1
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Hennis K, Piantoni C, Biel M, Fenske S, Wahl-Schott C. Pacemaker Channels and the Chronotropic Response in Health and Disease. Circ Res 2024; 134:1348-1378. [PMID: 38723033 PMCID: PMC11081487 DOI: 10.1161/circresaha.123.323250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease-including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate-sensitive hyperpolarization-activated current (If) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate-dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.
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Affiliation(s)
- Konstantin Hennis
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Chiara Piantoni
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Stefanie Fenske
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Christian Wahl-Schott
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
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2
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Wolfson DW, Kim NK, Lee KH, Beyersdorf JP, Langberg JJ, Fernandez N, Choi D, Zureick N, Kim TY, Bae S, Gu JM, Kirschman JL, Fan J, Sheng CY, Gottlieb Sen D, Mettler B, Sung JH, Yoon YS, Park SJ, Santangelo PJ, Cho HC. Transient pacing in pigs with complete heart block via myocardial injection of mRNA coding for the T-box transcription factor 18. Nat Biomed Eng 2024:10.1038/s41551-024-01211-9. [PMID: 38698155 DOI: 10.1038/s41551-024-01211-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 04/02/2024] [Indexed: 05/05/2024]
Abstract
The adenovirus-mediated somatic transfer of the embryonic T-box transcription factor 18 (TBX18) gene can convert chamber cardiomyocytes into induced pacemaker cells. However, the translation of therapeutic TBX18-induced cardiac pacing faces safety challenges. Here we show that the myocardial expression of synthetic TBX18 mRNA in animals generates de novo pacing and limits innate and inflammatory immune responses. In rats, intramyocardially injected mRNA remained localized, whereas direct myocardial injection of an adenovirus carrying a reporter gene resulted in diffuse expression and in substantial spillover to the liver, spleen and lungs. Transient expression of TBX18 mRNA in rats led to de novo automaticity and pacemaker properties and, compared with the injection of adenovirus, to substantial reductions in the expression of inflammatory genes and in activated macrophage populations. In rodent and clinically relevant porcine models of complete heart block, intramyocardially injected TBX18 mRNA provided rate-adaptive cardiac pacing for one month that strongly correlated with the animal's sinus rhythm and physical activity. TBX18 mRNA may aid the development of biological pacemakers.
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Affiliation(s)
- David W Wolfson
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Nam Kyun Kim
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Ki Hong Lee
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Chonnam National University Medical School, Gwangju, South Korea
| | - Jared P Beyersdorf
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Jonathan J Langberg
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Natasha Fernandez
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Dahim Choi
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Nadine Zureick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Tae Yun Kim
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Seongho Bae
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Jin-Mo Gu
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Jonathan L Kirschman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Jinqi Fan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Division of Pediatric Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Christina Y Sheng
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Danielle Gottlieb Sen
- Division of Pediatric Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Bret Mettler
- Division of Pediatric Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jung Hoon Sung
- Department of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, South Korea
| | - Young-Sup Yoon
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Sung-Jin Park
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Philip J Santangelo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
| | - Hee Cheol Cho
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
- Division of Pediatric Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Blalock-Taussig-Thomas Pediatric and Congenital Heart Center, The Johns Hopkins Children's Center, Baltimore, MD, USA.
- Department of Biomedical Engineering, Johns Hopkins Whiting School of Engineering, Baltimore, MD, USA.
- Department of Anesthesia and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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3
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Lee C, Xu S, Samad T, Goodyer WR, Raissadati A, Heinrich P, Wu SM. The cardiac conduction system: History, development, and disease. Curr Top Dev Biol 2024; 156:157-200. [PMID: 38556422 DOI: 10.1016/bs.ctdb.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
The heart is the first organ to form during embryonic development, establishing the circulatory infrastructure necessary to sustain life and enable downstream organogenesis. Critical to the heart's function is its ability to initiate and propagate electrical impulses that allow for the coordinated contraction and relaxation of its chambers, and thus, the movement of blood and nutrients. Several specialized structures within the heart, collectively known as the cardiac conduction system (CCS), are responsible for this phenomenon. In this review, we discuss the discovery and scientific history of the mammalian cardiac conduction system as well as the key genes and transcription factors implicated in the formation of its major structures. We also describe known human diseases related to CCS development and explore existing challenges in the clinical context.
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Affiliation(s)
- Carissa Lee
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
| | - Sidra Xu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States
| | - Tahmina Samad
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States; Division of Pediatric Cardiology, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States; Department of Pediatrics, Stanford University, Stanford, CA, United States
| | - William R Goodyer
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States; Division of Pediatric Cardiology, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States
| | - Alireza Raissadati
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States; Division of Pediatric Cardiology, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States
| | - Paul Heinrich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States; Regenerative Medicine in Cardiovascular Diseases, First Department of Medicine, Cardiology, Klinikum Rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
| | - Sean M Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA, United States; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States.
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4
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Liu CM, Chen YC, Hu YF. Harnessing cell reprogramming for cardiac biological pacing. J Biomed Sci 2023; 30:74. [PMID: 37633890 PMCID: PMC10463311 DOI: 10.1186/s12929-023-00970-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/22/2023] [Indexed: 08/28/2023] Open
Abstract
Electrical impulses from cardiac pacemaker cardiomyocytes initiate cardiac contraction and blood pumping and maintain life. Abnormal electrical impulses bring patients with low heart rates to cardiac arrest. The current therapy is to implant electronic devices to generate backup electricity. However, complications inherent to electronic devices remain unbearable suffering. Therefore, cardiac biological pacing has been developed as a hardware-free alternative. The approaches to generating biological pacing have evolved recently using cell reprogramming technology to generate pacemaker cardiomyocytes in-vivo or in-vitro. Different from conventional methods by electrical re-engineering, reprogramming-based biological pacing recapitulates various phenotypes of de novo pacemaker cardiomyocytes and is more physiological, efficient, and easy for clinical implementation. This article reviews the present state of the art in reprogramming-based biological pacing. We begin with the rationale for this new approach and review its advances in creating a biological pacemaker to treat bradyarrhythmia.
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Affiliation(s)
- Chih-Min Liu
- Division of Cardiology, Department of Medicine, Heart Rhythm Center, Taipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine and Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chun Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Institute of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yu-Feng Hu
- Division of Cardiology, Department of Medicine, Heart Rhythm Center, Taipei Veterans General Hospital, Taipei, Taiwan.
- Faculty of Medicine and Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
- Institute of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan.
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5
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Sanchez L, Mesquita T, Zhang R, Liao K, Rogers R, Lin YN, Miguel-dos-Santos R, Akhmerov A, Li L, Nawaz A, Holm K, Marbán E, Cingolani E. MicroRNA-dependent suppression of biological pacemaker activity induced by TBX18. Cell Rep Med 2022; 3:100871. [PMID: 36543116 PMCID: PMC9798022 DOI: 10.1016/j.xcrm.2022.100871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/18/2022] [Accepted: 11/19/2022] [Indexed: 12/24/2022]
Abstract
Chemically modified mRNA (CMmRNA) with selectively altered nucleotides are used to deliver transgenes, but translation efficiency is variable. We have transfected CMmRNA encoding human T-box transcription factor 18 (CMmTBX18) into heart cells or the left ventricle of rats with atrioventricular block. TBX18 protein expression from CMmTBX18 is weak and transient, but Acriflavine, an Argonaute 2 inhibitor, boosts TBX18 levels. Small RNA sequencing identified two upregulated microRNAs (miRs) in CMmTBX18-transfected cells. Co-administration of miR-1-3p and miR-1b antagomiRs with CMmTBX18 prolongs TBX18 expression in vitro and in vivo and is sufficient to generate electrical stimuli capable of pacing the heart. Different suppressive miRs likewise limit the expression of VEGF-A CMmRNA. Cells therefore resist translation of CMmRNA therapeutic transgenes by upregulating suppressive miRs. Blockade of suppressive miRs enhances CMmRNA expression of genes driving biological pacing or angiogenesis. Such counterstrategies constitute an approach to boost the efficacy and efficiency of CMmRNA therapies.
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Affiliation(s)
- Lizbeth Sanchez
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Thassio Mesquita
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Rui Zhang
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Ke Liao
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Russell Rogers
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Yen-Nien Lin
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Rodrigo Miguel-dos-Santos
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Akbarshakh Akhmerov
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Liang Li
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Asma Nawaz
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Kevin Holm
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Eduardo Marbán
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA
| | - Eugenio Cingolani
- Smidt Heart Institute, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, Los Angeles, CA 90048, USA,Corresponding author
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6
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Foster DB, Gu JM, Kim EH, Wolfson DW, O’Meally R, Cole RN, Cho HC. Tbx18 Orchestrates Cytostructural Transdifferentiation of Cardiomyocytes to Pacemaker Cells by Recruiting the Epithelial-Mesenchymal Transition Program. J Proteome Res 2022; 21:2277-2292. [PMID: 36006872 PMCID: PMC9552783 DOI: 10.1021/acs.jproteome.2c00133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Indexed: 11/29/2022]
Abstract
Previously, we reported that heterologous expression of an embryonic transcription factor, Tbx18, reprograms ventricular cardiomyocytes into induced pacemaker cells (Tbx18-iPMs), though the key pathways are unknown. Here, we have used a tandem mass tag proteomic approach to characterize the impact of Tbx18 on neonatal rat ventricular myocytes. Tbx18 expression triggered vast proteome remodeling. Tbx18-iPMs exhibited increased expression of known pacemaker ion channels, including Hcn4 and Cx45 as well as upregulation of the mechanosensitive ion channels Piezo1, Trpp2 (PKD2), and TrpM7. Metabolic pathways were broadly downregulated, as were ion channels associated with ventricular excitation-contraction coupling. Tbx18-iPMs also exhibited extensive intracellular cytoskeletal and extracellular matrix remodeling, including 96 differentially expressed proteins associated with the epithelial-to-mesenchymal transition (EMT). RNAseq extended coverage of low abundance transcription factors, revealing upregulation of EMT-inducing Snai1, Snai2, Twist1, Twist2, and Zeb2. Finally, network diffusion mapping of >200 transcriptional regulators indicates EMT and heart development factors occupy adjacent network neighborhoods downstream of Tbx18 but upstream of metabolic control factors. In conclusion, transdifferentiation of cardiac myocytes into pacemaker cells entails massive electrogenic, metabolic, and cytostructural remodeling. Structural changes exhibit hallmarks of the EMT. The results aid ongoing efforts to maximize the yield and phenotypic stability of engineered biological pacemakers.
