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Boulgakoff L, D'Amato G, Miquerol L. Molecular Regulation of Cardiac Conduction System Development. Curr Cardiol Rep 2024:10.1007/s11886-024-02094-7. [PMID: 38990492 DOI: 10.1007/s11886-024-02094-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/02/2024] [Indexed: 07/12/2024]
Abstract
PURPOSE OF REVIEW The cardiac conduction system, composed of pacemaker cells and conducting cardiomyocytes, orchestrates the propagation of electrical activity to synchronize heartbeats. The conduction system plays a crucial role in the development of cardiac arrhythmias. In the embryo, the cells of the conduction system derive from the same cardiac progenitors as the contractile cardiomyocytes and and the key question is how this choice is made during development. RECENT FINDINGS This review focuses on recent advances in developmental biology using the mouse as animal model to better understand the cellular origin and molecular regulations that control morphogenesis of the cardiac conduction system, including the latest findings in single-cell transcriptomics. The conducting cell fate is acquired during development starting with pacemaking activity and last with the formation of a complex fast-conducting network. Cardiac conduction system morphogenesis is controlled by complex transcriptional and gene regulatory networks that differ in the components of the cardiac conduction system.
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Affiliation(s)
| | - Gaetano D'Amato
- Aix-Marseille Université, CNRS IBDM UMR7288, Marseille, France
| | - Lucile Miquerol
- Aix-Marseille Université, CNRS IBDM UMR7288, Marseille, France.
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2
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Gourdie RG. The enigmatic role of macrophages in cardiac electrical signalling. Cardiovasc Res 2022; 118:660-661. [PMID: 34894215 DOI: 10.1093/cvr/cvab358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Robert G Gourdie
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA, USA
- Department of Emergency Medicine, Virginia Tech Carilion School of Medicine and Center for Vascular and Heart Research, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA
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3
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Lahiri SK, Hulsurkar MM, Wehrens XH. Cellular regeneration as a potential strategy to treat cardiac conduction disorders. J Clin Invest 2021; 131:e152185. [PMID: 34596049 PMCID: PMC8483745 DOI: 10.1172/jci152185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Loss of atrioventricular conduction system (AVCS) cells due to either inherited or acquired deficits leads to conduction diseases, which can deteriorate into fatal cardiac arrhythmias and sudden death. In this issue of the JCI, Wang et al. constructed a mouse model of atrioventricular block (AVB) by inducing AVCS cell-specific injury using the Cx30.2 enhancer to drive expression of diphtheria toxin fragment A. AVCS cell ablation in adult mice led to irreversible AVB. jkjkIn contrast, AVCS cell injury in neonatal mice was followed by spontaneous recovery in a subset of mice, revealing a limited postnatal time window during which the regeneration of AVCS cells can occur as a result of cellular plasticity. This exciting study paves the way for future research into biological or cellular treatment approaches for cardiac conduction diseases by exploiting the regenerative potential of AVCS cells.
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Affiliation(s)
- Satadru K. Lahiri
- Cardiovascular Research Institute
- Department of Molecular Physiology and Biophysics
| | - Mohit M. Hulsurkar
- Cardiovascular Research Institute
- Department of Molecular Physiology and Biophysics
| | - Xander H.T. Wehrens
- Cardiovascular Research Institute
- Department of Molecular Physiology and Biophysics
- Department of Medicine (Cardiology)
- Department of Neuroscience
- Department of Pediatrics (Cardiology), and
- Center for Space Medicine, Baylor College of Medicine, Houston, Texas, USA
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4
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Gao J, Yuan G, Xu Z, Lan L, Xin W. Chenodeoxycholic and deoxycholic acids induced positive inotropic and negative chronotropic effects on rat heart. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:765-773. [PMID: 32808070 DOI: 10.1007/s00210-020-01962-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/06/2020] [Indexed: 12/25/2022]
Abstract
Bile acids are endogenous amphiphilic steroids from the metabolites of cholesterol. Studies showed that they might contribute to the pathogenesis of cardiopathy in cholestatic liver diseases. Chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) is associated with colon cancer, gallstones, and gastrointestinal disorders. However, little information is available regarding their cardiac effects. Here, we reported that CDCA (100 μM) and DCA (100 μM) significantly increased the left ventricular developed pressure of the isolated rat hearts to 122.3 ± 5.6% and 145.1 ± 13.7%, and the maximal rate of the pressure development rising and descending (± dP/dtmax) to 103.4 ± 17.6% and 124.4 ± 37.7% of the basal levels, respectively. They decreased the heart rate and prolonged the RR, QRS, and QT intervals of Langendorff-perfused hearts in a concentration-dependent manner. Moreover, CDCA and DCA increased the developed tension of left ventricular muscle and the cytosolic Ca2+ concentrations in left ventricular myocytes; these functions positively coordinated with their inotropic effects on hearts. Additionally, CDCA (150 μM) and DCA (100 μM) decreased the sinoatrial node beating rate to 80.6 ± 3.0% and 79.7 ± 0.9% of the basal rate (334.2 ± 10.7 bpm), respectively. These results were consistent with their chronotropic effects. In conclusion, CDCA and DCA induced positive inotropic effects by elevating the Ca2+ in left ventricular myocytes. They exerted negative chronotropic effects by lowering the pace of the sinoatrial node in rat heart. These results indicated that the potential role of bile acids in cardiopathy related to cholestasis.
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Affiliation(s)
- Jie Gao
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, 2 Tiansheng Road, Beibei, Chongqing, 400715, China
| | - Guanyin Yuan
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, 2 Tiansheng Road, Beibei, Chongqing, 400715, China
| | - Zhan Xu
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, 2 Tiansheng Road, Beibei, Chongqing, 400715, China
| | - Luyao Lan
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, 2 Tiansheng Road, Beibei, Chongqing, 400715, China
| | - Wenkuan Xin
- College of Pharmaceutical Sciences and Chinese Medicine, Southwest University, 2 Tiansheng Road, Beibei, Chongqing, 400715, China.
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5
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Abstract
Cardiac development is a complex developmental process that is initiated soon after gastrulation, as two sets of precardiac mesodermal precursors are symmetrically located and subsequently fused at the embryonic midline forming the cardiac straight tube. Thereafter, the cardiac straight tube invariably bends to the right, configuring the first sign of morphological left–right asymmetry and soon thereafter the atrial and ventricular chambers are formed, expanded and progressively septated. As a consequence of all these morphogenetic processes, the fetal heart acquired a four-chambered structure having distinct inlet and outlet connections and a specialized conduction system capable of directing the electrical impulse within the fully formed heart. Over the last decades, our understanding of the morphogenetic, cellular, and molecular pathways involved in cardiac development has exponentially grown. Multiples aspects of the initial discoveries during heart formation has served as guiding tools to understand the etiology of cardiac congenital anomalies and adult cardiac pathology, as well as to enlighten novels approaches to heal the damaged heart. In this review we provide an overview of the complex cellular and molecular pathways driving heart morphogenesis and how those discoveries have provided new roads into the genetic, clinical and therapeutic management of the diseased hearts.
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6
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Wittig JG, Münsterberg A. The Chicken as a Model Organism to Study Heart Development. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a037218. [PMID: 31767650 DOI: 10.1101/cshperspect.a037218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heart development is a complex process and begins with the long-range migration of cardiac progenitor cells during gastrulation. This culminates in the formation of a simple contractile tube with multiple layers, which undergoes remodeling into a four-chambered heart. During this morphogenesis, additional cell populations become incorporated. It is important to unravel the underlying genetic and cellular mechanisms to be able to identify the embryonic origin of diseases, including congenital malformations, which impair cardiac function and may affect life expectancy or quality. Owing to the evolutionary conservation of development, observations made in nonamniote and amniote vertebrate species allow us to extrapolate to human. This review will focus on the contributions made to a better understanding of heart development through studying avian embryos-mainly the chicken but also quail embryos. We will illustrate the classic and recent approaches used in the avian system, give an overview of the important discoveries made, and summarize the early stages of cardiac development up to the establishment of the four-chambered heart.
