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Wang S, Aljirafi FO, Payne GF, Bentley WE. Excite the unexcitable: engineering cells and redox signaling for targeted bioelectronic control. Curr Opin Biotechnol 2024; 85:103052. [PMID: 38150921 DOI: 10.1016/j.copbio.2023.103052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/17/2023] [Accepted: 11/28/2023] [Indexed: 12/29/2023]
Abstract
The ever-growing influence of technology in our lives has led to an increasing interest in the development of smart electronic devices to interrogate and control biological systems. Recently, redox-mediated electrogenetics introduced a novel avenue that enables direct bioelectronic control at the genetic level. In this review, we discuss recent advances in methodologies for bioelectronic control, ranging from electrical stimulation to engineering efforts that allow traditionally unexcitable cells to be electrically 'programmable.' Alongside ion-transport signaling, we suggest redox as a route for rational engineering because it is a native form of electronic communication in biology. Using redox as a common language allows the interfacing of electronics and biology. This newfound connection opens a gateway of possibilities for next-generation bioelectronic tools.
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Affiliation(s)
- Sally Wang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA; Fischell Institute of Biomedical Devices, University of Maryland, College Park, MD, USA
| | - Futoon O Aljirafi
- Fischell Institute of Biomedical Devices, University of Maryland, College Park, MD, USA; Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD, USA
| | - Gregory F Payne
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA; Fischell Institute of Biomedical Devices, University of Maryland, College Park, MD, USA
| | - William E Bentley
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA; Fischell Institute of Biomedical Devices, University of Maryland, College Park, MD, USA
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2
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Luo L, Li Y, Bao Z, Zhu D, Chen G, Li W, Xiao Y, Wang Z, Zhang Y, Liu H, Chen Y, Liao Y, Cheng K, Li Z. Pericardial Delivery of SDF-1α Puerarin Hydrogel Promotes Heart Repair and Electrical Coupling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2302686. [PMID: 37665792 DOI: 10.1002/adma.202302686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/02/2023] [Indexed: 09/06/2023]
Abstract
The stromal-derived factor 1α/chemokine receptor 4 (SDF-1α/CXCR4) axis contributes to myocardial protection after myocardial infarction (MI) by recruiting endogenous stem cells into the ischemic tissue. However, excessive inflammatory macrophages are also recruited simultaneously, aggravating myocardial damage. More seriously, the increased inflammation contributes to abnormal cardiomyocyte electrical coupling, leading to inhomogeneities in ventricular conduction and retarded conduction velocity. It is highly desirable to selectively recruit the stem cells but block the inflammation. In this work, SDF-1α-encapsulated Puerarin (PUE) hydrogel (SDF-1α@PUE) is capable of enhancing endogenous stem cell homing and simultaneously polarizing the recruited monocyte/macrophages into a repairing phenotype. Flow cytometry analysis of the treated heart tissue shows that endogenous bone marrow mesenchymal stem cells, hemopoietic stem cells, and immune cells are recruited while SDF-1α@PUE efficiently polarizes the recruited monocytes/macrophages into the M2 type. These macrophages influence the preservation of connexin 43 (Cx43) expression which modulates intercellular coupling and improves electrical conduction. Furthermore, by taking advantage of the improved "soil", the recruited stem cells mediate an improved cardiac function by preventing deterioration, promoting neovascular architecture, and reducing infarct size. These findings demonstrate a promising therapeutic platform for MI that not only facilitates heart regeneration but also reduces the risk of cardiac arrhythmias.
