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Trayanova NA, Lyon A, Shade J, Heijman J. Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation. Physiol Rev 2024; 104:1265-1333. [PMID: 38153307 DOI: 10.1152/physrev.00017.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023] Open
Abstract
The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.
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Affiliation(s)
- Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Aurore Lyon
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Julie Shade
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
- Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, Maryland, United States
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
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2
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Hussaini S, Mamyraiym Kyzy A, Schröder-Schetelig J, Lädke SL, Venkatesan V, Diaz-Maue L, Quiñonez Uribe RA, Richter C, Biktashev VN, Majumder R, Krinski V, Luther S. Efficient termination of cardiac arrhythmias using optogenetic resonant feedback pacing. CHAOS (WOODBURY, N.Y.) 2024; 34:031103. [PMID: 38526981 DOI: 10.1063/5.0191519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 01/03/2024] [Indexed: 03/27/2024]
Abstract
Malignant cardiac tachyarrhythmias are associated with complex spatiotemporal excitation of the heart. The termination of these life-threatening arrhythmias requires high-energy electrical shocks that have significant side effects, including tissue damage, excruciating pain, and worsening prognosis. This significant medical need has motivated the search for alternative approaches that mitigate the side effects, based on a comprehensive understanding of the nonlinear dynamics of the heart. Cardiac optogenetics enables the manipulation of cellular function using light, enhancing our understanding of nonlinear cardiac function and control. Here, we investigate the efficacy of optically resonant feedback pacing (ORFP) to terminate ventricular tachyarrhythmias using numerical simulations and experiments in transgenic Langendorff-perfused mouse hearts. We show that ORFP outperforms the termination efficacy of the optical single-pulse (OSP) approach. When using ORFP, the total energy required for arrhythmia termination, i.e., the energy summed over all pulses in the sequence, is 1 mJ. With a success rate of 50%, the energy per pulse is 40 times lower than with OSP with a pulse duration of 10 ms. We demonstrate that even at light intensities below the excitation threshold, ORFP enables the termination of arrhythmias by spatiotemporal modulation of excitability inducing spiral wave drift.
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Affiliation(s)
- S Hussaini
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - A Mamyraiym Kyzy
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - J Schröder-Schetelig
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - S L Lädke
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - V Venkatesan
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - L Diaz-Maue
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
- Research Electronics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - R A Quiñonez Uribe
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - C Richter
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
- WG Cardiovascular Optogenetics, Lab Animal Science Unit, Leibniz Institute for Primate Research, Göttingen 37077, Germany
| | - V N Biktashev
- Department of Mathematics and Statistics, University of Exeter, Exeter EX4 4QF, United Kingdom
| | - R Majumder
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - V Krinski
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - S Luther
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
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3
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Ochs AR, Boyle PM. Optogenetic Modulation of Arrhythmia Triggers: Proof-of-Concept from Computational Modeling. Cell Mol Bioeng 2023; 16:243-259. [PMID: 37810996 PMCID: PMC10550900 DOI: 10.1007/s12195-023-00781-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 08/14/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Early afterdepolarizations (EADs) are secondary voltage depolarizations associated with reduced repolarization reserve (RRR) that can trigger lethal arrhythmias. Relating EADs to triggered activity is difficult to study, so the ability to suppress or provoke EADs would be experimentally useful. Here, we use computational simulations to assess the feasibility of subthreshold optogenetic stimulation modulating the propensity for EADs (cell-scale) and EAD-associated ectopic beats (organ-scale). Methods We modified a ventricular ionic model by reducing rapid delayed rectifier potassium (0.25-0.1 × baseline) and increasing L-type calcium (1.0-3.5 × baseline) currents to create RRR conditions with varying severity. We ran simulations in models of single cardiomyocytes and left ventricles from post-myocardial infarction patient MRI scans. Optogenetic stimulation was simulated using either ChR2 (depolarizing) or GtACR1 (repolarizing) opsins. Results In cell-scale simulations without illumination, EADs were seen for 164 of 416 RRR conditions. Subthreshold stimulation of GtACR1 reduced EAD incidence by up to 84.8% (25/416 RRR conditions; 0.1 μW/mm2); in contrast, subthreshold ChR2 excitation increased EAD incidence by up to 136.6% (388/416 RRR conditions; 50 μW/mm2). At the organ scale, we assumed simultaneous, uniform illumination of the epicardial and endocardial surfaces. GtACR1-mediated suppression (10-50 μW/mm2) and ChR2-mediated unmasking (50-100 μW/mm2) of EAD-associated ectopic beats were feasible in three distinct ventricular models. Conclusions Our findings suggest that optogenetics could be used to silence or provoke both EADs and EAD-associated ectopic beats. Validation in animal models could lead to exciting new experimental regimes and potentially to novel anti-arrhythmia treatments. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-023-00781-z.
