1
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Kim SL, Trembley MA, Lee KY, Choi S, MacQueen LA, Zimmerman JF, de Wit LHC, Shani K, Henze DE, Drennan DJ, Saifee SA, Loh LJ, Liu X, Parker KK, Pu WT. Spatiotemporal cell junction assembly in human iPSC-CM models of arrhythmogenic cardiomyopathy. Stem Cell Reports 2023; 18:1811-1826. [PMID: 37595583 PMCID: PMC10545490 DOI: 10.1016/j.stemcr.2023.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/20/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disorder that causes life-threatening arrhythmias and myocardial dysfunction. Pathogenic variants in Plakophilin-2 (PKP2), a desmosome component within specialized cardiac cell junctions, cause the majority of ACM cases. However, the molecular mechanisms by which PKP2 variants induce disease phenotypes remain unclear. Here we built bioengineered platforms using genetically modified human induced pluripotent stem cell-derived cardiomyocytes to model the early spatiotemporal process of cardiomyocyte junction assembly in vitro. Heterozygosity for truncating variant PKP2R413X reduced Wnt/β-catenin signaling, impaired myofibrillogenesis, delayed mechanical coupling, and reduced calcium wave velocity in engineered tissues. These abnormalities were ameliorated by SB216763, which activated Wnt/β-catenin signaling, improved cytoskeletal organization, restored cell junction integrity in cell pairs, and improved calcium wave velocity in engineered tissues. Together, these findings highlight the therapeutic potential of modulating Wnt/β-catenin signaling in a human model of ACM.
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Affiliation(s)
- Sean L Kim
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA; Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Michael A Trembley
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Keel Yong Lee
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA; Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul 05006, Republic of Korea
| | - Suji Choi
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Luke A MacQueen
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - John F Zimmerman
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Lousanne H C de Wit
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Kevin Shani
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA; Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Douglas E Henze
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Daniel J Drennan
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Shaila A Saifee
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Li Jun Loh
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Xujie Liu
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA; Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA.
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2
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Weinberg SH. Sodium channel subpopulations with distinct biophysical properties and subcellular localization enhance cardiac conduction. J Gen Physiol 2023; 155:e202313382. [PMID: 37285024 PMCID: PMC10250552 DOI: 10.1085/jgp.202313382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/02/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023] Open
Abstract
Sodium (Na+) current is responsible for the rapid depolarization of cardiac myocytes that triggers the cardiac action potential upstroke. Recent studies have illustrated the presence of multiple pools of Na+ channels with distinct biophysical properties and subcellular localization, including clustering of channels at the intercalated disk and along the lateral membrane. Computational studies predict that Na+ channel clusters at the intercalated disk can regulate cardiac conduction via modulation of the narrow intercellular cleft between electrically coupled myocytes. However, these studies have primarily focused on the redistribution of Na+ channels between intercalated disk and lateral membranes and have not considered the distinct biophysical properties of the Na+ channel subpopulations. In this study, we use computational modeling to simulate computational models of single cardiac cells and one-dimensional cardiac tissues and predict the function of distinct Na+ channel subpopulations. Single-cell simulations predict that a subpopulation of Na+ channels with shifted steady-state activation and inactivation voltage dependency promotes an earlier action potential upstroke. In cardiac tissues that account for distinct subcellular spatial localization, simulations predict that shifted Na+ channels contribute to faster and more robust conduction in response to changes in tissue structure (i.e., cleft width), gap junctional coupling, and rapid pacing rates. Simulations predict that the intercalated disk-localized shifted Na+ channels contribute proportionally more to total Na+ charge than lateral membrane-localized Na+ channels. Importantly, our work supports the hypothesis that Na+ channel redistribution may be a critical mechanism by which cells can respond to perturbations to support fast and robust conduction.
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Affiliation(s)
- Seth H. Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
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3
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Otani NF, Figueroa E, Garrison J, Hewson M, Muñoz L, Fenton FH, Karma A, Weinberg SH. Ephaptic Coupling as a Resolution to the Paradox of Action Potential Wave Speed and Discordant Alternans Spatial Scales in the Heart. PHYSICAL REVIEW LETTERS 2023; 130:218401. [PMID: 37295103 PMCID: PMC10688031 DOI: 10.1103/physrevlett.130.218401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 03/07/2023] [Indexed: 06/12/2023]
Abstract
Previous computer simulations have suggested that existing models of action potential wave propagation in the heart are not consistent with observed wave propagation behavior. Specifically, computer models cannot simultaneously reproduce the rapid wave speeds and small spatial scales of discordant alternans patterns measured experimentally in the same simulation. The discrepancy is important, because discordant alternans can be a key precursor to the development of abnormal and dangerous rapid rhythms in the heart. In this Letter, we show that this paradox can be resolved by allowing so-called ephaptic coupling to play a primary role in wave front propagation in place of conventional gap-junction coupling. With this modification, physiological wave speeds and small discordant alternans spatial scales both occur with gap-junction resistance values that are more in line with those observed in experiments. Our theory thus also provides support to the hypothesis that ephaptic coupling plays an important role in normal wave propagation.
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Affiliation(s)
- Niels F. Otani
- Rochester Institute of Technology, Rochester, New York 14623, USA
| | - Eileen Figueroa
- Rochester Institute of Technology, Rochester, New York 14623, USA
| | - James Garrison
- Hampden-Sydney College, Hampden-Sydney, Virginia 23943, USA
| | - Michelle Hewson
- Western Carolina University, Cullowhee, North Carolina 28723, USA
| | - Laura Muñoz
- Rochester Institute of Technology, Rochester, New York 14623, USA
| | | | - Alain Karma
- Northeastern University, Boston, Massachusetts 02115, USA
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4
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Otani NF, Figueroa E, Garrison J, Hewson M, Muñoz L, Fenton FH, Karma A, Weinberg SH. Role of ephaptic coupling in discordant alternans domain sizes and action potential propagation in the heart. Phys Rev E 2023; 107:054407. [PMID: 37329030 PMCID: PMC10688036 DOI: 10.1103/physreve.107.054407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
Discordant alternans, the spatially out-of-phase alternation of the durations of propagating action potentials in the heart, has been linked to the onset of fibrillation, a major cardiac rhythm disorder. The sizes of the regions, or domains, within which these alternations are synchronized are critical in this link. However, computer models employing standard gap junction-based coupling between cells have been unable to reproduce simultaneously the small domain sizes and rapid action potential propagation speeds seen in experiments. Here we use computational methods to show that rapid wave speeds and small domain sizes are possible when a more detailed model of intercellular coupling that accounts for so-called ephaptic effects is used. We provide evidence that the smaller domain sizes are possible, because different coupling strengths can exist on the wavefronts, for which both ephaptic and gap-junction coupling are involved, in contrast to the wavebacks, where only gap-junction coupling plays an active role. The differences in coupling strength are due to the high density of fast-inward (sodium) channels known to localize on the ends of cardiac cells, which are only active (and thus engage ephaptic coupling) during wavefront propagation. Thus, our results suggest that this distribution of fast-inward channels, as well as other factors responsible for the critical involvement of ephaptic coupling in wave propagation, including intercellular cleft spacing, play important roles in increasing the vulnerability of the heart to life-threatening tachyarrhythmias. Our results, combined with the absence of short-wavelength discordant alternans domains in standard gap-junction-dominated coupling models, also provide evidence that both gap-junction and ephaptic coupling are critical in wavefront propagation and waveback dynamics.
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Affiliation(s)
- Niels F. Otani
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - Eileen Figueroa
- Department of Electrical, Computer and Telecommunications Engineering Technology, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - James Garrison
- Department of Mathematics and Computer Science, Hampden-Sydney College, Hampden-Sydney, Virginia 23943, USA
| | - Michelle Hewson
- Department of Mathematics and Computer Science, Western Carolina University, Cullowhee, North Carolina 28723, USA
| | - Laura Muñoz
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Alain Karma
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA
| | - Seth H. Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, USA
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5
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Liu W, Han JL, Tomek J, Bub G, Entcheva E. Simultaneous Widefield Voltage and Dye-Free Optical Mapping Quantifies Electromechanical Waves in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. ACS PHOTONICS 2023; 10:1070-1083. [PMID: 37096210 PMCID: PMC10119986 DOI: 10.1021/acsphotonics.2c01644] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Indexed: 05/03/2023]
Abstract
Coupled electromechanical waves define a heart's function in health and diseases. Optical mapping of electrical waves using fluorescent labels offers mechanistic insights into cardiac conduction abnormalities. Dye-free/label-free mapping of mechanical waves presents an attractive non-invasive alternative. In this study, we developed a simultaneous widefield voltage and interferometric dye-free optical imaging methodology that was used as follows: (1) to validate dye-free optical mapping for quantification of cardiac wave properties in human iPSC-cardiomyocytes (CMs); (2) to demonstrate low-cost optical mapping of electromechanical waves in hiPSC-CMs using recent near-infrared (NIR) voltage sensors and orders of magnitude cheaper miniature industrial CMOS cameras; (3) to uncover previously underexplored frequency- and space-varying parameters of cardiac electromechanical waves in hiPSC-CMs. We find similarity in the frequency-dependent responses of electrical (NIR fluorescence-imaged) and mechanical (dye-free-imaged) waves, with the latter being more sensitive to faster rates and showing steeper restitution and earlier appearance of wavefront tortuosity. During regular pacing, the dye-free-imaged conduction velocity and electrical wave velocity are correlated; both modalities are sensitive to pharmacological uncoupling and dependent on gap-junctional protein (connexins) determinants of wave propagation. We uncover the strong frequency dependence of the electromechanical delay (EMD) locally and globally in hiPSC-CMs on a rigid substrate. The presented framework and results offer new means to track the functional responses of hiPSC-CMs inexpensively and non-invasively for counteracting heart disease and aiding cardiotoxicity testing and drug development.
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Affiliation(s)
- Wei Liu
- Department
of Biomedical Engineering, George Washington
University, Washington, D.C. 20052, United States
| | - Julie L. Han
- Department
of Biomedical Engineering, George Washington
University, Washington, D.C. 20052, United States
| | - Jakub Tomek
- Department
of Pharmacology, University of California−Davis, Davis, California 95616, United States
| | - Gil Bub
- Department
of Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Emilia Entcheva
- Department
of Biomedical Engineering, George Washington
University, Washington, D.C. 20052, United States
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6
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Rexius-Hall ML, Khalil NN, Escopete SS, Li X, Hu J, Yuan H, Parker SJ, McCain ML. A myocardial infarct border-zone-on-a-chip demonstrates distinct regulation of cardiac tissue function by an oxygen gradient. SCIENCE ADVANCES 2022; 8:eabn7097. [PMID: 36475790 PMCID: PMC9728975 DOI: 10.1126/sciadv.abn7097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
After a myocardial infarction, the boundary between the injured, hypoxic tissue and the adjacent viable, normoxic tissue, known as the border zone, is characterized by an oxygen gradient. Yet, the impact of an oxygen gradient on cardiac tissue function is poorly understood, largely due to limitations of existing experimental models. Here, we engineered a microphysiological system to controllably expose engineered cardiac tissue to an oxygen gradient that mimics the border zone and measured the effects of the gradient on electromechanical function and the transcriptome. The gradient delayed calcium release, reuptake, and propagation; decreased diastolic and peak systolic stress; and increased expression of inflammatory cascades that are hallmarks of myocardial infarction. These changes were distinct from those observed in tissues exposed to uniform normoxia or hypoxia, demonstrating distinct regulation of cardiac tissue phenotypes by an oxygen gradient. Our border-zone-on-a-chip model advances functional and mechanistic insight into oxygen-dependent cardiac tissue pathophysiology.