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Affiliation(s)
- D. Brian Foster
- Division
of Cardiology, Department of Medicine, The
Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Jin-mo Gu
- Department
of Pediatrics, Emory University, Atlanta, Georgia 30322, United States
| | - Elizabeth H. Kim
- Cedars-Sinai
Medical Center, Los Angeles, California 90048, United States
| | - David W. Wolfson
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Robert O’Meally
- Proteomics
Core Facility, The Johns Hopkins University
School of Medicine, Baltimore, Maryland 21205, United States
| | - Robert N. Cole
- Proteomics
Core Facility, The Johns Hopkins University
School of Medicine, Baltimore, Maryland 21205, United States
| | - Hee Cheol Cho
- Department
of Surgery, The Johns Hopkins University
School of Medicine, Baltimore, Maryland 21205, United States
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7
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Farraha M, Rao R, Igoor S, Le TYL, Barry MA, Davey C, Kok C, Chong JJ, Kizana E. Recombinant Adeno-Associated Viral Vector-Mediated Gene Transfer of hTBX18 Generates Pacemaker Cells from Ventricular Cardiomyocytes. Int J Mol Sci 2022; 23:ijms23169230. [PMID: 36012498 PMCID: PMC9408910 DOI: 10.3390/ijms23169230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 12/03/2022] Open
Abstract
Sinoatrial node dysfunction can manifest as bradycardia, leading to symptoms of syncope and sudden cardiac death. Electronic pacemakers are the current standard of care but are limited due to a lack of biological chronotropic control, cost of revision surgeries, and risk of lead- and device-related complications. We therefore aimed to develop a biological alternative to electronic devices by using a clinically relevant gene therapy vector to demonstrate conversion of cardiomyocytes into sinoatrial node-like cells in an in vitro context. Neonatal rat ventricular myocytes were transduced with recombinant adeno-associated virus vector 6 encoding either hTBX18 or green fluorescent protein and maintained for 3 weeks. At the endpoint, qPCR, Western blot analysis and immunocytochemistry were used to assess for reprogramming into pacemaker cells. Cell morphology and Arclight action potentials were imaged via confocal microscopy. Compared to GFP, hTBX18-transduced cells showed that hTBX18, HCN4 and Cx45 were upregulated. Cx43 was significantly downregulated, while sarcomeric α-actinin remained unchanged. Cardiomyocytes transduced with hTBX18 acquired the tapering morphology of native pacemaker cells, as compared to the block-like, striated appearance of ventricular cardiomyocytes. Analysis of the action potentials showed phase 4 depolarization and a significant decrease in the APD50 of the hTBX18-transduced cells. We have demonstrated that rAAV-hTBX18 gene transfer to ventricular myocytes results in morphological, molecular, physiological, and functional changes, recapitulating the pacemaker phenotype in an in vitro setting. The generation of these induced pacemaker-like cells using a clinically relevant vector opens new prospects for biological pacemaker development.
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Affiliation(s)
- Melad Farraha
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Renuka Rao
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Sindhu Igoor
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Thi Y. L. Le
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - Michael A. Barry
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
| | - Christopher Davey
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- School of Physics, the University of Sydney, Sydney 2006, Australia
| | - Cindy Kok
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
| | - James J.H. Chong
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
| | - Eddy Kizana
- Sydney Medical School, the University of Sydney, Sydney 2006, Australia
- Centre for Heart Research, the Westmead Institute for Medical Research, Sydney 2145, Australia
- Department of Cardiology, Westmead Hospital, Sydney 2145, Australia
- Correspondence:
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8
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Rashid SA, Blanchard AT, Combs JD, Fernandez N, Dong Y, Cho HC, Salaita K. DNA Tension Probes Show that Cardiomyocyte Maturation Is Sensitive to the Piconewton Traction Forces Transmitted by Integrins. ACS NANO 2022; 16:5335-5348. [PMID: 35324164 PMCID: PMC11238821 DOI: 10.1021/acsnano.1c04303] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cardiac muscle cells (CMCs) are the unit cells that comprise the heart. CMCs go through different stages of differentiation and maturation pathways to fully mature into beating cells. These cells can sense and respond to mechanical cues through receptors such as integrins which influence maturation pathways. For example, cell traction forces are important for the differentiation and development of functional CMCs, as CMCs cultured on varying substrate stiffness function differently. Most work in this area has focused on understanding the role of bulk extracellular matrix stiffness in mediating the functional fate of CMCs. Given that stiffness sensing mechanisms are mediated by individual integrin receptors, an important question in this area pertains to the specific magnitude of integrin piconewton (pN) forces that can trigger CMC functional maturation. To address this knowledge gap, we used DNA adhesion tethers that rupture at specific thresholds of force (∼12, ∼56, and ∼160 pN) to test whether capping peak integrin tension to specific magnitudes affects CMC function. We show that adhesion tethers with greater force tolerance lead to functionally mature CMCs as determined by morphology, twitching frequency, transient calcium flux measurements, and protein expression (F-actin, vinculin, α-actinin, YAP, and SERCA2a). Additionally, sarcomeric actinin alignment and multinucleation were significantly enhanced as the mechanical tolerance of integrin tethers was increased. Taken together, the results show that CMCs harness defined pN integrin forces to influence early stage development. This study represents an important step toward biophysical characterization of the contribution of pN forces in early stage cardiac differentiation.
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Affiliation(s)
- Sk Aysha Rashid
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Aaron T Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, Georgia 30332, United States
| | - J Dale Combs
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Natasha Fernandez
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 1405 Clifton Road NE, Atlanta, Georgia 30322, United States
| | - Yixiao Dong
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Hee Cheol Cho
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 1405 Clifton Road NE, Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, Georgia 30332, United States
| | - Khalid Salaita
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, Georgia 30332, United States
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9
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Zhang W, Zhao H, Quan D, Tang Y, Wang X, Huang C. Tbx18 promoted the conversion of human-induced pluripotent stem cell-derived cardiomyocytes into sinoatrial node-like pacemaker cells. Cell Biol Int 2021; 46:403-414. [PMID: 34882885 DOI: 10.1002/cbin.11738] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/16/2021] [Accepted: 12/04/2021] [Indexed: 01/22/2023]
Abstract
Sinoatrial node (SAN) pacemaker cells originate from T-box transcription factor 18 (Tbx18)-expressing progenitor cells. The present study aimed to investigate whether overexpression of human transcription factor Tbx18 could reprogram human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) into SAN-like pacemaker cells (SANLPCs) in vitro. In the study, hiPSCs were first differentiated into hiPSC-CMs through regulating the Wnt/β-catenin pathway, then purified hiPSC-CMs were transfected by Tbx18 adenovirus (Tbx18-CMs group) or green fluorescent protein (GFP) adenovirus (GFP-CMs group). The beating frequency of the Tbx18-CMs group was significantly higher than that of the hiPSC-CMs group and GFP-CMs group. Compared with the other two groups, the expression levels of hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4, connexin-45 in the Tbx18-CMs group were markedly upregulated, while the expressions of transcription factor NKX2.5, CX43 were significantly downregulated. Whole-cell patch-clamp results illustrated that action potential and "funny" current (If ) similar to SAN pacemaker cells could be recorded in the Tbx18-CMs group. In conclusion, this present study demonstrated that overexpression of Tbx18 promoted the conversion of hiPSC-CMs into SANLPCs.
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Affiliation(s)
- Wei Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Hongyi Zhao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Dajun Quan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Yanhong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
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10
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Komosa ER, Wolfson DW, Bressan M, Cho HC, Ogle BM. Implementing Biological Pacemakers: Design Criteria for Successful. Circ Arrhythm Electrophysiol 2021; 14:e009957. [PMID: 34592837 PMCID: PMC8530973 DOI: 10.1161/circep.121.009957] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Each heartbeat that pumps blood throughout the body is initiated by an electrical impulse generated in the sinoatrial node (SAN). However, a number of disease conditions can hamper the ability of the SAN's pacemaker cells to generate consistent action potentials and maintain an orderly conduction path, leading to arrhythmias. For symptomatic patients, current treatments rely on implantation of an electronic pacing device. However, complications inherent to the indwelling hardware give pause to categorical use of device therapy for a subset of populations, including pediatric patients or those with temporary pacing needs. Cellular-based biological pacemakers, derived in vitro or in situ, could function as a therapeutic alternative to current electronic pacemakers. Understanding how biological pacemakers measure up to the SAN would facilitate defining and demonstrating its advantages over current treatments. In this review, we discuss recent approaches to creating biological pacemakers and delineate design criteria to guide future progress based on insights from basic biology of the SAN. We emphasize the need for long-term efficacy in vivo via maintenance of relevant proteins, source-sink balance, a niche reflective of the native SAN microenvironment, and chronotropic competence. With a focus on such criteria, combined with delivery methods tailored for disease indications, clinical implementation will be attainable.
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Affiliation(s)
- Elizabeth R Komosa
- Department of Biomedical Engineering (E.R.K., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
- Stem Cell Institute (E.R.K., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - David W Wolfson
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta (D.W.W., H.C.C.)
| | - Michael Bressan
- Department of Cell Biology and Physiology (M.B.), University of North Carolina-Chapel Hill
- McAllister Heart Institute (M.B.), University of North Carolina-Chapel Hill
| | - Hee Cheol Cho
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta (D.W.W., H.C.C.)
- Department of Pediatrics, Emory University, Atlanta, GA (H.C.C.)
| | - Brenda M Ogle
- Department of Biomedical Engineering (E.R.K., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
- Stem Cell Institute (E.R.K., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
- Department of Pediatrics (B.M.O), University of Minnesota-Twin Cities, Minneapolis
- Lillehei Heart Institute (B.M.O), University of Minnesota-Twin Cities, Minneapolis
- Institute for Engineering in Medicine (B.M.O), University of Minnesota-Twin Cities, Minneapolis
- Masonic Cancer Center (B.M.O), University of Minnesota-Twin Cities, Minneapolis
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11
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Mandla R, Jung C, Vedantham V. Transcriptional and Epigenetic Landscape of Cardiac Pacemaker Cells: Insights Into Cellular Specialization in the Sinoatrial Node. Front Physiol 2021; 12:712666. [PMID: 34335313 PMCID: PMC8322687 DOI: 10.3389/fphys.2021.712666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/23/2021] [Indexed: 01/23/2023] Open
Abstract
Cardiac pacemaker cells differentiate and functionally specialize early in embryonic development through activation of critical gene regulatory networks. In general, cellular specification and differentiation require that combinations of cell type-specific transcriptional regulators activate expression of key effector genes by binding to DNA regulatory elements including enhancers and promoters. However, because genomic DNA is tightly packaged by histones that must be covalently modified in order to render DNA regulatory elements and promoters accessible for transcription, the process of development and differentiation is intimately connected to the epigenetic regulation of chromatin accessibility. Although the difficulty of obtaining sufficient quantities of pure populations of pacemaker cells has limited progress in this field, the advent of low-input genomic technologies has the potential to catalyze a rapid growth of knowledge in this important area. The goal of this review is to outline the key transcriptional networks that control pacemaker cell development, with particular attention to our emerging understanding of how chromatin accessibility is modified and regulated during pacemaker cell differentiation. In addition, we will discuss the relevance of these findings to adult sinus node function, sinus node diseases, and origins of genetic variation in heart rhythm. Lastly, we will outline the current challenges facing this field and promising directions for future investigation.
