1
|
Sakamoto T, Kelly DP. Cardiac maturation. J Mol Cell Cardiol 2024; 187:38-50. [PMID: 38160640 PMCID: PMC10923079 DOI: 10.1016/j.yjmcc.2023.12.008] [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: 10/31/2023] [Revised: 12/12/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The heart undergoes a dynamic maturation process following birth, in response to a wide range of stimuli, including both physiological and pathological cues. This process entails substantial re-programming of mitochondrial energy metabolism coincident with the emergence of specialized structural and contractile machinery to meet the demands of the adult heart. Many components of this program revert to a more "fetal" format during development of pathological cardiac hypertrophy and heart failure. In this review, emphasis is placed on recent progress in our understanding of the transcriptional control of cardiac maturation, encompassing the results of studies spanning from in vivo models to cardiomyocytes derived from human stem cells. The potential applications of this current state of knowledge to new translational avenues aimed at the treatment of heart failure is also addressed.
Collapse
Affiliation(s)
- Tomoya Sakamoto
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel P Kelly
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
2
|
Inazumi H, Kuwahara K. NRSF/REST-Mediated Epigenomic Regulation in the Heart: Transcriptional Control of Natriuretic Peptides and Beyond. BIOLOGY 2022; 11:biology11081197. [PMID: 36009824 PMCID: PMC9405064 DOI: 10.3390/biology11081197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Reactivation of the fetal cardiac gene program, such as those encoding atrial and brain natriuretic peptides (ANP and BNP, respectively), is a characteristic feature of failing hearts. We previously revealed that a transcriptional repressor, neuron-restrictive silencer factor (NRSF), also called repressor element-1-silencing transcription factor (REST), plays a crucial role in the transcriptional control of ANP, BNP and other fetal cardiac genes through collaboration with various other transcription factors to maintain physiological cardiac function and electrical stability. Increased production of ANP and BNP prevents the progression of heart failure, but reactivation of Gαo and fetal-type cardiac ion channels (T-type Ca2+ and HCN channels) leads to deteriorated cardiac function and lethal arrhythmias observed in mice with disturbed NRSF function. Epigenetic regulators with which NRSF forms a complex modify histone acetylation and methylation, thereby participating in NRSF-mediated transcriptional regulation. Further comprehensive studies will lead to clarification of the molecular mechanisms underlying the development of cardiac dysfunction and heart failure. Abstract Reactivation of fetal cardiac genes, including those encoding atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), is a key feature of pathological cardiac remodeling and heart failure. Intensive studies on the regulation of ANP and BNP have revealed the involvement of numerous transcriptional factors in the regulation of the fetal cardiac gene program. Among these, we identified that a transcriptional repressor, neuron-restrictive silencer factor (NRSF), also named repressor element-1-silencing transcription factor (REST), which was initially detected as a transcriptional repressor of neuron-specific genes in non-neuronal cells, plays a pivotal role in the transcriptional regulation of ANP, BNP and other fetal cardiac genes. Here we review the transcriptional regulation of ANP and BNP gene expression and the role of the NRSF repressor complex in the regulation of cardiac gene expression and the maintenance of cardiac homeostasis.
Collapse
Affiliation(s)
- Hideaki Inazumi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Koichiro Kuwahara
- Department of Cardiovascular Medicine, School of Medicine, Shinshu University, 3-1-1 Asahi, Nagano 390-8621, Japan
- Correspondence: ; Tel.: +81-263-37-3191; Fax: +81-263-37-3195
| |
Collapse
|
3
|
Pai VP, Levin M. HCN2 Channel-induced Rescue of Brain, Eye, Heart, and Gut Teratogenesis Caused by Nicotine, Ethanol, and Aberrant Notch Signaling. Wound Repair Regen 2022; 30:681-706. [PMID: 35662339 DOI: 10.1111/wrr.13032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/28/2022] [Accepted: 05/19/2022] [Indexed: 11/30/2022]
Abstract
Organogenesis is a complex process that can be disrupted by embryonic exposure to teratogens or mutation-induced alterations in signaling pathways, both of which result in organ mispatterning. Building on prior work in Xenopus laevis that showed that increased HCN2 ion channel activity rescues nicotine-induced brain & eye morphogenesis, we demonstrate much broader HCN2-based rescue of organ patterning defects. Induced HCN2 expression in both local or distant tissues can rescue CNS (brain & eye) as well as non-CNS (heart, & gut) organ defects induced by three different teratogenic conditions: nicotine exposure, ethanol exposure, or aberrant Notch protein. Rescue can also be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. Our results suggest that HCN2 (likely mediated by bioelectric signals) can be an effective regulator of organogenesis from all three germ layers (ectoderm, mesoderm, and endoderm) and reveal non-cell-autonomous influences on organ formation that work at considerable distance during embryonic development. These results suggest molecular bioelectric strategies for repair that could be explored in the future for regenerative medicine. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, Massachusetts, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, Massachusetts, USA
| |
Collapse
|
4
|
Oknińska M, Paterek A, Zambrowska Z, Mackiewicz U, Mączewski M. Effect of Ivabradine on Cardiac Ventricular Arrhythmias: Friend or Foe? J Clin Med 2021; 10:4732. [PMID: 34682854 PMCID: PMC8537674 DOI: 10.3390/jcm10204732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Life-threatening ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation remain an ongoing clinical problem and their prevention and treatment require optimization. Conventional antiarrhythmic drugs are associated with significant proarrhythmic effects that often outweigh their benefits. Another option, the implantable cardioverter defibrillator, though clearly the primary therapy for patients at high risk of ventricular arrhythmias, is costly, invasive, and requires regular monitoring. Thus there is a clear need for new antiarrhythmic treatment strategies. Ivabradine, a heartrate-reducing agent, an inhibitor of HCN channels, may be one of such options. In this review we discuss emerging data from experimental studies that indicate new mechanism of action of this drug and further areas of investigation and potential use of ivabradine as an antiarrhythmic agent. However, clinical evidence is limited, and the jury is still out on effects of ivabradine on cardiac ventricular arrhythmias in the clinical setting.
Collapse
Affiliation(s)
| | | | | | | | - Michał Mączewski
- Centre of Postgraduate Medical Education, Department of Clinical Physiology, ul. Marymoncka 99/103, 01-813 Warsaw, Poland; (M.O.); (A.P.); (Z.Z.); (U.M.)
| |
Collapse
|
5
|
Dual role of miR-1 in the development and function of sinoatrial cells. J Mol Cell Cardiol 2021; 157:104-112. [PMID: 33964276 DOI: 10.1016/j.yjmcc.2021.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 11/20/2022]
Abstract
miR-1, the most abundant miRNA in the heart, modulates expression of several transcription factors and ion channels. Conditions affecting the heart rate, such as endurance training and cardiac diseases, show a concomitant miR-1 up- or down-regulation. Here, we investigated the role of miR-1 overexpression in the development and function of sinoatrial (SAN) cells using murine embryonic stem cells (mESC). We generated mESCs either overexpressing miR-1 and EGFP (miR1OE) or EGFP only (EM). SAN-like cells were selected from differentiating mESC using the CD166 marker. Gene expression and electrophysiological analysis were carried out on both early mES-derived cardiac progenitors and SAN-like cells and on beating neonatal rat ventricular cardiomyocytes (NRVC) over-expressing miR-1. miR1OE cells increased significantly the proportion of CD166+ SAN precursors compared to EM cells (23% vs 12%) and the levels of the transcription factors TBX5 and TBX18, both involved in SAN development. miR1OE SAN-like cells were bradycardic (1,3 vs 2 Hz) compared to EM cells. In agreement with data on native SAN cells, EM SAN-like cardiomyocytes show two populations of cells expressing either slow- or fast-activating If currents; miR1OE SAN-like cells instead have only fast-activating If with a significantly reduced conductance. Western Blot and immunofluorescence analysis showed a reduced HCN4 signal in miR-1OE vs EM CD166+ precursors. Together these data point out to a specific down-regulation of the slow-activating HCN4 subunit by miR-1. Importantly, the rate and If alterations were independent of the developmental effects of miR-1, being similar in NRVC transiently overexpressing miR-1. In conclusion, we demonstrated a dual role of miR-1, during development it controls the proper development of sinoatrial-precursor, while in mature SAN-like cells it modulates the HCN4 pacemaker channel translation and thus the beating rate.
Collapse
|
6
|
Paterek A, Sochanowicz B, Oknińska M, Śmigielski W, Kruszewski M, Mackiewicz U, Mączewski M, Leszek P. Ivabradine prevents deleterious effects of dopamine therapy in heart failure: No role for HCN4 overexpression. Biomed Pharmacother 2021; 136:111250. [PMID: 33450487 DOI: 10.1016/j.biopha.2021.111250] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/27/2020] [Accepted: 01/03/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Exacerbations of chronic heart failure (CHF) are often treated with catecholamines to provide short term inotropic support, but this strategy is associated with long-term detrimental hemodynamic effects and increased ventricular arrhythmias (VA), possibly related to increased heart rate (HR). We hypothesized that ivabradine may prevent adverse effects of short-term dopamine treatment in CHF. METHODS Rats with post-myocardial infarction CHF received 2-week infusion of saline, dopamine(D), ivabradine(I) or D&I; cardiac function was assessed using echocardiography and pressure-volume loops while VA were assessed using telemetric ECG recording. Expression of HCN4, a potentially proarrhythmic channel blocked by ivabradine, was assessed in left ventricular (LV) myocardium. HCN4 expression was also assessed in human explanted normal and failing hearts and correlated with VA. FINDINGS Dopamine infusion had detrimental effects on hemodynamic parameters and LV remodeling and induced VA in CHF rats, while ivabradine completely prevented these effects. CHF rats demonstrated HCN4 overexpression in LV myocardium, and ivabradine and, unexpectedly, dopamine prevented this. Failing human hearts also exhibited HCN4 overexpression in LV myocardium that was unrelated to patient's sex, CHF etiology, VA severity or plasma NT-proBNP. INTERPRETATION HR reduction offered by ivabradine may be a feasible strategy to extract benefits of inotropic support in CHF exacerbations, avoiding detrimental effects on CHF biology or VA. Ivabradine may offer additional beneficial effects in this setting, going beyond pure HR reduction, however prevention of ventricular HCN4 overexpression is unlikely to play a major role.