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Affiliation(s)
- Johannes G Wittig
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Andrea Münsterberg
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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Follow Me! A Tale of Avian Heart Development with Comparisons to Mammal Heart Development. J Cardiovasc Dev Dis 2020; 7:jcdd7010008. [PMID: 32156044 PMCID: PMC7151090 DOI: 10.3390/jcdd7010008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/16/2020] [Accepted: 02/21/2020] [Indexed: 12/19/2022] Open
Abstract
Avian embryos have been used for centuries to study development due to the ease of access. Because the embryos are sheltered inside the eggshell, a small window in the shell is ideal for visualizing the embryos and performing different interventions. The window can then be covered, and the embryo returned to the incubator for the desired amount of time, and observed during further development. Up to about 4 days of chicken development (out of 21 days of incubation), when the egg is opened the embryo is on top of the yolk, and its heart is on top of its body. This allows easy imaging of heart formation and heart development using non-invasive techniques, including regular optical microscopy. After day 4, the embryo starts sinking into the yolk, but still imaging technologies, such as ultrasound, can tomographically image the embryo and its heart in vivo. Importantly, because like the human heart the avian heart develops into a four-chambered heart with valves, heart malformations and pathologies that human babies suffer can be replicated in avian embryos, allowing a unique developmental window into human congenital heart disease. Here, we review avian heart formation and provide comparisons to the mammalian heart.
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8
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Aoyama J, Homma K, Tanabe N, Usui S, Miyagi Y, Matsuura K, Kaneda M, Nitta T. Spatiotemporal imaging documented the maturation of the cardiomyocytes from human induced pluripotent stem cells. J Thorac Cardiovasc Surg 2019; 159:2260-2271.e7. [PMID: 31409490 DOI: 10.1016/j.jtcvs.2019.06.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Cardiomyocytes derived from human induced pluripotent stem cells are a promising source of cells for regenerative medicine. However, contractions in such derived cardiomyocytes are often irregular and asynchronous, especially at early stages of differentiation. This study aimed to determine the differentiation stage of initiation of synchronized and regular contractions, using spatiotemporal imaging and physiological and genetic analyses. METHODS Knock-in human induced pluripotent stem cell lines were established with clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated protein 9 to analyze cardiac and pacemaker cell maturation. Time-frequency analysis and Ca2+ imaging were performed, and the expression of related proteins and specific cardiac/pacemaker mRNAs in contracting embryoid bodies was analyzed at various differentiation stages. RESULTS Time-frequency analysis and Ca2+ imaging revealed irregular, asynchronous contractions at the early stage of differentiation with altered electrophysiological properties upon differentiation. Genes associated with electrophysiological properties were upregulated after 70 days of culturing in differentiation media, whereas pacemaker genes were initially upregulated during the early stage and downregulated at the later stage. CONCLUSIONS A differentiation period >70 days is required for adequate development of cardiac elements including ion channels and gap junctions and for sarcomere maturation.
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Affiliation(s)
- Junya Aoyama
- Department of Cardiovascular Surgery, Nippon Medical School, Tokyo, Japan; Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Kohei Homma
- Department of Physiology, Nippon Medical School, Tokyo, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Nari Tanabe
- SUWA, Tokyo University of Science, Nagano, Japan
| | - Sumiko Usui
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Yasuo Miyagi
- Department of Cardiovascular Surgery, Nippon Medical School, Tokyo, Japan
| | - Katsuhisa Matsuura
- Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Takashi Nitta
- Department of Cardiovascular Surgery, Nippon Medical School, Tokyo, Japan.
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9
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Goudy J, Henley T, Méndez HG, Bressan M. Simplified platform for mosaic in vivo analysis of cellular maturation in the developing heart. Sci Rep 2019; 9:10716. [PMID: 31341189 PMCID: PMC6656758 DOI: 10.1038/s41598-019-47009-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022] Open
Abstract
Cardiac cells develop within an elaborate electro-mechanical syncytium that continuously generates and reacts to biophysical force. The complexity of the cellular interactions, hemodynamic stresses, and electrical circuitry within the forming heart present significant challenges for mechanistic research into the cellular dynamics of cardiomyocyte maturation. Simply stated, it is prohibitively difficult to replicate the native electro-mechanical cardiac microenvironment in tissue culture systems favorable to high-resolution cellular/subcellular analysis, and current transgenic models of higher vertebrate heart development are limited in their ability to manipulate and assay the behavior of individual cells. As such, cardiac research currently lacks a simple experimental platform for real-time evaluation of cellular function under conditions that replicate native development. Here we report the design and validation of a rapid, low-cost system for stable in vivo somatic transgenesis that allows for individual cells to be genetically manipulated, tracked, and examined at subcellular resolution within the forming four-chambered heart. This experimental platform has several advantages over current technologies, chief among these being that mosaic cellular perturbations can be conducted without globally altering cardiac function. Consequently, direct analysis of cellular behavior can be interrogated in the absence of the organ level adaptions that often confound data interpretation in germline transgenic model organisms.
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Affiliation(s)
- Julie Goudy
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, USA.,McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Trevor Henley
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, USA.,McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Hernán G Méndez
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Michael Bressan
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, USA. .,McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, USA.
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10
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Mao Z, Wang Y, Peng H, He F, Zhu L, Huang H, Huang X, Lu X, Tan X. A newly identified missense mutation in CLCA2 is associated with autosomal dominant cardiac conduction block. Gene 2019; 714:143990. [PMID: 31326550 DOI: 10.1016/j.gene.2019.143990] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/15/2019] [Accepted: 07/17/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND Progressive cardiac conduction defect (PCCD), also known as Lenegre-Lev disease, is one of the most common heart conduction abnormalities. Previous studies have screened for known mutation sites that cause heart block in a 68-person family with a history of PCCD, revealed no mutations. OBJECTIVE To screen pathogenic genes of the PCCD family and to study the function of the gene mutations related to heart block diseases. METHODS Whole exome sequencing (WES) was performed on two PCCD patients and one non-PCCD family member to find the related pathogenic gene. After family co-segregation and preliminary functional analysis, we identified the mutant gene CLCA2. To study the function of this gene, we constructed mutant-gene mice using CRISPR-Cas9 technology, and electrocardiogram monitoring was performed after genotype verification. RESULTS The CLCA2 c.G1725T mutation was identified and co-segregated with the phenotype. The analysis showed that the CLCA2 c.G1725T mutation is harmful and mainly affects protein glycosylation. Immunofluorescence staining revealed that CLCA2 was highly expressed in the sinoatrial node (SAN) tissues. Electrocardiogram monitoring of the mice revealed that CLCA2 point mutations induced mild conduction block and ectopic pacemakers. CONCLUSION Our findings indicate that a novel heterozygous missense mutation c.G1725T of the CLCA2 gene may be associated with heart block disease and the mutation in this gene may lead to sinus node lesions and conduction blocking.
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Affiliation(s)
- Zhuo Mao
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Yi Wang
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Hao Peng
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Fang He
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Li Zhu
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - He Huang
- Cardiovascular Medicine of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Xianghong Huang
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Xiaowei Lu
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China
| | - Xiaojun Tan
- Reproductive and Genetic Center of Central Hospital of Xiangtan, 120 Heping Road, Yuhu District, Xiangtan City 411100, Hunan Province, China.