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Affiliation(s)
- Li Luo
- The Tenth Affiliated Hospital of Southern Medical University, Dongguan, Guangdong, 523059, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
| | - Yuetong Li
- The Tenth Affiliated Hospital of Southern Medical University, Dongguan, Guangdong, 523059, China
| | - Ziwei Bao
- Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Dashuai Zhu
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, 27606, USA
| | - Guoqin Chen
- Cardiology Department of Panyu Central Hospital and Cardiovascular Disease Institute of Panyu District, Guangzhou, 511400, P. R. China
| | - Weirun Li
- The Tenth Affiliated Hospital of Southern Medical University, Dongguan, Guangdong, 523059, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
| | - Yingxian Xiao
- The Tenth Affiliated Hospital of Southern Medical University, Dongguan, Guangdong, 523059, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
| | - Zhenzhen Wang
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, 27606, USA
| | - Yixin Zhang
- College of Pharmaceutical Science, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, Hebei University, Baoding, 071002, China
| | - Huifang Liu
- College of Pharmaceutical Science, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, Hebei University, Baoding, 071002, China
| | - Yanmei Chen
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yulin Liao
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Ke Cheng
- Department of Biomedical Engineering, Columbia University, New York, 10032, USA
| | - Zhenhua Li
- The Tenth Affiliated Hospital of Southern Medical University, Dongguan, Guangdong, 523059, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, 510515, China
- Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation, Guangzhou, 510515, China
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Needs D, Wu T, Nguyen HX, Henriquez CS, Bursac N. Prokaryotic voltage-gated sodium channels are more effective than endogenous Na v1.5 channels in rescuing cardiac action potential conduction: an in silico study. Am J Physiol Heart Circ Physiol 2023; 325:H1178-H1192. [PMID: 37737736 PMCID: PMC10908372 DOI: 10.1152/ajpheart.00287.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Methods to augment Na+ current in cardiomyocytes hold potential for the treatment of various cardiac arrhythmias involving conduction slowing. Because the gene coding cardiac Na+ channel (Nav1.5) is too large to fit in a single adeno-associated virus (AAV) vector, new gene therapies are being developed to enhance endogenous Nav1.5 current (by overexpression of chaperon molecules or use of multiple AAV vectors) or to exogenously introduce prokaryotic voltage-gated Na+ channels (BacNav) whose gene size is significantly smaller than that of the Nav1.5. In this study, based on experimental measurements in heterologous expression systems, we developed an improved computational model of the BacNav channel, NavSheP D60A. We then compared in silico how NavSheP D60A expression vs. Nav1.5 augmentation affects the electrophysiology of cardiac tissue. We found that the incorporation of BacNav channels in both adult guinea pig and human cardiomyocyte models increased their excitability and reduced action potential duration. When compared with equivalent augmentation of Nav1.5 current in simulated settings of reduced tissue excitability, the addition of the BacNav current was superior in improving the safety of conduction under conditions of current source-load mismatch, reducing the vulnerability to unidirectional conduction block during premature pacing, preventing the instability and breakup of spiral waves, and normalizing the conduction and ECG in Brugada syndrome tissues with mutated Nav1.5. Overall, our studies show that compared with a potential enhancement of the endogenous Nav1.5 current, expression of the BacNav channels with their slower inactivation kinetics can provide greater anti-arrhythmic benefits in hearts with compromised action potential conduction.NEW & NOTEWORTHY Slow action potential conduction is a common cause of various cardiac arrhythmias; yet, current pharmacotherapies cannot augment cardiac conduction. This in silico study compared the efficacy of recently proposed antiarrhythmic gene therapy approaches that increase peak sodium current in cardiomyocytes. When compared with the augmentation of endogenous sodium current, expression of slower-inactivating bacterial sodium channels was superior in preventing conduction block and arrhythmia induction. These results further the promise of antiarrhythmic gene therapies targeting sodium channels.
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Affiliation(s)
- Daniel Needs
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Tianyu Wu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Hung X Nguyen
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Craig S Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
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Moghimianavval H, Patel C, Mohapatra S, Hwang SW, Kayikcioglu T, Bashirzadeh Y, Liu AP, Ha T. Engineering Functional Membrane-Membrane Interfaces by InterSpy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2202104. [PMID: 35618485 PMCID: PMC9789529 DOI: 10.1002/smll.202202104] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Engineering synthetic interfaces between membranes has potential applications in designing non-native cellular communication pathways and creating synthetic tissues. Here, InterSpy is introduced as a synthetic biology tool consisting of a heterodimeric protein engineered to form and maintain membrane-membrane interfaces between apposing synthetic as well as cell membranes through the SpyTag/SpyCatcher interaction. The inclusion of split fluorescent protein fragments in InterSpy allows tracking of the formation of a membrane-membrane interface and reconstitution of functional fluorescent protein in the space between apposing membranes. First, InterSpy is demonstrated by testing split protein designs using a mammalian cell-free expression (CFE) system. By utilizing co-translational helix insertion, cell-free synthesized InterSpy fragments are incorporated into the membrane of liposomes and supported lipid bilayers with the desired topology. Functional reconstitution of split fluorescent protein between the membranes is strictly dependent on SpyTag/SpyCatcher. Finally, InterSpy is demonstrated in mammalian cells by detecting fluorescence reconstitution of split protein at the membrane-membrane interface between two cells each expressing a component of InterSpy. InterSpy demonstrates the power of CFE systems in the functional reconstitution of synthetic membrane interfaces via proximity-inducing proteins. This technology may also prove useful where cell-cell contacts and communication are recreated in a controlled manner using minimal components.