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Affiliation(s)
- Ravi Mandla
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
| | - Catherine Jung
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
| | - Vasanth Vedantham
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
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12
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Li Y, Wang K, Li Q, Hancox JC, Zhang H. Reciprocal interaction between IK1 and If in biological pacemakers: A simulation study. PLoS Comput Biol 2021; 17:e1008177. [PMID: 33690622 PMCID: PMC7984617 DOI: 10.1371/journal.pcbi.1008177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/22/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022] Open
Abstract
Pacemaking dysfunction (PD) may result in heart rhythm disorders, syncope or even death. Current treatment of PD using implanted electronic pacemakers has some limitations, such as finite battery life and the risk of repeated surgery. As such, the biological pacemaker has been proposed as a potential alternative to the electronic pacemaker for PD treatment. Experimentally and computationally, it has been shown that bio-engineered pacemaker cells can be generated from non-rhythmic ventricular myocytes (VMs) by knocking out genes related to the inward rectifier potassium channel current (IK1) or by overexpressing hyperpolarization-activated cyclic nucleotide gated channel genes responsible for the "funny" current (If). However, it is unclear if a bio-engineered pacemaker based on the modification of IK1- and If-related channels simultaneously would enhance the ability and stability of bio-engineered pacemaking action potentials. In this study, the possible mechanism(s) responsible for VMs to generate spontaneous pacemaking activity by regulating IK1 and If density were investigated by a computational approach. Our results showed that there was a reciprocal interaction between IK1 and If in ventricular pacemaker model. The effect of IK1 depression on generating ventricular pacemaker was mono-phasic while that of If augmentation was bi-phasic. A moderate increase of If promoted pacemaking activity but excessive increase of If resulted in a slowdown in the pacemaking rate and even an unstable pacemaking state. The dedicated interplay between IK1 and If in generating stable pacemaking and dysrhythmias was evaluated. Finally, a theoretical analysis in the IK1/If parameter space for generating pacemaking action potentials in different states was provided. In conclusion, to the best of our knowledge, this study provides a wide theoretical insight into understandings for generating stable and robust pacemaker cells from non-pacemaking VMs by the interplay of IK1 and If, which may be helpful in designing engineered biological pacemakers for application purposes.
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Affiliation(s)
- Yacong Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- * E-mail: (KW); (HZ)
| | - Qince Li
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
- Peng Cheng Laboratory, Shenzhen, China
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Henggui Zhang
- Peng Cheng Laboratory, Shenzhen, China
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- * E-mail: (KW); (HZ)
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13
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The Quantitative Relationship among the Number of the Pacing Cells Required, the Dimension, and the Diffusion Coefficient. BIOMED RESEARCH INTERNATIONAL 2020; 2020:3608015. [PMID: 32685474 PMCID: PMC7335384 DOI: 10.1155/2020/3608015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/18/2020] [Accepted: 04/15/2020] [Indexed: 11/17/2022]
Abstract
The purpose of the paper is to derive a formula to describe the quantitative relationship among the number of the pacing cells required (NPR), the dimension i, and the diffusion coefficient D (electrical coupling or gap junction G). The relationship between NPR and G has been investigated in different dimensions, respectively. That is, for each fixed i, there is a formula to describe the relationship between NPR and G; and three formulas are required for the three dimensions. However, there is not a universal expression to describe the relationship among NPR, G, and i together. In the manuscript, surveying and investigating the basic law among the existed data, we speculate the preliminary formula of the relationship among the NPR, i, and G; and then, employing the cftool in MATLAB, the explicit formulas are derived for different cases. In addition, the goodness of fit (R 2) is computed to evaluate the fitting of the formulas. Moreover, the 1D and 2D ventricular tissue models containing biological pacemakers are developed to derive more data to validate the formula. The results suggest that the relationship among the NPR, i, and the G (D) could be described by a universal formula, where the NPR scales with the i (the dimension) power of the product of the square root of G (D) and a constant b which is dependent on the strength of the pacing cells and so on.
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14
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Abstract
PURPOSE OF REVIEW The goal of this paper is to review present knowledge regarding biological pacemakers created by somatic reprogramming as a platform for mechanistic and metabolic understanding of the rare subpopulation of pacemaker cells, with the ultimate goal of creating biological alternatives to electronic pacing devices. RECENT FINDINGS Somatic reprogramming of cardiomyocytes by reexpression of embryonic transcription factor T-box 18 (TBX18) converts them into pacemaker-like. Recent studies take advantage of this model to gain insight into the electromechanical, metabolic, and architectural intricacies of the cardiac pacemaker cell across various models, including a surgical model of complete atrioventricular block (CAVB) in adult rats. The studies reviewed here reinforce the potential utility of TBX18-induced pacemaker myocytes (iPMS) as a minimally invasive treatment for heart block. Several challenges which must be overcome to develop a viable therapeutic intervention based on these observations are discussed.
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15
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Liang W, Han P, Kim EH, Mak J, Zhang R, Torrente AG, Goldhaber JI, Marbán E, Cho HC. Canonical Wnt signaling promotes pacemaker cell specification of cardiac mesodermal cells derived from mouse and human embryonic stem cells. Stem Cells 2019; 38:352-368. [PMID: 31648393 DOI: 10.1002/stem.3106] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 08/30/2019] [Indexed: 01/03/2023]
Abstract
Cardiac differentiation of embryonic stem cells (ESCs) can give rise to de novo chamber cardiomyocytes and nodal pacemaker cells. Compared with our understanding of direct differentiation toward atrial and ventricular myocytes, the mechanisms for nodal pacemaker cell commitment are not well understood. Taking a cue from the prominence of canonical Wnt signaling during cardiac pacemaker tissue development in chick embryos, we asked if modulations of Wnt signaling influence cardiac progenitors to bifurcate to either chamber cardiomyocytes or pacemaker cells. Omitting an exogenous Wnt inhibitor, which is routinely added to maximize cardiac myocyte yield during differentiation of mouse and human ESCs, led to increased yield of spontaneously beating cardiomyocytes with action potential properties similar to those of native sinoatrial node pacemaker cells. The pacemaker phenotype was accompanied by enhanced expression of genes and gene products that mark nodal pacemaker cells such as Hcn4, Tbx18, Tbx3, and Shox2. Addition of exogenous Wnt3a ligand, which activates canonical Wnt/β-catenin signaling, increased the yield of pacemaker-like myocytes while reducing cTNT-positive pan-cardiac differentiation. Conversely, addition of inhibitors of Wnt/β-catenin signaling led to increased chamber myocyte lineage development at the expense of pacemaker cell specification. The positive impact of canonical Wnt signaling on nodal pacemaker cell differentiation was evidenced in direct differentiation of two human ESC lines and human induced pluripotent stem cells. Our data identify the Wnt/β-catenin pathway as a critical determinant of cardiac myocyte subtype commitment during ESC differentiation: endogenous Wnt signaling favors the pacemaker lineage, whereas its suppression promotes the chamber cardiomyocyte lineage.
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Affiliation(s)
- Wenbin Liang
- University of Ottawa Heart Institute and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Pengcheng Han
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Elizabeth H Kim
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Jordan Mak
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Rui Zhang
- Cedars-Sinai Heart Institute, Los Angeles, California
| | | | | | | | - Hee Cheol Cho
- Department of Pediatrics, Emory University, Atlanta, Georgia.,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
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16
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Park JS, Grijalva SI, Jung D, Li S, Junek GV, Chi T, Cho HC, Wang H. Intracellular cardiomyocytes potential recording by planar electrode array and fibroblasts co-culturing on multi-modal CMOS chip. Biosens Bioelectron 2019; 144:111626. [DOI: 10.1016/j.bios.2019.111626] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/11/2019] [Accepted: 08/21/2019] [Indexed: 01/19/2023]
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17
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Grijalva SI, Gu J, Li J, Fernandez N, Fan J, Sung JH, Lee SY, Herndon C, Buckley EM, Park S, Fenton FH, Cho HC. Engineered Cardiac Pacemaker Nodes Created by TBX18 Gene Transfer Overcome Source-Sink Mismatch. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1901099. [PMID: 31763140 PMCID: PMC6864514 DOI: 10.1002/advs.201901099] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Every heartbeat originates from a tiny tissue in the heart called the sinoatrial node (SAN). The SAN harbors only ≈10 000 cardiac pacemaker cells, initiating an electrical impulse that captures the entire heart, consisting of billions of cardiomyocytes for each cardiac contraction. How these rare cardiac pacemaker cells (the electrical source) can overcome the electrically hyperpolarizing and quiescent myocardium (the electrical sink) is incompletely understood. Due to the scarcity of native pacemaker cells, this concept of source-sink mismatch cannot be tested directly with live cardiac tissue constructs. By exploiting TBX18 induced pacemaker cells by somatic gene transfer, 3D cardiac pacemaker spheroids can be tissue-engineered. The TBX18 induced pacemakers (sphTBX18) pace autonomously and drive the contraction of neighboring myocardium in vitro. TBX18 spheroids demonstrate the need for reduced electrical coupling and physical separation from the neighboring ventricular myocytes, successfully recapitulating a key design principle of the native SAN. β-Adrenergic stimulation as well as electrical uncoupling significantly increase sphTBX18s' ability to pace-and-drive the neighboring myocardium. This model represents the first platform to test design principles of the SAN for mechanistic understanding and to better engineer biological pacemakers for therapeutic translation.