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Affiliation(s)
- Megan L. Rexius-Hall
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Natalie N. Khalil
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Sean S. Escopete
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Xin Li
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Jiayi Hu
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Hongyan Yuan
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Sarah J. Parker
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Megan L. McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
- Corresponding author.
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7
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Abstract
An ensemble of in vitro cardiac tissue models has been developed over the past several decades to aid our understanding of complex cardiovascular disorders using a reductionist approach. These approaches often rely on recapitulating single or multiple clinically relevant end points in a dish indicative of the cardiac pathophysiology. The possibility to generate disease-relevant and patient-specific human induced pluripotent stem cells has further leveraged the utility of the cardiac models as screening tools at a large scale. To elucidate biological mechanisms in the cardiac models, it is critical to integrate physiological cues in form of biochemical, biophysical, and electromechanical stimuli to achieve desired tissue-like maturity for a robust phenotyping. Here, we review the latest advances in the directed stem cell differentiation approaches to derive a wide gamut of cardiovascular cell types, to allow customization in cardiac model systems, and to study diseased states in multiple cell types. We also highlight the recent progress in the development of several cardiovascular models, such as cardiac organoids, microtissues, engineered heart tissues, and microphysiological systems. We further expand our discussion on defining the context of use for the selection of currently available cardiac tissue models. Last, we discuss the limitations and challenges with the current state-of-the-art cardiac models and highlight future directions.
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Affiliation(s)
- Dilip Thomas
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.).,Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.)
| | - Suji Choi
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA (S.C., K.K.P.)
| | - Christina Alamana
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.).,Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.)
| | - Kevin Kit Parker
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA (S.C., K.K.P.).,Harvard Stem Cell Institute, Harvard University, Cambridge, MA, Wyss Institute for Biologically Inspired Engineering, Boston, MA (K.K.P.)
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.).,Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA (D.T., C.A., J.C.W.).,Greenstone Biosciences, Palo Alto, CA (J.C.W.)
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8
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Greiner J, Sankarankutty AC, Seidel T, Sachse FB. Confocal microscopy-based estimation of intracellular conductivities in myocardium for modeling of the normal and infarcted heart. Comput Biol Med 2022; 146:105579. [PMID: 35588677 DOI: 10.1016/j.compbiomed.2022.105579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 04/12/2022] [Accepted: 04/30/2022] [Indexed: 11/03/2022]
Abstract
Ventricular arrhythmias are the leading cause of mortality in patients with ischemic heart diseases, such as myocardial infarction (MI). Computational simulation of cardiac electrophysiology provides insights into these arrhythmias and their treatment. However, only sparse information is available on crucial model parameters, for instance, the anisotropic intracellular electrical conductivities. Here, we introduced an approach to estimate these conductivities in normal and MI hearts. We processed and analyzed images from confocal microscopy of left ventricular tissue of a rabbit MI model to generate 3D reconstructions. We derived tissue features including the volume fraction of myocytes (Vmyo), gap junctions-containing voxels (Vgj), and fibrosis (Vfibrosis). We generated models of the intracellular space and intercellular coupling. Applying numerical methods for solving Poisson's equation for stationary electrical currents, we calculated normal (σmyo,n), longitudinal (σmyo,l), and transverse (σmyo,t) intracellular conductivities. Using linear regression analysis, we assessed relationships of conductivities to tissue features. Vgj and Vmyo were reduced in MI vs. control, but Vfibrosis was increased. Both σmyo,l and σmyo,n were lower in MI than in control. Differences of σmyo,t between control and MI were not significant. We found strong positive relationships of σmyo,l with Vmyo and Vgj, and a strong negative relationship with Vfibrosis. The relationships of σmyo,n with these tissue features were similar but less pronounced. Our study provides quantitative insights into the intracellular conductivities in the normal and MI heart. We suggest that our study establishes a framework for the estimation of intracellular electrical conductivities of myocardium with various pathologies.
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Affiliation(s)
- Joachim Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Aparna C Sankarankutty
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, USA
| | - Thomas Seidel
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Frank B Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA; Department of Biomedical Engineering, University of Utah, Salt Lake City, USA.
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9
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Gu Y, Wang C, Kim N, Zhang J, Wang TM, Stowe J, Nasiri R, Li J, Zhang D, Yang A, Hsu LHH, Dai X, Mu J, Liu Z, Lin M, Li W, Wang C, Gong H, Chen Y, Lei Y, Hu H, Li Y, Zhang L, Huang Z, Zhang X, Ahadian S, Banik P, Zhang L, Jiang X, Burke PJ, Khademhosseini A, McCulloch AD, Xu S. Three-dimensional transistor arrays for intra- and inter-cellular recording. NATURE NANOTECHNOLOGY 2022; 17:292-300. [PMID: 34949774 PMCID: PMC8994210 DOI: 10.1038/s41565-021-01040-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/27/2021] [Indexed: 06/14/2023]
Abstract
Electrical impulse generation and its conduction within cells or cellular networks are the cornerstone of electrophysiology. However, the advancement of the field is limited by sensing accuracy and the scalability of current recording technologies. Here we describe a scalable platform that enables accurate recording of transmembrane potentials in electrogenic cells. The platform employs a three-dimensional high-performance field-effect transistor array for minimally invasive cellular interfacing that produces faithful recordings, as validated by the gold standard patch clamp. Leveraging the high spatial and temporal resolutions of the field-effect transistors, we measured the intracellular signal conduction velocity of a cardiomyocyte to be 0.182 m s-1, which is about five times the intercellular velocity. We also demonstrate intracellular recordings in cardiac muscle tissue constructs and reveal the signal conduction paths. This platform could provide new capabilities in probing the electrical behaviours of single cells and cellular networks, which carries broad implications for understanding cellular physiology, pathology and cell-cell interactions.
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Affiliation(s)
- Yue Gu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Chunfeng Wang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Namheon Kim
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Jingxin Zhang
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
| | - Tsui Min Wang
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jennifer Stowe
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Rohollah Nasiri
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA, USA
| | - Jinfeng Li
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Daibo Zhang
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Albert Yang
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Leo Huan-Hsuan Hsu
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - Xiaochuan Dai
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - Jing Mu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Zheyuan Liu
- Electrochemical Energy Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Muyang Lin
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Weixin Li
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Chonghe Wang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Hua Gong
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Yimu Chen
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Yusheng Lei
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Hongjie Hu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Yang Li
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Lin Zhang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Zhenlong Huang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Xingcai Zhang
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Samad Ahadian
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA, USA
| | - Pooja Banik
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Liangfang Zhang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA
| | - Xiaocheng Jiang
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - Peter J Burke
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, USA
| | | | - Andrew D McCulloch
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sheng Xu
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA.
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, USA.
- Departments of Bioengineering and Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Radiology, University of California San Diego, La Jolla, CA, USA.
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
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10
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Nowak MB, Veeraraghavan R, Poelzing S, Weinberg SH. Cellular Size, Gap Junctions, and Sodium Channel Properties Govern Developmental Changes in Cardiac Conduction. Front Physiol 2021; 12:731025. [PMID: 34759834 PMCID: PMC8573326 DOI: 10.3389/fphys.2021.731025] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/28/2021] [Indexed: 11/26/2022] Open
Abstract
Electrical conduction in cardiac ventricular tissue is regulated via sodium (Na+) channels and gap junctions (GJs). We and others have recently shown that Na+channels preferentially localize at the site of cell-cell junctions, the intercalated disc (ID), in adult cardiac tissue, facilitating coupling via the formation of intercellular Na+nanodomains, also termed ephaptic coupling (EpC). Several properties governing EpC vary with age, including Na+channel and GJ expression and distribution and cell size. Prior work has shown that neonatal cardiomyocytes have immature IDs with Na+channels and GJs diffusively distributed throughout the sarcolemma, while adult cells have mature IDs with preferentially localized Na+channels and GJs. In this study, we perform an in silico investigation of key age-dependent properties to determine developmental regulation of cardiac conduction. Simulations predict that conduction velocity (CV) biphasically depends on cell size, depending on the strength of GJ coupling. Total cell Na+channel conductance is predictive of CV in cardiac tissue with high GJ coupling, but not correlated with CV for low GJ coupling. We find that ephaptic effects are greatest for larger cells with low GJ coupling typically associated with intermediate developmental stages. Finally, simulations illustrate how variability in cellular properties during different developmental stages can result in a range of possible CV values, with a narrow range for both neonatal and adult myocardium but a much wider range for an intermediate developmental stage. Thus, we find that developmental changes predict associated changes in cardiac conduction.
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Affiliation(s)
- Madison B Nowak
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States.,The Ohio State University Wexner Medical Center, Davis Heart and Lung Research Institute, Columbus, OH, United States
| | - Steven Poelzing
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.,Virginia Polytechnic Institute and State University, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - Seth H Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States.,The Ohio State University Wexner Medical Center, Davis Heart and Lung Research Institute, Columbus, OH, United States
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11
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Ai X, Yan J, Pogwizd SM. Serine-threonine protein phosphatase regulation of Cx43 dephosphorylation in arrhythmogenic disorders. Cell Signal 2021; 86:110070. [PMID: 34217833 PMCID: PMC8963383 DOI: 10.1016/j.cellsig.2021.110070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022]
Abstract
Regulation of cell-to-cell communication in the heart by the gap junction protein Connexin43 (Cx43) involves modulation of Cx43 phosphorylation state by protein kinases, and dephosphorylation by protein phosphatases. Dephosphorylation of Cx43 has been associated with impaired intercellular coupling and enhanced arrhythmogenesis in various pathologic states. While there has been extensive study of the protein kinases acting on Cx43, there has been limited studies of the protein phosphatases that may underlie Cx43 dephosphorylation. The focus of this review is to introduce serine-threonine protein phosphatase regulation of Cx43 phosphorylation state and cell-to-cell communication, and its impact on arrhythmogenesis in the setting of chronic heart failure and myocardial ischemia, as well as on atrial fibrillation. We also discuss the therapeutic potential of modulating protein phosphatases to treat arrhythmias in these clinical settings.
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Affiliation(s)
- Xun Ai
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Jiajie Yan
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Steven M Pogwizd
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.
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12
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Moise N, Struckman HL, Dagher C, Veeraraghavan R, Weinberg SH. Intercalated disk nanoscale structure regulates cardiac conduction. J Gen Physiol 2021; 153:212474. [PMID: 34264306 PMCID: PMC8287520 DOI: 10.1085/jgp.202112897] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/13/2021] [Accepted: 06/07/2021] [Indexed: 12/31/2022] Open
Abstract
The intercalated disk (ID) is a specialized subcellular region that provides electrical and mechanical connections between myocytes in the heart. The ID has a clearly defined passive role in cardiac tissue, transmitting mechanical forces and electrical currents between cells. Recent studies have shown that Na+ channels, the primary current responsible for cardiac excitation, are preferentially localized at the ID, particularly within nanodomains such as the gap junction-adjacent perinexus and mechanical junction-associated adhesion-excitability nodes, and that perturbations of ID structure alter cardiac conduction. This suggests that the ID may play an important, active role in regulating conduction. However, the structures of the ID and intercellular cleft are not well characterized and, to date, no models have incorporated the influence of ID structure on conduction in cardiac tissue. In this study, we developed an approach to generate realistic finite element model (FEM) meshes replicating nanoscale of the ID structure, based on experimental measurements from transmission electron microscopy images. We then integrated measurements of the intercellular cleft electrical conductivity, derived from the FEM meshes, into a novel cardiac tissue model formulation. FEM-based calculations predict that the distribution of cleft conductances is sensitive to regional changes in ID structure, specifically the intermembrane separation and gap junction distribution. Tissue-scale simulations predict that ID structural heterogeneity leads to significant spatial variation in electrical polarization within the intercellular cleft. Importantly, we found that this heterogeneous cleft polarization regulates conduction by desynchronizing the activation of postjunctional Na+ currents. Additionally, these heterogeneities lead to a weaker dependence of conduction velocity on gap junctional coupling, compared with prior modeling formulations that neglect or simplify ID structure. Further, we found that disruption of local ID nanodomains can either slow or enhance conduction, depending on gap junctional coupling strength. Our study therefore suggests that ID nanoscale structure can play a significant role in regulating cardiac conduction.