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Affiliation(s)
- Alexander R. Ochs
- Department of Bioengineering, UW Bioengineering, University of Washington, 3720 15th Ave NE N107, UW Mailbox 355061, Seattle, WA 98195 USA
| | - Patrick M. Boyle
- Department of Bioengineering, UW Bioengineering, University of Washington, 3720 15th Ave NE N107, UW Mailbox 355061, Seattle, WA 98195 USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA USA
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Formozov A, Dieter A, Wiegert JS. A flexible and versatile system for multi-color fiber photometry and optogenetic manipulation. CELL REPORTS METHODS 2023; 3:100418. [PMID: 37056369 PMCID: PMC10088095 DOI: 10.1016/j.crmeth.2023.100418] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 12/20/2022] [Accepted: 02/08/2023] [Indexed: 03/09/2023]
Abstract
Here, we present simultaneous fiber photometry recordings and optogenetic stimulation based on a multimode fused fiber coupler for both light delivery and collection without the need for dichroic beam splitters. In combination with a multi-color light source and appropriate optical filters, our approach offers remarkable flexibility in experimental design and facilitates the exploration of new molecular tools in vivo at minimal cost. We demonstrate straightforward re-configuration of the setup to operate with green, red, and near-infrared calcium indicators with or without simultaneous optogenetic stimulation and further explore the multi-color photometry capabilities of the system. The ease of assembly, operation, characterization, and customization of this platform holds the potential to foster the development of experimental strategies for multi-color fused fiber photometry combined with optogenetics far beyond its current state.
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Affiliation(s)
- Andrey Formozov
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Alexander Dieter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - J. Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Neurophysiology, MCTN, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
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Konishi Y, Terai K. In vivo imaging of inflammatory response in cancer research. Inflamm Regen 2023; 43:10. [PMID: 36750856 PMCID: PMC9903460 DOI: 10.1186/s41232-023-00261-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Inflammation can contribute to the development and progression of cancer. The inflammatory responses in the tumor microenvironment are shaped by complex sequences of dynamic intercellular cross-talks among diverse types of cells, and recapitulation of these dynamic events in vitro has yet to be achieved. Today, intravital microscopy with two-photon excitation microscopes (2P-IVM) is the mainstay technique for observing intercellular cross-talks in situ, unraveling cellular and molecular mechanisms in the context of their spatiotemporal dynamics. In this review, we summarize the current state of 2P-IVM with fluorescent indicators of signal transduction to reveal the cross-talks between cancer cells and surrounding cells including both immune and non-immune cells. We also discuss the potential application of red-shifted indicators along with optogenetic tools to 2P-IVM. In an era of single-cell transcriptomics and data-driven research, 2P-IVM will remain a key advantage in delivering the missing spatiotemporal context in the field of cancer research.
