC at baseline, Cav1.3 inhibition completely reversed the effect of β-adrenergic stimulation on AP and the frequency of Ca2+ transients. Confocal calcium imaging of SANC showed that the β-adrenergic-induced synchronization of LCRs is regulated by the activity of Cav1.3 channels. Conclusions: Our study shows a novel role of Cav1.3 channels in initiating and maintaining automaticity in dormant SANC upon β-adrenergic stimulation.
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Affiliation(s)
- Julien Louradour
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM U1046, UMR CNRS, 34090 Montpellier, France;
| | - Olivier Bortolotti
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
| | - Eleonora Torre
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
| | - Isabelle Bidaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
| | - Ned Lamb
- Mammalian Stem Cell Biology Group, Institute of Human Genetics, Université de Montpellier, CNRS, 34090 Montpellier, France; (N.L.); (A.F.)
| | - Anne Fernandez
- Mammalian Stem Cell Biology Group, Institute of Human Genetics, Université de Montpellier, CNRS, 34090 Montpellier, France; (N.L.); (A.F.)
| | - Jean-Yves Le Guennec
- PhyMedExp, Université de Montpellier, INSERM U1046, UMR CNRS, 34090 Montpellier, France;
| | - Matteo E. Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
- Correspondence: (M.E.M.); (P.M.)
| | - Pietro Mesirca
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France; (J.L.); (O.B.); (E.T.); (I.B.)
- LabEx Ion Channels Science and Therapeutics (ICST), 34090 Montpellier, France
- Correspondence: (M.E.M.); (P.M.)
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50
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Dunham CS, Mackenzie ME, Nakano H, Kim AR, Juda MB, Nakano A, Stieg AZ, Gimzewski JK. Pacemaker translocations and power laws in 2D stem cell-derived cardiomyocyte cultures. PLoS One 2022; 17:e0263976. [PMID: 35286321 PMCID: PMC8920264 DOI: 10.1371/journal.pone.0263976] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/01/2022] [Indexed: 11/18/2022] Open
Abstract
Power laws are of interest to several scientific disciplines because they can provide important information about the underlying dynamics (e.g. scale invariance and self-similarity) of a given system. Because power laws are of increasing interest to the cardiac sciences as potential indicators of cardiac dysfunction, it is essential that rigorous, standardized analytical methods are employed in the evaluation of power laws. This study compares the methods currently used in the fields of condensed matter physics, geoscience, neuroscience, and cardiology in order to provide a robust analytical framework for evaluating power laws in stem cell-derived cardiomyocyte cultures. One potential power law-obeying phenomenon observed in these cultures is pacemaker translocations, or the spatial and temporal instability of the pacemaker region, in a 2D cell culture. Power law analysis of translocation data was performed using increasingly rigorous methods in order to illustrate how differences in analytical robustness can result in misleading power law interpretations. Non-robust methods concluded that pacemaker translocations adhere to a power law while robust methods convincingly demonstrated that they obey a doubly truncated power law. The results of this study highlight the importance of employing comprehensive methods during power law analysis of cardiomyocyte cultures.
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Affiliation(s)
- Christopher S. Dunham
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Madelynn E. Mackenzie
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, California, United States of America
| | - Haruko Nakano
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, United States of America
| | - Alexis R. Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Michal B. Juda
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Atsushi Nakano
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, California, United States of America
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, California, United States of America
- Department of Cell Physiology, The Jikei University, Tokyo, Japan
| | - Adam Z. Stieg
- California NanoSystems Institute, University of California, Los Angeles, California, United States of America
- International Center for Materials Nanoarchitectonics (MANA), National Institute of Materials Science, Tsukuba, Japan
| | - James K. Gimzewski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
- California NanoSystems Institute, University of California, Los Angeles, California, United States of America
- International Center for Materials Nanoarchitectonics (MANA), National Institute of Materials Science, Tsukuba, Japan
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