Collapse
Affiliation(s)
- Aleksandra Paterek
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Barbara Sochanowicz
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warsaw, Poland
| | - Marta Oknińska
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Witold Śmigielski
- Department of Epidemiology, Cardiovascular Disease Prevention and Health Promotion, The Cardinal Stefan Wyszyński National Institute of Cardiology, Warsaw, Poland
| | - Marcin Kruszewski
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warsaw, Poland; Department of Molecular Biology and Translational Research, Institute of Rural Health, Lublin, Poland; Department of Medical Biology and Translational Research, Faculty of Medicine, University of Information Technology and Management, Rzeszów, Poland
| | - Urszula Mackiewicz
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Michał Mączewski
- Department of Clinical Physiology, Centre of Postgraduate Medical Education, Warsaw, Poland.
| | - Przemysław Leszek
- Department of Heart Failure and Transplantology, The Cardinal Stefan Wyszyński National Institute of Cardiology, Warsaw, Poland
| |
Collapse
|
7
|
Chakraborty P, Rose RA, Nair K, Downar E, Nanthakumar K. The rationale for repurposing funny current inhibition for management of ventricular arrhythmia. Heart Rhythm 2020; 18:130-137. [PMID: 32738405 DOI: 10.1016/j.hrthm.2020.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/14/2020] [Accepted: 07/25/2020] [Indexed: 11/26/2022]
Abstract
Management of ventricular arrhythmia in structural heart disease is complicated by the toxicity of the limited antiarrhythmic options available. In others, proarrhythmia and deleterious hemodynamic and noncardiac effects prevent practical use. This necessitates new thinking in therapeutic agents for ventricular arrhythmia in structural heart disease. Ivabradine, a funny current (If) inhibitor, has proven safety in heart failure, angina, and inappropriate sinus tachycardia. Although it is commonly known that funny channels are primarily expressed in the sinoatrial node, atrioventricular node, and conducting system of the ventricle, ivabradine is known to exert effects on metabolism, ion homeostasis, and membrane electrophysiology of remodeled ventricular myocardium. This review considers novel concepts and evidence from clinical and experimental studies regarding this paradigm, with a potential role of ivabradine in ventricular arrhythmia.
Collapse
Affiliation(s)
- Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, An entity of the University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - Krishnakumar Nair
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Eugene Downar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada.
| |
Collapse
|
8
|
Pai VP, Cervera J, Mafe S, Willocq V, Lederer EK, Levin M. HCN2 Channel-Induced Rescue of Brain Teratogenesis via Local and Long-Range Bioelectric Repair. Front Cell Neurosci 2020; 14:136. [PMID: 32528251 PMCID: PMC7264377 DOI: 10.3389/fncel.2020.00136] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/22/2020] [Indexed: 12/21/2022] Open
Abstract
Embryonic exposure to the teratogen nicotine results in brain defects, by disrupting endogenous spatial pre patterns necessary for normal brain size and patterning. Extending prior work in Xenopus laevis that showed that misexpression of ion channels can rescue morphogenesis, we demonstrate and characterize a novel aspect of developmental bioelectricity: channel-dependent repair signals propagate long-range across the embryo. We show that distal HCN2 channel misexpression and distal transplants of HCN2-expressing tissue, non-cell-autonomously reverse profound defects, rescuing brain anatomy, gene expression, and learning. Moreover, such rescue can be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. We present a simple, versatile computational model of bioelectrical signaling upstream of key patterning genes such as OTX2 and XBF1, which predicts long-range repair induced by ion channel activity, and experimentally validate the predictions of this model. Our results and quantitative model identify a powerful morphogenetic control mechanism that could be targeted by future regenerative medicine exploiting ion channel modulating drugs approved for human use.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Javier Cervera
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Salvador Mafe
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Emma K Lederer
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
| |
Collapse
|
9
|
Ribeiro AJS, Guth BD, Engwall M, Eldridge S, Foley CM, Guo L, Gintant G, Koerner J, Parish ST, Pierson JB, Brock M, Chaudhary KW, Kanda Y, Berridge B. Considerations for an In Vitro, Cell-Based Testing Platform for Detection of Drug-Induced Inotropic Effects in Early Drug Development. Part 2: Designing and Fabricating Microsystems for Assaying Cardiac Contractility With Physiological Relevance Using Human iPSC-Cardiomyocytes. Front Pharmacol 2019; 10:934. [PMID: 31555128 PMCID: PMC6727630 DOI: 10.3389/fphar.2019.00934] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022] Open
Abstract
Contractility of the myocardium engines the pumping function of the heart and is enabled by the collective contractile activity of its muscle cells: cardiomyocytes. The effects of drugs on the contractility of human cardiomyocytes in vitro can provide mechanistic insight that can support the prediction of clinical cardiac drug effects early in drug development. Cardiomyocytes differentiated from human-induced pluripotent stem cells have high potential for overcoming the current limitations of contractility assays because they attach easily to extracellular materials and last long in culture, while having human- and patient-specific properties. Under these conditions, contractility measurements can be non-destructive and minimally invasive, which allow assaying sub-chronic effects of drugs. For this purpose, the function of cardiomyocytes in vitro must reflect physiological settings, which is not observed in cultured cardiomyocytes derived from induced pluripotent stem cells because of the fetal-like properties of their contractile machinery. Primary cardiomyocytes or tissues of human origin fully represent physiological cellular properties, but are not easily available, do not last long in culture, and do not attach easily to force sensors or mechanical actuators. Microengineered cellular systems with a more mature contractile function have been developed in the last 5 years to overcome this limitation of stem cell-derived cardiomyocytes, while simultaneously measuring contractile endpoints with integrated force sensors/actuators and image-based techniques. Known effects of engineered microenvironments on the maturity of cardiomyocyte contractility have also been discovered in the development of these systems. Based on these discoveries, we review here design criteria of microengineered platforms of cardiomyocytes derived from pluripotent stem cells for measuring contractility with higher physiological relevance. These criteria involve the use of electromechanical, chemical and morphological cues, co-culture of different cell types, and three-dimensional cellular microenvironments. We further discuss the use and the current challenges for developing and improving these novel technologies for predicting clinical effects of drugs based on contractility measurements with cardiomyocytes differentiated from induced pluripotent stem cells. Future research should establish contexts of use in drug development for novel contractility assays with stem cell-derived cardiomyocytes.
Collapse
Affiliation(s)
- Alexandre J S Ribeiro
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translation Sciences, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Brian D Guth
- Department of Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach an der Riss, Germany.,PreClinical Drug Development Platform (PCDDP), North-West University, Potchefstroom, South Africa
| | - Michael Engwall
- Safety Pharmacology and Animal Research Center, Amgen Research, Thousand Oaks, CA, United States
| | - Sandy Eldridge
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - C Michael Foley
- Department of Integrative Pharmacology, Integrated Sciences and Technology, AbbVie, North Chicago, IL, United States
| | - Liang Guo
- Laboratory of Investigative Toxicology, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Gary Gintant
- Department of Integrative Pharmacology, Integrated Sciences and Technology, AbbVie, North Chicago, IL, United States
| | - John Koerner
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translation Sciences, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Stanley T Parish
- Health and Environmental Sciences Institute, Washington, DC, United States
| | - Jennifer B Pierson
- Health and Environmental Sciences Institute, Washington, DC, United States
| | - Mathew Brock
- Department of Safety Assessment, Genentech, South San Francisco, CA, United States
| | - Khuram W Chaudhary
- Global Safety Pharmacology, GlaxoSmithKline plc, Collegeville, PA, United States
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences, Kanagawa, Japan
| | - Brian Berridge
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States
| |
Collapse
|
10
|
Augmentation of myocardial I f dysregulates calcium homeostasis and causes adverse cardiac remodeling. Nat Commun 2019; 10:3295. [PMID: 31337768 PMCID: PMC6650438 DOI: 10.1038/s41467-019-11261-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 06/28/2019] [Indexed: 01/18/2023] Open
Abstract
HCN channels underlie the depolarizing funny current (If) that contributes importantly to cardiac pacemaking. If is upregulated in failing and infarcted hearts, but its implication in disease mechanisms remained unresolved. We generated transgenic mice (HCN4tg/wt) to assess functional consequences of HCN4 overexpression-mediated If increase in cardiomyocytes to levels observed in human heart failure. HCN4tg/wt animals exhibit a dilated cardiomyopathy phenotype with increased cellular arrhythmogenicity but unchanged heart rate and conduction parameters. If augmentation induces a diastolic Na+ influx shifting the Na+/Ca2+ exchanger equilibrium towards ‘reverse mode’ leading to increased [Ca2+]i. Changed Ca2+ homeostasis results in significantly higher systolic [Ca2+]i transients and stimulates apoptosis. Pharmacological inhibition of If prevents the rise of [Ca2+]i and protects from ventricular remodeling. Here we report that augmented myocardial If alters intracellular Ca2+ homeostasis leading to structural cardiac changes and increased arrhythmogenicity. Inhibition of myocardial Ifper se may constitute a therapeutic mechanism to prevent cardiomyopathy. The depolarizing funny current contributing to cardiac pacemaking is upregulated in the myocardium of failing and infarcted hearts, but whether the current is implied in disease mechanisms is unclear. Here the authors generate HCN4 transgenic mice and show that upregulation of funny current to the levels observed in human heart failure alters calcium homeostasis leading to cardiac remodelling and arrhythmia.