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Affiliation(s)
| | | | | | - Rengasayee Veeraraghavan
- The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Seth H Weinberg
- The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH
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13
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Zhao Y, Iyer S, Tavanaei M, Nguyen NT, Lin A, Nguyen TP. Proarrhythmic Electrical Remodeling by Noncardiomyocytes at Interfaces With Cardiomyocytes Under Oxidative Stress. Front Physiol 2021; 11:622613. [PMID: 33603677 PMCID: PMC7884825 DOI: 10.3389/fphys.2020.622613] [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: 10/29/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Life-threatening ventricular arrhythmias, typically arising from interfaces between fibrosis and surviving cardiomyocytes, are feared sequelae of structurally remodeled hearts under oxidative stress. Incomplete understanding of the proarrhythmic electrical remodeling by fibrosis limits the development of novel antiarrhythmic strategies. To define the mechanistic determinants of the proarrhythmia in electrical crosstalk between cardiomyocytes and noncardiomyocytes, we developed a novel in vitro model of interface between neonatal rat ventricular cardiomyocytes (NRVMs) and controls [NRVMs or connexin43 (Cx43)-deficient HeLa cells] vs. Cx43+ noncardiomyocytes [aged rat ventricular myofibroblasts (ARVFs) or HeLaCx43 cells]. We performed high-speed voltage-sensitive optical imaging at baseline and following acute H2O2 exposure. In NRVM-NRVM and NRVM-HeLa controls, no arrhythmias occurred under either experimental condition. In the NRVM-ARVF and NRVM-HeLaCx43 groups, Cx43+ noncardiomyocytes enabled passive decremental propagation of electrical impulses and impaired NRVM activation and repolarization, thereby slowing conduction and prolonging action potential duration. Following H2O2 exposure, arrhythmia triggers, automaticity, and non-reentrant and reentrant arrhythmias emerged. This study reveals that myofibroblasts (which generate cardiac fibrosis) and other noncardiomyocytes can induce not only structural remodeling but also electrical remodeling and that electrical remodeling by noncardiomyocytes can be particularly arrhythmogenic in the presence of an oxidative burst. Synergistic electrical remodeling between H2O2 and noncardiomyocytes may account for the clinical arrhythmogenicity of myofibroblasts at fibrotic interfaces with cardiomyocytes in ischemic/non-ischemic cardiomyopathies. Understanding the enhanced arrhythmogenicity of synergistic electrical remodeling by H2O2 and noncardiomyocytes may guide novel safe-by-design antiarrhythmic strategies for next-generation iatrogenic interfaces between surviving native cardiomyocytes and exogenous stem cells or engineered tissues in cardiac regenerative therapies.
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Affiliation(s)
- Yali Zhao
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Shankar Iyer
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Maryam Tavanaei
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Nicole T Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Andrew Lin
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Thao P Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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14
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Yu J, Cai P, Chen X. Structural Regulation of Myocytes in Engineered Healthy and Diseased Cardiac Models. ACS APPLIED BIO MATERIALS 2021; 4:267-276. [DOI: 10.1021/acsabm.0c01270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jing Yu
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Pingqiang Cai
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Xiaodong Chen
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
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15
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Gupta D, Santoso JW, McCain ML. Characterization of Gelatin Hydrogels Cross-Linked with Microbial Transglutaminase as Engineered Skeletal Muscle Substrates. Bioengineering (Basel) 2021; 8:bioengineering8010006. [PMID: 33418892 PMCID: PMC7825108 DOI: 10.3390/bioengineering8010006] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/18/2020] [Accepted: 12/30/2020] [Indexed: 12/12/2022] Open
Abstract
Engineered in vitro models of skeletal muscle are essential for efficiently screening drug safety and efficacy. However, conventional culture substrates poorly replicate physical features of native muscle and do not support long-term culture, which limits tissue maturity. Micromolded gelatin hydrogels cross-linked with microbial transglutaminase (gelatin-MTG hydrogels) have previously been shown to induce C21C2 myotube alignment and improve culture longevity. However, several properties of gelatin-MTG hydrogels have not been systematically characterized, such as changes in elastic modulus during incubation in culture-like conditions and their ability to support sarcomere maturation. In this study, various gelatin-MTG hydrogels were fabricated and incubated in ambient or culture-like conditions. Elastic modulus, mass, and transmittance were measured over a one- or two-week period. Compared to hydrogels in phosphate buffered saline (PBS) or ambient air, hydrogels in Dulbecco’s Modified Eagle Medium (DMEM) and 5% CO2 demonstrated the most stable elastic modulus. A subset of gelatin-MTG hydrogels was micromolded and seeded with C2C12 or primary chick myoblasts, which aligned and fused into multinucleated myotubes with relatively mature sarcomeres. These data are important for fabricating gelatin-MTG hydrogels with predictable and stable mechanical properties and highlight their advantages as culture substrates for engineering relatively mature and stable muscle tissues.
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Affiliation(s)
- Divya Gupta
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, 1042 Downey Way, DRB 140, Los Angeles, CA 90089, USA; (D.G.); (J.W.S.)
| | - Jeffrey W. Santoso
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, 1042 Downey Way, DRB 140, Los Angeles, CA 90089, USA; (D.G.); (J.W.S.)
| | - Megan L. McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, 1042 Downey Way, DRB 140, Los Angeles, CA 90089, USA; (D.G.); (J.W.S.)
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, 1975 Zonal Ave, Los Angeles, CA 90033, USA
- Correspondence:
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16
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Abstract
Organs-on-chips are broadly defined as microfabricated surfaces or devices designed to engineer cells into microscale tissues with native-like features and then extract physiologically relevant readouts at scale. Because they are generally compatible with patient-derived cells, these technologies can address many of the human relevance limitations of animal models. As a result, organs-on-chips have emerged as a promising new paradigm for patient-specific disease modeling and drug development. Because neuromuscular diseases span a broad range of rare conditions with diverse etiology and complex pathophysiology, they have been especially challenging to model in animals and thus are well suited for organ-on-chip approaches. In this Review, we first briefly summarize the challenges in neuromuscular disease modeling with animal models. Next, we describe a variety of existing organ-on-chip approaches for neuromuscular tissues, including a survey of cell sources for both muscle and nerve, and two- and three-dimensional neuromuscular tissue-engineering techniques. Although researchers have made tremendous advances in modeling neuromuscular diseases on a chip, the remaining challenges in cell sourcing, cell maturity, tissue assembly and readout capabilities limit their integration into the drug development pipeline today. However, as the field advances, models of healthy and diseased neuromuscular tissues on a chip, coupled with animal models, have vast potential as complementary tools for modeling multiple aspects of neuromuscular diseases and identifying new therapeutic strategies. Summary: Modeling neuromuscular diseases is challenging due to their complex etiology and pathophysiology. Here, we review the cell sources and tissue-engineering procedures that are being integrated as emerging neuromuscular disease models.
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Affiliation(s)
- Jeffrey W Santoso
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Megan L McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA .,Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA 90033, USA
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17
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Song C, Zhang X, Wang L, Wen F, Xu K, Xiong W, Li C, Li B, Wang Q, Xing MMQ, Qiu X. An Injectable Conductive Three-Dimensional Elastic Network by Tangled Surgical-Suture Spring for Heart Repair. ACS NANO 2019; 13:14122-14137. [PMID: 31774656 DOI: 10.1021/acsnano.9b06761] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Designing scaffolds with persistent elasticity and conductivity to mimic microenvironments becomes a feasible way to repair cardiac tissue. Injectable biomaterials for cardiac tissue engineering have demonstrated the ability to restore cardiac function by preventing ventricular dilation, enhancing angiogenesis, and improving conduction velocity. However, limitations are still among them, such as poor mechanical stability, low conductivity, and complicated procedure. Here, we developed thermal plastic poly(glycolic acid) surgical suture and mussel-inspired conductive particle's adhesion into a highly elastic, conductive spring-like coils. The polypyrrole (PPy)-coated biospring acted as an electrode and then was assembled into a solid-state supercapacitor. After being injected through a syringe needle (0.33 mm inner diameter), the tangled coils formed an elastically conductive three-dimensional (3-D) network to modulate cardiac function. We found that cardiomyocytes (CMs) grew along the spring coils' track with elongated morphologies and formed highly oriented sarcomeres. The biospring enhanced the CMs' maturation in synchronous contraction accompanied by high expressions of cardiac-specific proteins, α-actinin, and connexin 43 (cx43). After the elastic, conductive biosprings were injected into the myocardial infarction (MI) area, the left ventricular fractional shortening was improved by about 12.6% and the infarct size was decreased by about 34%. Interestingly, the spring can be utilized as a sensor to measure the CMs' contractile force, which was 1.57 × 10-3 ± 0.26 × 10-3 mN (∼4.1 × 106 cells). Accordingly, this study highlights an injectable biospring to form a tangled conductive 3-D network in vivo for MI repair.
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Affiliation(s)
- Chen Song
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
- Department of Mechanical Engineering, Faculty of Engineering, Department of Biochemistry and Biomedical Genetics, Faculty of Medicine , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Xingying Zhang
- Department of Mechanical Engineering, Faculty of Engineering, Department of Biochemistry and Biomedical Genetics, Faculty of Medicine , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Leyu Wang
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
| | - Feng Wen
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
| | - Kaige Xu
- Department of Mechanical Engineering, Faculty of Engineering, Department of Biochemistry and Biomedical Genetics, Faculty of Medicine , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Weirong Xiong
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
| | - Chuangkun Li
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
| | - Bingyun Li
- Department of Orthopedics, School of Medicine , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Quan Wang
- Department of Civil and Environmental Engineering , Shantou University , Shantou , Guangdong 515063 , China
| | - Malcolm M Q Xing
- Department of Mechanical Engineering, Faculty of Engineering, Department of Biochemistry and Biomedical Genetics, Faculty of Medicine , University of Manitoba , Winnipeg , Manitoba R3T 2N2 , Canada
| | - Xiaozhong Qiu
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, School of Basic Medical Science; Biomaterials Research Center, School of Biomedical Engineering , Southern Medical University , Guangzhou , Guangdong 510515 , China
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18
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Large scale and integrated platform for digital mass culture of anchorage dependent cells. Nat Commun 2019; 10:4824. [PMID: 31645567 PMCID: PMC6811641 DOI: 10.1038/s41467-019-12777-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/26/2019] [Indexed: 01/17/2023] Open
Abstract
Industrial applications of anchorage-dependent cells require large-scale cell culture with multifunctional monitoring of culture conditions and control of cell behaviour. Here, we introduce a large-scale, integrated, and smart cell-culture platform (LISCCP) that facilitates digital mass culture of anchorage-dependent cells. LISCCP is devised through large-scale integration of ultrathin sensors and stimulator arrays in multiple layers. LISCCP provides real-time, 3D, and multimodal monitoring and localized control of the cultured cells, which thereby allows minimizing operation labour and maximizing cell culture performance. Wireless integration of multiple LISCCPs across multiple incubators further amplifies the culture scale and enables digital monitoring and local control of numerous culture layers, making the large-scale culture more efficient. Thus, LISCCP can transform conventional labour-intensive and high-cost cell cultures into efficient digital mass cell cultures. This platform could be useful for industrial applications of cell cultures such as in vitro toxicity testing of drugs and cosmetics and clinical scale production of cells for cell therapy. Large scale culture of adherent cells would benefit from a platform for continuous monitoring and control of cell growth and culture conditions. Here the authors develop an integrated, smart cell culture platform where cells are grown on multiple layers of thin sensors that can be wirelessly integrated across several incubators.