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Affiliation(s)
- Sandra I. Grijalva
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
| | - Jin‐mo Gu
- Department of PediatricsEmory UniversityAtlantaGA30322USA
| | - Jun Li
- Department of PediatricsEmory UniversityAtlantaGA30322USA
| | | | - Jinqi Fan
- Department of PediatricsEmory UniversityAtlantaGA30322USA
| | - Jung Hoon Sung
- Department of PediatricsEmory UniversityAtlantaGA30322USA
- Department of Internal MedicineCHA Bundang Medical CenterSeoul13557South Korea
| | - Seung Yup Lee
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
| | - Conner Herndon
- Department of PhysicsGeorgia Institute of TechnologyAtlantaGA30332USA
| | - Erin M. Buckley
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
| | - Sung‐Jin Park
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
| | - Flavio H. Fenton
- Department of PhysicsGeorgia Institute of TechnologyAtlantaGA30332USA
| | - Hee Cheol Cho
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGA30332USA
- Department of PediatricsEmory UniversityAtlantaGA30322USA
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18
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Induced cardiac pacemaker cells survive metabolic stress owing to their low metabolic demand. Exp Mol Med 2019; 51:1-12. [PMID: 31519870 PMCID: PMC6802647 DOI: 10.1038/s12276-019-0303-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/07/2019] [Accepted: 05/14/2019] [Indexed: 11/29/2022] Open
Abstract
Cardiac pacemaker cells of the sinoatrial node initiate each and every heartbeat. Compared with our understanding of the constituents of their electrical excitation, little is known about the metabolic underpinnings that drive the automaticity of pacemaker myocytes. This lack is largely owing to the scarcity of native cardiac pacemaker myocytes. Here, we take advantage of induced pacemaker myocytes generated by TBX18-mediated reprogramming (TBX18-iPMs) to investigate comparative differences in the metabolic program between pacemaker myocytes and working cardiomyocytes. TBX18-iPMs were more resistant to metabolic stresses, exhibiting higher cell viability upon oxidative stress. TBX18-induced pacemaker myocytes (iPMs) expensed a lower degree of oxidative phosphorylation and displayed a smaller capacity for glycolysis compared with control ventricular myocytes. Furthermore, the mitochondria were smaller in TBX18-iPMs than in the control. We reasoned that a shift in the balance between mitochondrial fusion and fission was responsible for the smaller mitochondria observed in TBX18-iPMs. We identified a mitochondrial inner membrane fusion protein, Opa1, as one of the key mediators of this process and demonstrated that the suppression of Opa1 expression increases the rate of synchronous automaticity in TBX18-iPMs. Taken together, our data demonstrate that TBX18-iPMs exhibit a low metabolic demand that matches their mitochondrial morphology and ability to withstand metabolic insult. The heart’s pacemaker cells contain mitochondria that are smaller than average and require less energy than other heart cells, properties that help make them naturally resilient to stress. Cardiac pacemaker cells constitute a tiny proportion of the heart’s cells, yet play a critical role in maintaining a steady heartbeat. However, quite how pacemaker cells maintain their automatic rhythm is unclear because their scarcity makes them difficult to study. To examine the cells’ metabolic state further, Hee Cheol Cho at Emory University, Atlanta, and Brian Foster at Johns Hopkins University School of Medicine, Baltimore, and co-workers therefore induced pacemaker cells by adding an embryonic protein to heart muscle cells. The induced pacemaker cells survived well under oxidative stress. The team identified a protein in the pacemakers’ mitochondrial membranes, the expression of which directly influences rhythm responses.
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19
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Novel method for action potential measurements from intact cardiac monolayers with multiwell microelectrode array technology. Sci Rep 2019; 9:11893. [PMID: 31417144 PMCID: PMC6695445 DOI: 10.1038/s41598-019-48174-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 07/26/2019] [Indexed: 01/09/2023] Open
Abstract
The cardiac action potential (AP) is vital for understanding healthy and diseased cardiac biology and drug safety testing. However, techniques for high throughput cardiac AP measurements have been limited. Here, we introduce a novel technique for reliably increasing the coupling of cardiomyocyte syncytium to planar multiwell microelectrode arrays, resulting in a stable, label-free local extracellular action potential (LEAP). We characterized the reliability and stability of LEAP, its relationship to the field potential, and its efficacy for quantifying AP morphology of human induced pluripotent stem cell derived and primary rodent cardiomyocytes. Rise time, action potential duration, beat period, and triangulation were used to quantify compound responses and AP morphology changes induced by genetic modification. LEAP is the first high throughput, non-invasive, label-free, stable method to capture AP morphology from an intact cardiomyocyte syncytium. LEAP can accelerate our understanding of stem cell models, while improving the automation and accuracy of drug testing.
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20
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Sayegh MN, Fernandez N, Cho HC. Strength-duration relationship as a tool to prioritize cardiac tissue properties that govern electrical excitability. Am J Physiol Heart Circ Physiol 2019; 317:H13-H25. [PMID: 30925072 PMCID: PMC7199233 DOI: 10.1152/ajpheart.00161.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Engineered cardiac tissue and cardiomyocyte cell cultures offer wide opportunities for improved therapeutic intervention and laboratory heart models. Electrical field excitation is a common intervention in the production of engineered tissue and the investigation of the electrical properties of in vitro cell cultures. In this work, we use strength-duration relationships to investigate systematically factors influencing electrical excitability of two- (2D) and three-dimensional (3D) neonatal rat ventricular myocyte cultures. We find that the strength of the voltage pulse is negatively correlated with the threshold duration, as predicted by the Lapicque-Hill equation, and show that higher pacing frequencies require higher thresholds to capture paced cultures. We also study the impact of properties intrinsic to the 2D and 3D cultures on strength-duration relationships. We show that a smaller culture dimension, perpendicular anisotropic culture orientation with respect to electrical field, higher proportion of added fibroblasts, and TBX18-induced pacemaker reprogramming independently result in higher stimulation thresholds. These properties reflect the characteristics of the well-insulated endogenous pacemaking tissue in the heart (sinoatrial node) and should guide the engineering of biological pacemakers for improved outcomes. NEW & NOTEWORTHY Gaps exist in the availability of in vitro functional assessment tools that can emulate the integration of regenerative cells and tissues to the host myocardium. We use strength-duration relationships of electrically stimulated two- and three-dimensional myocardial constructs to study the effects of pacing frequency, culture dimensions, anisotropic cell alignment, fibroblast content, and pacemaker phenotype on electrical excitability. Our study delivers electrical strength-duration as a quantifiable parameter to evaluate design parameters of engineered cardiac tissue constructs.
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Affiliation(s)
- Michael N. Sayegh
- 1Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia,2Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Natasha Fernandez
- 1Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Hee Cheol Cho
- 1Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia,2Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
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21
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Kim NK, Wolfson D, Fernandez N, Shin M, Cho HC. A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies. Sci Rep 2019; 9:6930. [PMID: 31061413 PMCID: PMC6502940 DOI: 10.1038/s41598-019-43300-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 04/09/2019] [Indexed: 11/09/2022] Open
Abstract
Complete atrioventricular block (CAVB) is a life-threatening arrhythmia. A small animal model of chronic CAVB that properly reflects clinical indices of bradycardia would accelerate the understanding of disease progression and pathophysiology, and the development of therapeutic strategies. We sought to develop a surgical model of CAVB in adult rats, which could recapitulate structural remodeling and arrhythmogenicity expected in chronic CAVB. Upon right thoracotomy, we delivered electrosurgical energy subepicardially via a thin needle into the atrioventricular node (AVN) region of adult rats to create complete AV block. The chronic CAVB animals developed dilated and hypertrophied ventricles with preserved systolic functions due to compensatory hemodynamic remodeling. Ventricular tachyarrhythmias, which are difficult to induce in the healthy rodent heart, could be induced upon programmed electrical stimulation in chronic CAVB rats and worsened when combined with β-adrenergic stimulation. Focal somatic gene transfer of TBX18 to the left ventricular apex in the CAVB rats resulted in ectopic ventricular beats within days, achieving a de novo ventricular rate faster than the slow atrioventricular (AV) junctional escape rhythm observed in control CAVB animals. The model offers new opportunities to test therapeutic approaches to treat chronic and severe CAVB which have previously only been testable in large animal models.
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Affiliation(s)
- Nam Kyun Kim
- Department of Pediatrics, Emory University, Atlanta, GA, USA.,Department of Pediatrics, Yonsei University College of Medicine, Seoul, South Korea
| | - David Wolfson
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | | | - Minji Shin
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Hee Cheol Cho
- Department of Pediatrics, Emory University, Atlanta, GA, USA. .,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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22
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Gorabi AM, Hajighasemi S, Khori V, Soleimani M, Rajaei M, Rabbani S, Atashi A, Ghiaseddin A, Saeid AK, Ahmadi Tafti H, Sahebkar A. Functional biological pacemaker generation by T-Box18 protein expression via stem cell and viral delivery approaches in a murine model of complete heart block. Pharmacol Res 2019; 141:443-450. [PMID: 30677516 DOI: 10.1016/j.phrs.2019.01.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/09/2019] [Accepted: 01/17/2019] [Indexed: 11/26/2022]
Abstract
Despite recent advances in the treatment of cardiac arrhythmia, the available options are still limited and associated with some complications. Induction of biological pacemakers via Tbx18 gene insertion in the heart tissue has been suggested as a promising therapeutic strategy for cardiac arrhythmia. Following a previous in vitro study reporting the production of Tbx18-expressing human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs), we aimed to investigate the efficacy of these engineered cells to generate pacemaker rhythms in a murine model of complete heart block. We also attempted to generate a functional pacemaker by Tbx18 overexpression in native cardiac cells of rat heart. The hiPSC-derived pacemaker cells were produced by lentiviral delivery of Tbx18 gene to stem cells during a small molecule-based differentiation process. In the present study, 16 male albino Wistar rats were randomly assigned to Tbx18-lentivirus (n = 4) and Tbx18-pacemaker cells (n = 4) administered via injection into the left ventricular anterolateral wall. The control rats received GFP-lentiviruses (n = 4) and GFP-pacemaker cells (n = 4). Fourteen days after the injection, the rats were sacrificed and analyzed by electrocardiography (ECG) recording using a Langendorff-perfused heart model following complete heart block induced by hypokalemia and crashing. Immunofluorescence staining was used to investigate the expression of Tbx18, HCN4 and connexin 43 (Cx43) proteins in Tbx18-delivered cells of heart tissues. The heart rate was significantly reduced after complete heart block in all of the experimental rats (P < 0.05). Heart beating in the Tbx18-transduced hearts was slower compared with rats receiving Tbx18-pacemaker cells (P = 0.04). The duration of ventricular fibrillation (VF) was higher in the lentiviral Tbx18 group compared with the GFP-injected controls (P = 0.02) and the Tbx18-pacemaker cell group (P = 0.02). The ECG recording data showed spontaneous pacemaker rhythms in both intervention groups with signal propagation in Tbx18-transduced ventricles. Immunostaining results confirmed the overexpression of HCN4 and downregulation of Cx43 as a result of the expression of the Tbx18 gene and spontaneously contracting myocyte formation. We confirmed the formation of a functional pacemaker after introduction of Tbx18 via cell and gene therapy strategies. Although the pacemaker activity was better in gene-received hearts since there were longer VF duration and signal propagation from the injection site, more data should be gathered from the long-term activity of such pacemakers in different hosts.