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11
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Gyenes DL, McBrien AH, Bohun CM, Serrano-Lomelin J, Alvarez SGV, Howley LW, Savard W, Jain V, Motan T, Atallah J, Hornberger LK. Evolution of the Fetal Atrioventricular Interval from 6 to 40 Weeks of Gestation. Am J Cardiol 2019; 123:1709-1714. [PMID: 30871745 DOI: 10.1016/j.amjcard.2019.02.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/06/2019] [Accepted: 02/13/2019] [Indexed: 11/17/2022]
Abstract
Doppler-based methods of estimating the atrioventricular interval are commonly used as a surrogate for the electrical PR in fetuses at risk of conduction abnormalities; however, to date, normal values for the fetal atrioventricular interval and an understanding of the evolution of its components in the late first trimester are lacking. We sought to investigate changes in the fetal atrioventricular interval from the first trimester to 40 weeks gestational age, and to explore functional and electrophysiological events that potentially impact its evolution. We prospectively examined healthy pregnancies by fetal echocardiography from 6 to 40 weeks' gestational age. The atrioventricular interval, heart rate, isovolumic contraction time, and A-wave duration were measured from simultaneous ventricular inflow-outflow Doppler tracings. Regression analysis was used to examine relations with gestational age, and linear relations with heart rate were assessed by Pearson's correlation coefficient. Data were collected in 305 fetuses from 279 pregnancies. Atrioventricular interval demonstrated an inverse relation with heart rate (r = -0.45, p <0.0001), dramatically decreasing before 10 weeks and slowly increasing thereafter. Between 6 and 9 weeks, isovolumic contraction time acutely decreased approaching 0, thereafter minimally increasing to term. In contrast, from 6 weeks, the A-wave duration linearly increased through gestation, and negatively correlated with heart rate (r = -0.62, p <0.0001). In conclusion, we have established normal measures of the atrioventricular interval from 6 to 40 weeks' gestational age. Before 10 weeks, a prolonged atrioventricular interval in healthy fetuses largely reflects the lengthened isovolumic contraction time which is likely influenced by the evolution of ventricular function and afterload.
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Affiliation(s)
- Dora L Gyenes
- Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada; Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Angela H McBrien
- Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada; Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - C Monique Bohun
- Department of Pediatrics/Cardiology, The University of New Mexico, Albuquerque, New Mexico
| | - Jesus Serrano-Lomelin
- Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada; School of Public Health, University of Alberta, Edmonton, Alberta, Canada
| | | | - Lisa W Howley
- The Heart Institute, Children's Hospital Colorado/University of Colorado, Aurora, Colorado
| | - Winnie Savard
- Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada; Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Venu Jain
- Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada; Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | - Tarek Motan
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph Atallah
- Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada
| | - Lisa K Hornberger
- Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada; Women's and Children's Health Research Institute and Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada; Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada.
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12
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Bhattacharyya S, Duan J, Wang L, Li B, Bhakta M, Fernandez-Perez A, Hon GC, Munshi NV. Using Gjd3-CreEGFP mice to examine atrioventricular node morphology and composition. Sci Rep 2019; 9:2106. [PMID: 30765799 PMCID: PMC6375990 DOI: 10.1038/s41598-019-38683-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
The atrioventricular node (AVN) coordinates the timing of atrial and ventricular contraction to optimize cardiac performance. To study this critical function using mouse genetics, however, new reagents are needed that allow AVN-specific manipulation. Here we describe a novel Gjd3-CreEGFP mouse line that successfully recombines floxed alleles within the AVN beginning at E12.5. These mice have been engineered to express CreEGFP under the control of endogenous Gjd3 regulatory elements without perturbing native protein expression. Detailed histological analysis of Gjd3-CreEGFP mice reveals specific labeling of AVN cardiomyocytes and a subset of cardiac endothelial cells. Importantly, we show that Gjd3-CreEGFP mice have preserved cardiac mechanical and electrical function. In one application of our newly described mouse line, we provide a three-dimensional (3D) view of the AVN using tissue clearing combined with confocal microscopy. With this 3D model as a reference, we identify specific AVN sub-structures based on marker staining characteristics. In addition, we use our Gjd3-CreEGFP mice to guide microdissection of the AVN and construction of a single-cell atlas. Thus, our results establish a new transgenic tool for AVN-specific recombination, provide an updated model of AVN morphology, and describe a roadmap for exploring AVN cellular heterogeneity.
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Affiliation(s)
- Samadrita Bhattacharyya
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jialei Duan
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Lin Wang
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Boxun Li
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Minoti Bhakta
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Antonio Fernandez-Perez
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Gary C Hon
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.,Hamon Center for Regenerative Science and Medicine, Dallas, TX, 75390, USA
| | - Nikhil V Munshi
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,Hamon Center for Regenerative Science and Medicine, Dallas, TX, 75390, USA.
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13
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Vinogradova TM, Tagirova Sirenko S, Lakatta EG. Unique Ca 2+-Cycling Protein Abundance and Regulation Sustains Local Ca 2+ Releases and Spontaneous Firing of Rabbit Sinoatrial Node Cells. Int J Mol Sci 2018; 19:ijms19082173. [PMID: 30044420 PMCID: PMC6121616 DOI: 10.3390/ijms19082173] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 11/16/2022] Open
Abstract
Spontaneous beating of the heart pacemaker, the sinoatrial node, is generated by sinoatrial node cells (SANC) and caused by gradual change of the membrane potential called diastolic depolarization (DD). Submembrane local Ca2+ releases (LCR) from sarcoplasmic reticulum (SR) occur during late DD and activate an inward Na+/Ca2+ exchange current, which accelerates the DD rate leading to earlier occurrence of an action potential. A comparison of intrinsic SR Ca2+ cycling revealed that, at similar physiological Ca2+ concentrations, LCRs are large and rhythmic in permeabilized SANC, but small and random in permeabilized ventricular myocytes (VM). Permeabilized SANC spontaneously released more Ca2+ from SR than VM, despite comparable SR Ca2+ content in both cell types. In this review we discuss specific patterns of expression and distribution of SR Ca2+ cycling proteins (SR Ca2+ ATPase (SERCA2), phospholamban (PLB) and ryanodine receptors (RyR)) in SANC and ventricular myocytes. We link ability of SANC to generate larger and rhythmic LCRs with increased abundance of SERCA2, reduced abundance of the SERCA inhibitor PLB. In addition, an increase in intracellular [Ca2+] increases phosphorylation of both PLB and RyR exclusively in SANC. The differences in SR Ca2+ cycling protein expression between SANC and VM provide insights into diverse regulation of intrinsic SR Ca2+ cycling that drives automaticity of SANC.
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Affiliation(s)
- Tatiana M Vinogradova
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
| | - Syevda Tagirova Sirenko
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, 251 Bayview Blvd, Room 8B-123, Baltimore, MD 21224, USA.
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14
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Klimek-Piotrowska W, Krawczyk-Ożóg A, Suski M, Kapusta P, Wołkow PP, Hołda MK. Comparative iTRAQ analysis of protein abundance in the human sinoatrial node and working cardiomyocytes. J Anat 2018; 232:956-964. [PMID: 29484645 DOI: 10.1111/joa.12798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2018] [Indexed: 02/06/2023] Open
Abstract
Our objective was to assess the changes in protein abundance in the human sinoatrial node (SAN) compared with working cardiomyocytes to identify SAN-specific protein signatures. Four pairs of samples (the SAN and working cardiomyocytes) were obtained postmortem from four human donors with no evidence of cardiovascular disease. We performed protein identification and quantitation using two-dimensional chromatography-tandem mass spectrometry with isobaric peptide labeling (iTRAQ). We identified 451 different proteins expressed in both the SAN and working cardiomyocytes, 166 of which were differentially regulated (110 were upregulated in the SAN and 56 in the working cardiomyocytes). We identified sarcomere structural proteins in both tissues, although they were differently distributed among the tested samples. For example, myosin light chain 4, myosin regulatory light chain 2-atrial isoform, and tropomyosin alpha-3 chain levels were twofold higher in the SAN than in working cardiomyocytes, and myosin light chain 3 and myosin regulatory light chain 2-ventricular/cardiac muscle isoform levels were twofold higher in the ventricle tissue than in SAN. We identified many mitochondrial oxidative phosphorylation, β-oxidation, and tricarboxylic acid cycle proteins that were predominantly associated with working cardiomyocytes tissue. We detected upregulation of the fatty acid omega activation pathway proteins in the SAN samples. Some proteins specific for smooth muscle tissue were highly upregulated in the SAN (e.g. transgelin), which indicates that the SAN tissue might act as the bridge between the working myocardium and the smooth muscle. Our results show possible implementation of proteomic strategies to identify in-depth functional differences between various heart sub-structures.