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Affiliation(s)
- Hossein Moghimianavval
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Chintan Patel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sonisilpa Mohapatra
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sung-Won Hwang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Tunc Kayikcioglu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yashar Bashirzadeh
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, Baltimore, MD 21205, USA
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Tieu A, Phillips KG, Costa KD, Mayourian J. Computational design of custom therapeutic cells to correct failing human cardiomyocytes. FRONTIERS IN SYSTEMS BIOLOGY 2023; 3:1102467. [PMID: 36743445 PMCID: PMC9894098 DOI: 10.3389/fsysb.2023.1102467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background Myocardial delivery of non-excitable cells-namely human mesenchymal stem cells (hMSCs) and c-kit+ cardiac interstitial cells (hCICs)-remains a promising approach for treating the failing heart. Recent empirical studies attempt to improve such therapies by genetically engineering cells to express specific ion channels, or by creating hybrid cells with combined channel expression. This study uses a computational modeling approach to test the hypothesis that custom hypothetical cells can be rationally designed to restore a healthy phenotype when coupled to human heart failure (HF) cardiomyocytes. Methods Candidate custom cells were simulated with a combination of ion channels from non-excitable cells and healthy human cardiomyocytes (hCMs). Using a genetic algorithm-based optimization approach, candidate cells were accepted if a root mean square error (RMSE) of less than 50% relative to healthy hCM was achieved for both action potential and calcium transient waveforms for the cell-treated HF cardiomyocyte, normalized to the untreated HF cardiomyocyte. Results Custom cells expressing only non-excitable ion channels were inadequate to restore a healthy cardiac phenotype when coupled to either fibrotic or non-fibrotic HF cardiomyocytes. In contrast, custom cells also expressing cardiac ion channels led to acceptable restoration of a healthy cardiomyocyte phenotype when coupled to fibrotic, but not non-fibrotic, HF cardiomyocytes. Incorporating the cardiomyocyte inward rectifier K+ channel was critical to accomplishing this phenotypic rescue while also improving single-cell action potential metrics associated with arrhythmias, namely resting membrane potential and action potential duration. The computational approach also provided insight into the rescue mechanisms, whereby heterocellular coupling enhanced cardiomyocyte L-type calcium current and promoted calcium-induced calcium release. Finally, as a therapeutically translatable strategy, we simulated delivery of hMSCs and hCICs genetically engineered to express the cardiomyocyte inward rectifier K+ channel, which decreased action potential and calcium transient RMSEs by at least 24% relative to control hMSCs and hCICs, with more favorable single-cell arrhythmia metrics. Conclusion Computational modeling facilitates exploration of customizable engineered cell therapies. Optimized cells expressing cardiac ion channels restored healthy action potential and calcium handling phenotypes in fibrotic HF cardiomyocytes and improved single-cell arrhythmia metrics, warranting further experimental validation studies of the proposed custom therapeutic cells.