Collapse
|
11
|
Wang J, Yang Y, Li Y, Zhu J, Lian H, Shao X, Zhang H, Fu Y, Zhang L. Long‐term treatment with ivabradine in transgenic atrial fibrillation mice counteracts hyperpolarization‐activated cyclic nucleotide gated channel overexpression. J Cardiovasc Electrophysiol 2018; 30:242-252. [PMID: 30302853 DOI: 10.1111/jce.13772] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/24/2018] [Accepted: 10/08/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Juan Wang
- Emergency and Intensive Care Center, State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing China
| | - Yan‐min Yang
- Emergency and Intensive Care Center, State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing China
| | - Yang Li
- Department of CardiologyChinese PLA General HospitalBeijing China
| | - Jun Zhu
- Emergency and Intensive Care Center, State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing China
| | - Hong Lian
- State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular diseases, Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing China
| | - Xing‐hui Shao
- Emergency and Intensive Care Center, State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing China
| | - Han Zhang
- Emergency and Intensive Care Center, State Key Laboratory of Cardiovascular DiseaseFuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing China
| | - Yi‐cheng Fu
- Department of GeriatricsPeking University Third HospitalBeijing China
| | - Lian‐feng Zhang
- Key Laboratory of Human Disease Comparative MedicineMinistry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing China
| |
Collapse
|
12
|
Pai VP, Pietak A, Willocq V, Ye B, Shi NQ, Levin M. HCN2 Rescues brain defects by enforcing endogenous voltage pre-patterns. Nat Commun 2018. [PMID: 29519998 PMCID: PMC5843655 DOI: 10.1038/s41467-018-03334-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Endogenous bioelectrical signaling coordinates cell behaviors toward correct anatomical outcomes. Lack of a model explaining spatialized dynamics of bioelectric states has hindered the understanding of the etiology of some birth defects and the development of predictive interventions. Nicotine, a known neuroteratogen, induces serious defects in brain patterning and learning. Our bio-realistic computational model explains nicotine’s effects via the disruption of endogenous bioelectrical gradients and predicts that exogenous HCN2 ion channels would restore the endogenous bioelectric prepatterns necessary for brain patterning. Voltage mapping in vivo confirms these predictions, and exogenous expression of the HCN2 ion channel rescues nicotine-exposed embryos, resulting in normal brain morphology and molecular marker expression, with near-normal learning capacity. By combining molecular embryology, electrophysiology, and computational modeling, we delineate a biophysical mechanism of developmental brain damage and its functional rescue. The authors have previously shown that membrane voltage can influence embryonic patterning during development. Here, the authors computationally model how nicotine disrupts Xenopus embryogenesis by perturbing voltage gradients, and rescue nicotine-inducted defects with HCN2 channel expression.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Alexis Pietak
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Bin Ye
- Veridian Biotechnology Limited, Biotech Center 2, Hong Kong, China
| | - Nian-Qing Shi
- Department of Developmental, Molecular, and Chemical Biology, Tufts University, Boston, MA, 02111, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA.
| |
Collapse
|
13
|
Zhao X, Gu T. Dysfunctional Hyperpolarization-Activated Cyclic Nucleotide-gated Ion Channels in Cardiac Diseases. Braz J Cardiovasc Surg 2017; 31:203-6. [PMID: 27556324 PMCID: PMC5062718 DOI: 10.5935/1678-9741.20160030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are reverse
voltage-dependent, and their activation depends on the hyperpolarization of the
membrane and may be directly or indirectly regulated by the cyclic adenosine
monophosphate (cAMP) or other signal-transduction cascades. The distribution,
quantity and activation states of HCN channels differ in tissues throughout the
body. Evidence exhibits that HCN channels play critical roles in the generation
and conduction of the electrical impulse and the physiopathological process of
some cardiac diseases. They may constitute promising drug targets in the
treatment of these cardiac diseases. Pharmacological treatment targeting HCN
channels is of benefit to these cardiac conditions.
Collapse
Affiliation(s)
- Xiaoqi Zhao
- Department of Cardiac Surgery ICU, First Affiliated Hospital, China Medical University, Shenyang, China
| | - Tianxiang Gu
- Department of Cardiac Surgery ICU, First Affiliated Hospital, China Medical University, Shenyang, China
| |
Collapse
|
14
|
Pai VP, Willocq V, Pitcairn EJ, Lemire JM, Paré JF, Shi NQ, McLaughlin KA, Levin M. HCN4 ion channel function is required for early events that regulate anatomical left-right patterning in a nodal and lefty asymmetric gene expression-independent manner. Biol Open 2017; 6:1445-1457. [PMID: 28818840 PMCID: PMC5665463 DOI: 10.1242/bio.025957] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/12/2017] [Indexed: 12/13/2022] Open
Abstract
Laterality is a basic characteristic of all life forms, from single cell organisms to complex plants and animals. For many metazoans, consistent left-right asymmetric patterning is essential for the correct anatomy of internal organs, such as the heart, gut, and brain; disruption of left-right asymmetry patterning leads to an important class of birth defects in human patients. Laterality functions across multiple scales, where early embryonic, subcellular and chiral cytoskeletal events are coupled with asymmetric amplification mechanisms and gene regulatory networks leading to asymmetric physical forces that ultimately result in distinct left and right anatomical organ patterning. Recent studies have suggested the existence of multiple parallel pathways regulating organ asymmetry. Here, we show that an isoform of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of ion channels (hyperpolarization-activated cyclic nucleotide-gated channel 4, HCN4) is important for correct left-right patterning. HCN4 channels are present very early in Xenopus embryos. Blocking HCN channels (Ih currents) with pharmacological inhibitors leads to errors in organ situs. This effect is only seen when HCN4 channels are blocked early (pre-stage 10) and not by a later block (post-stage 10). Injections of HCN4-DN (dominant-negative) mRNA induce left-right defects only when injected in both blastomeres no later than the 2-cell stage. Analysis of key asymmetric genes' expression showed that the sidedness of Nodal, Lefty, and Pitx2 expression is largely unchanged by HCN4 blockade, despite the randomization of subsequent organ situs, although the area of Pitx2 expression was significantly reduced. Together these data identify a novel, developmental role for HCN4 channels and reveal a new Nodal-Lefty-Pitx2 asymmetric gene expression-independent mechanism upstream of organ positioning during embryonic left-right patterning.
Collapse
Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Emily J Pitcairn
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Joan M Lemire
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Jean-François Paré
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Nian-Qing Shi
- Department of Medicine at University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Kelly A McLaughlin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, 200 Boston Ave, Suite 4600, Medford, MA 02155, USA
| |
Collapse
|
15
|
Naushad W, Surriya O, Sadia H. Prevalence of EBV, HPV and MMTV in Pakistani breast cancer patients: A possible etiological role of viruses in breast cancer. INFECTION GENETICS AND EVOLUTION 2017; 54:230-237. [PMID: 28705719 DOI: 10.1016/j.meegid.2017.07.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 01/04/2023]
Abstract
BACKGROUND Breast cancer being a multifactorial disease, the role of infectious agent in development of disease is of great interest. The high incidence of breast cancer around the world has woken the interest in a viral etiology of breast cancer. Despite decades of research, no etiologic factor(s) for human breast cancer has been known and the quest for a contributing cause has all but been abandoned during the past years. Recent investigations have linked breast cancer to viral infections, such as Epstein-Barr virus (EBV), Human papillomavirus (HPV) and mouse mammary tumor virus. AIM To investigate the possible association of EBV, HPV and MMTV infection with breast cancer development and progression. METHODS Screening of isolated genomic DNA from FFPE breast cancer tissue biopsies (n=250) using standard polymerase chain reaction and correlation of virus prevalence with BC disease outcomes using statistical analysis software (SPSS 16.0). RESULTS Our findings suggest the prevalence of EBV (24.4%), HPV (18.1%) and MMTV (29.3%), while coinfection of HPV and EBV was detected in 9.2% (23/250), co infection of HPV and MMTV in 3.2% (8/250) and coinfection of EBV and MMTV in 6% (15/250) of breast cancer samples. No virus was detected in 59.5% of the breast cancer samples. Mono infection of EBV and HPV do not statistically co-relate with the clinico-pathological outcomes of breast cancer disease, though MMTV infection does co-relate with age and grade of breast cancer disease. In our study, the prevalence of coinfection of HPV, EBV and MMTV in Pakistani breast cancer patients is rare, still there is a possibility of synergistic carcinogenic effect of different viruses in the development of breast cancer disease. CONCLUSION The significant percentage of virus prevalence shows potential role in breast cancer development. However, this study provides substantial but not conclusive evidence for the involvement of viruses in BC disease development and progressiveness.
Collapse
Affiliation(s)
- Wasifa Naushad
- Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, Pakistan; Department of Microbiology, University of Iowa, Iowa, USA
| | - Orooj Surriya
- Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, Pakistan
| | - Hajra Sadia
- Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, Pakistan.
| |
Collapse
|
16
|
Pitcairn E, Harris H, Epiney J, Pai VP, Lemire JM, Ye B, Shi NQ, Levin M, McLaughlin KA. Coordinating heart morphogenesis: A novel role for hyperpolarization-activated cyclic nucleotide-gated (HCN) channels during cardiogenesis in Xenopus laevis. Commun Integr Biol 2017; 10:e1309488. [PMID: 28702127 PMCID: PMC5501196 DOI: 10.1080/19420889.2017.1309488] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/16/2017] [Indexed: 12/18/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide gated channel (HCN) proteins are important regulators of both neuronal and cardiac excitability. Among the 4 HCN isoforms, HCN4 is known as a pacemaker channel, because it helps control the periodicity of contractions in vertebrate hearts. Although the physiological role of HCN4 channel has been studied in adult mammalian hearts, an earlier role during embryogenesis has not been clearly established. Here, we probe the embryonic roles of HCN4 channels, providing the first characterization of the expression profile of any of the HCN isoforms during Xenopus laevis development and investigate the consequences of altering HCN4 function on embryonic pattern formation. We demonstrate that both overexpression of HCN4 and injection of dominant-negative HCN4 mRNA during early embryogenesis results in improper expression of key patterning genes and severely malformed hearts. Our results suggest that HCN4 serves to coordinate morphogenetic control factors that provide positional information during heart morphogenesis in Xenopus.