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Affiliation(s)
- Armita Mahdavi Gorabi
- Research Center for Advanced Technologies in Cardiovascular Medicine, Tehran Heart Center, Tehran University of Medical Sciences, Iran
| | - Saeideh Hajighasemi
- Department of Medical Biotechnology, Faculty of Paramedicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Vahid Khori
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Masoud Soleimani
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Rajaei
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Shahram Rabbani
- Research Center for Advanced Technologies in Cardiovascular Medicine, Tehran Heart Center, Tehran University of Medical Sciences, Iran
| | - Amir Atashi
- Stem Cell and Tissue Engineering Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
| | | | - Ali Kazemi Saeid
- Department of Cardiology, Tehran University of Medical Science, Tehran, Iran; Research Department, Laboratory of Dr. Stanley Nattel, Montreal Heart Institute Research Center, Montreal University, Montreal, Canada.
| | - Hossein Ahmadi Tafti
- Research Center for Advanced Technologies in Cardiovascular Medicine, Tehran Heart Center, Tehran University of Medical Sciences, Iran.
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Tehran, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Tehran, Iran; School of Medicine, Mashhad University of Medical Sciences, Tehran, Iran
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23
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Park JS, Grijalva SI, Aziz MK, Chi T, Li S, Sayegh MN, Wang A, Cho HC, Wang H. Multi-parametric cell profiling with a CMOS quad-modality cellular interfacing array for label-free fully automated drug screening. LAB ON A CHIP 2018; 18:3037-3050. [PMID: 30168827 PMCID: PMC8513687 DOI: 10.1039/c8lc00156a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Cells are complex systems with concurrent multi-physical responses, and cell physiological signals are often encoded with spatiotemporal dynamics and further coupled with multiple cellular activities. However, most existing electronic sensors are only single-modality and cannot capture multi-parametric cellular responses. In this paper, a 1024-pixel CMOS quad-modality cellular interfacing array that enables multi-parametric cell profiling for drug development is presented. The quad-modality CMOS array features cellular impedance characterization, optical detection, extracellular potential recording, and biphasic current stimulation. The fibroblast transparency and surface adhesion are jointly monitored by cellular impedance and optical sensing modalities for comprehensive cell growth evaluation. Simultaneous current stimulation and opto-mechanical monitoring based on cardiomyocytes are demonstrated without any stimulation/sensing dead-zone. Furthermore, drug dose-dependent multi-parametric feature extractions in cardiomyocytes from their extracellular potentials and opto-mechanical signals are presented. The CMOS array demonstrates great potential for fully automated drug screening and drug safety assessments, which may substantially reduce the drug screening time and cost in future new drug development.
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Affiliation(s)
- Jong Seok Park
- The School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30308, USA.
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24
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Gorabi AM, Hajighasemi S, Tafti HA, Atashi A, Soleimani M, Aghdami N, Saeid AK, Khori V, Panahi Y, Sahebkar A. TBX18 transcription factor overexpression in human-induced pluripotent stem cells increases their differentiation into pacemaker-like cells. J Cell Physiol 2018; 234:1534-1546. [PMID: 30078203 DOI: 10.1002/jcp.27018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 06/26/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND The discovery of gene- and cell-based strategies has opened a new area to investigate novel approaches for the treatment of many conditions caused by cardiac cell failure. The TBX18 (T-box 18) transcription factor is considered as a prominent factor in the sinoatrial node (SAN) formation during the embryonic development. In this in vitro study, the effect of TBX18 gene expression on human-induced pluripotent-stem-cell-derived cardiomyocytes (hiPS-CMs) to induce pacemaker-like cells was examined. METHODS The human-dermal-fibroblast-derived iPSCs were transfected using chemical, physical, and Lentiviral methods of TBX18 gene delivery during differentiation into cardiomyocytes (CMs). After the differentiation process through small-molecule-based temporal modulation of the Wnt signaling pathway, the hiPSC-CMs were analyzed using the real-time polymerase chain reaction, immunocytochemistry, immunofluorescence, whole-cell patch-clamp recording, and western blotting to investigate the accuracy of differentiation and identify the effect exerted by TBX18. RESULTS The hiPS-CMs showed spontaneous beating and expressed specific markers of cardiac cells. The lentiviral-mediated TBX18 delivery was the most efficient method for transfection. The results showed the increment in Connexin 43 expression among untransfected hiPS-CMs, whereas this protein was significantly downregulated followed by TBX18 overexpression. TBX18-hiPSCMs were detected with pacemaker cell features. CONCLUSIONS It was demonstrated that the TBX18 gene is able to conduct hiPSCs to differentiate into pacemaker-like cells. The TBX18 gene delivery seems to have the potential for the development of biological pacemakers; however, more investigations are still needed to assess its usefulness to fix arrhythmic conditions with SAN failure basis.
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Affiliation(s)
- Armita M Gorabi
- Department of Basic and Clinical Research, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeideh Hajighasemi
- Department of Medical Biotechnology, Faculty of Paramedicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Hossein A Tafti
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Atashi
- Stem Cell and Tissue Engineering Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Masoud Soleimani
- Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nasser Aghdami
- Department of Regenerative Biomedicine, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Tehran, Iran
| | - Ali K Saeid
- Department of Cardiology, Tehran University of Medical Science, Tehran, Iran
| | - Vahid Khori
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Yunes Panahi
- Pharmacotherapy Department, School of Pharmacy, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,School of Pharmacy, Mashhad University of Medical Sciences, Tehran, Iran
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25
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Park JS, Aziz MK, Li S, Chi T, Grijalva SI, Sung JH, Cho HC, Wang H. 1024-Pixel CMOS Multimodality Joint Cellular Sensor/Stimulator Array for Real-Time Holistic Cellular Characterization and Cell-Based Drug Screening. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2018; 12:80-94. [PMID: 29377798 PMCID: PMC8552991 DOI: 10.1109/tbcas.2017.2759220] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This paper presents a fully integrated CMOS multimodality joint sensor/stimulator array with 1024 pixels for real-time holistic cellular characterization and drug screening. The proposed system consists of four pixel groups and four parallel signal-conditioning blocks. Every pixel group contains 16 × 16 pixels, and each pixel includes one gold-plated electrode, four photodiodes, and in-pixel circuits, within a pixel footprint. Each pixel supports real-time extracellular potential recording, optical detection, charge-balanced biphasic current stimulation, and cellular impedance measurement for the same cellular sample. The proposed system is fabricated in a standard 130-nm CMOS process. Rat cardiomyocytes are successfully cultured on-chip. Measured high-resolution optical opacity images, extracellular potential recordings, biphasic current stimulations, and cellular impedance images demonstrate the unique advantages of the system for holistic cell characterization and drug screening. Furthermore, this paper demonstrates the use of optical detection on the on-chip cultured cardiomyocytes to real-time track their cyclic beating pattern and beating rate.
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26
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Li Y, Yang M, Zhang G, Li L, Ye B, Huang C, Tang Y. Transcription factor TBX18 promotes adult rat bone mesenchymal stem cell differentiation to biological pacemaker cells. Int J Mol Med 2017; 41:845-851. [PMID: 29207072 PMCID: PMC5752232 DOI: 10.3892/ijmm.2017.3259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/01/2017] [Indexed: 01/17/2023] Open
Abstract
Bone mesenchymal stem cells (BMSCs) are currently considered the optimal stem cells for biological pacemaker cell transformation. The cardiac-specific transcription factor T-Box protein 18 (TBX18) is essential for sinoatrial node (SAN) formation, particularly formation of the head region that generates the electrical impulses that induce heart contraction. The present study aimed to confirm the effects of TBX18 on biological pace-maker differentiation of rat BMSCs. Flow cytometry was used to identify the surface markers of BMSCs, in order to acquire pure mesenchymal stem cells. Subsequently, BMSCs were transduced with TBX18 or green fluorescent protein adenovirus vectors. The effects of TBX18 were evaluated using SAN-specific makers including TBX18, α-actin, cardiac troponin I, hyperpolarization-activated cyclic nucleotide-gated channel 4 and connexin 43 by reverse transcription-quantitative polymerase chain reaction, western blotting and immunofluorescence. The findings demonstrated that direct conversion of BMSCs to biological pacemaker cells via TBX18 is a feasible method in the field of cardiology.
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Affiliation(s)
- Yanjun Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Mei Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Gege Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Le Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Bingjie Ye
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
| | - Yanhong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, Hubei 430060, P.R. China
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27
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Development of the cardiac pacemaker. Cell Mol Life Sci 2016; 74:1247-1259. [PMID: 27770149 DOI: 10.1007/s00018-016-2400-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 10/17/2016] [Indexed: 01/11/2023]
Abstract
The sinoatrial node (SAN) is the dominant pacemaker of the heart. Abnormalities in SAN formation and function can cause sinus arrhythmia, including sick sinus syndrome and sudden death. A better understanding of genes and signaling pathways that regulate SAN development and function is essential to develop more effective treatment to sinus arrhythmia, including biological pacemakers. In this review, we briefly summarize the key processes of SAN morphogenesis during development, and focus on the transcriptional network that drives SAN development.
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28
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Greulich F, Trowe MO, Leffler A, Stoetzer C, Farin HF, Kispert A. Misexpression of Tbx18 in cardiac chambers of fetal mice interferes with chamber-specific developmental programs but does not induce a pacemaker-like gene signature. J Mol Cell Cardiol 2016; 97:140-9. [PMID: 27180262 DOI: 10.1016/j.yjmcc.2016.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/13/2016] [Accepted: 05/09/2016] [Indexed: 11/20/2022]
Abstract
Initiation of cardiac excitation depends on a specialized group of cardiomyocytes at the venous pole of the heart, the sinoatrial node (SAN). The T-box transcription factor gene Tbx18 is expressed in the SAN myocardium and is required for formation of a large portion of the pacemaker. Previous studies suggested that Tbx18 is also sufficient to reprogram ventricular cardiomyocytes into SAN cells in rat, guinea-pig and pig hearts. To evaluate the consequences of misexpression of Tbx18 for imposing a nodal phenotype onto chamber myocardial cells in fetal mice, we used two independent conditional approaches with chamber-specific cre driver lines and an Hprt(Tbx18) misexpression allele. Myh6-Cre/+;Hprt(Tbx18/y) mice developed dilated atria with thickened walls, reduced right ventricles and septal defects that resulted in reduced embryonic and post-natal survival. Tagln-Cre/+;Hprt(Tbx18/y) mice exhibited slightly smaller hearts with rounded trabeculae that supported normal embryonic survival. Molecular analyses showed that the SAN gap junction and ion channel profile was not ectopically induced in chamber myocardium but the working myocardial gene program was partially inhibited in atria and ventricles of both misexpression models. Left atrial expression of Pitx2 was strongly repressed in Myh6-Cre/+;Hprt(Tbx18/y) embryos. We conclude that exclusion of Tbx18 expression from the developing atria and (right) ventricle is important to achieve normal cardiac left-right patterning and myocardial differentiation, and that Tbx18 is not sufficient to induce full SAN differentiation of chamber cardiomyocytes in fetal mice.