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Affiliation(s)
- Wiesława Klimek-Piotrowska
- HEART - Heart Embryology and Anatomy Research Team, Department of Anatomy, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Agata Krawczyk-Ożóg
- HEART - Heart Embryology and Anatomy Research Team, Department of Anatomy, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Maciej Suski
- Department of Pharmacology, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Przemysław Kapusta
- Center for Medical Genomics OMICRON, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Paweł P Wołkow
- Center for Medical Genomics OMICRON, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland.,Department of Pharmacology, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Mateusz K Hołda
- HEART - Heart Embryology and Anatomy Research Team, Department of Anatomy, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
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15
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Van Malderen S, Wijchers S, Akca F, Caliskan K, Szili-Torok T. Mismatch between the origin of premature ventricular complexes and the noncompacted myocardium in patients with noncompaction cardiomyopathy patients: involvement of the conduction system? Ann Noninvasive Electrocardiol 2016; 22. [PMID: 27568851 DOI: 10.1111/anec.12394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Noncompaction cardiomyopathy (NCCM) is considered to be the result of an arrest in the normal myocardial embryogenesis. The histological, developmental, and electrophysiological explanation of ventricular arrhythmias in NCCM is still unknown. The aim of this study was to determine the origin of premature ventricular contractions (PVCs) in NCCM and to identify any predominant arrhythmic foci. METHODS Retrospective data from our NCCM registry including 101 patients were analyzed. A total number of 2069 electrocardiograms (ECGs) were studied to determine the origin of PVCs. Echocardiographic data were analyzed in patients with PVCs in all 12 leads. Segments affected by noncompaction (NC) were compared with the origin of PVCs. RESULTS PVCs were documented in 250 ECGs from 55 (54%) patients. Thirty-five ECGs recorded PVCs on all 12 leads and the origin of 20 types of PVCs could be determined. Ninety-five percent of PVCs did not originate from left ventricular NC myocardial areas and two PVCs (10%) had a true myocardial origin. All other PVCs originated from structures such as the outflow tracts (8/20), the fascicles (7/20), especially the posteromedial fascicle (6/20), and the mitral and tricuspid annulus (3/20). CONCLUSIONS Our data suggest that PVCs in NCCM mainly originate from the conduction system and related myocardium.
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Affiliation(s)
- Sophie Van Malderen
- Department of Clinical Electrophysiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sip Wijchers
- Department of Clinical Electrophysiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ferdi Akca
- Department of Clinical Electrophysiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kadir Caliskan
- Department of Heart Failure/Heart Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Tamas Szili-Torok
- Department of Clinical Electrophysiology, Erasmus Medical Center, Rotterdam, The Netherlands
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16
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Weisbrod D, Khun SH, Bueno H, Peretz A, Attali B. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels. Acta Pharmacol Sin 2016; 37:82-97. [PMID: 26725737 PMCID: PMC4722971 DOI: 10.1038/aps.2015.135] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/25/2015] [Indexed: 12/25/2022] Open
Abstract
The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.
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Affiliation(s)
- David Weisbrod
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shiraz Haron Khun
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hanna Bueno
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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17
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Prosheva VI, Kaseva NN. Location and functional characterization of the right atrioventricular pacemaker ring in the adult avian heart. J Morphol 2015; 277:363-9. [DOI: 10.1002/jmor.20502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/22/2015] [Accepted: 11/15/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Valentina I. Prosheva
- Institute of Physiology; Komi Science Centre, The Russian Academy of Sciences; 50 Pervomayskaya Street, 167982 GSP-2 Syktyvkar Komi Republic Russia
| | - Natalya N. Kaseva
- Institute of Physiology; Komi Science Centre, The Russian Academy of Sciences; 50 Pervomayskaya Street, 167982 GSP-2 Syktyvkar Komi Republic Russia
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18
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Abstract
PURPOSE OF REVIEW Progressive cardiac conduction disorder (PCCD) is an inherited cardiac disease that may present as a primary electrical disease or be associated with structural heart disease. In this brief review, we present recent clinical, genetic, and molecular findings relating to PCCD. RECENT FINDINGS Inherited PCCD in structurally normal hearts has been found to be linked to genetic variants in the ion channel genes SCN5A, SCN1B, SCN10A, TRPM4, and KCNK17, as well as in genes coding for cardiac connexin proteins. In addition, several SCN5A mutations lead to 'cardiac sodium channelopathy overlap syndrome'. Other genes coding for cardiac transcription factors, such as NKX2.5 and TBX5, are involved in the development of the cardiac conduction system and in the morphogenesis of the heart. Mutations in these two genes have been shown to cause cardiac conduction disorders associated with various congenital heart defects. SUMMARY PCCD is a hereditary syndrome, and genetic variants in multiple genes have been described to date. Genetic screening and identification of the causal mutation are crucial for risk stratification and family counselling.
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19
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Sedmera D, Kockova R, Vostarek F, Raddatz E. Arrhythmias in the developing heart. Acta Physiol (Oxf) 2015; 213:303-20. [PMID: 25363044 DOI: 10.1111/apha.12418] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/08/2014] [Accepted: 10/23/2014] [Indexed: 01/10/2023]
Abstract
Prevalence of cardiac arrhythmias increases gradually with age; however, specific rhythm disturbances can appear even prior to birth and markedly affect foetal development. Relatively little is known about these disorders, chiefly because of their relative rarity and difficulty in diagnosis. In this review, we cover the most common forms found in human pathology, specifically congenital heart block, pre-excitation, extrasystoles and long QT syndrome. In addition, we cover pertinent literature data from prenatal animal models, providing a glimpse into pathogenesis of arrhythmias and possible strategies for treatment.
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Affiliation(s)
- D. Sedmera
- Institute of Anatomy; First Faculty of Medicine; Charles University; Prague Czech Republic
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - R. Kockova
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague Czech Republic
- Department of Cardiology; Institute of Clinical and Experimental Medicine; Prague Czech Republic
| | - F. Vostarek
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - E. Raddatz
- Department of Physiology; Faculty of Biology and Medicine; University of Lausanne; Lausanne Switzerland
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20
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Liang X, Evans SM, Sun Y. Insights into cardiac conduction system formation provided by HCN4 expression. Trends Cardiovasc Med 2015; 25:1-9. [PMID: 25442735 PMCID: PMC5544420 DOI: 10.1016/j.tcm.2014.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 11/22/2022]
Abstract
Specialized myocytes of the cardiac conduction system (CCS) are essential to coordinate sequential contraction of cardiac atria and ventricles. Anomalies of the CCS can result in lethal cardiac arrhythmias, including sick sinus syndrome and atrial or ventricular fibrillation. To develop future therapies and regenerative medicine aimed at cardiac arrhythmias, it is important to understand formation and function of distinct components of the CCS. Essential to this understanding is the development of CCS-specific markers. In this review, we briefly summarize available mouse models of CCS markers and focus on those involving the hyperpolarization cation-selective nucleotide-gated cation channel, HCN4, which selectively marks all components of the specialized CCS in adult heart. Recent studies have revealed, however, that HCN4 expression during development is highly dynamic in cardiac precursors. These studies have offered insights into the contributions of the first and second heart field to myocyte and conduction system lineages and suggested the timing of allocation of specific conduction system precursors during development. Altogether, they have highlighted the utility of HCN4 as a cell surface marker for distinct components of the CCS at distinct stages of development, which can be utilized to facilitate purification and characterization of CCS precursors in mouse and human model systems and pave the way for regenerative therapies.
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Affiliation(s)
- Xingqun Liang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, China; Department of Medicine, University of California, San Diego, San Diego, CA
| | - Sylvia M Evans
- Department of Medicine, University of California, San Diego, San Diego, CA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA; Department of Pharmacology, University of California, San Diego, San Diego, CA.
| | - Yunfu Sun
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai, China.
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21
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Abstract
Purkinje fibers were the first discovered component of the cardiac conduction system. Originally described in sheep in 1839 as pale subendocardial cells, they were found to be present, although with different morphology, in all mammalian and avian hearts. Here we review differences in their appearance and extent in different species, summarize the current state of knowledge of their function, and provide an update on markers for these cells. Special emphasis is given to popular model species and human anatomy.