Collapse
Affiliation(s)
- Emily Pitcairn
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Hannah Harris
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Justine Epiney
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Vaibhav P Pai
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Joan M Lemire
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Bin Ye
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Nian-Qing Shi
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael Levin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| | - Kelly A McLaughlin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, USA
| |
Collapse
|
17
|
Xing J, Zhang C, Jiang W, Hao J, Liu Z, Luo A, Zhang P, Fan X, Ma J. The Inhibitory Effects of Ketamine on Human Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels and Action Potential in Rabbit Sinoatrial Node. Pharmacology 2017; 99:226-235. [DOI: 10.1159/000452975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/01/2016] [Indexed: 11/19/2022]
|
18
|
Ritchie HE, Ragnerstam C, Gustafsson E, Jonsson JM, Webster WS. Control of the heart rate of rat embryos during the organogenic period. HYPOXIA 2016; 4:147-159. [PMID: 27878135 PMCID: PMC5108485 DOI: 10.2147/hp.s115050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to gain insight into whether the first trimester embryo could control its own heart rate (HR) in response to hypoxia. The gestational day 13 rat embryo is a good model for the human embryo at 5–6 weeks gestation, as the heart is comparable in development and, like the human embryo, has no functional autonomic nerve supply at this stage. Utilizing a whole-embryo culture technique, we examined the effects of different pharmacological agents on HR under normoxic (95% oxygen) and hypoxic (20% oxygen) conditions. Oxygen concentrations ≤60% caused a concentration-dependent decrease in HR from normal levels of ~210 bpm. An adenosine agonist, AMP-activated protein kinase (AMPK) activator and KATP channel opener all caused bradycardia in normoxic conditions; however, putative antagonists for these systems failed to prevent or ameliorate hypoxia-induced bradycardia. This suggests that the activation of one or more of these systems is not the primary cause of the observed hypoxia-induced bradycardia. Inhibition of oxidative phosphorylation also decreased HR in normoxic conditions, highlighting the importance of ATP levels. The β-blocker metoprolol caused a concentration-dependent reduction in HR supporting reports that β1-adrenergic receptors are present in the early rat embryonic heart. The cAMP inducer colforsin induced a positive chronotropic effect in both normoxic and hypoxic conditions. Overall, the embryonic HR at this stage of development is responsive to the level of oxygenation, probably as a consequence of its influence on ATP production.
Collapse
Affiliation(s)
- Helen E Ritchie
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Lidcombe
| | - Carolina Ragnerstam
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Elin Gustafsson
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Johanna M Jonsson
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - William S Webster
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
19
|
Liu J, Laksman Z, Backx PH. The electrophysiological development of cardiomyocytes. Adv Drug Deliv Rev 2016; 96:253-73. [PMID: 26788696 DOI: 10.1016/j.addr.2015.12.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/23/2015] [Accepted: 12/31/2015] [Indexed: 02/07/2023]
Abstract
The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered.
Collapse
|
20
|
Weisbrod D, Khun SH, Bueno H, Peretz A, Attali B. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels. Acta Pharmacol Sin 2016; 37:82-97. [PMID: 26725737 PMCID: PMC4722971 DOI: 10.1038/aps.2015.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/25/2015] [Indexed: 12/25/2022] Open
Abstract
The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.
Collapse
Affiliation(s)
- David Weisbrod
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shiraz Haron Khun
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hanna Bueno
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| |
Collapse
|
21
|
Vedantham V. New Approaches to Biological Pacemakers: Links to Sinoatrial Node Development. Trends Mol Med 2015; 21:749-761. [PMID: 26611337 DOI: 10.1016/j.molmed.2015.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 12/30/2022]
Abstract
Irreversible degeneration of the cardiac conduction system is a common disease that can cause activity intolerance, fainting, and death. While electronic pacemakers provide effective treatment, alternative approaches are needed when long-term indwelling hardware is undesirable. Biological pacemakers comprise electrically active cells that functionally integrate with the heart. Recent findings on cardiac pacemaker cells (PCs) within the sinoatrial node (SAN), along with developments in stem cell technology, have opened a new era in biological pacing. Recent experiments that have derived PC-like cells from non-PCs have brought the field closer than ever before to biological pacemakers that can faithfully recapitulate SAN activity. In this review, I discuss these approaches in the context of SAN biology and address the potential for clinical translation.
Collapse
Affiliation(s)
- Vasanth Vedantham
- Department of Medicine, Cardiology Division, University of California, San Francisco, CA, USA; Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA.
| |
Collapse
|
22
|
Huang X, Yang P, Yang Z, Zhang H, Ma A. Age-associated expression of HCN channel isoforms in rat sinoatrial node. Exp Biol Med (Maywood) 2015; 241:331-9. [PMID: 26341471 DOI: 10.1177/1535370215603515] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 08/04/2015] [Indexed: 11/16/2022] Open
Abstract
The expression of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channel isoforms varies among species, cardiac tissues, developmental stages, and disease generation. However, alterations in the HCN channels during aging remain unclear. We investigated the protein expressions of HCN channel isoforms, HCN1-HCN4, in the sinoatrial nodes (SANs) from young (1-month-old), adult (4-month-old), and aged (30-month-old) rats. We found that HCN2 and HCN4 proteins were present in rat SAN using immunohistochemistry; therefore, we quantitatively analyzed their expression by Western blot. Aim to correlate protein expression and pacemaking function, specific blockade of HCN channels with 3 µmol/L ivabradine prolonged the cycle length in the intact rat heart. During the senescent process, the HCN2 and HCN4 protein levels declined, which was accompanied with a decreased effect of ivabradine on rat SAN automaticity. These results indicated the age-associated expression and relative function of HCN channel isoforms.
Collapse
Affiliation(s)
- Xin Huang
- Department of Cardiology, First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Ion Channel Disease Laboratory, Key Laboratory of Environment and Genes related to Diseases of Education Ministry, Xi'an, Shaanxi 710061, P.R. China
| | - Pei Yang
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710004, P.R. China
| | - Zhao Yang
- Institute of Medical Electronics in Medical School, Key Laboratory of Biomedical Information Engineering, Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Hong Zhang
- School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China
| | - Aiqun Ma
- Department of Cardiology, First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Ion Channel Disease Laboratory, Key Laboratory of Environment and Genes related to Diseases of Education Ministry, Xi'an, Shaanxi 710061, P.R. China
| |
Collapse
|
23
|
Günther A, Baumann A. Distinct expression patterns of HCN channels in HL-1 cardiomyocytes. BMC Cell Biol 2015; 16:18. [PMID: 26141616 PMCID: PMC4490601 DOI: 10.1186/s12860-015-0065-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 06/05/2015] [Indexed: 01/05/2023] Open
Abstract
Background Cardiac rhythmic activity is initiated in functionally specialized areas of the heart. Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are fundamental for these processes of cardiac physiology. Results Here we investigated transcript and protein expression patterns of HCN channels in HL-1 cardiomyocytes using a combination of quantitative PCR analysis and immunocytochemistry. Gene expression profiles of hcn1, hcn2 and hcn4 were acutely affected during HL-1 cell propagation. In addition, distinct expression patterns were uncovered for HCN1, HCN2 and HCN4 proteins. Conclusions Our results suggest that HCN channel isoforms might be involved in the concerted differentiation of HL-1 cells and may indirectly affect the occurrence of contractile HL-1 cell activity. We expect that these findings will promote studies on other molecular markers that contribute to cardiac physiology. Electronic supplementary material The online version of this article (doi:10.1186/s12860-015-0065-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Anne Günther
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Wilhelm-Johnen-Straße, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Arnd Baumann
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Wilhelm-Johnen-Straße, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| |
Collapse
|
24
|
Barbuti A, Robinson RB. Stem Cell–Derived Nodal-Like Cardiomyocytes as a Novel Pharmacologic Tool: Insights from Sinoatrial Node Development and Function. Pharmacol Rev 2015; 67:368-88. [DOI: 10.1124/pr.114.009597] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
25
|
Ectopic automaticity induced in ventricular myocytes by transgenic overexpression of HCN2. J Mol Cell Cardiol 2015; 80:81-9. [DOI: 10.1016/j.yjmcc.2014.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 12/05/2014] [Accepted: 12/22/2014] [Indexed: 11/22/2022]
|
26
|
Vedantham V, Galang G, Evangelista M, Deo RC, Srivastava D. RNA sequencing of mouse sinoatrial node reveals an upstream regulatory role for Islet-1 in cardiac pacemaker cells. Circ Res 2015; 116:797-803. [PMID: 25623957 DOI: 10.1161/circresaha.116.305913] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
RATIONALE Treatment of sinus node disease with regenerative or cell-based therapies will require a detailed understanding of gene regulatory networks in cardiac pacemaker cells (PCs). OBJECTIVE To characterize the transcriptome of PCs using RNA sequencing and to identify transcriptional networks responsible for PC gene expression. METHODS AND RESULTS We used laser capture microdissection on a sinus node reporter mouse line to isolate RNA from PCs for RNA sequencing. Differential expression and network analysis identified novel sinoatrial node-enriched genes and predicted that the transcription factor Islet-1 is active in developing PCs. RNA sequencing on sinoatrial node tissue lacking Islet-1 established that Islet-1 is an important transcriptional regulator within the developing sinoatrial node. CONCLUSIONS (1) The PC transcriptome diverges sharply from other cardiomyocytes; (2) Islet-1 is a positive transcriptional regulator of the PC gene expression program.