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Affiliation(s)
- Franziska Greulich
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany
| | - Mark-Oliver Trowe
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany
| | - Andreas Leffler
- Klinik für Anästhesiologie und Intensivmedizin, OE8050, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany
| | - Carsten Stoetzer
- Klinik für Anästhesiologie und Intensivmedizin, OE8050, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany
| | - Henner F Farin
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany
| | - Andreas Kispert
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str.1, D-30625 Hannover, Germany.
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29
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Brand T. Tbx18 and the generation of a biological pacemaker. Are we there yet? J Mol Cell Cardiol 2016; 97:263-5. [PMID: 27291063 PMCID: PMC5080448 DOI: 10.1016/j.yjmcc.2016.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 01/07/2023]
Affiliation(s)
- Thomas Brand
- Developmental Dynamics, Heart Science Center, National Heart and Lung Institute, Imperial College London, United Kingdom.
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30
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van Weerd JH, Christoffels VM. The formation and function of the cardiac conduction system. Development 2016; 143:197-210. [PMID: 26786210 DOI: 10.1242/dev.124883] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cardiac conduction system (CCS) consists of distinctive components that initiate and conduct the electrical impulse required for the coordinated contraction of the cardiac chambers. CCS development involves complex regulatory networks that act in stage-, tissue- and dose-dependent manners, and recent findings indicate that the activity of these networks is sensitive to common genetic variants associated with cardiac arrhythmias. Here, we review how these findings have provided novel insights into the regulatory mechanisms and transcriptional networks underlying CCS formation and function.
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Affiliation(s)
- Jan Hendrik van Weerd
- Department of Anatomy, Embryology & Physiology, Academic Medical Center, Amsterdam 1105 AZ, The Netherlands
| | - Vincent M Christoffels
- Department of Anatomy, Embryology & Physiology, Academic Medical Center, Amsterdam 1105 AZ, The Netherlands
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31
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Abstract
The heartbeat originates within the sinoatrial node (SA node or SAN), a small highly specialized structure containing <10,000 genuine pacemaker cells. The ~5 billion working cardiomyocytes downstream of the SAN remain quiescent when it fails, leading to circulatory collapse and fueling a $6B/year electronic pacemaker industry. The electronic pacemaker devices work quite well. But, device-related problems persist. These include lead failure/repositioning, finite battery life, and infection. For pediatric patients, the children outgrow the length of the leads, necessitating replacement with longer leads. These pitfalls have motivated creation of biological pacing. that are free from all hardware. Toward this goal, we and others have tested the concept of biological pacemakers. Combined with efforts to create clinically relevant, large animal models of biological pacing, the field is moving beyond a conceptual novelty toward a future with clinical reality.
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32
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Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K⁺ Current: A Simulation Study. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3830682. [PMID: 26998484 PMCID: PMC4779510 DOI: 10.1155/2016/3830682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/18/2022]
Abstract
Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker.
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33
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Xie Y, Ibrahim A, Cheng K, Wu Z, Liang W, Malliaras K, Sun B, Liu W, Shen D, Cheol Cho H, Li T, Lu L, Lu G, Marbán E. Importance of cell-cell contact in the therapeutic benefits of cardiosphere-derived cells. Stem Cells 2015; 32:2397-406. [PMID: 24802280 DOI: 10.1002/stem.1736] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 03/19/2014] [Accepted: 04/04/2014] [Indexed: 12/30/2022]
Abstract
Cardiosphere-derived cells (CDCs) effect therapeutic regeneration after myocardial infarction (MI) both in animal models and in humans. Here, we test the hypothesis that cell-cell contact plays a role in mediating the observed therapeutic benefits of CDCs, above and beyond conventional paracrine effects. Human CDCs or vehicle were injected into immunodeficient (SCID) mouse hearts during acute MI. CDC transplantation augmented the proportion of cycling (Ki67(+) ) cardiomyocytes and improved ventricular function. CDC-conditioned media only modestly augmented the percentage of Ki67(+) cardiomyocytes (>control but <CDCs), but did not improve pump function. When neonatal rat ventricular myocytes (NRVMs) were cocultured with human CDCs in vitro, the percentage of cycling NRVMs (Ki67(+) or BrdU(+) nuclei) increased relative to solitary NRVM culture. To further dissect the relative contributions of soluble factors versus contact-dependent mechanisms, we compared CDCs grown with NRVMs in a transwell contact-free system versus admixed coculture. The percentage of cycling NRVMs was higher in admixed coculture than in the contact-free system. Pretreatment with inhibitors of MEK and PI3K, or with β1 integrin neutralizing antibody, blocked the ability of CDCs to promote myocyte cycling. While conditioned media are not inert, direct apposition of CDCs to cardiomyocytes produces greater enhancement of cardiomyocyte proliferation in vitro and in vivo, and improves function post-MI. Intact cardiomyocyte β1 integrin signaling is necessary for the contact-dependent cardioproliferative effects of CDCs.
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Affiliation(s)
- Yucai Xie
- Cedars-Sinai Heart Institute, Los Angeles, California, USA; Department of Cardiology, Shanghai Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
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34
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Vedantham V. New Approaches to Biological Pacemakers: Links to Sinoatrial Node Development. Trends Mol Med 2015; 21:749-761. [PMID: 26611337 DOI: 10.1016/j.molmed.2015.10.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 12/30/2022]
Abstract
Irreversible degeneration of the cardiac conduction system is a common disease that can cause activity intolerance, fainting, and death. While electronic pacemakers provide effective treatment, alternative approaches are needed when long-term indwelling hardware is undesirable. Biological pacemakers comprise electrically active cells that functionally integrate with the heart. Recent findings on cardiac pacemaker cells (PCs) within the sinoatrial node (SAN), along with developments in stem cell technology, have opened a new era in biological pacing. Recent experiments that have derived PC-like cells from non-PCs have brought the field closer than ever before to biological pacemakers that can faithfully recapitulate SAN activity. In this review, I discuss these approaches in the context of SAN biology and address the potential for clinical translation.
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Affiliation(s)
- Vasanth Vedantham
- Department of Medicine, Cardiology Division, University of California, San Francisco, CA, USA; Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA.
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35
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Schulz R, Görge PM, Görbe A, Ferdinandy P, Lampe PD, Leybaert L. Connexin 43 is an emerging therapeutic target in ischemia/reperfusion injury, cardioprotection and neuroprotection. Pharmacol Ther 2015; 153:90-106. [PMID: 26073311 DOI: 10.1016/j.pharmthera.2015.06.005] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/29/2015] [Indexed: 12/22/2022]
Abstract
Connexins are widely distributed proteins in the body that are crucially important for heart and brain functions. Six connexin subunits form a connexon or hemichannel in the plasma membrane. Interactions between two hemichannels in a head-to-head arrangement result in the formation of a gap junction channel. Gap junctions are necessary to coordinate cell function by passing electrical current flow between heart and nerve cells or by allowing exchange of chemical signals and energy substrates. Apart from its localization at the sarcolemma of cardiomyocytes and brain cells, connexins are also found in the mitochondria where they are involved in the regulation of mitochondrial matrix ion fluxes and respiration. Connexin expression is affected by age and gender as well as several pathophysiological alterations such as hypertension, hypertrophy, diabetes, hypercholesterolemia, ischemia, post-myocardial infarction remodeling or heart failure, and post-translationally connexins are modified by phosphorylation/de-phosphorylation and nitros(yl)ation which can modulate channel activity. Using knockout/knockin technology as well as pharmacological approaches, one of the connexins, namely connexin 43, has been identified to be important for cardiac and brain ischemia/reperfusion injuries as well as protection from it. Therefore, the current review will focus on the importance of connexin 43 for irreversible injury of heart and brain tissues following ischemia/reperfusion and will highlight the importance of connexin 43 as an emerging therapeutic target in cardio- and neuroprotection.
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Affiliation(s)
- Rainer Schulz
- Institut für Physiologie, JustusLiebig Universität Giessen, Gießen, Germany.
| | | | - Anikó Görbe
- Cardiovascular Research Group, Department of Biochemistry, Faculty of Medicine, University of Szeged, Hungary; Pharmahungary Group, Szeged, Hungary
| | - Péter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary; Pharmahungary Group, Szeged, Hungary
| | - Paul D Lampe
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Luc Leybaert
- Physiology Group, Department Basic Medical Sciences, Ghent University, Belgium
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36
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Hensley MT, de Andrade J, Keene B, Meurs K, Tang J, Wang Z, Caranasos TG, Piedrahita J, Li TS, Cheng K. Cardiac regenerative potential of cardiosphere-derived cells from adult dog hearts. J Cell Mol Med 2015; 19:1805-13. [PMID: 25854418 PMCID: PMC4549031 DOI: 10.1111/jcmm.12585] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/27/2015] [Indexed: 11/28/2022] Open
Abstract
The regenerative potential of cardiosphere-derived cells (CDCs) for ischaemic heart disease has been demonstrated in mice, rats, pigs and a recently completed clinical trial. The regenerative potential of CDCs from dog hearts has yet to be tested. Here, we show that canine CDCs can be produced from adult dog hearts. These cells display similar phenotypes in comparison to previously studied CDCs derived from rodents and human beings. Canine CDCs can differentiate into cardiomyocytes, smooth muscle cells and endothelial cells in vitro. In addition, conditioned media from canine CDCs promote angiogenesis but inhibit cardiomyocyte death. In a doxorubicin-induced mouse model of dilated cardiomyopathy (DCM), intravenous infusion of canine CDCs improves cardiac function and decreases cardiac fibrosis. Histology revealed that injected canine CDCs engraft in the mouse heart and increase capillary density. Out study demonstrates the regenerative potential of canine CDCs in a mouse model of DCM.