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19
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Eweje F, Ardoña HAM, Zimmerman JF, O'Connor BB, Ahn S, Grevesse T, Rivera KN, Bitounis D, Demokritou P, Parker KK. Quantifying the effects of engineered nanomaterials on endothelial cell architecture and vascular barrier integrity using a cell pair model. NANOSCALE 2019; 11:17878-17893. [PMID: 31553035 PMCID: PMC6779057 DOI: 10.1039/c9nr04981a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Engineered nanomaterials (ENMs) are increasingly used in consumer products due to their unique physicochemical properties, but the specific hazards they pose to the structural and functional integrity of endothelial barriers remain elusive. When assessing the effects of ENMs on vascular barrier function, endothelial cell monolayers are commonly used as in vitro models. Monolayer models, however, do not offer a granular understanding of how the structure-function relationships between endothelial cells and tissues are disrupted due to ENM exposure. To address this issue, we developed a micropatterned endothelial cell pair model to quantitatively evaluate the effects of 10 ENMs (8 metal/metal oxides and 2 organic ENMs) on multiple cellular parameters and determine how these parameters correlate to changes in vascular barrier function. This minimalistic approach showed concerted changes in endothelial cell morphology, intercellular junction formation, and cytoskeletal organization due to ENM exposure, which were then quantified and compared to unexposed pairs using a "similarity scoring" method. Using the cell pair model, this study revealed dose-dependent changes in actin organization and adherens junction formation following exposure to representative ENMs (Ag, TiO2 and cellulose nanocrystals), which exhibited trends that correlate with changes in tissue permeability measured using an endothelial monolayer assay. Together, these results demonstrate that we can quantitatively evaluate changes in endothelial architecture emergent from nucleo-cytoskeletal network remodeling using micropatterned cell pairs. The endothelial pair model therefore presents potential applicability as a standardized assay for systematically screening ENMs and other test agents for their cellular-level structural effects on vascular barriers.
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Affiliation(s)
- Feyisayo Eweje
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
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20
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Rubart M, Tao W, Lu XL, Conway SJ, Reuter SP, Lin SF, Soonpaa MH. Electrical coupling between ventricular myocytes and myofibroblasts in the infarcted mouse heart. Cardiovasc Res 2019; 114:389-400. [PMID: 29016731 DOI: 10.1093/cvr/cvx163] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/10/2017] [Indexed: 12/20/2022] Open
Abstract
Aims Recent studies have demonstrated electrotonic coupling between scar tissue and the surrounding myocardium in cryoinjured hearts. However, the electrical dynamics occurring at the myocyte-nonmyocyte interface in the fibrotic heart remain undefined. Here, we sought to develop an assay to interrogate the nonmyocyte cell type contributing to heterocellular coupling and to characterize, on a cellular scale, its voltage response in the infarct border zone of living hearts. Methods and results We used two-photon laser scanning microscopy in conjunction with a voltage-sensitive dye to record transmembrane voltage changes simultaneously from cardiomyocytes and adjoined nonmyocytes in Langendorff-perfused mouse hearts with healing myocardial infarction. Transgenic mice with cardiomyocyte-restricted expression of a green fluorescent reporter protein underwent permanent coronary artery ligation and their hearts were subjected to voltage imaging 7-10 days later. Reporter-negative cells, i.e. nonmyocytes, in the infarct border zone exhibited depolarizing transients at a 1:1 coupling ratio with action potentials recorded simultaneously from adjacent, reporter-positive ventricular myocytes. The electrotonic responses in the nonmyocytes exhibited slower rates of de- and repolarization compared to the action potential waveform of juxtaposed myocytes. Voltage imaging in infarcted hearts expressing a fluorescent reporter specifically in myofibroblasts revealed that the latter were electrically coupled to border zone myocytes. Their voltage transient properties were indistinguishable from those of nonmyocytes in hearts with cardiomyocyte-restricted reporter expression. The density of connexin43 expression at myofibroblast-cardiomyocyte junctions was ∼5% of that in the intercalated disc regions of paired ventricular myocytes in the remote, uninjured myocardium, whereas the ratio of connexin45 to connexin43 expression levels at heterocellular contacts was ∼1%. Conclusion Myofibroblasts contribute to the population of electrically coupled nonmyocytes in the infarct border zone. The slower kinetics of myofibroblast voltage responses may reflect low electrical conductivity across heterocellular junctions, in accordance with the paucity of connexin expression at myofibroblast-cardiomyocyte contacts.
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Affiliation(s)
- Michael Rubart
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
| | - Wen Tao
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
| | - Xiao-Long Lu
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
| | - Simon J Conway
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
| | - Sean P Reuter
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
| | - Shien-Fong Lin
- Institute of Biomedical Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Mark H Soonpaa
- Wells Centre for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA.,Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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21
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Ariyasinghe NR, Lyra-Leite DM, McCain ML. Engineering cardiac microphysiological systems to model pathological extracellular matrix remodeling. Am J Physiol Heart Circ Physiol 2018; 315:H771-H789. [PMID: 29906229 PMCID: PMC6230901 DOI: 10.1152/ajpheart.00110.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/27/2018] [Accepted: 06/08/2018] [Indexed: 12/11/2022]
Abstract
Many cardiovascular diseases are associated with pathological remodeling of the extracellular matrix (ECM) in the myocardium. ECM remodeling is a complex, multifactorial process that often contributes to declines in myocardial function and progression toward heart failure. However, the direct effects of the many forms of ECM remodeling on myocardial cell and tissue function remain elusive, in part because conventional model systems used to investigate these relationships lack robust experimental control over the ECM. To address these shortcomings, microphysiological systems are now being developed and implemented to establish direct relationships between distinct features in the ECM and myocardial function with unprecedented control and resolution in vitro. In this review, we will first highlight the most prominent characteristics of ECM remodeling in cardiovascular disease and describe how these features can be mimicked with synthetic and natural biomaterials that offer independent control over multiple ECM-related parameters, such as rigidity and composition. We will then detail innovative microfabrication techniques that enable precise regulation of cellular architecture in two and three dimensions. We will also describe new approaches for quantifying multiple aspects of myocardial function in vitro, such as contractility, action potential propagation, and metabolism. Together, these collective technologies implemented as cardiac microphysiological systems will continue to uncover important relationships between pathological ECM remodeling and myocardial cell and tissue function, leading to new fundamental insights into cardiovascular disease, improved human disease models, and novel therapeutic approaches.
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Affiliation(s)
- Nethika R Ariyasinghe
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California , Los Angeles, California
| | - Davi M Lyra-Leite
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California , Los Angeles, California
| | - Megan L McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California , Los Angeles, California
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California
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22
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Barbiero S, Aimo A, Castiglione V, Giannoni A, Vergaro G, Passino C, Emdin M. Healthy hearts at hectic pace: From daily life stress to abnormal cardiomyocyte function and arrhythmias. Eur J Prev Cardiol 2018; 25:1419-1430. [PMID: 30052067 DOI: 10.1177/2047487318790614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The hectic pace of contemporary life is a major source of acute and chronic stress, which may have a deleterious impact on body health . In the field of cardiovascular disease, acute emotional stress has been associated with coronary spasm and Takotsubo cardiomyopathy, whereas the manifestations of chronic stress have been overlooked, and most underlying pathophysiology remains to be elucidated. Chronic stress affects the neuronal circuitry composed of cortico-limbic structures and the nuclei regulating autonomic function, eliciting a sympatho-vagal imbalance, characterised by adrenergic activation and vagal withdrawal. Sympathetic terminals are connected to cardiomyocytes in a quasi-synaptic way, producing the so called 'neuro-cardiac junction'. During chronic stress, norepinephrine release is increased, leading to overstimulation of cardiomyocytes via β1-adrenergic receptors, influencing mainly calcium dynamics, and β2-adrenergic receptors, which control housekeeping functions. The circadian rhythm of cardiomyocytes is then impaired, with elongation of the catabolic ('light' phase) over the anabolic ('nocturnal') phase. This leads to a depletion of cell energy storage, and a decreased turnover of cell constituents. Even cell interactions are affected, as coupling between cardiomyocytes decreases while coupling between cardiomyocytes and fibroblasts increases. The ultimate results are changes in the shape and velocity of action potential, fibroblast activation and deposition of extracellular matrix. These alterations may predispose to arrhythmias and may favour the development of a stress-related cardiomyopathy. A better comprehension of this cascade of events may allow us to identify screening protocols and treatment strategies (meditation, yoga, physical activity, psychological assistance, β-blockers) to prevent or relieve ongoing cardiac damage.
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Affiliation(s)
- Silvia Barbiero
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy
| | - Alberto Aimo
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,2 Cardiology Division, University Hospital of Pisa, Italy
| | | | - Alberto Giannoni
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Giuseppe Vergaro
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Claudio Passino
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
| | - Michele Emdin
- 1 Institute of Life Sciences, Scuola Superiore Sant'Anna, Italy.,3 Cardiology Division, Fondazione Toscana Gabriele Monasterio, Italy
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Microenvironmental Modulation of Calcium Wave Propagation Velocity in Engineered Cardiac Tissues. Cell Mol Bioeng 2018; 11:337-352. [PMID: 31719889 DOI: 10.1007/s12195-018-0522-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022] Open
Abstract
Introduction In the myocardium, rapid propagation of action potentials and subsequent calcium waves is critical for synchronizing the contraction of cardiac myocytes and maximizing cardiac output. In many pathological settings, diverse remodeling of the tissue microenvironment is correlated with arrhythmias and decreased cardiac output, but the precise impact of tissue remodeling on propagation is not completely understood. Our objective was to delineate how multiple features within the cardiac tissue microenvironment modulate propagation velocity. Methods To recapitulate diverse myocardial tissue microenvironments, we engineered substrates with tunable elasticity, patterning, composition, and topography using two formulations of polydimethylsiloxane (PDMS) micropatterned with fibronectin and gelatin hydrogels with flat or micromolded features. We cultured neonatal rat ventricular myocytes on these substrates and quantified cell density, tissue alignment, and cell shape. We used a fluorescent calcium indicator, high-speed microscopy, and newly-developed analysis software to record and quantify calcium wave propagation velocity (CPV). Results For all substrates, tissue alignment and cell aspect ratio were higher in aligned compared to isotropic tissues. Isotropic CPV and longitudinal CPV were similar across conditions, but transverse CPV was lower on micromolded gelatin hydrogels compared to micropatterned soft and stiff PDMS. In aligned tissues, the anisotropy ratio of CPV (longitudinal CPV/transverse CPV) was lower on micropatterned soft PDMS compared to micropatterned stiff PDMS and micromolded gelatin hydrogels. Conclusion Propagation velocity in engineered cardiac tissues is sensitive to features in the tissue microenvironment, such as alignment, matrix elasticity, and matrix topography, which may underlie arrhythmias in conditions with pathological tissue remodeling.