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Affiliation(s)
- Yoshinobu Konishi
- grid.65499.370000 0001 2106 9910Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Kenta Terai
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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Pyari G, Bansal H, Roy S. Ultra-low power deep sustained optogenetic excitation of human ventricular cardiomyocytes with red-shifted opsins: A computational study. J Physiol 2022; 600:4653-4676. [PMID: 36068951 DOI: 10.1113/jp283366] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/31/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Formulation of accurate theoretical models of optogenetic control of HVCMs expressed with newly-discovered opsins (ChRmine, bReaChES, and CsChrimson). Under continuous illumination, action potentials in each opsin-expressing HVCMs can only be evoked in a certain range of irradiances. Action potentials in ChRmine-expressing HVCMs can be triggered at ultra-low power (6 μW/mm2 at 10 ms pulse or 0.7 μW/mm2 at 100 ms pulse at 585 nm), which is 2-3 orders of magnitude lower than reported results. Ongoing APs in ChRmine-expressing HVCMs can be suppressed by continuous illumination of 585 nm light at 2 μW/mm2 . ChRmine enables sustained excitation due to its faster recovery from the desensitized state. Optogenetic excitation of deeply situated cardiac cells is possible upto ∼ 7.46 mm and 10.2 mm with ChRmine on illuminating the outer surface of pericardium at safe irradiance at 585 nm and 650 nm, respectively. The study opens up prospects for designing energy-efficient light-induced pacemakers, resynchronization, and termination of ventricular tachycardia. ABSTRACT The main challenge in cardiac optogenetics is to have low-power, high-fidelity, and deep excitation of cells with minimal invasiveness and heating. We present a detailed computational study of optogenetic excitation of human ventricular cardiomyocytes (HVCMs) with new ChRmine, bReaChES and CsChrimson red-shifted opsins to overcome the challenge. Action potentials (APs) in ChRmine expressing HVCMs can be triggered at 6 μW/mm2 (10 ms pulse) and 0.7 μW/mm2 (100 ms pulse) at 585 nm which are two orders of magnitude lower than ChR2(H134R). This enables safe sustained excitation of deeply situated cardiac cells with ChRmine (7.46 mm) and with bReaChES (6.21 mm) with the light source at the pericardium surface. Deeper excitation upto 10.2 mm can be achieved with ChRmine by illuminating at 650 nm. Photostimulation conditions for minimum charge transfer during AP have been determined, which are important for tissue health under sustained excitation. The action potential duration for all the opsins is constant upto 100 ms pulse-width but increases thereafter. Interestingly, the AP frequency increases with irradiance under continuous illumination, which gets suppressed at higher irradiances. Optimal range of irradiance for each opsin to excite HVCMs has been determined. Under optimal photostimulation conditions, each opsin can precisely excite APs up to 2.5 Hz, while latency and power of light pulse for each AP in a sequence remain most stable and an order lower respectively, in ChRmine-expressing HVCMs. The study highlights the importance of ChRmine and bReaChES for resynchronization, termination of ventricular tachycardia, and designing optogenetic cardiac pacemakers with enhanced battery life. Abstract figure legend Deep optogenetic excitation of opsin-expressing cardiomyocytes by placing the light source (maximum output 5.5 mW/mm2 ) at the outer surface of the pericardium. Excitation of cardiomyocytes upto 10.2 mm (at 650 nm) and 7.46 mm (at 585 nm) is possible with ChRmine. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Gur Pyari
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Himanshu Bansal
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
| | - Sukhdev Roy
- Department of Physics and Computer Science, Dayalbagh Educational Institute, Agra, 282005, INDIA
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Imboden M, Chen S, Gudozhnik O, Pollock C, Javor J, Bishop D, Shea H, Rosset S. The Integration of Optical Stimulation in a Mechanically Dynamic Cell Culture Substrate. Front Bioeng Biotechnol 2022; 10:934756. [PMID: 35928941 PMCID: PMC9344002 DOI: 10.3389/fbioe.2022.934756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 05/30/2022] [Indexed: 12/14/2022] Open
Abstract
A cell culture well with integrated mechanical and optical stimulation is presented. This is achieved by combining dielectric elastomer soft actuators, also known as artificial muscles, and a varifocal micro-electromechanical mirror that couples light from an optical fiber and focuses it onto the transparent cell substrate. The device enables unprecedented control of in vitro cell cultures by allowing the experimenter to tune and synchronize mechanical and optical stimuli, thereby enabling new experimental assays in optogenetics, fluorescent microscopy, or laser stimulation that include dynamic mechanical strain as a controlled input parameter.