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Affiliation(s)
- D Sedmera
- Department of Cardiovascular Morphogenesis, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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22
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Lindsey SE, Butcher JT, Yalcin HC. Mechanical regulation of cardiac development. Front Physiol 2014; 5:318. [PMID: 25191277 DOI: 10.3389/fphys.2014.00318/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/03/2014] [Indexed: 05/25/2023] Open
Abstract
Mechanical forces are essential contributors to and unavoidable components of cardiac formation, both inducing and orchestrating local and global molecular and cellular changes. Experimental animal studies have contributed substantially to understanding the mechanobiology of heart development. More recent integration of high-resolution imaging modalities with computational modeling has greatly improved our quantitative understanding of hemodynamic flow in heart development. Merging these latest experimental technologies with molecular and genetic signaling analysis will accelerate our understanding of the relationships integrating mechanical and biological signaling for proper cardiac formation. These advances will likely be essential for clinically translatable guidance for targeted interventions to rescue malforming hearts and/or reconfigure malformed circulations for optimal performance. This review summarizes our current understanding on the levels of mechanical signaling in the heart and their roles in orchestrating cardiac development.
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Affiliation(s)
| | - Jonathan T Butcher
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
| | - Huseyin C Yalcin
- Department of Mechanical Engineering, Dogus University Istanbul, Turkey
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23
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Lindsey SE, Butcher JT, Yalcin HC. Mechanical regulation of cardiac development. Front Physiol 2014; 5:318. [PMID: 25191277 PMCID: PMC4140306 DOI: 10.3389/fphys.2014.00318] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/03/2014] [Indexed: 12/21/2022] Open
Abstract
Mechanical forces are essential contributors to and unavoidable components of cardiac formation, both inducing and orchestrating local and global molecular and cellular changes. Experimental animal studies have contributed substantially to understanding the mechanobiology of heart development. More recent integration of high-resolution imaging modalities with computational modeling has greatly improved our quantitative understanding of hemodynamic flow in heart development. Merging these latest experimental technologies with molecular and genetic signaling analysis will accelerate our understanding of the relationships integrating mechanical and biological signaling for proper cardiac formation. These advances will likely be essential for clinically translatable guidance for targeted interventions to rescue malforming hearts and/or reconfigure malformed circulations for optimal performance. This review summarizes our current understanding on the levels of mechanical signaling in the heart and their roles in orchestrating cardiac development.
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Affiliation(s)
| | - Jonathan T Butcher
- Department of Biomedical Engineering, Cornell University Ithaca, NY, USA
| | - Huseyin C Yalcin
- Department of Mechanical Engineering, Dogus University Istanbul, Turkey
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24
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Sakurai M, Kuninaga N, Takeuchi T, Tsuka T, Morita T. Congenital multifocal increase of Purkinje fibres in a calf with cardiac conduction delay. J Comp Pathol 2014; 151:234-7. [PMID: 25084712 DOI: 10.1016/j.jcpa.2014.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 05/29/2014] [Accepted: 06/05/2014] [Indexed: 11/17/2022]
Abstract
A female 4-month-old Holstein-Friesian calf was presented in heart failure. Microscopical examination of samples of the cardiac wall taken at necropsy examination revealed numerous aggregates of Purkinje fibres, particularly in the perivascular areas. Some Purkinje fibres were stained strongly with phosphotungstic acid haematoxylin and immunohistochemically were shown to express alpha smooth muscle actin, indicating an embryonic-like Purkinje fibre phenotype. A diagnosis of congenital multifocal increase of Purkinje fibres was made. The histological features of this case resemble multifocal cardiac Purkinje cell tumour of the heart in man.
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Affiliation(s)
- M Sakurai
- Department of Veterinary Pathology, Tottori University, Tottori, Japan
| | - N Kuninaga
- Department of Veterinary Pathology, Tottori University, Tottori, Japan
| | - T Takeuchi
- Department of Veterinary Laboratory Medicine, Tottori University, Tottori, Japan
| | - T Tsuka
- Department of Veterinary Diagnostic Imaging, Tottori University, Tottori, Japan
| | - T Morita
- Department of Veterinary Pathology, Tottori University, Tottori, Japan.
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25
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Karppinen S, Rapila R, Mäkikallio K, Hänninen SL, Rysä J, Vuolteenaho O, Tavi P. Endothelin-1 signalling controls early embryonic heart rate in vitro and in vivo. Acta Physiol (Oxf) 2014; 210:369-80. [PMID: 24325624 DOI: 10.1111/apha.12194] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 04/10/2013] [Accepted: 01/11/2013] [Indexed: 12/13/2022]
Abstract
AIM Spontaneous activity of embryonic cardiomyocytes originates from sarcoplasmic reticulum (SR) Ca(2+) release during early cardiogenesis. However, the regulation of heart rate during embryonic development is still not clear. The aim of this study was to determine how endothelin-1 (ET-1) affects the heart rate of embryonic mice, as well as the pathway through which it exerts its effects. METHODS The effects of ET-1 and ET-1 receptor inhibition on cardiac contraction were studied using confocal Ca(2+) imaging of isolated mouse embryonic ventricular cardiomyocytes and ultrasonographic examination of embryonic cardiac contractions in utero. In addition, the amount of ET-1 peptide and ET receptor a (ETa) and b (ETb) mRNA levels were measured during different stages of development of the cardiac muscle. RESULTS High ET-1 concentration and expression of both ETa and ETb receptors was observed in early cardiac tissue. ET-1 was found to increase the frequency of spontaneous Ca(2+) oscillations in E10.5 embryonic cardiomyocytes in vitro. Non-specific inhibition of ET receptors with tezosentan caused arrhythmia and bradycardia in isolated embryonic cardiomyocytes and in whole embryonic hearts both in vitro (E10.5) and in utero (E12.5). ET-1-mediated stimulation of early heart rate was found to occur via ETb receptors and subsequent inositol trisphosphate receptor activation and increased SR Ca(2+) leak. CONCLUSION Endothelin-1 is required to maintain a sufficient heart rate, as well as to prevent arrhythmia during early development of the mouse heart. This is achieved through ETb receptor, which stimulates Ca(2+) leak through IP3 receptors.
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Affiliation(s)
- S. Karppinen
- Department of Biotechnology and Molecular Medicine; A.I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - R. Rapila
- Department of Biotechnology and Molecular Medicine; A.I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - K. Mäkikallio
- Department of Obstetrics and Gynecology; University of Oulu; Oulu Finland
| | - S. L. Hänninen
- Department of Physiology; Institute of Biomedicine; University of Oulu; Oulu Finland
| | - J. Rysä
- Department of Pharmacology and Toxicology; Institute of Biomedicine; University of Oulu; Oulu Finland
| | - O. Vuolteenaho
- Department of Physiology; Institute of Biomedicine; University of Oulu; Oulu Finland
| | - P. Tavi
- Department of Biotechnology and Molecular Medicine; A.I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
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26
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Kaese S, Verheule S. Cardiac electrophysiology in mice: a matter of size. Front Physiol 2012; 3:345. [PMID: 22973235 PMCID: PMC3433738 DOI: 10.3389/fphys.2012.00345] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/09/2012] [Indexed: 12/27/2022] Open
Abstract
Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias.