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Braun CK, Kalbitz M, Halbgebauer R, Eisele P, Messerer DAC, Weckbach S, Schultze A, Braumüller S, Gebhard F, Huber-Lang MS. Early structural changes of the heart after experimental polytrauma and hemorrhagic shock. PLoS One 2017; 12:e0187327. [PMID: 29084268 PMCID: PMC5662170 DOI: 10.1371/journal.pone.0187327] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/17/2017] [Indexed: 02/07/2023] Open
Abstract
Evidence is emerging that systemic inflammation after trauma drives structural and functional impairment of cardiomyocytes and leads to cardiac dysfunction, thus worsening the outcome of polytrauma patients. This study investigates the structural and molecular changes in heart tissue 4 h after multiple injuries with additional hemorrhagic shock using a clinically relevant rodent model of polytrauma. We determined mediators of systemic inflammation (keratinocyte chemoattractant, macrophage chemotactic protein 1), activated complement component C3a and cardiac troponin I in plasma and assessed histological specimen of the mouse heart via standard histomorphology and immunohistochemistry for cellular and subcellular damage and ongoing apoptosis. Further we investigated spatial and quantitative changes of connexin 43 by immunohistochemistry and western blotting. Our results show significantly increased plasma levels of both keratinocyte chemoattractant and cardiac troponin I 4 h after polytrauma and 2 h after induction of hypovolemia. Although we could not detect any morphological changes, immunohistochemical evaluation showed increased level of tissue high-mobility group box 1, which is both a damage-associated molecule and actively released as a danger response signal. Additionally, there was marked lateralization of the cardiac gap-junction protein connexin 43 following combined polytrauma and hemorrhagic shock. These results demonstrate a molecular manifestation of remote injury of cardiac muscle cells in the early phase after polytrauma and hemorrhagic shock with marked disruption of the cardiac gap junction. This disruption of an important component of the electrical conduction system of the heart may lead to arrhythmia and consequently to cardiac dysfunction.
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Affiliation(s)
- Christian K. Braun
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Miriam Kalbitz
- Department of Orthopedic Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Ulm, Ulm, Germany
| | - Rebecca Halbgebauer
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Philipp Eisele
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - David A. C. Messerer
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Sebastian Weckbach
- Department of Orthopedic Surgery, University Hospital of Ulm, Ulm, Germany
| | - Anke Schultze
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Sonja Braumüller
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Florian Gebhard
- Department of Orthopedic Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Ulm, Ulm, Germany
| | - Markus S. Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
- * E-mail:
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25
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Gui YJ, Yang T, Liu Q, Liao CX, Chen JY, Wang YT, Hu JH, Xu DY. Soluble epoxide hydrolase inhibitors, t-AUCB, regulated microRNA-1 and its target genes in myocardial infarction mice. Oncotarget 2017; 8:94635-94649. [PMID: 29212255 PMCID: PMC5706901 DOI: 10.18632/oncotarget.21831] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/20/2017] [Indexed: 02/04/2023] Open
Abstract
Purpose Soluble epoxide hydrolase inhibitors (sEHIs) had been demonstrated to produce cardioprotective effects against ischemia-induced lethal arrhythmias, but the exact mechanisms remain unknown. The present study was designed to investigate whether the beneficial effects of sEHIs are related to regulation of microRNA-1, which was a proarrhythmic factor in the ischemic heart. Methods A mousemyocardial infarction (MI) model was established by ligating the coronary artery. sEHI t-AUCB (0.2, 1, 5 mg/L in drinking-water) was administered daily seven days before MI. The incidence of arrhythmias was assessed by in vivo electrophysiologic studies. miR-1, KCNJ2 (encoding the K+ channel subunit Kir2.1), and GJA1 (encoding connexin 43 [Cx43]) mRNA were measured by real-time PCR; Kir2.1 and Cx43 protein were assessed by western blotting and immunohistochemistry. Results We demonstrated that sEHIs reduced the myocardium infarct size and incidence of inducible arrhythmias in MI mice. Up-regulation of miR-1 and down-regulation of KCNJ2/Kir2.1 and GJA1/Cx43 mRNA/protein were observed in ischemic myocaridum, whereas administration of sEHIs produced an opposite effect. In addition, miR-1 overexpression inhibited expression of the target mRNA and their corresponding proteins, whereas t-AUCB reversed the effects. Our results further revealed that PI3K/Akt signaling pathway might participate in the negatively regulation of miR-1 by sEHi. Conclusions We conclude that sEHIs can repress miR-1, thus stimulate expression of KCNJ2/Kir2.1 and GJA1/Cx43 mRNA/protein in MI mice, suggesting a possible mechanism for its potential therapeutic application in ischemic arrhythmias.
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Affiliation(s)
- Ya-Jun Gui
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Tao Yang
- Department of Cardiology, Internal Medicine, Changsha Central Hospital, Changsha, Hunan 410011, China
| | - Qiong Liu
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Cai-Xiu Liao
- Department of Geratology, Internal Medicine, The Third Hospital of Changsha, Changsha, Hunan 410011, China
| | - Jing-Yuan Chen
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Ya-Ting Wang
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Jia-Hui Hu
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Dan-Yan Xu
- Department of Cardiology, Internal Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
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26
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Basheer WA, Xiao S, Epifantseva I, Fu Y, Kleber AG, Hong T, Shaw RM. GJA1-20k Arranges Actin to Guide Cx43 Delivery to Cardiac Intercalated Discs. Circ Res 2017; 121:1069-1080. [PMID: 28923791 DOI: 10.1161/circresaha.117.311955] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 01/21/2023]
Abstract
RATIONALE Delivery of Cx43 (connexin 43) to the intercalated disc is a continuous and rapid process critical for intercellular coupling. By a pathway of targeted delivery involving microtubule highways, vesicles of Cx43 hemichannels are efficiently trafficked to adherens junctions at intercalated discs. It has also been identified that actin provides rest stops for Cx43 forward trafficking and that Cx43 has a 20 kDa internally translated small C terminus isoform, GJA1-20k (Gap Junction Protein Alpha 1- 20 kDa), which is required for full-length Cx43 trafficking, but by an unknown mechanism. OBJECTIVE We explored the mechanism by which the GJA1-20k isoform is required for full-length Cx43 forward trafficking to intercalated discs. METHODS AND RESULTS Using an in vivo Adeno-associated virus serotype 9-mediated gene transfer system, we confirmed in whole animal that GJA1-20k markedly increases endogenous myocardial Cx43 gap junction plaque size at the intercalated discs. In micropatterned cell pairing systems, we found that exogenous GJA1-20k expression stabilizes filamentous actin without affecting actin protein expression and that GJA1-20k complexes with both actin and tubulin. We also found that filamentous actin regulates microtubule organization as inhibition of actin polymerization with a low dose of latrunculin A disrupts the targeting of microtubules to cell-cell junctions. GJA1-20k protects actin filament from latrunculin A disruption, preserving microtubule trajectory to the cell-cell border. For therapeutic implications, we found that prior in vivo Adeno-associated virus serotype 9-mediated gene delivery of GJA1-20k to the heart protects Cx43 localization to the intercalated discs against acute ischemic injury. CONCLUSIONS The internally translated GJA1-20k isoform stabilizes actin filaments, which guides growth trajectories of the Cx43 microtubule trafficking machinery, increasing delivery of Cx43 hemichannels to cardiac intercalated discs. Exogenous GJA1-20k helps to maintain cell-cell coupling in instances of anticipated myocardial ischemia.
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Affiliation(s)
- Wassim A Basheer
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - Shaohua Xiao
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - Irina Epifantseva
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - Ying Fu
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - Andre G Kleber
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - TingTing Hong
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.)
| | - Robin M Shaw
- From the Cedars-Sinai Heart Institute (W.A.B., S.X., I.E., Y.F., T.H., R.M.S.) and Department of Medicine (T.H., R.M.S.), Cedars-Sinai Medical Center and UCLA, Los Angeles, CA; and Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.G.K.).
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27
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Hood AR, Ai X, Pogwizd SM. Regulation of cardiac gap junctions by protein phosphatases. J Mol Cell Cardiol 2017; 107:52-57. [PMID: 28478048 DOI: 10.1016/j.yjmcc.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/13/2017] [Accepted: 05/02/2017] [Indexed: 01/16/2023]
Abstract
Sufficient connexin-mediated intercellular coupling is critical to maintain gap junctional communication for proper cardiac function. Alterations in connexin phosphorylation state, particularly dephosphorylation of connexin 43 (Cx43), may impact cell coupling and conduction in disease states. Cx43 dephosphorylation may be carried out by protein phosphatase activity. Here, we present an overview of the key phosphatases known to interact with Cx43 or modulators of Cx43, as well as some possible therapeutic targets to regulate phosphatase activity in the heart.
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Affiliation(s)
- Ashleigh R Hood
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Xun Ai
- Department of Biophysics and Physiology, Rush University, Chicago, IL, United States
| | - Steven M Pogwizd
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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28
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Desplantez T. Cardiac Cx43, Cx40 and Cx45 co-assembling: involvement of connexins epitopes in formation of hemichannels and Gap junction channels. BMC Cell Biol 2017; 18:3. [PMID: 28124623 PMCID: PMC5267329 DOI: 10.1186/s12860-016-0118-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background This review comes after the International Gap Junction Conference (IGJC 2015) and describes the current knowledge on the function of the specific motifs of connexins in the regulation of the formation of gap junction channels. Moreover the review is complemented by a summarized description of the distinct contribution of gap junction channels in the electrical coupling. Results Complementary biochemical and functional characterization on cell models and primary cells have improved our understanding on the oligomerization of connexins and the formation and the electrical properties of gap junction channels. Studies mostly focused cardiac connexins Cx43 and Cx40 expressed in myocytes, while Cx45 and Cx30.2 have been less investigated, for which main findings are reviewed to highlight their critical contribution in the formation of gap junction channels for ensuring the orchestrated electrical impulse propagation and coordination of atrial and ventricular contraction and heart function, whereas connexin dysfunction and remodeling are pro-arrhythmic factors. Common and specific motifs of residues identified in different domain of each type of connexin determine the connexin homo- and hetero-oligomerization and the channels formation, which leads to specific electrical properties. Conclusions These motifs and the resulting formation of gap junction channels are keys to ensure the tissue homeostasis and function in each connexin expression pattern in various tissues of multicellular organisms. Altogether, the findings to date have significantly improved our understanding on the function of the different connexin expression patterns in healthy and diseased tissues, and promise further investigations on the contribution in the different types of connexin.
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Affiliation(s)
- Thomas Desplantez
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Campus X. Arnozan, Avenue Haut Leveque, 33600, Pessac- Bordeaux, France. .,Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France. .,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
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29
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Wei N, Mori Y, Tolkacheva EG. The dual effect of ephaptic coupling on cardiac conduction with heterogeneous expression of connexin 43. J Theor Biol 2016; 397:103-14. [PMID: 26968493 DOI: 10.1016/j.jtbi.2016.02.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/25/2016] [Accepted: 02/19/2016] [Indexed: 11/30/2022]
Abstract
Decreased and heterogeneous expression of connexin 43 (Cx43) are common features in animal heart failure models. Ephpatic coupling, which relies on the presence of junctional cleft space between the ends of adjacent cells, has been suggested to play a more active role in mediating intercellular electrical communication when gap junctions are reduced. To better understand the interplay of Cx43 expression and ephaptic coupling on cardiac conduction during heart failure, we performed numerical simulations on our model when Cx43 expression is reduced and heterogeneous. Under severely reduced Cx43 expression, we identified three new phenomena in the presence of ephaptic coupling: alternating conduction, in which ephaptic and gap junction-mediated mechanisms alternate; instability of planar fronts; and small amplitude action potential (SAP), which has a smaller potential amplitude than the normal action potential. In the presence of heterogeneous Cx43 expression, ephaptic coupling can either prevent or promote conduction block (CB) depending on the Cx43 knockout (Cx43KO) content. When Cx43KO content is relatively high, ephaptic coupling reduces the probabilities of CB. However, ephaptic coupling promotes CB when Cx43KO and wild type cells are mixed in roughly equal proportion, which can be attributed to an increase in current-to-load mismatch.
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Affiliation(s)
- Ning Wei
- School of Mathematics, University of Minnesota, 206 Church St. SE, Minneapolis, MN 55455, United States
| | - Yoichiro Mori
- School of Mathematics, University of Minnesota, 206 Church St. SE, Minneapolis, MN 55455, United States
| | - Elena G Tolkacheva
- Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, 6-128 Nils Hasselmo Hall, Minneapolis, MN 55455, United States.