Collapse
Affiliation(s)
- Vasanth Vedantham
- From the Gladstone Institute of Cardiovascular Disease, San Francisco, CA (V.V., G.G., M.E., D.S.); and Division of Cardiology, Departments of Medicine (V.V., G.G., R.C.D.), Pediatrics (D.S.), and Biochemistry and Biophysics (R.C.D., D.S.), Institute for Human Genetics, California Institute for Quantitative Biosciences (R.C.D.), and Cardiovascular Research Institute (V.V., G.G., M.E., R.C.D.), University of California, San Francisco
| | - Giselle Galang
- From the Gladstone Institute of Cardiovascular Disease, San Francisco, CA (V.V., G.G., M.E., D.S.); and Division of Cardiology, Departments of Medicine (V.V., G.G., R.C.D.), Pediatrics (D.S.), and Biochemistry and Biophysics (R.C.D., D.S.), Institute for Human Genetics, California Institute for Quantitative Biosciences (R.C.D.), and Cardiovascular Research Institute (V.V., G.G., M.E., R.C.D.), University of California, San Francisco
| | - Melissa Evangelista
- From the Gladstone Institute of Cardiovascular Disease, San Francisco, CA (V.V., G.G., M.E., D.S.); and Division of Cardiology, Departments of Medicine (V.V., G.G., R.C.D.), Pediatrics (D.S.), and Biochemistry and Biophysics (R.C.D., D.S.), Institute for Human Genetics, California Institute for Quantitative Biosciences (R.C.D.), and Cardiovascular Research Institute (V.V., G.G., M.E., R.C.D.), University of California, San Francisco
| | - Rahul C Deo
- From the Gladstone Institute of Cardiovascular Disease, San Francisco, CA (V.V., G.G., M.E., D.S.); and Division of Cardiology, Departments of Medicine (V.V., G.G., R.C.D.), Pediatrics (D.S.), and Biochemistry and Biophysics (R.C.D., D.S.), Institute for Human Genetics, California Institute for Quantitative Biosciences (R.C.D.), and Cardiovascular Research Institute (V.V., G.G., M.E., R.C.D.), University of California, San Francisco.
| | - Deepak Srivastava
- From the Gladstone Institute of Cardiovascular Disease, San Francisco, CA (V.V., G.G., M.E., D.S.); and Division of Cardiology, Departments of Medicine (V.V., G.G., R.C.D.), Pediatrics (D.S.), and Biochemistry and Biophysics (R.C.D., D.S.), Institute for Human Genetics, California Institute for Quantitative Biosciences (R.C.D.), and Cardiovascular Research Institute (V.V., G.G., M.E., R.C.D.), University of California, San Francisco.
| |
Collapse
|
27
|
Wang P, Tang M, Gao L, Luo H, Wang G, Ma X, Duan Y. Roles of I(f) and intracellular Ca2+ release in spontaneous activity of ventricular cardiomyocytes during murine embryonic development. J Cell Biochem 2013; 114:1852-62. [PMID: 23463619 DOI: 10.1002/jcb.24527] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/21/2013] [Indexed: 01/01/2023]
Abstract
In recent years, the contribution of I(f), an important pacemaker current, and intracellular Ca(2+) release (ICR) from sarcoplasmic reticulum to pacemaking and arrhythmia has been intensively studied. However, their functional roles in embryonic heart remain uncertain. Using patch clamp, Ca(2+) imaging, and RT-PCR, we found that I(f) regulated the firing rate in early and late stage embryonic ventricular cells, as ivabradine (30 µM), a specific blocker of I(f), slowed down action potential (AP) frequency. This inhibitory effect was even stronger in late stage cells, though I(f) was down-regulated. In contrast to I(f), ICR was found to be indispensable for the occurrence of APs in ventricular cells of different stages, because abolishment of ICR with ryanodine and 2-aminoethoxydiphenyl borate (2-APB), specific blockers of ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs), completely abolished APs. In addition, we noticed that RyR- and IP3R-mediated ICR coexisted in early-stage ventricular cells and RyRs functionally dominated. While at late stage RyRs, but not IP3Rs, mediated ICR. In both early and late stage ventricular cells, Na-Ca exchanger current (I(Na/Ca)) mediated ICR-triggered depolarization of membrane potential and resulted in the initiation of APs. We also observed that different from I(f), which presented as the substantial component of the earlier diastolic depolarization current, application of ryanodine, and/or 2-APB slowed the late phase of diastolic depolarization. Thus, we conclude that in murine embryonic ventricular cells I(f) regulates firing rate, while RyRs and IP3Rs (early stage) or RyRs (late stage)-mediated ICR determines the occurrence of APs.
Collapse
Affiliation(s)
- Peng Wang
- Department of Physiology, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | | | | | | | | | | | | |
Collapse
|
28
|
Okubo C, Sano HI, Naito Y, Tomita M. Contribution of quantitative changes in individual ionic current systems to the embryonic development of ventricular myocytes: a simulation study. J Physiol Sci 2013; 63:355-67. [PMID: 23760774 PMCID: PMC3751412 DOI: 10.1007/s12576-013-0271-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/20/2013] [Indexed: 12/29/2022]
Abstract
Early embryonic rodent ventricular cells exhibit spontaneous action potential (AP), which disappears in later developmental stages. Here, we used 3 mathematical models-the Kyoto, Ten Tusscher-Panfilov, and Luo-Rudy models-to present an overview of the functional landscape of developmental changes in embryonic ventricular cells. We switched the relative current densities of 9 ionic components in the Kyoto model, and 160 of 512 representative combinations were predicted to result in regular spontaneous APs, in which the quantitative changes in Na(+) current (I Na) and funny current (I f) made large contributions to a wide range of basic cycle lengths. In all three models, the increase in inward rectifier current (I K1) before the disappearance of I f was predicted to result in abnormally high intracellular Ca(2+) concentrations. Thus, we demonstrated that the developmental changes in APs were well represented, as I Na increased before the disappearance of I f, followed by a 10-fold increase in I K1.
Collapse
Affiliation(s)
- Chikako Okubo
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Hitomi I. Sano
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Yasuhiro Naito
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| |
Collapse
|
29
|
Kuwabara Y, Kuwahara K, Takano M, Kinoshita H, Arai Y, Yasuno S, Nakagawa Y, Igata S, Usami S, Minami T, Yamada Y, Nakao K, Yamada C, Shibata J, Nishikimi T, Ueshima K, Nakao K. Increased expression of HCN channels in the ventricular myocardium contributes to enhanced arrhythmicity in mouse failing hearts. J Am Heart Assoc 2013; 2:e000150. [PMID: 23709563 PMCID: PMC3698776 DOI: 10.1161/jaha.113.000150] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/30/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND The efficacy of pharmacological interventions to prevent sudden arrhythmic death in patients with chronic heart failure remains limited. Evidence now suggests increased ventricular expression of hyperpolarization-activated cation (HCN) channels in hypertrophied and failing hearts contributes to their arrythmicity. Still, the role of induced HCN channel expression in the enhanced arrhythmicity associated with heart failure and the capacity of HCN channel blockade to prevent lethal arrhythmias remains undetermined. METHODS AND RESULTS We examined the effects of ivabradine, a specific HCN channel blocker, on survival and arrhythmicity in transgenic mice (dnNRSF-Tg) expressing a cardiac-specific dominant-negative form of neuron-restrictive silencer factor, a useful mouse model of dilated cardiomyopathy leading to sudden death. Ivabradine (7 mg/kg per day orally) significantly reduced ventricular tachyarrhythmias and improved survival among dnNRSF-Tg mice while having no significant effect on heart rate or cardiac structure or function. Ivabradine most likely prevented the increase in automaticity otherwise seen in dnNRSF-Tg ventricular myocytes. Moreover, cardiac-specific overexpression of HCN2 in mice (HCN2-Tg) made hearts highly susceptible to arrhythmias induced by chronic β-adrenergic stimulation. Indeed, ventricular myocytes isolated from HCN2-Tg mice were highly susceptible to β-adrenergic stimulation-induced abnormal automaticity, which was inhibited by ivabradine. CONCLUSIONS HCN channel blockade by ivabradine reduces lethal arrhythmias associated with dilated cardiomyopathy in mice. Conversely, cardiac-specific overexpression of HCN2 channels increases arrhythmogenicity of β-adrenergic stimulation. Our findings demonstrate the contribution of HCN channels to the increased arrhythmicity seen in failing hearts and suggest HCN channel blockade is a potentially useful approach to preventing sudden death in patients with heart failure.
Collapse
Affiliation(s)
- Yoshihiro Kuwabara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Koichiro Kuwahara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, Japan (M.T., S.I.)
| | - Hideyuki Kinoshita
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Yuji Arai
- Department of Bioscience, National Cerebral and Cardiovascular Center Research Institute, Japan (Y.A.)
| | - Shinji Yasuno
- EBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan (S.Y., K.U.)
| | - Yasuaki Nakagawa
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Sachiyo Igata
- Department of Physiology, Kurume University School of Medicine, Japan (M.T., S.I.)
| | - Satoru Usami
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Takeya Minami
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Yuko Yamada
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Kazuhiro Nakao
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Chinatsu Yamada
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Junko Shibata
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Toshio Nishikimi
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| | - Kenji Ueshima
- EBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan (S.Y., K.U.)
| | - Kazuwa Nakao
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan (Y.K., K.K., H.K., Y.N., S.U., T.M., Y.Y., K.N., C.Y., J.S., T.N., K.N.)
| |
Collapse
|
30
|
Kurata Y, Hisatome I, Tanida M, Shibamoto T. Effect of hyperpolarization-activated current I(f) on robustness of sinoatrial node pacemaking: theoretical study on influence of intracellular Na(+) concentration. Am J Physiol Heart Circ Physiol 2013; 304:H1337-51. [PMID: 23504184 DOI: 10.1152/ajpheart.00777.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To elucidate the effects of hyperpolarization-activated current I(f) on robustness of sinoatrial node (SAN) pacemaking in connection with intracellular Na(+) concentration (Na(i)) changes, we theoretically investigated 1) the impacts of I(f) on dynamical properties of SAN model cells during inhibition of L-type Ca(2+) channel currents (I(CaL)) or hyperpolarizing loads and 2) I(f)-dependent changes in Na(i) and their effects on dynamical properties of model cells. Bifurcation analyses were performed for Na(i)-variable and Na(i)-fixed versions of mathematical models for rabbit SAN cells; equilibrium points (EPs), limit cycles (LCs), and their stability were determined as functions of model parameters. Increasing I(f) conductance (g(f)) shrank I(CaL) conductance (g(CaL)) regions of unstable EPs and stable LCs (rhythmic firings) in the Na(i)-variable system but slightly broadened that of rhythmic firings at lower g(f) in the Na(i)-fixed system. In the Na(i)-variable system, increased g(f) yielded elevations in Na(i) at EPs and during spontaneous oscillations, which caused EP stabilization and shrinkage in the parameter regions of unstable EPs and rhythmic firings. As g(f) increased, parameter regions of unstable EPs and stable LCs determined for hyperpolarizing loads shrank in the Na(i)-variable system but were enlarged in the Na(i)-fixed system. These findings suggest that 1) I(f) does not enhance but rather attenuates robustness of rabbit SAN cells via facilitating EP stabilization and LC destabilization even in physiological g(f) ranges; and 2) the enhancing effect of I(f) on robustness of pacemaker activity, which could be observed at lower g(f) when Na(i) was fixed, is actually reversed by I(f)-dependent changes in Na(i).