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Affiliation(s)
- Sven Kaese
- Division of Experimental and Clinical Electrophysiology, Department of Cardiology and Angiology, University Hospital Münster Münster, Germany
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27
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Normal and abnormal development of the cardiac conduction system; implications for conduction and rhythm disorders in the child and adult. Differentiation 2012; 84:131-48. [DOI: 10.1016/j.diff.2012.04.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 04/16/2012] [Indexed: 11/20/2022]
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Aránega A, De La Rosa AJ, Franco D. Cardiac conduction system anomalies and sudden cardiac death: insights from murine models. Front Physiol 2012; 3:211. [PMID: 22783196 PMCID: PMC3390691 DOI: 10.3389/fphys.2012.00211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/29/2012] [Indexed: 01/18/2023] Open
Abstract
The cardiac conduction system (CCS) is composed of a group of myocardial tissues that control and coordinate the heart. Alterations in the CCS – especially in the His–Purkinje system, have been identified as a major cause of lethal arrhythmias. Unstable arrhythmias secondary to channelopathies significantly increase the risk of sudden cardiac death (SCD). SCD is a major contributor to mortality in industrialized countries, and most cases of SCD in the young are related to inherited ion channel diseases. In this paper, we review a series of studies with murine transgenic models that revealed that some arrhythmias are associated with the CCS and may lead to SCD
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Affiliation(s)
- Amelia Aránega
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén Jaén, Spain
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29
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Sizarov A, Devalla HD, Anderson RH, Passier R, Christoffels VM, Moorman AFM. Molecular analysis of patterning of conduction tissues in the developing human heart. Circ Arrhythm Electrophysiol 2011; 4:532-42. [PMID: 21576278 DOI: 10.1161/circep.111.963421] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Recent studies in experimental animals have revealed some molecular mechanisms underlying the differentiation of the myocardium making up the conduction system. To date, lack of gene expression data for the developing human conduction system has precluded valid extrapolations from experimental studies to the human situation. METHODS AND RESULTS We performed immunohistochemical analyses of the expression of key transcription factors, such as ISL1, TBX3, TBX18, and NKX2-5, ion channel HCN4, and connexins in the human embryonic heart. We supplemented our molecular analyses with 3-dimensional reconstructions of myocardial TBX3 expression. TBX3 is expressed in the developing conduction system and in the right venous valve, atrioventricular ring bundles, and retro-aortic nodal region. TBX3-positive myocardium, with exception of the top of the ventricular septum, is devoid of fast-conducting connexin40 and connexin43 and hence identifies slowly conducting pathways. In the early embryonic heart, we found wide expression of the pacemaker channel HCN4 at the venous pole, including the atrial chambers. HCN4 expression becomes confined during later developmental stages to the components of the conduction system. Patterns of expression of transcription factors, known from experimental studies to regulate the development of the sinus node and atrioventricular conduction system, are similar in the human and mouse developing hearts. CONCLUSIONS Our findings point to the comparability of mechanisms governing the development of the cardiac conduction patterning in human and mouse, which provide a molecular basis for understanding the functioning of the human developing heart before formation of a discrete conduction system.
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Affiliation(s)
- Aleksander Sizarov
- Heart Failure Research Center, Academic Medical Center, Amsterdam, The Netherlands
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30
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Abstract
Regulation of organ growth is critical during embryogenesis. At the cellular level, mechanisms controlling the size of individual embryonic organs include cell proliferation, differentiation, migration, and attrition through cell death. All these mechanisms play a role in cardiac morphogenesis, but experimental studies have shown that the major determinant of cardiac size during prenatal development is myocyte proliferation. As this proliferative capacity becomes severely restricted after birth, the number of cell divisions that occur during embryogenesis limits the growth potential of the postnatal heart. We summarize here current knowledge concerning regional control of myocyte proliferation as related to cardiac morphogenesis and dysmorphogenesis. There are significant spatial and temporal differences in rates of cell division, peaking during the preseptation period and then gradually decreasing toward birth. Analysis of regional rates of proliferation helps to explain the mechanics of ventricular septation, chamber morphogenesis, and the development of the cardiac conduction system. Proliferation rates are influenced by hemodynamic loading, and transduced by autocrine and paracrine signaling by means of growth factors. Understanding the biological response of the developing heart to such factors and physical forces will further our progress in engineering artificial myocardial tissues for heart repair and designing optimal treatment strategies for congenital heart disease.
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Affiliation(s)
- David Sedmera
- Charles University in Prague, First Faculty of Medicine, Institute of Anatomy, Prague, Czech Republic.
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31
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Miquerol L, Beyer S, Kelly RG. Establishment of the mouse ventricular conduction system. Cardiovasc Res 2011; 91:232-42. [DOI: 10.1093/cvr/cvr069] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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33
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Abstract
Duplication or absence of parts of the specialized cardiac conduction system in patients with heterotaxy syndrome causes significant clinical disease, but the mechanistic basis by which embryonic disruption of left-right patterning alters conduction system patterning in these patients is not well understood. We sought to determine whether a mouse model of X-linked human heterotaxy recapitulates conduction system abnormalities identified in patients with heterotaxy. Cardiac structure and conduction system patterning were evaluated in Zic3 null embryos from e9.5 to e16.5 using genetic and molecular methods. Severe structural abnormalities involving atrial, ventricular, and conotruncal development were associated with a spectrum of disorganized and ambiguous arrangements throughout the conduction system, including the appearance of duplicated structures. The severity and location of conduction system abnormalities correlated with the severity and location of associated structural heart disease and were identifiable at the earliest stages examined. The Zic3 mouse model provides a novel tool to dissect the mechanistic underpinnings of conduction system patterning and dysfunction and its relationship to cardiovascular malformations, making it a promising model to improve understanding and risk assessment in the clinical arena.
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Affiliation(s)
- Richard J Czosek
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA
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Weeke-Klimp A, Bax NAM, Bellu AR, Winter EM, Vrolijk J, Plantinga J, Maas S, Brinker M, Mahtab EAF, Gittenberger-de Groot AC, van Luyn MJA, Harmsen MC, Lie-Venema H. Epicardium-derived cells enhance proliferation, cellular maturation and alignment of cardiomyocytes. J Mol Cell Cardiol 2010; 49:606-16. [PMID: 20655924 DOI: 10.1016/j.yjmcc.2010.07.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 06/24/2010] [Accepted: 07/15/2010] [Indexed: 01/19/2023]
Abstract
During heart development, cells from the proepicardial organ spread over the naked heart tube to form the epicardium. From here, epicardium-derived cells (EPDCs) migrate into the myocardium. EPDCs proved to be indispensable for the formation of the ventricular compact zone and myocardial maturation, by largely unknown mechanisms. In this study we investigated in vitro how EPDCs affect cardiomyocyte proliferation, cellular alignment and contraction, as well as the expression and cellular distribution of proteins involved in myocardial maturation. Embryonic quail EPDCs induced proliferation of neonatal mouse cardiomyocytes. This required cell-cell interactions, as proliferation was not observed in transwell cocultures. Western blot analysis showed elevated levels of electrical and mechanical junctions (connexin43, N-cadherin), sarcomeric proteins (Troponin-I, alpha-actinin), extracellular matrix (collagen I and periostin) in cocultures of EPDCs and cardiomyocytes. Immunohistochemistry indicated more membrane-bound expression of Cx43, N-cadherin, the mechanotransduction molecule focal adhesion kinase, and higher expression of the sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a). Newly developed software for analysis of directionality in immunofluorescent stainings showed a quantitatively determined enhanced cellular alignment of cardiomyocytes. This was functionally related to increased contraction. The in vitro effects of EPDCs on cardiomyocytes were confirmed in three reciprocal in vivo models for EPDC-depletion (chicken and mice) in which downregulation of myocardial N-cadherin, Cx43, and FAK were observed. In conclusion, direct interaction of EPDCs with cardiomyocytes induced proliferation, correct mechanical and electrical coupling of cardiomyocytes, ECM-deposition and concurrent establishment of cellular array. These findings implicate that EPDCs are ideal candidates as adjuvant cells for cardiomyocyte integration during cardiac (stem) cell therapy.