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30
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Aratyn-Schaus Y, Pasqualini FS, Yuan H, McCain ML, Ye GJC, Sheehy SP, Campbell PH, Parker KK. Coupling primary and stem cell-derived cardiomyocytes in an in vitro model of cardiac cell therapy. J Cell Biol 2016; 212:389-97. [PMID: 26858266 PMCID: PMC4754718 DOI: 10.1083/jcb.201508026] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 01/15/2016] [Indexed: 12/22/2022] Open
Abstract
Coupling of stronger primary and weaker stem cell–derived cardiomyocytes results in junctional substrate adhesions that maintain structural integrity but impair force transmission and this may contribute to the limited efficacy of cell therapy in vivo. The efficacy of cardiac cell therapy depends on the integration of existing and newly formed cardiomyocytes. Here, we developed a minimal in vitro model of this interface by engineering two cell microtissues (μtissues) containing mouse cardiomyocytes, representing spared myocardium after injury, and cardiomyocytes generated from embryonic and induced pluripotent stem cells, to model newly formed cells. We demonstrated that weaker stem cell–derived myocytes coupled with stronger myocytes to support synchronous contraction, but this arrangement required focal adhesion-like structures near the cell–cell junction that degrade force transmission between cells. Moreover, we developed a computational model of μtissue mechanics to demonstrate that a reduction in isometric tension is sufficient to impair force transmission across the cell–cell boundary. Together, our in vitro and in silico results suggest that mechanotransductive mechanisms may contribute to the modest functional benefits observed in cell-therapy studies by regulating the amount of contractile force effectively transmitted at the junction between newly formed and spared myocytes.
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Affiliation(s)
- Yvonne Aratyn-Schaus
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Francesco S Pasqualini
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Hongyan Yuan
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Megan L McCain
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - George J C Ye
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Sean P Sheehy
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Patrick H Campbell
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
| | - Kevin Kit Parker
- Disease Biophysics Group, Wyss Institute of Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
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31
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Capulli AK, MacQueen LA, Sheehy SP, Parker KK. Fibrous scaffolds for building hearts and heart parts. Adv Drug Deliv Rev 2016; 96:83-102. [PMID: 26656602 PMCID: PMC4807693 DOI: 10.1016/j.addr.2015.11.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Extracellular matrix (ECM) structure and biochemistry provide cell-instructive cues that promote and regulate tissue growth, function, and repair. From a structural perspective, the ECM is a scaffold that guides the self-assembly of cells into distinct functional tissues. The ECM promotes the interaction between individual cells and between different cell types, and increases the strength and resilience of the tissue in mechanically dynamic environments. From a biochemical perspective, factors regulating cell-ECM adhesion have been described and diverse aspects of cell-ECM interactions in health and disease continue to be clarified. Natural ECMs therefore provide excellent design rules for tissue engineering scaffolds. The design of regenerative three-dimensional (3D) engineered scaffolds is informed by the target ECM structure, chemistry, and mechanics, to encourage cell infiltration and tissue genesis. This can be achieved using nanofibrous scaffolds composed of polymers that simultaneously recapitulate 3D ECM architecture, high-fidelity nanoscale topography, and bio-activity. Their high porosity, structural anisotropy, and bio-activity present unique advantages for engineering 3D anisotropic tissues. Here, we use the heart as a case study and examine the potential of ECM-inspired nanofibrous scaffolds for cardiac tissue engineering. We asked: Do we know enough to build a heart? To answer this question, we tabulated structural and functional properties of myocardial and valvular tissues for use as design criteria, reviewed nanofiber manufacturing platforms and assessed their capabilities to produce scaffolds that meet our design criteria. Our knowledge of the anatomy and physiology of the heart, as well as our ability to create synthetic ECM scaffolds have advanced to the point that valve replacement with nanofibrous scaffolds may be achieved in the short term, while myocardial repair requires further study in vitro and in vivo.
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Affiliation(s)
- A K Capulli
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - L A MacQueen
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Sean P Sheehy
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K K Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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Fridman MD, Liu J, Sun Y, Hamilton RM. Microinjection Technique for Assessment of Gap Junction Function. Methods Mol Biol 2016; 1437:145-154. [PMID: 27207292 DOI: 10.1007/978-1-4939-3664-9_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Gap junctions are essential for the proper function of many native mammalian tissues including neurons, cardiomyocytes, embryonic tissues, and muscle. Assessing these channels is therefore fundamental to understanding disease pathophysiology, developing therapies for a multitude of acquired and genetic conditions, and providing novel approaches to drug delivery and cellular communication. Microinjection is a robust, albeit difficult, technique, which provides considerable information that is superior to many of the simpler techniques due to its ability to isolate cells, quantify kinetics, and allow cross-comparison of multiple cell lines. Despite its user-dependent nature, the strengths of the technique are considerable and with the advent of new, automation technologies may improve further. This text describes the basic technique of microinjection and briefly discusses modern automation advances that can improve the success rates of this technique.
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Affiliation(s)
- Michael D Fridman
- Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Jun Liu
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Robert M Hamilton
- Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, ON, Canada.
- Department of Pediatrics - Division of Cardiology, Hospital for Sick Children, Toronto, ON, Canada.
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33
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Relating specific connexin co-expression ratio to connexon composition and gap junction function. J Mol Cell Cardiol 2015; 89:195-202. [PMID: 26550940 DOI: 10.1016/j.yjmcc.2015.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 10/05/2015] [Accepted: 11/04/2015] [Indexed: 12/15/2022]
Abstract
Cardiac connexin 43 (Cx43), Cx40 and Cx45 are co-expressed at distinct ratios in myocytes. This pattern is considered a key factor in regulating the gap junction channels composition, properties and function and remains poorly understood. This work aims to correlate gap junction function with the connexin composition of the channels at accurate ratios Cx43:Cx40 and Cx43:Cx45. Rat liver epithelial cells that endogenously express Cx43 were stably transfected to induce expression of accurate levels of Cx40 or Cx45 that may be present in various areas of the heart (e.g. atria and ventricular conduction system). Induction of Cx40 does not increase the amounts of junctional connexins (Cx43 and Cx40), whereas induction of Cx45 increases the amounts of junctional connexins (Cx43 and Cx45). Interestingly, the non-junctional fraction of Cx43 remains unaffected upon induction of Cx40 and Cx45. Co-immunoprecipitation studies show low level of Cx40/Cx43 heteromerisation and undetectable Cx45/Cx43 heteromerisation. Functional characterisation shows that induction of Cx40 and Cx45 decreases Lucifer Yellow transfer. Electrical coupling is decreased by Cx45 induction, whereas it is decreased at low induction of Cx40 and increased at high induction. These data indicate a fine regulation of the gap junction channel make-up in function of the type and the ratio of co-expressed Cxs that specifically regulates chemical and electrical coupling. This reflects specific gap junction function in regulating impulse propagation in the healthy heart, and a pro-arrhythmic potential of connexin remodelling in the diseased heart.
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Kucera JP, Prudat Y, Marcu IC, Azzarito M, Ullrich ND. Slow conduction in mixed cultured strands of primary ventricular cells and stem cell-derived cardiomyocytes. Front Cell Dev Biol 2015; 3:58. [PMID: 26442264 PMCID: PMC4585316 DOI: 10.3389/fcell.2015.00058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/09/2015] [Indexed: 11/30/2022] Open
Abstract
Modern concepts for the treatment of myocardial diseases focus on novel cell therapeutic strategies involving stem cell-derived cardiomyocytes (SCMs). However, functional integration of SCMs requires similar electrophysiological properties as primary cardiomyocytes (PCMs) and the ability to establish intercellular connections with host myocytes in order to contribute to the electrical and mechanical activity of the heart. The aim of this project was to investigate the properties of cardiac conduction in a co-culture approach using SCMs and PCMs in cultured cell strands. Murine embryonic SCMs were pooled with fetal ventricular cells and seeded in predefined proportions on microelectrode arrays to form patterned strands of mixed cells. Conduction velocity (CV) was measured during steady state pacing. SCM excitability was estimated from action potentials measured in single cells using the patch clamp technique. Experiments were complemented with computer simulations of conduction using a detailed model of cellular architecture in mixed cell strands. CV was significantly lower in strands composed purely of SCMs (5.5 ± 1.5 cm/s, n = 11) as compared to PCMs (34.9 ± 2.9 cm/s, n = 21) at similar refractoriness (100% SCMs: 122 ± 25 ms, n = 9; 100% PCMs: 139 ± 67 ms, n = 14). In mixed strands combining both cell types, CV was higher than in pure SCMs strands, but always lower than in 100% PCM strands. Computer simulations demonstrated that both intercellular coupling and electrical excitability limit CV. These data provide evidence that in cultures of murine ventricular cardiomyocytes, SCMs cannot restore CV to control levels resulting in slow conduction, which may lead to reentry circuits and arrhythmias.
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Affiliation(s)
- Jan P Kucera
- Department of Physiology, University of Bern Bern, Switzerland
| | - Yann Prudat
- Department of Physiology, University of Bern Bern, Switzerland
| | - Irene C Marcu
- Department of Physiology, University of Bern Bern, Switzerland ; Department of Physiology and Pathophysiology, Heidelberg University Heidelberg, Germany
| | | | - Nina D Ullrich
- Department of Physiology and Pathophysiology, Heidelberg University Heidelberg, Germany
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Marcu IC, Illaste A, Heuking P, Jaconi ME, Ullrich ND. Functional Characterization and Comparison of Intercellular Communication in Stem Cell-Derived Cardiomyocytes. Stem Cells 2015; 33:2208-18. [PMID: 25968594 DOI: 10.1002/stem.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/08/2015] [Indexed: 02/05/2023]
Abstract
One novel treatment strategy for the diseased heart focuses on the use of pluripotent stem cell-derived cardiomyocytes (SC-CMs) to overcome the heart's innate deficiency for self-repair. However, targeted application of SC-CMs requires in-depth characterization of their true cardiogenic potential in terms of excitability and intercellular coupling at cellular level and in multicellular preparations. In this study, we elucidated the electrical characteristics of single SC-CMs and intercellular coupling quality of cell pairs, and concomitantly compared them with well-characterized murine native neonatal and immortalized HL-1 cardiomyocytes. Firstly, we investigated the electrical properties and Ca(2+) signaling mechanisms specific to cardiac contraction in single SC-CMs. Despite heterogeneity of the new cardiac cell population, their electrophysiological activity and Ca(2+) handling were similar to native cells. Secondly, we investigated the capability of paired SC-CMs to form an adequate subunit of a functional syncytium and analyzed gap junctions and signal transmission by dye transfer in cell pairs. We discovered significantly diminished coupling in SC-CMs compared with native cells, which could not be enhanced by a coculture approach combining SC-CMs and primary CMs. Moreover, quantitative and structural analysis of gap junctions presented significantly reduced connexin expression levels compared with native CMs. Strong dependence of intercellular coupling on gap junction density was further confirmed by computational simulations. These novel findings demonstrate that despite the cardiogenic electrophysiological profile, SC-CMs present significant limitations in intercellular communication. Inadequate coupling may severely impair functional integration and signal transmission, which needs to be carefully considered for the prospective use of SC-CMs in cardiac repair. Stem Cells 2015;33:2208-2218.