Collapse
Affiliation(s)
- Yasutaka Kurata
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan.
| | | | | | | |
Collapse
|
31
|
In vitro epigenetic reprogramming of human cardiac mesenchymal stromal cells into functionally competent cardiovascular precursors. PLoS One 2012; 7:e51694. [PMID: 23284745 PMCID: PMC3524246 DOI: 10.1371/journal.pone.0051694] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/05/2012] [Indexed: 01/22/2023] Open
Abstract
Adult human cardiac mesenchymal-like stromal cells (CStC) represent a relatively accessible cell type useful for therapy. In this light, their conversion into cardiovascular precursors represents a potential successful strategy for cardiac repair. The aim of the present work was to reprogram CStC into functionally competent cardiovascular precursors using epigenetically active small molecules. CStC were exposed to low serum (5% FBS) in the presence of 5 µM all-trans Retinoic Acid (ATRA), 5 µM Phenyl Butyrate (PB), and 200 µM diethylenetriamine/nitric oxide (DETA/NO), to create a novel epigenetically active cocktail (EpiC). Upon treatment the expression of markers typical of cardiac resident stem cells such as c-Kit and MDR-1 were up-regulated, together with the expression of a number of cardiovascular-associated genes including KDR, GATA6, Nkx2.5, GATA4, HCN4, NaV1.5, and α-MHC. In addition, profiling analysis revealed that a significant number of microRNA involved in cardiomyocyte biology and cell differentiation/proliferation, including miR 133a, 210 and 34a, were up-regulated. Remarkably, almost 45% of EpiC-treated cells exhibited a TTX-sensitive sodium current and, to a lower extent in a few cells, also the pacemaker I(f) current. Mechanistically, the exposure to EpiC treatment introduced global histone modifications, characterized by increased levels of H3K4Me3 and H4K16Ac, as well as reduced H4K20Me3 and H3s10P, a pattern compatible with reduced proliferation and chromatin relaxation. Consistently, ChIP experiments performed with H3K4me3 or H3s10P histone modifications revealed the presence of a specific EpiC-dependent pattern in c-Kit, MDR-1, and Nkx2.5 promoter regions, possibly contributing to their modified expression. Taken together, these data indicate that CStC may be epigenetically reprogrammed to acquire molecular and biological properties associated with competent cardiovascular precursors.
Collapse
|
32
|
Abstract
Heart attack remains the leading cause of death in both men and women worldwide. Stem cell-based therapies, including the use of engineered cardiac tissues, have the potential to treat the massive cell loss and pathological remodeling resulting from heart attack. Specifically, embryonic and induced pluripotent stem cells are a promising source for generation of therapeutically relevant numbers of functional cardiomyocytes and engineering of cardiac tissues in vitro. This review will describe methodologies for successful differentiation of pluripotent stem cells towards the cardiovascular cell lineages as they pertain to the field of cardiac tissue engineering. The emphasis will be placed on comparing the functional maturation in engineered cardiac tissues and developing heart and on methods to quantify cardiac electrical and mechanical function at different spatial scales.
Collapse
Affiliation(s)
- Brian Liau
- Department of Biomedical Engineering, Faculty of Cardiology, Duke University, Room 136 Hudson Hall, Durham, NC 27708, USA
| | | | | |
Collapse
|
33
|
Herrmann S, Hofmann F, Stieber J, Ludwig A. HCN channels in the heart: lessons from mouse mutants. Br J Pharmacol 2012; 166:501-9. [PMID: 22141457 DOI: 10.1111/j.1476-5381.2011.01798.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Hyperpolarization-activated cation channels generate the I(f) current in the heart. In the sino-atrial node (SAN), I(f) is thought to play an essential role in setting the heart rate and mediating its autonomic control. This review focuses on the role of I(f) in pacemaking and non-pacemaking cardiomyocytes and the resulting therapeutic implications. HCN4 represents the principal isoform underlying sino-atrial I(f) , but other isoforms may also be of importance. To examine the functional role of cardiac channels, several mouse mutants, most of them targeting HCN4, have been generated by different groups. Unexpectedly, these lines display greatly different and as yet unexplained phenotypes. We provide an overview about these HCN mutants and suggest an interpretation of the functional significance of I(f) in the SAN in light of these studies. HCN channels are also present in ventricular myocytes, and an up-regulation of I(f) in the hypertrophic and failing heart may contribute to arrhythmogenesis. Inhibition of I(f) by HCN channel blockers is a novel approach in the treatment of cardiac disorders, and ivabradine is approved for treatment of stable angina pectoris. Remarkably, a recent clinical trial assessing this substance in heart failure showed a significantly improved outcome. The mechanism underlying this beneficial effect is not yet clear and might lie beyond heart rate slowing. Thus, the growing knowledge about cardiac HCN channels will undoubtedly promote the development of the promising class of HCN channel blockers.
Collapse
Affiliation(s)
- S Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
| | | | | | | |
Collapse
|
34
|
Suffredini S, Stillitano F, Comini L, Bouly M, Brogioni S, Ceconi C, Ferrari R, Mugelli A, Cerbai E. Long-term treatment with ivabradine in post-myocardial infarcted rats counteracts f-channel overexpression. Br J Pharmacol 2012; 165:1457-66. [PMID: 21838751 DOI: 10.1111/j.1476-5381.2011.01627.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent clinical data suggest beneficial effects of ivabradine, a specific heart rate (HR)-lowering drug, in heart failure patients. However, the mechanisms responsible for these effects have not been completely clarified. Thus, we investigated functional/molecular changes in I(f), the specific target of ivabradine, in the failing atrial and ventricular myocytes where this current is up-regulated as a consequence of maladaptive remodelling. EXPERIMENTAL APPROACH We investigated the effects of ivabradine (IVA; 10 mg·kg(-1) ·day(-1) for 90 days) on electrophysiological remodelling in left atrial (LA), left ventricular (LV) and right ventricular (RV) myocytes from post-mycardial infarcted (MI) rats, with sham-operated (sham or sham + IVA) rats as controls. I(f) current was measured by patch-clamp; hyperpolarization-activated cyclic nucleotide-gated (HCN) channel isoforms and microRNA (miRNA-1 and miR-133) expression were evaluated by reverse transcription quantitative PCR. KEY RESULTS Maximal specific conductance of I(f) was increased in MI, versus sham, in LV (P < 0.01) and LA myocytes (P < 0.05). Ivabradine reduced HR in both MI and sham rats (P < 0.05). In MI + IVA, I(f) overexpression was attenuated and HCN4 transcription reduced by 66% and 54% in LV and RV tissue, respectively, versus MI rats (all P < 0.05). miR-1 and miR-133, which modulate post-transcriptional expression of HCN2 and HCN4 genes, were significantly increased in myocytes from MI + IVA. CONCLUSION AND IMPLICATION The beneficial effects of ivabradine may be due to the reversal of electrophysiological cardiac remodelling in post-MI rats by reduction of functional overexpression of HCN channels. This is attributable to transcriptional and post-transcriptional mechanisms.
Collapse
Affiliation(s)
- S Suffredini
- Center of Molecular Medicine (C.I.M.M.B.A.), Florence, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Paci M, Sartiani L, Del Lungo M, Jaconi M, Mugelli A, Cerbai E, Severi S. Mathematical modelling of the action potential of human embryonic stem cell derived cardiomyocytes. Biomed Eng Online 2012; 11:61. [PMID: 22929020 PMCID: PMC3477113 DOI: 10.1186/1475-925x-11-61] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 06/27/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human embryonic stem cell derived cardiomyocytes (hESC-CMs) hold high potential for basic and applied cardiovascular research. The development of a reliable simulation platform able to mimic the functional properties of hESC-CMs would be of considerable value to perform preliminary test complementing in vitro experimentations. METHODS We developed the first computational model of hESC-CM action potential by integrating our original electrophysiological recordings of transient-outward, funny, and sodium-calcium exchanger currents and data derived from literature on sodium, calcium and potassium currents in hESC-CMs. RESULTS The model is able to reproduce basal electrophysiological properties of hESC-CMs at 15 40 days of differentiation (Early stage). Moreover, the model reproduces the modifications occurring through the transition from Early to Late developmental stage (50-110, days of differentiation). After simulated blockade of ionic channels and pumps of the sarcoplasmic reticulum, Ca2+ transient amplitude was decreased by 12% and 33% in Early and Late stage, respectively, suggesting a growing contribution of a functional reticulum during maturation. Finally, as a proof of concept, we tested the effects induced by prototypical channel blockers, namely E4031 and nickel, and their qualitative reproduction by the model. CONCLUSIONS This study provides a novel modelling tool that may serve useful to investigate physiological properties of hESC-CMs.