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Affiliation(s)
- Alida Weeke-Klimp
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, The Netherlands
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Bakker ML, Moorman AF, Christoffels VM. The Atrioventricular Node: Origin, Development, and Genetic Program. Trends Cardiovasc Med 2010; 20:164-71. [DOI: 10.1016/j.tcm.2011.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 10/07/2010] [Indexed: 12/15/2022]
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The Cardiac Pacemaker and Conduction System Develops From Embryonic Myocardium that Retains Its Primitive Phenotype. J Cardiovasc Pharmacol 2010; 56:6-15. [DOI: 10.1097/fjc.0b013e3181e775d3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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37
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Sankova B, Machalek J, Sedmera D. Effects of mechanical loading on early conduction system differentiation in the chick. Am J Physiol Heart Circ Physiol 2010; 298:H1571-6. [DOI: 10.1152/ajpheart.00721.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The primary ring, a horseshoe-shaped structure situated between the left and right ventricle and connected superiorly to the atrioventricular canal, is the first specialized fast ventricular conduction pathway in the embryonic heart. It has been first defined immunohistochemically and is characterized as a region of slow myocyte proliferation. Recent studies have shown that it participates in spreading the ventricular electrical activation during stages preceding ventricular septation in the mouse, chick, and rat. Here we demonstrate its presence using optical mapping in chicks between embryonic days (ED) 3–5. We then tested the effects of hemodynamic unloading in the organ culture system upon its functionality. In ED3 hearts cultured without hemodynamic loading for 24 h, we observed a significant decrease in the percentage activated through the primary ring conduction pathway. A morphological examination revealed arrested growth, collapse, and elongation of the outflow tract and disorganized trabeculation. A similar reversal toward more primitive activation patterns was observed with culture between ED4 and ED5. This phenotype was completely rescued with the artificial loading of the ventricles with a droplet of silicone oil. We conclude that an appropriate loading is required during the early phases of the conduction system formation and maturation.
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Affiliation(s)
- Barbora Sankova
- Institute of Anatomy, First Faculty of Medicine, Charles University in Prague
- Institute of Physiology; and
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jakub Machalek
- Institute of Anatomy, First Faculty of Medicine, Charles University in Prague
| | - David Sedmera
- Institute of Anatomy, First Faculty of Medicine, Charles University in Prague
- Institute of Physiology; and
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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38
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Abstract
Diseases of the cardiovascular system that cause sudden cardiac deaths are often caused by lethal arrhythmias that originate from defects in the cardiac conduction system. Development of the cardiac conduction system is a complex biological process that can be wrought with problems. Although several genes involved in mature conduction system function have been identified, their association with development of specific subcomponents of the cardiac conduction system remains challenging. Several transcription factors, including homeodomain proteins and T-box proteins, are essential for cardiac conduction system morphogenesis and activation or repression of key regulatory genes. In addition, several transcription factors modify expression of genes encoding the ion channel proteins that contribute to the electrophysiological properties of the conduction system and govern contraction of the surrounding myocardium. Loss of transcriptional regulation during cardiac development has detrimental effects on cardiogenesis that may lead to arrhythmias. Human genetic mutations in some of these transcription factors have been identified and are known to cause congenital heart diseases that include cardiac conduction system malformations. In this review, we summarize the contributions of several key transcription factors to specification, patterning, maturation, and function of the cardiac conduction system. Further analysis of the molecular programs involved in this process should lead to improved diagnosis and therapy of conduction system disease.
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Affiliation(s)
- Cathy J Hatcher
- Center for Molecular Cardiology, Greenberg Division of Cardiology, Weill Medical College of Cornell University, New York, NY 10065, USA.
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39
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Damon BJ, Rémond MC, Bigelow MR, Trusk TC, Xie W, Perucchio R, Sedmera D, Denslow S, Thompson RP. Patterns of muscular strain in the embryonic heart wall. Dev Dyn 2009; 238:1535-46. [PMID: 19418446 DOI: 10.1002/dvdy.21958] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hypothesis that inner layers of contracting muscular tubes undergo greater strain than concentric outer layers was tested by numerical modeling and by confocal microscopy of strain within the wall of the early chick heart. We modeled the looped heart as a thin muscular shell surrounding an inner layer of sponge-like trabeculae by two methods: calculation within a two-dimensional three-variable lumped model and simulated expansion of a three-dimensional, four-layer mesh of finite elements. Analysis of both models, and correlative microscopy of chamber dimensions, sarcomere spacing, and membrane leaks, indicate a gradient of strain decreasing across the wall from highest strain along inner layers. Prediction of wall thickening during expansion was confirmed by ultrasonography of beating hearts. Degree of stretch determined by radial position may thus contribute to observed patterns of regional myocardial conditioning and slowed proliferation, as well as to the morphogenesis of ventricular trabeculae and conduction fascicles. Developmental Dynamics 238:1535-1546, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Brooke J Damon
- Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina, USA
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40
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Horsthuis T, Buermans HPJ, Brons JF, Verkerk AO, Bakker ML, Wakker V, Clout DEW, Moorman AFM, 't Hoen PAC, Christoffels VM. Gene expression profiling of the forming atrioventricular node using a novel tbx3-based node-specific transgenic reporter. Circ Res 2009; 105:61-9. [PMID: 19498200 DOI: 10.1161/circresaha.108.192443] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The atrioventricular (AV) node is a recurrent source of potentially life-threatening arrhythmias. Nevertheless, limited data are available on its developmental control or molecular phenotype. We used a novel AV nodal myocardium-specific reporter mouse to gain insight into the gene programs determining the formation and phenotype of the developing AV node. In this reporter, green fluorescent protein (GFP) expression was driven by a 160-kbp bacterial artificial chromosome with Tbx3 and flanking sequences. GFP was selectively active in the AV canal of embryos and AV node of adults, whereas the Tbx3-positive AV bundle and sinus node were devoid of GFP, demonstrating that distinct regulatory sequences and pathways control expression in the components of the conduction system. Fluorescent AV nodal and complementary Nppa-positive chamber myocardial cell populations of embryonic day 10.5 embryos and of embryonic day 17.5 fetuses were purified using fluorescence-activated cell sorting, and their expression profiles were assessed by genome-wide microarray analysis, providing valuable information concerning their molecular identities. We constructed a comprehensive list of sodium, calcium, and potassium channel genes specific for developing nodal or chamber myocardium. Furthermore, the data revealed that the AV node and the chamber (working) myocardium phenotypes diverge during development but that the functional gene classes characterizing both subtypes are maintained. One of the repertoires identified in the AV node-specific gene profiles consists of multiple neurotrophic factors and semaphorins, not yet appreciated to play a role in nodal development, revealing shared characteristics between nodal and nervous system development.
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Affiliation(s)
- Thomas Horsthuis
- Heart Failure Research Center, University of Amsterdam, The Netherlands
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Aanhaanen WTJ, Brons JF, Domínguez JN, Rana MS, Norden J, Airik R, Wakker V, de Gier-de Vries C, Brown NA, Kispert A, Moorman AFM, Christoffels VM. The Tbx2+ primary myocardium of the atrioventricular canal forms the atrioventricular node and the base of the left ventricle. Circ Res 2009; 104:1267-74. [PMID: 19423846 DOI: 10.1161/circresaha.108.192450] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The primary myocardium of the embryonic heart, including the atrioventricular canal and outflow tract, is essential for septation and valve formation. In the chamber-forming heart, the expression of the T-box transcription factor Tbx2 is restricted to the primary myocardium. To gain insight into the cellular contributions of the Tbx2+ primary myocardium to the components of the definitive heart, genetic lineage tracing was performed using a novel Tbx2Cre allele. These analyses revealed that progeny of Tbx2+ cells provide an unexpectedly large contribution to the Tbx2-negative ventricles. Contrary to common assumption, we found that the embryonic left ventricle only forms the left part of the definitive ventricular septum and the apex. The atrioventricular node, but not the atrioventricular bundle, was found to derive from Tbx2+ cells. The Tbx2+ outflow tract formed the right ventricle and right part of the ventricular septum. In Tbx2-deficient embryos, the left-sided atrioventricular canal was found to prematurely differentiate to chamber myocardium and to proliferate at increased rates similar to those of chamber myocardium. As a result, the atrioventricular junction and base of the left ventricle were malformed. Together, these observations indicate that Tbx2 temporally suppresses differentiation and proliferation of primary myocardial cells. A subset of these Tbx2Cre-marked cells switch off expression of Tbx2, which allows them to differentiate into chamber myocardium, to initiate proliferation, and to provide a large contribution to the ventricles. These findings imply that errors in the development of the early atrioventricular canal may affect a much larger region than previously anticipated, including the ventricular base.