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Affiliation(s)
- Michael Taylor Hensley
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - James de Andrade
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Bruce Keene
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Kathryn Meurs
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Center for Comparative Medicine and Translational Researches, North Carolina State University, Raleigh, NC, USA
| | - Junnan Tang
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Department of Cardiology, First Affiliated Hospital, College of Medicine, Zhengzhou University, Zhengzhou, China
| | - Zegen Wang
- The Cyrus Tang Hematology Center, Soochow University, Suzhou, China
| | - Thomas G Caranasos
- Division of Cardiothoracic Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jorge Piedrahita
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Center for Comparative Medicine and Translational Researches, North Carolina State University, Raleigh, NC, USA
| | - Tao-Sheng Li
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Ke Cheng
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.,Center for Comparative Medicine and Translational Researches, North Carolina State University, Raleigh, NC, USA.,The Cyrus Tang Hematology Center, Soochow University, Suzhou, China.,Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
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37
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Hu YF, Dawkins JF, Cho HC, Marbán E, Cingolani E. Biological pacemaker created by minimally invasive somatic reprogramming in pigs with complete heart block. Sci Transl Med 2015; 6:245ra94. [PMID: 25031269 DOI: 10.1126/scitranslmed.3008681] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Somatic reprogramming by reexpression of the embryonic transcription factor T-box 18 (TBX18) converts cardiomyocytes into pacemaker cells. We hypothesized that this could be a viable therapeutic avenue for pacemaker-dependent patients afflicted with device-related complications, and therefore tested whether adenoviral TBX18 gene transfer could create biological pacemaker activity in vivo in a large-animal model of complete heart block. Biological pacemaker activity, originating from the intramyocardial injection site, was evident in TBX18-transduced animals starting at day 2 and persisted for the duration of the study (14 days) with minimal backup electronic pacemaker use. Relative to controls transduced with a reporter gene, TBX18-transduced animals exhibited enhanced autonomic responses and physiologically superior chronotropic support of physical activity. Induced sinoatrial node cells could be identified by their distinctive morphology at the site of injection in TBX18-transduced animals, but not in controls. No local or systemic safety concerns arose. Thus, minimally invasive TBX18 gene transfer creates physiologically relevant pacemaker activity in complete heart block, providing evidence for therapeutic somatic reprogramming in a clinically relevant disease model.
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Affiliation(s)
- Yu-Feng Hu
- Cedars-Sinai Heart Institute, Los Angeles, CA 90048, USA. Division of Cardiology, Department of Internal Medicine, Taipei Veterans General Hospital and National Yang-Ming University, Taipei 112, Taiwan
| | | | - Hee Cheol Cho
- Cedars-Sinai Heart Institute, Los Angeles, CA 90048, USA
| | - Eduardo Marbán
- Cedars-Sinai Heart Institute, Los Angeles, CA 90048, USA.
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Yaniv Y, Tsutsui K, Lakatta EG. Potential effects of intrinsic heart pacemaker cell mechanisms on dysrhythmic cardiac action potential firing. Front Physiol 2015; 6:47. [PMID: 25755643 PMCID: PMC4337365 DOI: 10.3389/fphys.2015.00047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 02/03/2015] [Indexed: 02/05/2023] Open
Abstract
The heart's regular electrical activity is initiated by specialized cardiac pacemaker cells residing in the sinoatrial node. The rate and rhythm of spontaneous action potential firing of sinoatrial node cells are regulated by stochastic mechanisms that determine the level of coupling of chemical to electrical clocks within cardiac pacemaker cells. This coupled-clock system is modulated by autonomic signaling from the brain via neurotransmitter release from the vagus and sympathetic nerves. Abnormalities in brain-heart clock connections or in any molecular clock activity within pacemaker cells lead to abnormalities in the beating rate and rhythm of the pacemaker tissue that initiates the cardiac impulse. Dysfunction of pacemaker tissue can lead to tachy-brady heart rate alternation or exit block that leads to long atrial pauses and increases susceptibility to other cardiac arrhythmia. Here we review evidence for the idea that disturbances in the intrinsic components of pacemaker cells may be implemented in arrhythmia induction in the heart.
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Affiliation(s)
- Yael Yaniv
- Biomedical Engineering Faculty, Technion-Israel Institute of Technology Haifa, Israel
| | - Kenta Tsutsui
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, National Institutes of Health Baltimore, MD, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, National Institutes of Health Baltimore, MD, USA
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Epigenetic regulation of Tbx18 gene expression during endochondral bone formation. Cell Tissue Res 2014; 359:503-512. [PMID: 25380565 DOI: 10.1007/s00441-014-2028-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 10/09/2014] [Indexed: 10/24/2022]
Abstract
Endochondral bone formation is tightly regulated by the spatial and sequential expression of a series of transcription factors. To disclose the roles of TBX18, a member of the T-box transcription factor family, during endochondral bone formation, its spatial and temporal expression patterns were characterized in the limb skeletal region of the developing mouse together with those of established osteochondrogenic markers Sox9, Col2a1, and Runx2. TBX18 expression first appeared in condensed mesenchymal cells (chondro-progenitors) in embryonic-day-10.5 (E10.5) limb bud and was co-localized with Sox9 expression, whereas at E11.5 and E12.5, it became undetectable in mesenchymal cells committed to the chondrocyte lineage. From E13.5 to E18.5, TBX18 expression reappeared in chondrocytes, correlating strongly with Col2a1 expression; furthermore, low level TBX18 expression was found in the Runx2-positive perichondral osteoblastic cell lineage. At the postnatal stage, TBX18 expression was observed in epiphyseal chondrocytes and osteocytes within the lacunae of mature trabecular bone. On the assumption that such characteristic Tbx18 gene expression is epigenetically regulated during mouse limb development, we examined the methylation status of the CpG-island in the mouse Tbx18 gene by methylation-specific polymerase chain reaction. Hypermethylation of the Tbx18 gene promoter became evident at an early embryonic stage in TBX18-negative cells and then disappeared at a late embryonic stage in TBX18-positive cells. Therefore, the temporal suppression of Tbx18 gene expression by the hypermethylation of its promoter seems to trigger the differentiation of mesenchymal cells into hypertrophic chondrocytes in the early stages of endochondral ossification.
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Cheng K, Ibrahim A, Hensley MT, Shen D, Sun B, Middleton R, Liu W, Smith RR, Marbán E. Relative roles of CD90 and c-kit to the regenerative efficacy of cardiosphere-derived cells in humans and in a mouse model of myocardial infarction. J Am Heart Assoc 2014; 3:e001260. [PMID: 25300435 PMCID: PMC4323830 DOI: 10.1161/jaha.114.001260] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Background The regenerative potential of cardiosphere‐derived cells (CDCs) for ischemic heart disease has been demonstrated in mice, rats, pigs, and a recently completed clinical trial (CADUCEUS). CDCs are CD105+ stromal cells of intrinsic cardiac origin, but the antigenic characteristics of the active fraction remain to be defined. CDCs contain a small minority of c‐kit+ cells, which have been argued to be cardiac progenitors, and a variable fraction of CD90+ cells whose bioactivity is unclear. Methods We performed a retrospective analysis of data from the CADUCEUS trial and a prospective mouse study to elucidate the roles of c‐kit+ and CD90+ cells in human CDCs. Here, we show, surprisingly, that c‐kit expression has no relationship to CDCs' therapeutic efficacy in humans, and depletion of c‐kit+ cells does not undermine the structural and functional benefits of CDCs in a mouse model of myocardial infarction (MI). In contrast, CD90 expression negatively correlates with the therapeutic benefit of CDCs in humans (ie, higher CD90 expression associated with lower efficacy). Depletion of CD90+ cells augments the functional potency of CDCs in murine MI. CD90− CDCs secrete lower levels of inflammatory cytokines and can differentiate into cardiomyocytes in vitro and in vivo. Conclusion The majority population of CDCs (CD105+/CD90−/c‐kit−) constitutes the active fraction, both in terms of therapeutic efficacy and in the ability to undergo cardiomyogenic differentiation. The c‐kit+ fraction is neither necessary for, nor contributory to, the regenerative efficacy of CDCs.
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Affiliation(s)
- Ke Cheng
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.) Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC (K.C., T.H.) Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University Raleigh, NC (K.C.)
| | - Ahmed Ibrahim
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.)
| | - M Taylor Hensley
- Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC (K.C., T.H.)
| | - Deliang Shen
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China (D.S.)
| | - Baiming Sun
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.)
| | - Ryan Middleton
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.)
| | - Weixin Liu
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.)
| | - Rachel R Smith
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.) Capricor Therapeutics Inc, Beverly Hills, CA (R.R.S.)
| | - Eduardo Marbán
- Cedars-Sinai Heart Institute, Los Angeles, CA (K.C., A.I., B.S., R.M., W.L., R.R.S., E.M.)
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Zhang SS, Shaw RM. Trafficking highways to the intercalated disc: new insights unlocking the specificity of connexin 43 localization. ACTA ACUST UNITED AC 2014; 21:43-54. [PMID: 24460200 DOI: 10.3109/15419061.2013.876014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
With each heartbeat, billions of cardiomyocytes work in concert to propagate the electrical excitation needed to effectively circulate blood. Regulated expression and timely delivery of connexin proteins to form gap junctions at the specialized cell-cell contact region, known as the intercalated disc, is essential to ventricular cardiomyocyte coupling. We focus this review on several regulatory mechanisms that have been recently found to govern the lifecycle of connexin 43 (Cx43), the short-lived and most abundantly expressed connexin in cardiac ventricular muscle. The Cx43 lifecycle begins with gene expression, followed by oligomerization into hexameric channels, and then cytoskeletal-based transport toward the disc region. Once delivered, hemichannels interact with resident disc proteins and are organized to effect intercellular coupling. We highlight recent studies exploring regulation of Cx43 localization to the intercalated disc, with emphasis on alternatively translated Cx43 isoforms and cytoskeletal transport machinery that together regulate Cx43 gap junction coupling between cardiomyocytes.
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Cheng K, Shen D, Hensley MT, Middleton R, Sun B, Liu W, De Couto G, Marbán E. Magnetic antibody-linked nanomatchmakers for therapeutic cell targeting. Nat Commun 2014; 5:4880. [PMID: 25205020 PMCID: PMC4175574 DOI: 10.1038/ncomms5880] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 07/31/2014] [Indexed: 12/15/2022] Open
Abstract
Stem cell transplantation is a promising strategy for therapeutic cardiac regeneration, but current therapies are limited by inefficient interaction between potentially beneficial cells (either exogenously transplanted or endogenously recruited) and the injured tissue. Here we apply targeted nanomedicine to achieve in vivo cell-mediated tissue repair, imaging and localized enrichment without cellular transplantation. Iron nanoparticles are conjugated with two types of antibodies (one against antigens on therapeutic cells and the other directed at injured cells) to produce magnetic bifunctional cell engager (MagBICE). The antibodies link the therapeutic cells to the injured cells, whereas the iron core of MagBICE enables physical enrichment and imaging. We treat acute myocardial infarction by targeting exogenous bone marrow-derived stem cells (expressing CD45) or endogenous CD34-positive cells to injured cardiomyocytes (expressing myosin light chain. Targeting can be further enhanced by magnetic attraction, leading to augmented functional benefits. MagBICE represents a generalizable platform technology for regenerative medicine.