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Affiliation(s)
- Irene C Marcu
- Department of Physiology, University of Bern, Bern, Switzerland.,Department of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Ardo Illaste
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Pernilla Heuking
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Marisa E Jaconi
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Nina D Ullrich
- Department of Physiology, University of Bern, Bern, Switzerland.,Department of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
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Kleber AG, Saffitz JE. Role of the intercalated disc in cardiac propagation and arrhythmogenesis. Front Physiol 2014; 5:404. [PMID: 25368581 PMCID: PMC4201087 DOI: 10.3389/fphys.2014.00404] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 09/30/2014] [Indexed: 01/28/2023] Open
Abstract
This review article discusses mechanisms underlying impulse propagation in cardiac muscle with specific emphasis on the role of the cardiac cell-to-cell junction, called the “intercalated disc.”The first part of this review deals with the role of gap junction channels, formed by connexin proteins, as a determinant of impulse propagation. It is shown that, depending on the underlying structure of the cellular network, decreasing the conductance of gap junction channels (so-called “electrical uncoupling”) may either only slow, or additionally stabilize propagation and reverse unidirectional propagation block to bidirectional propagation. This is because the safety factor for propagation increases with decreasing intercellular electrical conductance. The role of heterogeneous connexin expression, which may be present in disease states, is also discussed. The hypothesis that so-called ephaptic impulse transmission plays a role in heart and can substitute for electrical coupling has been revived recently. Whereas ephaptic transmission can be demonstrated in theoretical simulations, direct experimental evidence has not yet been presented. The second part of this review deals with the interaction of three protein complexes at the intercalated disc: (1) desmosomal and adherens junction proteins, (2) ion channel proteins, and (3) gap junction channels consisting of connexins. Recent work has revealed multiple interactions between these three protein complexes which occur, at least in part, at the level of protein trafficking. Such interactions are likely to play an important role in the pathogenesis of arrhythmogenic cardiomyopathy, and may reveal new therapeutic concepts and targets.
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Affiliation(s)
- Andre G Kleber
- Department of Pathology, Beth Israel Medical Center, Harvard Medical School Boston, MA, USA
| | - Jeffrey E Saffitz
- Department of Pathology, Beth Israel Medical Center, Harvard Medical School Boston, MA, USA
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Yang H, Borg TK, Schmidt LP, Gao BZ. Laser cell-micropatterned pair of cardiomyocytes: the relationship between basement membrane development and gap junction maturation. Biofabrication 2014; 6:045003. [PMID: 25215627 DOI: 10.1088/1758-5082/6/4/045003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The basement membrane (BM), a network of laminin and collagen IV, mechanically supports individual cells and directly mediates cell-cell and cell-extracellular matrix (ECM) interactions. For example, the BM network that tightly encloses each cardiomyocyte (CM) mediates the alignment of CMs with collagen I in the ECM. Additionally, the BM-laminin is involved in the formation of gap junctions (GJs), which regulate electrical coupling between two CMs in the myocardium. The role of BM in GJ maturation remains unclear because of the complicated in vivo structures and lack of an ideal in vitro culturing mode. In this study, our laser cell-micropatterning system was used to place two neonatal CMs (NCMs) in contact on an aligned collagen gel (ACG) to study the relationship between GJ maturation and BM development. The results of double immunofluorescence staining and confocal imaging showed that BM-laminin was deposited earlier than the formation of GJs in the intercellular space and that newly expressed connexin 43 clusters were preferentially assembled near the deposited BM structures. Eventually the BM network surrounded the GJs.
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Affiliation(s)
- Huaxiao Yang
- Department of Bioengineering, Clemson University, SC, USA
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Liu J, Siragam V, Chen J, Fridman MD, Hamilton RM, Sun Y. High-throughput measurement of gap junctional intercellular communication. Am J Physiol Heart Circ Physiol 2014; 306:H1708-13. [PMID: 24778169 DOI: 10.1152/ajpheart.00110.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gap junctional intercellular communication (GJIC) is a critical part of cellular activities and is necessary for electrical propagation among contacting cells. Disorders of gap junctions are a major cause for cardiac arrhythmias. Dye transfer through microinjection is a conventional technique for measuring GJIC. To overcome the limitations of manual microinjection and perform high-throughput GJIC measurement, here we present a new robotic microinjection system that is capable of injecting a large number of cells at a high speed. The highly automated system enables large-scale cell injection (thousands of cells vs. a few cells) without major operator training. GJIC of three cell lines of differing gap junction density, i.e., HeLa, HEK293, and HL-1, was evaluated. The effect of a GJIC inhibitor (18-α-glycyrrhetinic acid) was also quantified in the three cell lines. System operation speed, success rate, and cell viability rate were quantitatively evaluated based on robotic microinjection of over 4,000 cells. Injection speed was 22.7 cells per min, with 95% success for cell injection and >90% survival. Dye transfer cell counts and dye transfer distance correlated with the expected connexin expression of each cell type, and inhibition of dye transfer correlated with the concentration of GJIC inhibitor. Additionally, real-time monitoring of dye transfer enables the calculation of coefficients of molecular diffusion through gap junctions. This robotic microinjection dye transfer technique permits rapid assessment of gap junction function in confluent cell cultures.
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Affiliation(s)
- Jun Liu
- Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada; and
| | - Vinayakumar Siragam
- Division of Cardiology, the Hospital of Sick Children, Toronto, Ontario, Canada
| | - Jun Chen
- Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada; and
| | - Michael D Fridman
- Division of Cardiology, the Hospital of Sick Children, Toronto, Ontario, Canada
| | - Robert M Hamilton
- Division of Cardiology, the Hospital of Sick Children, Toronto, Ontario, Canada
| | - Yu Sun
- Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada; and
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McCain ML, Desplantez T, Kléber AG. Engineering Cardiac Cell JunctionsIn Vitroto Study the Intercalated Disc. ACTA ACUST UNITED AC 2014; 21:181-91. [DOI: 10.3109/15419061.2014.905931] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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40
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Dhillon PS, Chowdhury RA, Patel PM, Jabr R, Momin AU, Vecht J, Gray R, Shipolini A, Fry CH, Peters NS. Relationship between connexin expression and gap-junction resistivity in human atrial myocardium. Circ Arrhythm Electrophysiol 2014; 7:321-9. [PMID: 24610741 DOI: 10.1161/circep.113.000606] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [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
BACKGROUND The relative roles of the gap-junctional proteins connexin40 (Cx40) and connexin43 (Cx43) in determining human atrial myocardial resistivity is unknown. In addressing the hypothesis that changing relative expression of Cx40 and Cx43 underlies an increase in human atrial myocardial resistivity with age, this relationship was investigated by direct ex vivo measurement of gap-junctional resistivity and quantitative connexin immunoblotting and immunohistochemistry. METHODS AND RESULTS Oil-gap impedance measurements were performed to determine resistivity of the intracellular pathway (Ri), which correlated with total Cx40 quantification by Western blotting (rs=0.64, P<0.01, n=20). Specific gap-junctional resistivity (Rj) correlated not only with Western immunoquantification of Cx40 (rs=0.63, P=0.01, n=20), but also more specifically, with the Cx40 fraction localized to the intercalated disks on immunohistochemical quantification (rs=0.66, P=0.02, n=12). Although Cx43 expression showed no correlation with resistivity values, the proportional expression of the 2 connexins, (Cx40/[Cx40+Cx43]) correlated with Ri and Rj (rs=0.58, P<0.01 for Ri and rs=0.51, P=0.02 for Rj). Advancing age was associated with a rise in Ri (rs=0.77, P<0.0001), Rj (rs=0.65, P<0.001, n=23), Cx40 quantity (rs=0.54, P=0.01, n=20), and Cx40 gap-junction protein per unit area of en face disk (rs=0.61, P=0.02, n=12). CONCLUSIONS Cx40 is associated with human right atrial gap-junctional resistivity such that increased total, gap-junctional, and proportional Cx40 expression increases gap-junctional resistivity. Accordingly, advancing age is associated with an increase in Cx40 expression and a corresponding increase in gap-junctional resistivity. These findings are the first to demonstrate this relationship and a mechanistic explanation for changing atrial conduction and age-related arrhythmic tendency.
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Affiliation(s)
- Paramdeep S Dhillon
- Myocardial Function Section, Imperial College London and Imperial College NHS Trust, London, UK
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41
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A micropatterning approach for imaging dynamic Cx43 trafficking to cell-cell borders. FEBS Lett 2014; 588:1439-45. [PMID: 24444605 DOI: 10.1016/j.febslet.2014.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 12/31/2013] [Accepted: 01/04/2014] [Indexed: 11/22/2022]
Abstract
The precise expression and timely delivery of connexin 43 (Cx43) proteins to form gap junctions are essential for electrical coupling of cardiomyocytes. Growing evidence supports a cytoskeletal-based trafficking paradigm for Cx43 delivery directly to adherens junctions at the intercalated disc. A limitation of Cx43 localization assays in cultured cells, in which cell-cell contacts are essential, is the inability to control for cell geometry or reproducibly generate contact points. Here we present a micropatterned cell pairing system well suited for live microscopy to examine how the microtubule and actin cytoskeleton confer specificity to Cx43 trafficking to precisely defined cell-cell junctions. This system can be adapted for other cell types and used to study dynamic intracellular movements of other proteins important for cell-cell communication.
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42
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Dunn DA, Hodge AJ, Lipke EA. Biomimetic materials design for cardiac tissue regeneration. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2013; 6:15-39. [DOI: 10.1002/wnan.1241] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 07/10/2013] [Accepted: 07/29/2013] [Indexed: 01/12/2023]
Affiliation(s)
- David A. Dunn
- Department of Chemical Engineering, Auburn University, Auburn, AL, USA
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43
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den Haan AD, Veldkamp MW, Bakker D, Boink GJJ, Janssen RB, de Bakker JMT, Tan HL. Organ explant culture of neonatal rat ventricles: a new model to study gene and cell therapy. PLoS One 2013; 8:e59290. [PMID: 23516623 PMCID: PMC3596330 DOI: 10.1371/journal.pone.0059290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/13/2013] [Indexed: 11/25/2022] Open
Abstract
Testing cardiac gene and cell therapies in vitro requires a tissue substrate that survives for several days in culture while maintaining its physiological properties. The purpose of this study was to test whether culture of intact cardiac tissue of neonatal rat ventricles (organ explant culture) may be used as a model to study gene and cell therapy. We compared (immuno) histology and electrophysiology of organ explant cultures to both freshly isolated neonatal rat ventricular tissue and monolayers. (Immuno) histologic studies showed that organ explant cultures retained their fiber orientation, and that expression patterns of α-actinin, connexin-43, and α-smooth muscle actin did not change during culture. Intracellular voltage recordings showed that spontaneous beating was rare in organ explant cultures (20%) and freshly isolated tissue (17%), but common (82%) in monolayers. Accordingly, resting membrane potential was -83.9±4.4 mV in organ explant cultures, -80.5±3.5 mV in freshly isolated tissue, and -60.9±4.3 mV in monolayers. Conduction velocity, measured by optical mapping, was 18.2±1.0 cm/s in organ explant cultures, 18.0±1.2 cm/s in freshly isolated tissue, and 24.3±0.7 cm/s in monolayers. We found no differences in action potential duration (APD) between organ explant cultures and freshly isolated tissue, while APD of monolayers was prolonged (APD at 70% repolarization 88.8±7.8, 79.1±2.9, and 134.0±4.5 ms, respectively). Organ explant cultures and freshly isolated tissue could be paced up to frequencies within the normal range for neonatal rat (CL 150 ms), while monolayers could not. Successful lentiviral (LV) transduction was shown via Egfp gene transfer. Co-culture of organ explant cultures with spontaneously beating cardiomyocytes increased the occurrence of spontaneous beating activity of organ explant cultures to 86%. We conclude that organ explant cultures of neonatal rat ventricle are structurally and electrophysiologically similar to freshly isolated tissue and a suitable new model to study the effects of gene and cell therapy.
