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Ng R, Gokhan I, Stankey P, Akar FG, Campbell SG. Chronic diastolic stretch unmasks conduction defects in an in vitro model of arrhythmogenic cardiomyopathy. Am J Physiol Heart Circ Physiol 2023; 325:H1373-H1385. [PMID: 37830983 PMCID: PMC10977872 DOI: 10.1152/ajpheart.00709.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/14/2023]
Abstract
We seek to elucidate the precise nature of mechanical loading that precipitates conduction deficits in a concealed-phase model of arrhythmogenic cardiomyopathy (ACM). ACM is a progressive disorder often resulting from mutations in desmosomal proteins. Exercise has been shown to worsen disease progression and unmask arrhythmia vulnerability, yet the underlying pathomechanisms may depend on the type and intensity of exercise. Because exercise causes myriad changes to multiple inter-dependent hemodynamic parameters, it is difficult to isolate its effects to specific changes in mechanical load. Here, we use engineered heart tissues (EHTs) with iPSC-derived cardiomyocytes expressing R451G desmoplakin, an ACM-linked mutation, which results in a functionally null model of desmoplakin (DSP). We also use a novel bioreactor to independently perturb tissue strain at different time points during the cardiac cycle. We culture EHTs under three strain regimes: normal physiological shortening; increased diastolic stretch, simulating high preload; and isometric culture, simulating high afterload. DSPR451G EHTs that have been cultured isometrically undergo adaptation, with no change in action potential parameters, conduction velocity, or contractile function, a phenotype confirmed by global proteomic analysis. However, when DSPR451G EHTs are subjected to increased diastolic stretch, they exhibit concomitant reductions in conduction velocity and the expression of connexin-43. These effects are rescued by inhibition of both lysosome activity and ERK signaling. Our results indicate that the response of DSPR451G EHTs to mechanical stimuli depends on the strain and the timing of the applied stimulus, with increased diastolic stretch unmasking conduction deficits in a concealed-phase model of ACM.
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Affiliation(s)
- Ronald Ng
- Yale University, New Haven, United States
| | | | | | - Fadi G Akar
- Cardiovascular Medicine and Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Stuart G Campbell
- Division of Cardiology, Department of Internal Medicine, Yale University, New Haven, CT, United States
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Shen S, Sewanan LR, Shao S, Halder SS, Stankey P, Li X, Campbell SG. Physiological calcium combined with electrical pacing accelerates maturation of human engineered heart tissue. Stem Cell Reports 2022; 17:2037-2049. [PMID: 35931080 PMCID: PMC9481907 DOI: 10.1016/j.stemcr.2022.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 12/24/2022] Open
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have wide potential application in basic research, drug discovery, and regenerative medicine, but functional maturation remains challenging. Here, we present a method whereby maturation of hiPSC-CMs can be accelerated by simultaneous application of physiological Ca2+ and frequency-ramped electrical pacing in culture. This combination produces positive force-frequency behavior, physiological twitch kinetics, robust β-adrenergic response, improved Ca2+ handling, and cardiac troponin I expression within 25 days. This study provides insights into the role of Ca2+ in hiPSC-CM maturation and offers a scalable platform for translational and clinical research.
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Affiliation(s)
- Shi Shen
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Lorenzo R Sewanan
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephanie Shao
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Saiti S Halder
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Paul Stankey
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xia Li
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA.
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Affiliation(s)
- Ronald Ng
- Department of Biomedical Engineering (R.N., L.R.S., P.S., X.L., S.C.), Yale University, New Haven, CT
| | - Lorenzo R Sewanan
- Department of Biomedical Engineering (R.N., L.R.S., P.S., X.L., S.C.), Yale University, New Haven, CT
| | - Paul Stankey
- Department of Biomedical Engineering (R.N., L.R.S., P.S., X.L., S.C.), Yale University, New Haven, CT
| | - Xia Li
- Department of Biomedical Engineering (R.N., L.R.S., P.S., X.L., S.C.), Yale University, New Haven, CT
| | - Yibing Qyang
- Yale Stem Cell Center (Y.Q.), Yale University, New Haven, CT.,Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine (Y.Q.), Yale School of Medicine, New Haven, CT.,Department of Pathology (Y.Q.), Yale School of Medicine, New Haven, CT.,Vascular Biology and Therapeutics Program (Y.Q.), Yale School of Medicine, New Haven, CT
| | - Stuart Campbell
- Department of Biomedical Engineering (R.N., L.R.S., P.S., X.L., S.C.), Yale University, New Haven, CT
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Ng R, Sewanan LR, Brill AL, Stankey P, Li X, Qyang Y, Ehrlich BE, Campbell SG. Contractile work directly modulates mitochondrial protein levels in human engineered heart tissues. Am J Physiol Heart Circ Physiol 2020; 318:H1516-H1524. [PMID: 32383992 DOI: 10.1152/ajpheart.00055.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Engineered heart tissues (EHTs) have emerged as a robust in vitro model to study cardiac physiology. Although biomimetic culture environments have been developed to better approximate in vivo conditions, currently available methods do not permit full recapitulation of the four phases of the cardiac cycle. We have developed a bioreactor which allows EHTs to undergo cyclic loading sequences that mimic in vivo work loops. EHTs cultured under these working conditions exhibited enhanced concentric contractions but similar isometric contractions compared with EHTs cultured isometrically. EHTs that were allowed to shorten cyclically in culture had increased capacity for contractile work when tested acutely. Increased work production was correlated with higher levels of mitochondrial proteins and mitochondrial biogenesis; this effect was eliminated when tissues were cyclically shortened in the presence of a myosin ATPase inhibitor. Leveraging our novel in vitro method to precisely apply mechanical loads in culture, we grew EHTs under two loading regimes prescribing the same work output but with different associated afterloads. These groups showed no difference in mitochondrial protein expression. In loading regimes with the same afterload but different work output, tissues subjected to higher work demand exhibited elevated levels of mitochondrial protein. Our findings suggest that regulation of mitochondrial mass in cultured human EHTs is potently modulated by the mechanical work the tissue is permitted to perform in culture, presumably communicated through ATP demand. Precise application of mechanical loads to engineered heart tissues in culture represents a novel in vitro method for studying physiological and pathological cardiac adaptation.NEW & NOTEWORTHY In this work, we present a novel bioreactor that allows for active length control of engineered heart tissues during extended tissue culture. Specific length transients were designed so that engineered heart tissues generated complete cardiac work loops. Chronic culture with various work loops suggests that mitochondrial mass and biogenesis are directly regulated by work output.
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Affiliation(s)
- Ronald Ng
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Lorenzo R Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Allison L Brill
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut
| | - Paul Stankey
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Xia Li
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Yibing Qyang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Pathology, Yale School of Medicine, New Haven, Connecticut.,Yale Stem Cell Center, Yale University, New Haven, Connecticut.,Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, Connecticut
| | - Barbara E Ehrlich
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut.,Department of Pharmacology, Yale University, New Haven, Connecticut
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
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