Collapse
Affiliation(s)
- Michelangelo Paci
- Biomedical Engineering Laboratory - D.E.I.S. University of Bologna, Via Venezia 52, Cesena, 47521, Italy
| | | | | | | | | | | | | |
Collapse
|
36
|
Abd Allah ES, Aslanidi OV, Tellez JO, Yanni J, Billeter R, Zhang H, Dobrzynski H, Boyett MR. Postnatal development of transmural gradients in expression of ion channels and Ca2+-handling proteins in the ventricle. J Mol Cell Cardiol 2012; 53:145-55. [DOI: 10.1016/j.yjmcc.2012.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 03/06/2012] [Accepted: 04/06/2012] [Indexed: 01/30/2023]
|
37
|
Bucchi A, Barbuti A, Difrancesco D, Baruscotti M. Funny Current and Cardiac Rhythm: Insights from HCN Knockout and Transgenic Mouse Models. Front Physiol 2012; 3:240. [PMID: 22783204 PMCID: PMC3387723 DOI: 10.3389/fphys.2012.00240] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 06/12/2012] [Indexed: 01/01/2023] Open
Abstract
In the adult animal the sinoatrial node (SAN) rhythmically generates a depolarizing wave that propagates to the rest of the heart. However, the SAN is more than a simple clock; it is a clock that adjusts its pace according to the metabolic requirements of the organism. The Hyperpolarization-activated Cyclic Nucleotide-gated channels (HCN1–4) are the structural component of the funny (If) channels; in the SAN the If current is the main driving electrical force of the diastolic depolarization and the HCN4 is the most abundant isoform. The generation of HCN KO and transgenic mouse models has advanced the understanding of the role of these channels in cardiac excitability. The HCN4 KO models that were first developed allowed either global or cardiac-specific constitutive ablation of HCN4 channels, and resulted in embryonic lethality. A further progress was made with the development of three separate inducible HCN4 KO models; in one model KO was induced globally in the entire organism, in a second, ablation occurred only in HCN4-expressing cells, and finally in a third model KO was confined to cardiac cells. Unexpectedly, the three models yielded different results; similarities and differences among these models will be presented and discussed. The functional effects of HCN2 and HCN3 knockout models and transgenic HCN4 mouse models will also be discussed. In conclusion, HCN KO/transgenic models have allowed to evaluate the functional role of the If currents in intact animals as well as in single SAN cells isolated from the same animals. This opportunity is therefore unique since it allows (1) to verify the contribution of specific HCN isoforms to cardiac activity in intact animals, and (2) to compare these results to those obtained in single cell experiments. These combined studies were not possible prior to the development of KO models. Finally, these models represent critical tools to improve our understanding of the molecular basis of some inheritable arrhythmic human pathologies.
Collapse
Affiliation(s)
- Annalisa Bucchi
- Department of Biosciences, University of Milano Milano, Italy
| | | | | | | |
Collapse
|
38
|
Hofmann F, Fabritz L, Stieber J, Schmitt J, Kirchhof P, Ludwig A, Herrmann S. Ventricular HCN channels decrease the repolarization reserve in the hypertrophic heart. Cardiovasc Res 2012; 95:317-26. [PMID: 22652004 DOI: 10.1093/cvr/cvs184] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Cardiac hypertrophy is accompanied by reprogramming of gene expression, where the altered expression of ion channels decreases electrical stability and increases the risk of life-threatening arrhythmias. However, the underlying mechanisms are not fully understood. Here, we analysed the role of the depolarizing current I(f) which has been hypothesized to contribute to arrhythmogenesis in the hypertrophied ventricle. METHODS AND RESULTS We used transverse aortic constriction in mice to induce ventricular hypertrophy. This resulted in an increased number of I(f) positive ventricular myocytes as well as a strongly enhanced and accelerated I(f) when compared with controls. Of the four HCN (hyperpolarization-activated cyclic nucleotide-gated channels) isoforms mediating I(f), HCN2 and HCN4 were the predominantly expressed subunits in healthy as well as hypertrophied hearts. Unexpectedly, only the HCN1 transcript was significantly upregulated in response to hypertrophy. However, the combined deletion of HCN2 and HCN4 disrupted ventricular I(f) completely. The lack of I(f) in hypertrophic double-knockouts resulted in a strong attenuation of pro-arrhythmogenic parameters characteristically observed in hypertrophic hearts. In particular, prolongation of the action potential was significantly decreased and lengthening of the QT interval was reduced. CONCLUSIONS We suggest that the strongly increased HCN channel activity in hypertrophied myocytes prolongs the repolarization of the ventricular action potential and thereby may increase the arrhythmogenic potential. Our results provide for the first time a direct link between an upregulation of ventricular I(f) and a diminished repolarization reserve in cardiac hypertrophy.
Collapse
Affiliation(s)
- Florian Hofmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | | | | | | | | | | |
Collapse
|
39
|
Electrophysiological-metabolic modeling of microbes: applications in fuel cells and environment analysis. Methods Mol Biol 2012. [PMID: 22639221 DOI: 10.1007/978-1-61779-827-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
A formalism for simulating coupled metabolic and electrophysiological processes is presented. The resulting chemical kinetic and electrophysiological equations are solved numerically to create a cell simulator. Metabolic features of this simulator were adapted from Karyote, a multi-compartment biochemical cell modeling simulator. We present the mathematical formalism and its computational implementation as an integrated electrophysiological-metabolic model. Applications to Geobacter sulfurreducens in the environment and in a fuel cell are discussed.
Collapse
|
40
|
Novel insights into the distribution of cardiac HCN channels: An expression study in the mouse heart. J Mol Cell Cardiol 2011; 51:997-1006. [DOI: 10.1016/j.yjmcc.2011.09.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/05/2011] [Accepted: 09/06/2011] [Indexed: 11/22/2022]
|
41
|
Liau B, Christoforou N, Leong KW, Bursac N. Pluripotent stem cell-derived cardiac tissue patch with advanced structure and function. Biomaterials 2011; 32:9180-7. [PMID: 21906802 DOI: 10.1016/j.biomaterials.2011.08.050] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
Abstract
Recent advances in pluripotent stem cell research have provided investigators with potent sources of cardiogenic cells. However, tissue engineering methodologies to assemble cardiac progenitors into aligned, 3-dimensional (3D) myocardial tissues capable of physiologically relevant electrical conduction and force generation are lacking. In this study, we introduced 3D cell alignment cues in a fibrin-based hydrogel matrix to engineer highly functional cardiac tissues from genetically purified mouse embryonic stem cell-derived cardiomyocytes (CMs) and cardiovascular progenitors (CVPs). Procedures for CM and CVP derivation, purification, and functional differentiation in monolayer cultures were first optimized to yield robust intercellular coupling and maximize velocity of action potential propagation. A versatile soft-lithography technique was then applied to reproducibly fabricate engineered cardiac tissues with controllable size and 3D architecture. While purified CMs assembled into a functional 3D syncytium only when supplemented with supporting non-myocytes, purified CVPs differentiated into cardiomyocytes, smooth muscle, and endothelial cells, and autonomously supported the formation of functional cardiac tissues. After a total culture time similar to period of mouse embryonic development (21 days), the engineered cardiac tissues exhibited unprecedented levels of 3D organization and functional differentiation characteristic of native neonatal myocardium, including: 1) dense, uniformly aligned, highly differentiated and electromechanically coupled cardiomyocytes, 2) rapid action potential conduction with velocities between 22 and 25 cm/s, and 3) significant contractile forces of up to 2 mN. These results represent an important advancement in stem cell-based cardiac tissue engineering and provide the foundation for exploiting the exciting progress in pluripotent stem cell research in the future tissue engineering therapies for heart disease.
Collapse
Affiliation(s)
- Brian Liau
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | | | | |
Collapse
|
42
|
Itoh H, Naito Y, Tomita M. Simulation of developmental changes in action potentials with ventricular cell models. SYSTEMS AND SYNTHETIC BIOLOGY 2011; 1:11-23. [PMID: 19003434 PMCID: PMC2533146 DOI: 10.1007/s11693-006-9002-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
During cardiomyocyte development, early embryonic ventricular cells show spontaneous activity that disappears at a later stage. Dramatic changes in action potential are mediated by developmental changes in individual ionic currents. Hence, reconstruction of the individual ionic currents into an integrated mathematical model would lead to a better understanding of cardiomyocyte development. To simulate the action potential of the rodent ventricular cell at three representative developmental stages, quantitative changes in the ionic currents, pumps, exchangers, and sarcoplasmic reticulum (SR) Ca(2+) kinetics were represented as relative activities, which were multiplied by conductance or conversion factors for individual ionic systems. The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models. The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro. The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.
Collapse
Affiliation(s)
- Hitomi Itoh
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, 252-8520, Japan,
| | | | | |
Collapse
|
43
|
Fukuda K. Regeneration of cardiomyocytes from bone marrow: Use of mesenchymal stem cell for cardiovascular tissue engineering. Cytotechnology 2011; 41:165-75. [PMID: 19002953 DOI: 10.1023/a:1024882908173] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We have isolated a cardiomyogenic cell line (CMG cell) from murine bone marrow mesenchymal stem cells. The cells showed a fibroblast-like morphology, but the morphology changed after 5-azacytidine exposure. They began spontaneous beating after 2 weeks, and expressed ANP and BNP. Electron microscopy revealed a cardiomyocyte-like ultrastructure. These cells had several types of action potentials; sinus node-like and ventricular cell-like action potentials. The isoform of contractile protein genes indicated that their muscle phenotype was similar to fetal ventricular cardiomyocytes. They expressed alpha(1A), alpha(1B), alpha(1D), beta(1), and beta(2) adrenergic and M(1) and M(2) muscarinic receptors. Stimulation with phenylephrine, isoproterenol and carbachol increased ERK phosphorylation and second messengers. Isoproterenol increased the beating rate, which was blocked with CGP20712A (beta(1)-selective blocker). These findings indicated that cell transplantation therapy for the patients with heart failure might possibly be achieved using the regenerated cardiomyocytes from autologous bone marrow cells in the near future.