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Affiliation(s)
- Ke Cheng
- 1] Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA [2] Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, 1060 William Moore Drive, North Carolina State University, Raleigh, North Carolina 27607, USA [3] Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27607, USA
| | - Deliang Shen
- Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - M Taylor Hensley
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, 1060 William Moore Drive, North Carolina State University, Raleigh, North Carolina 27607, USA
| | - Ryan Middleton
- Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
| | - Baiming Sun
- Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
| | - Weixin Liu
- Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
| | - Geoffrey De Couto
- Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
| | - Eduardo Marbán
- Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
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43
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Mending broken hearts: cardiac development as a basis for adult heart regeneration and repair. Nat Rev Mol Cell Biol 2013; 14:529-41. [PMID: 23839576 DOI: 10.1038/nrm3619] [Citation(s) in RCA: 348] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
As the adult mammalian heart has limited potential for regeneration and repair, the loss of cardiomyocytes during injury and disease can result in heart failure and death. The cellular processes and regulatory mechanisms involved in heart growth and development can be exploited to repair the injured adult heart through 'reawakening' pathways that are active during embryogenesis. Heart function has been restored in rodents by reprogramming non-myocytes into cardiomyocytes, by expressing transcription factors (GATA4, HAND2, myocyte-specific enhancer factor 2C (MEF2C) and T-box 5 (TBX5)) and microRNAs (miR-1, miR-133, miR-208 and miR-499) that control cardiomyocyte identity. Stimulating cardiomyocyte dedifferentiation and proliferation by activating mitotic signalling pathways involved in embryonic heart growth represents a complementary approach for heart regeneration and repair. Recent advances in understanding the mechanistic basis of heart development offer exciting opportunities for effective therapies for heart failure.
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44
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Verheule S, Kaese S. Connexin diversity in the heart: insights from transgenic mouse models. Front Pharmacol 2013; 4:81. [PMID: 23818881 PMCID: PMC3694209 DOI: 10.3389/fphar.2013.00081] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/04/2013] [Indexed: 11/13/2022] Open
Abstract
Cardiac conduction is mediated by gap junction channels that are formed by connexin (Cx) protein subunits. The connexin family of proteins consists of more than 20 members varying in their biophysical properties and ability to combine with other connexins into heteromeric gap junction channels. The mammalian heart shows regional differences both in connexin expression profile and in degree of electrical coupling. The latter reflects functional requirements for conduction velocity which needs to be low in the sinoatrial and atrioventricular nodes and high in the ventricular conduction system. Over the past 20 years knowledge of the biology of gap junction channels and their role in the genesis of cardiac arrhythmias has increased enormously. This review focuses on the insights gained from transgenic mouse models. The mouse heart expresses Cx30, 30.2, 37, 40, 43, 45, and 46. For these connexins a variety of knock-outs, heart-specific knock-outs, conditional knock-outs, double knock-outs, knock-ins and overexpressors has been studied. We discuss the cardiac phenotype in these models and compare Cx expression between mice and men. Mouse models have enhanced our understanding of (patho)-physiological implications of Cx diversity in the heart. In principle connexin-specific modulation of electrical coupling in the heart represents an interesting treatment strategy for cardiac arrhythmias and conduction disorders.
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Affiliation(s)
- Sander Verheule
- Department of Physiology, Faculty of Medicine, Maastricht University Maastricht, Netherlands
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45
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Novel and functional variants within the TBX18 gene promoter in ventricular septal defects. Mol Cell Biochem 2013; 382:121-6. [DOI: 10.1007/s11010-013-1725-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/29/2013] [Indexed: 01/31/2023]
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46
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Direct conversion of quiescent cardiomyocytes to pacemaker cells by expression of Tbx18. Nat Biotechnol 2012; 31:54-62. [PMID: 23242162 DOI: 10.1038/nbt.2465] [Citation(s) in RCA: 230] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 11/28/2012] [Indexed: 01/09/2023]
Abstract
The heartbeat originates within the sinoatrial node (SAN), a small structure containing <10,000 genuine pacemaker cells. If the SAN fails, the ∼5 billion working cardiomyocytes downstream of it become quiescent, leading to circulatory collapse in the absence of electronic pacemaker therapy. Here we demonstrate conversion of rodent cardiomyocytes to SAN cells in vitro and in vivo by expression of Tbx18, a gene critical for early SAN specification. Within days of in vivo Tbx18 transduction, 9.2% of transduced, ventricular cardiomyocytes develop spontaneous electrical firing physiologically indistinguishable from that of SAN cells, along with morphological and epigenetic features characteristic of SAN cells. In vivo, focal Tbx18 gene transfer in the guinea-pig ventricle yields ectopic pacemaker activity, correcting a bradycardic disease phenotype. Myocytes transduced in vivo acquire the cardinal tapering morphology and physiological automaticity of native SAN pacemaker cells. The creation of induced SAN pacemaker (iSAN) cells opens new prospects for bioengineered pacemakers.
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Abstract
The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Given its critical role in coordinating cardiac performance, a detailed analysis of the molecular mechanisms underlying conduction system formation should inform our understanding of arrhythmia pathophysiology and affect the development of novel therapeutic strategies. Historically, the ability to distinguish cells of the conduction system from neighboring working myocytes presented a major technical challenge for performing comprehensive mechanistic studies. Early lineage tracing experiments suggested that conduction cells derive from cardiomyocyte precursors, and these claims have been substantiated by using more contemporary approaches. However, regional specialization of conduction cells adds an additional layer of complexity to this system, and it appears that different components of the conduction system utilize unique modes of developmental formation. The identification of numerous transcription factors and their downstream target genes involved in regional differentiation of the conduction system has provided insight into how lineage commitment is achieved. Furthermore, by adopting cutting-edge genetic techniques in combination with sophisticated phenotyping capabilities, investigators have made substantial progress in delineating the regulatory networks that orchestrate conduction system formation and their role in cardiac rhythm and physiology. This review describes the connectivity of these gene regulatory networks in cardiac conduction system development and discusses how they provide a foundation for understanding normal and pathological human cardiac rhythms.
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Affiliation(s)
- Nikhil V Munshi
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX 75390-8573, USA.
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48
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Karantalis V, Balkan W, Schulman IH, Hatzistergos KE, Hare JM. Cell-based therapy for prevention and reversal of myocardial remodeling. Am J Physiol Heart Circ Physiol 2012; 303:H256-70. [PMID: 22636682 DOI: 10.1152/ajpheart.00221.2012] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although pharmacological and interventional advances have reduced the morbidity and mortality of ischemic heart disease, there is an ongoing need for novel therapeutic strategies that prevent or reverse progressive ventricular remodeling following myocardial infarction, the process that forms the substrate for ventricular failure. The development of cell-based therapy as a strategy to repair or regenerate injured tissue offers extraordinary promise for a powerful anti-remodeling therapy. In this regard, the field of cell therapy has made major advancements in the past decade. Accumulating data from preclinical studies have provided novel insights into stem cell engraftment, differentiation, and interactions with host cellular elements, as well as the effectiveness of various methods of cell delivery and accuracy of diverse imaging modalities to assess therapeutic efficacy. These findings have in turn guided rationally designed translational clinical investigations. Collectively, there is a growing understanding of the parameters that underlie successful cell-based approaches for improving heart structure and function in ischemic and other cardiomyopathies.
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Affiliation(s)
- Vasileios Karantalis
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Florida, USA
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Cheng K, Shen D, Smith J, Galang G, Sun B, Zhang J, Marbán E. Transplantation of platelet gel spiked with cardiosphere-derived cells boosts structural and functional benefits relative to gel transplantation alone in rats with myocardial infarction. Biomaterials 2012; 33:2872-9. [PMID: 22243801 DOI: 10.1016/j.biomaterials.2011.12.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/20/2011] [Indexed: 10/14/2022]
Abstract
The emerging field of stem cell therapy and biomaterials has begun to provide promising strategies for the treatment of ischemic cardiomyopathy. Platelet gel and cardiosphere-derived cells (CDCs) are known to be beneficial when transplanted separately post-myocardial infarction (MI). We hypothesize that pre-seeding platelet gel with CDCs can enhance therapeutic efficacy. Platelet gel and CDCs were derived from venous blood and heart biopsies of syngeneic rats, respectively. In vitro, the viability, growth, and morphology of CDCs cultured in platelet gel were characterized. When delivered into infarcted rat hearts, platelet gel pre-seeded with CDCs was more efficiently populated with endogenous cardiomyocytes and endothelial cells than platelet gel alone. Recruitment of endogenous c-kit positive cells was enhanced in the hearts treated with gel with CDC. At 3 weeks, the hearts treated with CDC-seeded platelet gel exhibited the greatest attenuation of adverse left ventricular (LV) remodeling and the highest cardiac function (i.e., LV ejection fraction) as compared to hearts transplanted with Gel only or vehicle controls. Histological analysis revealed that, though some transplanted CDCs differentiated into cardiomyocytes and endothelial cells in the recipients' hearts, most of the incremental benefit arose from CDC-mediated endogenous repair. Pre-seeding platelet gel with CDCs enhanced the functional benefit of biomaterial therapy for treating myocardial infarction.
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Affiliation(s)
- Ke Cheng
- The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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50
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Oyamada M, Takebe K, Oyamada Y. Regulation of connexin expression by transcription factors and epigenetic mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:118-33. [PMID: 22244842 DOI: 10.1016/j.bbamem.2011.12.031] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 12/17/2011] [Accepted: 12/27/2011] [Indexed: 01/24/2023]
Abstract
Gap junctions are specialized cell-cell junctions that directly link the cytoplasm of neighboring cells. They mediate the direct transfer of metabolites and ions from one cell to another. Discoveries of human genetic disorders due to mutations in gap junction protein (connexin [Cx]) genes and experimental data on connexin knockout mice provide direct evidence that gap junctional intercellular communication is essential for tissue functions and organ development, and that its dysfunction causes diseases. Connexin-related signaling also involves extracellular signaling (hemichannels) and non-channel intracellular signaling. Thus far, 21 human genes and 20 mouse genes for connexins have been identified. Each connexin shows tissue- or cell-type-specific expression, and most organs and many cell types express more than one connexin. Connexin expression can be regulated at many of the steps in the pathway from DNA to RNA to protein. In recent years, it has become clear that epigenetic processes are also essentially involved in connexin gene expression. In this review, we summarize recent knowledge on regulation of connexin expression by transcription factors and epigenetic mechanisms including histone modifications, DNA methylation, and microRNA. This article is part of a Special Issue entitled: The communicating junctions, roles and dysfunctions.
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Affiliation(s)
- Masahito Oyamada
- Department of Food Science and Human Nutrition, Fuji Women's University, Ishikarishi, Japan.
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