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Affiliation(s)
- Andrew Tieu
- Cardiovascular Research Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Katherine G. Phillips
- Department of Cardiothoracic Surgery, NYU Langone Health, New York, NY, United States
| | - Kevin D. Costa
- Cardiovascular Research Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States,CORRESPONDENCE: Kevin D. Costa, Joshua Mayourian,
| | - Joshua Mayourian
- Department of Pediatrics, Boston Children’s Hospital, Boston, MA, United States,Department of Pediatrics, Harvard Medical School, Boston, MA, United States,Department of Pediatrics, Boston University, Boston, MA, United States,Department of Pediatrics, Boston Medical Center, Boston, MA, United States,CORRESPONDENCE: Kevin D. Costa, Joshua Mayourian,
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Xu Y, Qi J, Zhou W, Liu X, Zhang L, Yao X, Wu H. Generation of ring-shaped human iPSC-derived functional heart microtissues in a Möbius strip configuration. Biodes Manuf 2022. [DOI: 10.1007/s42242-022-00204-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AbstractAlthough human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been used for disease modeling and drug discovery, clinically relevant three-dimensional (3D) functional myocardial microtissues are lacking. Here, we developed a novel ring-shaped cardiac microtissue comprised of chamber-specific tissues to achieve a geometrically non-orientable ventricular myocardial band, similar to a Möbius loop. The ring-shaped cardiac tissue was constructed of hiPSC-CMs and human cardiac fibroblasts (hCFs) through a facile cellular self-assembly approach. It exhibited basic anatomical structure, positive cardiac troponin T (cTnT) immunostaining, regular calcium transients, and cardiac-like mechanical strength. The cardiac rings can be self-assembled and scaled up into various sizes with outstanding stability, suggesting their potential for precise therapy, pathophysiological investigation, and large-scale drug screening.
Graphic abstract
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Nguyen HX, Wu T, Needs D, Zhang H, Perelli RM, DeLuca S, Yang R, Pan M, Landstrom AP, Henriquez C, Bursac N. Engineered bacterial voltage-gated sodium channel platform for cardiac gene therapy. Nat Commun 2022; 13:620. [PMID: 35110560 PMCID: PMC8810800 DOI: 10.1038/s41467-022-28251-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/11/2022] [Indexed: 12/19/2022] Open
Abstract
Therapies for cardiac arrhythmias could greatly benefit from approaches to enhance electrical excitability and action potential conduction in the heart by stably overexpressing mammalian voltage-gated sodium channels. However, the large size of these channels precludes their incorporation into therapeutic viral vectors. Here, we report a platform utilizing small-size, codon-optimized engineered prokaryotic sodium channels (BacNav) driven by muscle-specific promoters that significantly enhance excitability and conduction in rat and human cardiomyocytes in vitro and adult cardiac tissues from multiple species in silico. We also show that the expression of BacNav significantly reduces occurrence of conduction block and reentrant arrhythmias in fibrotic cardiac cultures. Moreover, functional BacNav channels are stably expressed in healthy mouse hearts six weeks following intravenous injection of self-complementary adeno-associated virus (scAAV) without causing any adverse effects on cardiac electrophysiology. The large diversity of prokaryotic sodium channels and experimental-computational platform reported in this study should facilitate the development and evaluation of BacNav-based gene therapies for cardiac conduction disorders.
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Affiliation(s)
- Hung X Nguyen
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Tianyu Wu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Daniel Needs
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Hengtao Zhang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Robin M Perelli
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Sophia DeLuca
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Rachel Yang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Michael Pan
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Craig Henriquez
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
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Biomaterializing the promise of cardiac tissue engineering. Biotechnol Adv 2019; 42:107353. [PMID: 30794878 DOI: 10.1016/j.biotechadv.2019.02.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 12/14/2022]
Abstract
During an average individual's lifespan, the human heart pumps nearly 200 million liters of blood delivered by approximately 3 billion heartbeats. Therefore, it is not surprising that native myocardium under this incredible demand is extraordinarily complex, both structurally and functionally. As a result, successful engineering of adult-mimetic functional cardiac tissues is likely to require utilization of highly specialized biomaterials representative of the native extracellular microenvironment. There is currently no single biomaterial that fully recapitulates the architecture or the biochemical and biomechanical properties of adult myocardium. However, significant effort has gone toward designing highly functional materials and tissue constructs that may one day provide a ready source of cardiac tissue grafts to address the overwhelming burden of cardiomyopathic disease. In the near term, biomaterial-based scaffolds are helping to generate in vitro systems for querying the mechanisms underlying human heart homeostasis and disease and discovering new, patient-specific therapeutics. When combined with advances in minimally-invasive cardiac delivery, ongoing efforts will likely lead to scalable cell and biomaterial technologies for use in clinical practice. In this review, we describe recent progress in the field of cardiac tissue engineering with particular emphasis on use of biomaterials for therapeutic tissue design and delivery.