Collapse
Affiliation(s)
- Keiichi Fukuda
- Institute for Advanced Cardiac Therapeutics, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo, Japan (E-mail,
| |
Collapse
|
44
|
Avitabile D, Crespi A, Brioschi C, Parente V, Toietta G, Devanna P, Baruscotti M, Truffa S, Scavone A, Rusconi F, Biondi A, D'Alessandra Y, Vigna E, Difrancesco D, Pesce M, Capogrossi MC, Barbuti A. Human cord blood CD34+ progenitor cells acquire functional cardiac properties through a cell fusion process. Am J Physiol Heart Circ Physiol 2011; 300:H1875-84. [PMID: 21357510 DOI: 10.1152/ajpheart.00523.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The efficacy of cardiac repair by stem cell administration relies on a successful functional integration of injected cells into the host myocardium. Safety concerns have been raised about the possibility that stem cells may induce foci of arrhythmia in the ischemic myocardium. In a previous work (36), we showed that human cord blood CD34(+) cells, when cocultured on neonatal mouse cardiomyocytes, exhibit excitation-contraction coupling features similar to those of cardiomyocytes, even though no human genes were upregulated. The aims of the present work are to investigate whether human CD34(+) cells, isolated after 1 wk of coculture with neonatal ventricular myocytes, possess molecular and functional properties of cardiomyocytes and to discriminate, using a reporter gene system, whether cardiac differentiation derives from a (trans)differentiation or a cell fusion process. Umbilical cord blood CD34(+) cells were isolated by a magnetic cell sorting method, transduced with a lentiviral vector carrying the enhanced green fluorescent protein (EGFP) gene, and seeded onto primary cultures of spontaneously beating rat neonatal cardiomyocytes. Cocultured EGFP(+)/CD34(+)-derived cells were analyzed for their electrophysiological features at different time points. After 1 wk in coculture, EGFP(+) cells, in contact with cardiomyocytes, were spontaneously contracting and had a maximum diastolic potential (MDP) of -53.1 mV, while those that remained isolated from the surrounding myocytes did not contract and had a depolarized resting potential of -11.4 mV. Cells were then resuspended and cultured at low density to identify EGFP(+) progenitor cell derivatives. Under these conditions, we observed single EGFP(+) beating cells that had acquired an hyperpolarization-activated current typical of neonatal cardiomyocytes (EGFP(+) cells, -2.24 ± 0.89 pA/pF; myocytes, -1.99 ± 0.63 pA/pF, at -125 mV). To discriminate between cell autonomous differentiation and fusion, EGFP(+)/CD34(+) cells were cocultured with cardiac myocytes infected with a red fluorescence protein-lentiviral vector; under these conditions we found that 100% of EGFP(+) cells were also red fluorescent protein positive, suggesting cell fusion as the mechanism by which cardiac functional features are acquired.
Collapse
Affiliation(s)
- Daniele Avitabile
- Department of Biomolecular Sciences and Biotechnology, University of Milan, Milan, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Yu L, Gao S, Nie L, Tang M, Huang W, Luo H, Hu X, Xi J, Zhu M, Zheng Y, Gao L, Zhang L, Song Y, Hescheler J, Liang H. Molecular and Functional Changes in Voltage-Gated Na+ Channels in Cardiomyocytes During Mouse Embryogenesis. Circ J 2011; 75:2071-9. [DOI: 10.1253/circj.cj-10-1212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Liangzhu Yu
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Shijun Gao
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Li Nie
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Ming Tang
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Weifeng Huang
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Hongyan Luo
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Xinwu Hu
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Jiaoya Xi
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Minjie Zhu
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Yunjie Zheng
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Linlin Gao
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Lanqiu Zhang
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | - Yuanlong Song
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| | | | - Huamin Liang
- Chinese-German Stem Cell Center, Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology
| |
Collapse
|
46
|
Chung CY, Bien H, Sobie EA, Dasari V, McKinnon D, Rosati B, Entcheva E. Hypertrophic phenotype in cardiac cell assemblies solely by structural cues and ensuing self-organization. FASEB J 2010; 25:851-62. [PMID: 21084696 DOI: 10.1096/fj.10-168625] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In vitro models of cardiac hypertrophy focus exclusively on applying "external" dynamic signals (electrical, mechanical, and chemical) to achieve a hypertrophic state. In contrast, here we set out to demonstrate the role of "self-organized" cellular architecture and activity in reprogramming cardiac cell/tissue function toward a hypertrophic phenotype. We report that in neonatal rat cardiomyocyte culture, subtle out-of-plane microtopographic cues alter cell attachment, increase biomechanical stresses, and induce not only structural remodeling, but also yield essential molecular and electrophysiological signatures of hypertrophy. Increased cell size and cell binucleation, molecular up-regulation of released atrial natriuretic peptide, altered expression of classic hypertrophy markers, ion channel remodeling, and corresponding changes in electrophysiological function indicate a state of hypertrophy on par with other in vitro and in vivo models. Clinically used antihypertrophic pharmacological treatments partially reversed hypertrophic behavior in this in vitro model. Partial least-squares regression analysis, combining gene expression and functional data, yielded clear separation of phenotypes (control: cells grown on flat surfaces; hypertrophic: cells grown on quasi-3-dimensional surfaces and treated). In summary, structural surface features can guide cardiac cell attachment, and the subsequent syncytial behavior can facilitate trophic signals, unexpectedly on par with externally applied mechanical, electrical, and chemical stimulation.
Collapse
Affiliation(s)
- Chiung-yin Chung
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-8181, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
Prenatal exposure to toxicants, such as maternal smoking, may impair cardiovascular autonomic maturation in infants. We recently showed that exposure of pregnant rats to a mild concentration of carbon monoxide (CO), a component of cigarette smoke, delays postnatal electrophysiological maturation of ventricular myocytes from newborns rats, likely predisposing to life-threatening arrhythmias. To get a comprehensive view of developmental molecular abnormalities induced, at cardiac level, by prenatal CO exposure, we used microarray analysis approach on the rat heart at 4, 7 and 20 days postnatal life. The relationship between molecular and functional alterations was investigated by assessing the ventricular expression of f-current, an electrophysiological marker of immature cardiac phenotype. Rats were prenatally exposed to 0 (CTR) or 150 p.p.m. CO and mRNA obtained from ventricular samples. Differential analysis and biological pathway analysis of microarray data were performed by using Newton's approach and the GENMAPP/MAPPFinder, respectively. The real-time RT-PCR reactions were performed by TaqMan probe-based chemistry. Freshly isolated patch-clamped ventricular cardiomyocytes were used to measure I(f). Genes and pathways controlling cell cycle and excitation-contraction coupling were significantly modified in CO-exposed rats. The higher effect was observed in cardiomyocytes harvested from 7-day-old rats, in which mRNA expression for crucial sarcomeric proteins (myosin and actin subunits, troponin I), transporters (Ca(2+) transporting ATPase) and enzymes (aldolase) were significantly downregulated. Accordingly, the molecular and functional expression of f-channels, which represents a marker of fetal ventricular phenotype, was transiently greater in CO-exposed rats (+200%) than in control ones. In conclusion, our study provides new insights into the molecular and functional mechanisms underlying cardiac maturation and its impairment by prenatal exposure to toxic components of smoking, such as CO.
Collapse
|
48
|
|
49
|
Kim C, Majdi M, Xia P, Wei KA, Talantova M, Spiering S, Nelson B, Mercola M, Chen HSV. Non-cardiomyocytes influence the electrophysiological maturation of human embryonic stem cell-derived cardiomyocytes during differentiation. Stem Cells Dev 2010; 19:783-95. [PMID: 20001453 DOI: 10.1089/scd.2009.0349] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Various types of cardiomyocytes undergo changes in automaticity and electrical properties during fetal heart development. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs), like fetal cardiomyocytes, are electrophysiologically immature and exhibit automaticity. We used hESC-CMs to investigate developmental changes in mechanisms of automaticity and to determine whether electrophysiological maturation is driven by an intrinsic developmental clock and/or is regulated by interactions with non-cardiomyocytes in embryoid bodies (EBs). We isolated pure populations of hESC-CMs from EBs by lentivirus-engineered Puromycin resistance at various stages of differentiation. Using pharmacological agents, calcium (Ca(2+)) imaging, and intracellular recording techniques, we found that intracellular Ca(2+)-cycling mechanisms developed early and contributed to dominant automaticity throughout hESC-CM differentiation. Sarcolemmal ion channels evolved later upon further differentiation within EBs and played an increasing role in controlling automaticity and electrophysiological properties of hESC-CMs. In contrast to the development of intracellular Ca(2+)-handling proteins, ion channel development and electrophysiological maturation of hESC-CMs did not occur when hESC-CMs were isolated from EBs early and maintained in culture without further interaction with non-cardiomyocytes. Adding back non-cardiomyocytes to early-isolated hESC-CMs rescued the arrest of electrophysiological maturation, indicating that non-cardiomyocytes in EBs drive electrophysiological maturation of early hESC-CMs. Non-cardiomyocytes in EBs contain most cell types present in the embryonic heart that are known to influence early cardiac development. Our study is the first to demonstrate that non-cardiomyocytes influence electrophysiological maturation of early hESC-CMs in cultures. Defining the nature of these extrinsic signals will aid in the directed maturation of immature hESC-CMs to mitigate arrhythmogenic risks of cell-based therapies.
Collapse
Affiliation(s)
- Changsung Kim
- Center for Neuroscience, Aging and Stem Cell Research, Burnham Institute for Medical Research, La Jolla, California 92037, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Ou Y, Niu XL, Ren FX. Expression of key ion channels in the rat cardiac conduction system by laser capture microdissection and quantitative real-time PCR. Exp Physiol 2010; 95:938-45. [DOI: 10.1113/expphysiol.2009.051300] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|