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Affiliation(s)
- Matthias Imboden
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel, Switzerland
| | - Sophia Chen
- Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Olexandr Gudozhnik
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel, Switzerland
| | - Corey Pollock
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Josh Javor
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - David Bishop
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Herbert Shea
- Soft Transducers Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel, Switzerland
| | - Samuel Rosset
- Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- *Correspondence: Samuel Rosset,
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Sung YL, Wang TW, Lin TT, Lin SF. Optogenetics in cardiology: methodology and future applications. INTERNATIONAL JOURNAL OF ARRHYTHMIA 2022. [DOI: 10.1186/s42444-022-00060-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractOptogenetics is an emerging biological approach with the unique capability of specific targeting due to the precise light control with high spatial and temporal resolution. It uses selected light wavelengths to control and modulate the biological functions of cells, tissues, and organ levels. Optogenetics has been instrumental in different biomedical applications, including neuroscience, diabetes, and mitochondria, based on distinctive optical biomedical effects with light modulation. Nowadays, optogenetics in cardiology is rapidly evolving for the understanding and treatment of cardiovascular diseases. Several in vitro and in vivo research for cardiac optogenetics demonstrated visible progress. The optogenetics technique can be applied to address critical cardiovascular problems such as heart failure and arrhythmia. To this end, this paper reviews cardiac electrophysiology and the technical progress about experimental and clinical cardiac optogenetics and provides the background and evolution of cardiac optogenetics. We reviewed the literature to demonstrate the servo type, transfection efficiency, signal recording, and heart disease targets in optogenetic applications. Such literature review would hopefully expedite the progress of optogenetics in cardiology and further expect to translate into the clinical terminal in the future.
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Sarvazyan N. Building Valveless Impedance Pumps From Biological Components: Progress and Challenges. Front Physiol 2022; 12:770906. [PMID: 35173623 PMCID: PMC8842681 DOI: 10.3389/fphys.2021.770906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 12/08/2021] [Indexed: 01/20/2023] Open
Abstract
Valveless pumping based on Liebau mechanism entails asymmetrical positioning of the compression site relative to the attachment sites of the pump's elastic segment to the rest of the circuit. Liebau pumping is believed to play a key role during heart development and be involved in several other physiological processes. Until now studies of Liebau pump have been limited to numerical analyses, in silico modeling, experiments using non-biological elements, and a few indirect in vivo measurements. This review aims to stimulate experimental efforts to build Liebau pumps using biologically compatible materials in order to encourage further exploration of the fundamental mechanisms behind valveless pumping and its role in organ physiology. The covered topics include the biological occurrence of Liebau pumps, the main differences between them and the peristaltic flow, and the potential uses and body sites that can benefit from implantable valveless pumps based on Liebau principle. We then provide an overview of currently available tools to build such pumps and touch upon limitations imposed by the use of biological components. We also talk about the many variables that can impact Liebau pump performance, including the concept of resonant frequencies, the shape of the flowrate-frequency relationship, the flow velocity profiles, and the Womersley numbers. Lastly, the choices of materials to build valveless impedance pumps and possible modifications to increase their flow output are briefly discussed.
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Affiliation(s)
- Narine Sarvazyan
- Department of Pharmacology and Physiology, School of Medicine and Health Science, The George Washington University, Washington, DC, United States
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10
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Huang LD. Brighten the Future: Photobiomodulation and Optogenetics. FOCUS (AMERICAN PSYCHIATRIC PUBLISHING) 2022; 20:36-44. [PMID: 35746943 PMCID: PMC9063588 DOI: 10.1176/appi.focus.20210025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Safe, noninvasive, and effective treatments for brain conditions are everyone's dream. Low-level light therapy (LLLT) based on the photobiomodulation (PBM) phenomenon has recently been adopted in practice, with solid scientific evidence. Optogenetics provides high spatiotemporal resolution to precisely switch on and off a particular circuitry in the brain. However, there are currently no human trials of optogenetics on the human brain. These two approaches-PBM and optogenetics-are promising photonic treatments that target the brain using completely different technologies. PBM is based on the mitochondrial reaction to the photons for up- or downregulation on the cytochrome c oxidase synthase in cellular respiration. It is safe, noninvasive, and good for long-term treatments, with wide applications using light wavelengths ranging from 650 nm to ≈1,100 nm, the red to near-infrared range. Optogenetics is based on the expression of engineered opsins on targeted tissues through viral vectors. The opsins are engineered to be sensors, actuators, or switches and could be precisely controlled by light wavelength ranging from 450 nm to ≈650 nm, the visible light range. The penetration of visible light is limited, and thus the photons cannot be applied directly outside the head without surgical means to create a physical window. PBM using near-infrared light could reach deeper tissues for light directly applied outside the head. Detailed scientific foundations and the state of the art for both technologies are reviewed. Ongoing developments are discussed to provide insight for future research and applications.