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Nguyen HX, Bursac N. Ion channel engineering for modulation and de novo generation of electrical excitability. Curr Opin Biotechnol 2019; 58:100-107. [PMID: 30776744 DOI: 10.1016/j.copbio.2019.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 01/02/2019] [Indexed: 02/07/2023]
Abstract
Ion channels play essential roles in regulating electrical properties of excitable tissues. By leveraging various ion channel gating mechanisms, scientists have developed a versatile set of genetically encoded tools to modulate intrinsic tissue excitability under different experimental settings. In this article, we will review how ion channels activated by voltage, light, small chemicals, stretch, and temperature have been customized to enable control of tissue excitability both in vitro and in vivo. Advantages and limitations of each of these ion channel-engineering platforms will be discussed and notable applications will be highlighted. Furthermore, we will describe recent progress on de novo generation of excitable tissues via expression of appropriate sets of engineered voltage-gated ion channels and discuss potential therapeutic implications.
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Affiliation(s)
- Hung X Nguyen
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
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Gokhale TA, Asfour H, Verma S, Bursac N, Henriquez CS. Microheterogeneity-induced conduction slowing and wavefront collisions govern macroscopic conduction behavior: A computational and experimental study. PLoS Comput Biol 2018; 14:e1006276. [PMID: 30011279 PMCID: PMC6062105 DOI: 10.1371/journal.pcbi.1006276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 07/26/2018] [Accepted: 06/04/2018] [Indexed: 11/23/2022] Open
Abstract
The incidence of cardiac arrhythmias is known to be associated with tissue heterogeneities including fibrosis. However, the impact of microscopic structural heterogeneities on conduction in excitable tissues remains poorly understood. In this study, we investigated how acellular microheterogeneities affect macroscopic conduction under conditions of normal and reduced excitability by utilizing a novel platform of paired in vitro and in silico studies to examine the mechanisms of conduction. Regular patterns of nonconductive micro-obstacles were created in confluent monolayers of the previously described engineered-excitable Ex293 cell line. Increasing the relative ratio of obstacle size to intra-obstacle strand width resulted in significant conduction slowing up to 23.6% and a significant increase in wavefront curvature anisotropy, a measure of spatial variation in wavefront shape. Changes in bulk electrical conductivity and in path tortuosity were insufficient to explain these observed macroscopic changes. Rather, microscale behaviors including local conduction slowing due to microscale branching, and conduction acceleration due to wavefront merging were shown to contribute to macroscopic phenomena. Conditions of reduced excitability led to further conduction slowing and a reversal of wavefront curvature anisotropy due to spatially non-uniform effects on microscopic slowing and acceleration. This unique experimental and computation platform provided critical mechanistic insights in the impact of microscopic heterogeneities on macroscopic conduction, pertinent to settings of fibrotic heart disease. It is well known that perturbations in the heart structure are associated with the initiation and maintenance of clinically significant cardiac arrhythmia. While previous studies have examined how single structural perturbations affect local electrical conduction, our understanding of how numerous microscopic heterogeneities act in aggregate to alter macroscopic electrical behavior is limited. In this study, we utilized simplified engineered excitable cells that contain the minimal machinery of excitability and can be directly computationally modeled. By pairing experimental and computational studies, we showed that the microscopic branching and collisions of electrical waves slow and speed conduction, respectively, resulting in macroscopic changes in the speed and pattern of electrical activation. These microscale behaviors are significantly altered under reduced excitability, resulting in exaggerated collision effects. Overall, this study helps improve our understanding of how microscopic structural heterogeneities in excitable tissue lead to abnormal action potential propagation, conducive to arrhythmias.
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Affiliation(s)
- Tanmay A. Gokhale
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Huda Asfour
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Shravan Verma
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- * E-mail: (NB); (CSH)
| | - Craig S. Henriquez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- * E-mail: (NB); (CSH)
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