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Affiliation(s)
- Wim T J Aanhaanen
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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42
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Affiliation(s)
| | - Antoon F.M. Moorman
- From the Heart Failure Research Center, Academic Medical Center, Amsterdam, The Netherlands
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Schweickert A, Deissler K, Britsch S, Albrecht M, Ehmann H, Mauch V, Gaio U, Blum M. Left-asymmetric expression of Galanin in the linear heart tube of the mouse embryo is independent of the nodal co-receptor gene cryptic. Dev Dyn 2009; 237:3557-64. [PMID: 18773496 DOI: 10.1002/dvdy.21638] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Only very few left/right asymmetrically expressed genes are known in the mammalian embryo. In a screen for novel factors we identified the gene encoding the neuropeptide Galanin in mouse. At embryonic day (E) 8.5 asymmetric mRNA transcription was found in the left half of the linear heart tube. During heart looping and morphogenesis expression became restricted to the atrio-ventricular (AV) canal, followed by specific staining of the AV-node and AV-rings in the four-chambered heart. Expression was inverted in inv/inv and randomized in homozygous iv mutant embryos. Left-sided heart-specific transcription of mouse Gal thus should be controlled by the left-right pathway. The asymmetric pattern was retained in cryptic mutant embryos, in which the Nodal signaling cascade is disrupted. Surprisingly, Pitx2c was found to be expressed in 50% of cryptic mutant hearts as well, suggesting that some aspects of asymmetric gene expression in the heart are independent of cryptic.
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Affiliation(s)
- Axel Schweickert
- University of Hohenheim, Institute of Zoology, Stuttgart, Germany.
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44
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Abstract
This article concerns the development of myocardial architecture--crucial for contractile performance of the heart and its conduction system, essential for generation and coordinated spread of electrical activity. Topics discussed include molecular determination of cardiac phenotype (contractile and conducting), remodeling of ventricular wall architecture and its blood supply, and relation of trabecular compaction to noncompaction cardiomyopathy. Illustrated are the structure and function of the tubular heart, time course of trabecular compaction, and development of multilayered spiral systems of the compact layer.
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Affiliation(s)
- David Sedmera
- Institute of Animal Physiology and Genetics, Prague, Czech Republic.
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46
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Sedmera D, Harris BS, Grant E, Zhang N, Jourdan J, Kurkova D, Gourdie RG. Cardiac expression patterns of endothelin-converting enzyme (ECE): implications for conduction system development. Dev Dyn 2008; 237:1746-53. [PMID: 18489007 DOI: 10.1002/dvdy.21572] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The spatiotemporal distribution of the endothelin-converting enzyme (ECE) protein in the embryonic chick heart and the association of this polypeptide with the developing cardiac conduction system is described here for the first time. Further, we show how cardiac hemodynamic load directly affects ECE level and distribution. Endothelin (ET) is a cytokine involved in the inductive recruitment of Purkinje fibers. ET is produced by proteolytic cleavage of Big-ET by ECE. We generated an antibody against chick ECE recognizing a single band at approximately 70 kD to correlate the cardiac expression of this protein with that reported previously for its mRNA. ECE protein expression was more widespread compared to its mRNA, being present in endothelial cells, mesenchymal cells, and myocytes, and particularly enriched in the trabeculae and nascent ventricular conduction system. The myocardial expression was significantly modified under experimentally altered hemodynamic loading. In vivo, ET receptor blockade with bosentan delayed activation sequence maturation. These data support a role for ECE in avian cardiac conduction system differentiation and maturation.
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Affiliation(s)
- David Sedmera
- Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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47
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Bakker ML, Boukens BJ, Mommersteeg MTM, Brons JF, Wakker V, Moorman AFM, Christoffels VM. Transcription factor Tbx3 is required for the specification of the atrioventricular conduction system. Circ Res 2008; 102:1340-9. [PMID: 18467625 DOI: 10.1161/circresaha.107.169565] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The cardiac conduction system consists of distinctive heart muscle cells that initiate and propagate the electric impulse required for coordinated contraction. The conduction system expresses the transcriptional repressor Tbx3, which is required for vertebrate development and controls the formation of the sinus node. In humans, mutations in Tbx3 cause ulnar-mammary syndrome. Here, we investigated the role of Tbx3 in the molecular specification of the atrioventricular conduction system. Expression analysis revealed early delineation of the atrioventricular bundle and proximal bundle branches by Tbx3 expression in human, mouse, and chicken. Tbx3-deficient mice, which die between embryonic day 12.5 and 15.5, ectopically expressed genes for connexin (Cx)43, atrial natriuretic factor (Nppa), Tbx18, and Tbx20 in the atrioventricular bundle and proximal bundle branches. Cx40 was precociously upregulated in the atrioventricular bundle of Tbx3 mutants. Moreover, the atrioventricular bundle and branches failed to exit the cell cycle in Tbx3 mutant embryos. Finally, Tbx3-deficient embryos developed outflow tract malformations and ventricular septal defects. These data reveal that Tbx3 is required for the molecular specification of the atrioventricular bundle and bundle branches and for the development of the ventricular septum and outflow tract. Our data suggest a mechanism in which Tbx3 represses differentiation into ventricular working myocardium, thereby imposing the conduction system phenotype on cells within its expression domain.
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Affiliation(s)
- Martijn L Bakker
- Heart Failure Research Center, Academic Medical Center, Amsterdam, The Netherlands
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48
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Bruchez P, Sarre A, Kappenberger L, Raddatz E. The L-Type Ca+ and KATP channels may contribute to pacing-induced protection against anoxia-reoxygenation in the embryonic heart model. J Cardiovasc Electrophysiol 2008; 19:1196-202. [PMID: 18554212 DOI: 10.1111/j.1540-8167.2008.01218.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UNLABELLED L-Type Ca(2+) and K(ATP) Channels in Pacing-Induced Cardioprotection. AIMS The L-type Ca(2+) channel, the sarcolemmal (sarcK(ATP)), and mitochondrial K(ATP) (mitoK(ATP)) channels are involved in myocardial preconditioning. We aimed at determining to what extent these channels can also participate in pacing-induced cardioprotection. METHODS Hearts of 4-day-old chick embryos were paced in ovo during 12 hour using asynchronous intermittent ventricular stimulation at 110% of the intrinsic rate. Sham operated and paced hearts were then submitted in vitro to anoxia (30 minutes) and reoxygenation (60 minutes). These hearts were exposed to L-type Ca(2+) channel agonist Bay-K-8644 (BAY-K) or blocker verapamil, nonselective K(ATP) channel antagonist glibenclamide (GLIB), mitoK(ATP) channel agonist diazoxide (DIAZO), or antagonist 5-hydroxydecanoate. Electrocardiogram, electromechanical delay (EMD) reflecting excitation-contraction (E-C) coupling, and contractility were determined. RESULTS Under normoxia, heart rate, QT duration, conduction, EMD, and ventricular shortening were similar in sham and paced hearts. During reoxygenation, arrhythmias ceased earlier and ventricular EMD recovered faster in paced hearts than in sham hearts. In sham hearts, BAY-K (but not verapamil), DIAZO (but not 5-hydroxydecanoate) or GLIB accelerated recovery of ventricular EMD, reproducing the pacing-induced protection. By contrast, none of these agents further ameliorated recovery of the paced hearts. CONCLUSION The protective effect of chronic asynchronous pacing at near physiological rate on ventricular E-C coupling appears to be associated with subtle activation of L-type Ca(2+) channel, inhibition of sarcK(ATP) channel, and/or opening of mitoK(ATP) channel.
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Affiliation(s)
- Philippe Bruchez
- Department of Physiology, Faculty of Biology and Medicine, University Hospital, Lausanne, Switzerland
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49
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Sedmera D. Development of cardiac conduction system in mammals with a focus on the anatomical, functional and medical/genetical aspects. J Appl Biomed 2007. [DOI: 10.32725/jab.2007.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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50
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Rosenquist TH, Finnell RH. Another key role for the cardiac neural crest in heart development. Am J Physiol Heart Circ Physiol 2007; 292:H1225-6. [PMID: 17098821 DOI: 10.1152/ajpheart.01218.2006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Thomas H Rosenquist
- Univ of Nebraska Medical Center, 987878 Nebraska Medical Center, Omaha, NE 68198-7878, USA.
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