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Affiliation(s)
- A. Dénise den Haan
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Marieke W. Veldkamp
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Diane Bakker
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Geert J. J. Boink
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rob B. Janssen
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jacques M. T. de Bakker
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands
| | - Hanno L. Tan
- Heart Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Sheehy SP, Grosberg A, Parker KK. The contribution of cellular mechanotransduction to cardiomyocyte form and function. Biomech Model Mechanobiol 2012; 11:1227-39. [PMID: 22772714 DOI: 10.1007/s10237-012-0419-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/25/2012] [Indexed: 01/07/2023]
Abstract
Myocardial development is regulated by an elegantly choreographed ensemble of signaling events mediated by a multitude of intermediates that take a variety of forms. Cellular differentiation and maturation are a subset of vertically integrated processes that extend over several spatial and temporal scales to create a well-defined collective of cells that are able to function cooperatively and reliably at the organ level. Early efforts to understand the molecular mechanisms of cardiomyocyte fate determination focused primarily on genetic and chemical mediators of this process. However, increasing evidence suggests that mechanical interactions between the extracellular matrix (ECM) and cell surface receptors as well as physical interactions between neighboring cells play important roles in regulating the signaling pathways controlling the developmental processes of the heart. Interdisciplinary efforts have made it apparent that the influence of the ECM on cellular behavior occurs through a multitude of physical mechanisms, such as ECM boundary conditions, elasticity, and the propagation of mechanical signals to intracellular compartments, such as the nucleus. In addition to experimental studies, a number of mathematical models have been developed that attempt to capture the interplay between cells and their local microenvironment and the influence these interactions have on cellular self-assembly and functional behavior. Nevertheless, many questions remain unanswered concerning the mechanism through which physical interactions between cardiomyocytes and their environment are translated into biochemical cellular responses and how these signaling modalities can be utilized in vitro to fabricate myocardial tissue constructs from stem cell-derived cardiomyocytes that more faithfully represent their in vivo counterpart. These studies represent a broad effort to characterize biological form as a conduit for information transfer that spans the nanometer length scale of proteins to the meter length scale of the patient and may yield new insights into the contribution of mechanotransduction into heart development and disease.
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Affiliation(s)
- Sean P Sheehy
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, Pierce Hall Rm. 321, 29 Oxford St., Cambridge, MA 02138, USA
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Cooperative coupling of cell-matrix and cell-cell adhesions in cardiac muscle. Proc Natl Acad Sci U S A 2012; 109:9881-6. [PMID: 22675119 DOI: 10.1073/pnas.1203007109] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Adhesion between cardiac myocytes is essential for the heart to function as an electromechanical syncytium. Although cell-matrix and cell-cell adhesions reorganize during development and disease, the hierarchical cooperation between these subcellular structures is poorly understood. We reasoned that, during cardiac development, focal adhesions mechanically stabilize cells and tissues during myofibrillogenesis and intercalated disc assembly. As the intercalated disc matures, we postulated that focal adhesions disassemble as systolic stresses are transmitted intercellularly. Finally, we hypothesized that pathological remodeling of cardiac microenvironments induces excessive mechanical loading of intercalated discs, leading to assembly of stabilizing focal adhesions adjacent to the junction. To test our model, we engineered μtissues composed of two ventricular myocytes on deformable substrates of tunable elasticity to measure the dynamic organization and functional remodeling of myofibrils, focal adhesions, and intercalated discs as cooperative ensembles. Maturing μtissues increased systolic force while simultaneously developing into an electromechanical syncytium by disassembling focal adhesions at the cell-cell interface and forming mature intercalated discs that transmitted the systolic load. We found that engineering the microenvironment to mimic fibrosis resulted in focal adhesion formation adjacent to the cell-cell interface, suggesting that the intercalated disc required mechanical reinforcement. In these pathological microenvironments, μtissues exhibited further evidence of maladaptive remodeling, including lower work efficiency, longer contraction cycle duration, and weakened relationships between cytoskeletal organization and force generation. These results suggest that the cooperative balance between cell-matrix and cell-cell adhesions in the heart is guided by an architectural and functional hierarchy established during development and disrupted during disease.
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47
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Boink GJ, Lau DH, Shlapakova IN, Sosunov EA, Anyukhovsky EP, Driessen HE, Dun W, Chen M, Danilo P, Rosen TS, Őzgen N, Duffy HS, Kryukova Y, Boyden PA, Robinson RB, Brink PR, Cohen IS, Rosen MR. SkM1 and Cx32 improve conduction in canine myocardial infarcts yet only SkM1 is antiarrhythmic. Cardiovasc Res 2012; 94:450-9. [PMID: 22374989 PMCID: PMC3410408 DOI: 10.1093/cvr/cvs107] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 02/20/2012] [Accepted: 02/23/2012] [Indexed: 11/13/2022] Open
Abstract
AIMS Reentry accounts for most life-threatening arrhythmias, complicating myocardial infarction, and therapies that consistently prevent reentry from occurring are lacking. In this study, we compare antiarrhythmic effects of gene transfer of green fluorescent protein (GFP; sham), the skeletal muscle sodium channel (SkM1), the liver-specific connexin (Cx32), and SkM1/Cx32 in the subacute canine infarct. METHODS AND RESULTS Immediately after ligation of the left anterior descending artery, viral constructs were implanted in the epicardial border zone (EBZ). Five to 7 days later, efficient restoration of impulse propagation (narrow QRS and local electrogram duration) occurred in SkM1, Cx32, and SkM1/Cx32 groups (P< 0.05 vs. GFP). Programmed electrical stimulation from the EBZ induced sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) in 15/22 GFP dogs vs. 2/12 SkM1, 6/14 Cx32, and 8/10 SkM1/Cx32 (P< 0.05 SkM1 vs. GFP). GFP, SkM1, and SkM1/Cx32 had predominantly polymorphic VT/VF, whereas in Cx32 dogs, monomorphic VT predominated (P< 0.05 for Cx32 vs. GFP). Tetrazolium red staining showed significantly larger infarcts in Cx32- vs. GFP-treated animals (P< 0.05). CONCLUSION Whereas SkM1 gene transfer reduces the incidence of inducible VT/VF, Cx32 therapy to improve gap junctional conductance results in larger infarct size, a different VT morphology, and no antiarrhythmic efficacy.
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Affiliation(s)
- Gerard J.J. Boink
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - David H. Lau
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Iryna N. Shlapakova
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Operating Room RN, Meadowlands Hospital Medical Center, 55 Meadowlands Parkway, Secaucus, NJ 07094, USA
| | - Eugene A. Sosunov
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Evgeny P. Anyukhovsky
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Helen E. Driessen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Graduate School of Life Sciences, Utrecht University, Utrecht, The Netherlands
| | - Wen Dun
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Ming Chen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Peter Danilo
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Tove S. Rosen
- Department of Pediatrics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Nazira Őzgen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Heather S. Duffy
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Beth Israel Deaconess Medical Center, Harvard Medical School, Center for Life Sciences, CLS 913, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Yelena Kryukova
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Penelope A Boyden
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Richard B. Robinson
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
| | - Peter R. Brink
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Ira S. Cohen
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
| | - Michael R. Rosen
- Department of Pharmacology, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Center for Molecular Therapeutics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Department of Pediatrics, Columbia University, 630 West 168 Street, PH 7W-321, New York, NY 10032, USA
- Department of Physiology and Biophysics, Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA
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Beauchamp P, Desplantez T, McCain ML, Li W, Asimaki A, Rigoli G, Parker KK, Saffitz JE, Kleber AG. Electrical coupling and propagation in engineered ventricular myocardium with heterogeneous expression of connexin43. Circ Res 2012; 110:1445-53. [PMID: 22518032 DOI: 10.1161/circresaha.111.259705] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Spatial heterogeneity in connexin (Cx) expression has been implicated in arrhythmogenesis. OBJECTIVE This study was performed to quantify the relation between the degree of heterogeneity in Cx43 expression and disturbances in electric propagation. METHODS AND RESULTS Cell pairs and strands composed of mixtures of Cx43(-/-) (Cx43KO) or GFP-expressing Cx43(+/+) (WT(GFP)) murine ventricular myocytes were patterned using microlithographic techniques. At the interface between pairs of WT(GFP) and Cx43KO cells, dual-voltage clamp showed a marked decrease in electric coupling (approximately 5% of WT) and voltage gating suggested the presence of mixed Cx43/Cx45 channels. Cx43 and Cx45 immunofluorescence signals were not detectable at this interface, probably because of markedly reduced gap junction size. Macroscopic propagation velocity, measured by multisite high-resolution optical mapping of transmembrane potential in strands of cells of mixed Cx43 genotype, decreased with an increasing proportion of Cx43KO cells in the strand. A marked decrease in conduction velocity was observed in strands composed of <50% WT cells. Propagation at the microscopic scale showed a high degree of dissociation between WT(GFP) and Cx43KO cells, but consistent excitation without development of propagation block. CONCLUSIONS Heterogeneous ablation of Cx43 leads to a marked decrease in propagation velocity in tissue strands composed of <50% cells with WT Cx43 expression and marked dissociation of excitation at the cellular level. However, the small residual electric conductance between Cx43 and WT(GFP) myocytes assures excitation of Cx43(-/-) cells. This explains the previously reported undisturbed contractility in tissues with spatially heterogeneous downregulation of Cx43 expression.
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Desplantez T, McCain ML, Beauchamp P, Rigoli G, Rothen-Rutishauser B, Parker KK, Kleber AG. Connexin43 ablation in foetal atrial myocytes decreases electrical coupling, partner connexins, and sodium current. Cardiovasc Res 2012; 94:58-65. [PMID: 22287588 PMCID: PMC3307380 DOI: 10.1093/cvr/cvs025] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 01/10/2012] [Accepted: 01/23/2012] [Indexed: 11/15/2022] Open
Abstract
AIMS Remodelling and regional gradients in expression of connexins (Cx) are thought to contribute to atrial electrical dysfunction and atrial fibrillation. We assessed the effect of interaction between Cx43, Cx40, and Cx45 on atrial cell-to-cell coupling and inward Na current (I(Na)) in engineered pairs of atrial myocytes derived from wild-type mice (Cx43(+/+)) and mice with genetic ablation of Cx43 (Cx43(-/-)). METHODS AND RESULTS Cell pairs were engineered by microcontact printing from atrial Cx43(+/+) and Cx43(-/-) murine myocytes (1 day before birth, 3-5 days in culture). Dual and single voltage clamp were used to measure intercellular electrical conductance, g(j), and its dependence on transjunctional voltage, V(j), single gap junction channel conductances, and I(Na). 3D reconstructions of Cx43, Cx40, and Cx45 immunosignals in gap junctions were made from confocal slices. Full genetic Cx43 ablation produced a decrease in immunosignals of Cx40 to 62 ± 10% (mean ± SE; n= 17) and Cx45 to 66 ± 8% (n= 16). G(j) decreased from 80 ± 9 nS (Cx43(+/+), n= 17) to 24 ± 2 nS (Cx43(-/-), n= 35). Single channel analysis showed a shift in the main peak of the channel histogram from 49 ± 1.7 nS (Cx43(+/+)) to 67 ± 1.8 nS (Cx43(-/-)) with a second minor peak appearing at 27 ± 1.5 pS. The dependence of g(j) on V(j) decreased with Cx43 ablation. Importantly, peak I(Na) decreased from -350 ± 44 pA/pF (Cx43(+/+)) to -154 ± 28 pA/pF (Cx43(-/-)). CONCLUSIONS The dependence of Cx40, Cx45, and I(Na) on Cx43 expression indicates a complex interaction between connexins and I(Na) in the atrial intercalated discs that is likely to be of relevance for arrhythmogenesis.
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Affiliation(s)
| | - Megan L. McCain
- Disease Biophysics Group, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | | | | | | | - Kevin Kit Parker
- Disease Biophysics Group, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Andre G. Kleber
- Department of Physiology, University of Bern, Bern, Switzerland
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