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11
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Chen K, Ernst P, Liu XM, Zhou L. Optogenetic Studies of Mitochondria. Methods Mol Biol 2022; 2501:311-324. [PMID: 35857235 DOI: 10.1007/978-1-0716-2329-9_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
While optogenetic approaches have been widely used for remote control of cell membrane excitability and intracellular signaling pathways, their application in mitochondrial study has been limited, largely due to the challenge of effectively and specifically expressing heterologous light-gated rhodopsin channels in the mitochondria. Here, we describe the methods for expressing functional channelrhodopsin 2 (ChR2) proteins in the mitochondrial inner membrane with an unusually long mitochondrial leading sequence and characterizing optogenetic-mediated mitochondrial membrane potential (ΔΨm) depolarization. We then illustrate how this next-generation optogenetic approach can be used to study the effect of ΔΨm on mitochondrial functions such as mitophagy, programed cell death, and preconditioning-mediated cytoprotection. We anticipate that this innovative technology will enable new insights into the mechanisms by which changes in ΔΨm differentially impacts mitochondrial and cellular functions.
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Affiliation(s)
- Kai Chen
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Patrick Ernst
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Xiaoguang Margaret Liu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lufang Zhou
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA.
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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12
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Madrid MK, Brennan JA, Yin RT, Knight HS, Efimov IR. Advances in Implantable Optogenetic Technology for Cardiovascular Research and Medicine. Front Physiol 2021; 12:720190. [PMID: 34675815 PMCID: PMC8523791 DOI: 10.3389/fphys.2021.720190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Optogenetic technology provides researchers with spatiotemporally precise tools for stimulation, sensing, and analysis of function in cells, tissues, and organs. These tools can offer low-energy and localized approaches due to the use of the transgenically expressed light gated cation channel Channelrhodopsin-2 (ChR2). While the field began with many neurobiological accomplishments it has also evolved exceptionally well in animal cardiac research, both in vitro and in vivo. Implantable optical devices are being extensively developed to study particular electrophysiological phenomena with the precise control that optogenetics provides. In this review, we highlight recent advances in novel implantable optogenetic devices and their feasibility in cardiac research. Furthermore, we also emphasize the difficulties in translating this technology toward clinical applications and discuss potential solutions for successful clinical translation.
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Affiliation(s)
- Micah K Madrid
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Jaclyn A Brennan
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Rose T Yin
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Helen S Knight
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
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13
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Ochs AR, Karathanos TV, Trayanova NA, Boyle PM. Optogenetic Stimulation Using Anion Channelrhodopsin (GtACR1) Facilitates Termination of Reentrant Arrhythmias With Low Light Energy Requirements: A Computational Study. Front Physiol 2021; 12:718622. [PMID: 34526912 PMCID: PMC8435849 DOI: 10.3389/fphys.2021.718622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/23/2021] [Indexed: 12/24/2022] Open
Abstract
Optogenetic defibrillation of hearts expressing light-sensitive cation channels (e.g., ChR2) has been proposed as an alternative to conventional electrotherapy. Past modeling work has shown that ChR2 stimulation can depolarize enough myocardium to interrupt arrhythmia, but its efficacy is limited by light attenuation and high energy needs. These shortcomings may be mitigated by using new optogenetic proteins like Guillardia theta Anion Channelrhodopsin (GtACR1), which produces a repolarizing outward current upon illumination. Accordingly, we designed a study to assess the feasibility of GtACR1-based optogenetic arrhythmia termination in human hearts. We conducted electrophysiological simulations in MRI-based atrial or ventricular models (n = 3 each), with pathological remodeling from atrial fibrillation or ischemic cardiomyopathy, respectively. We simulated light sensitization via viral gene delivery of three different opsins (ChR2, red-shifted ChR2, GtACR1) and uniform endocardial illumination at the appropriate wavelengths (blue, red, or green light, respectively). To analyze consistency of arrhythmia termination, we varied pulse timing (three evenly spaced intervals spanning the reentrant cycle) and intensity (atrial: 0.001–1 mW/mm2; ventricular: 0.001–10 mW/mm2). In atrial models, GtACR1 stimulation with 0.005 mW/mm2 green light consistently terminated reentry; this was 10–100x weaker than the threshold levels for ChR2-mediated defibrillation. In ventricular models, defibrillation was observed in 2/3 models for GtACR1 stimulation at 0.005 mW/mm2 (100–200x weaker than ChR2 cases). In the third ventricular model, defibrillation failed in nearly all cases, suggesting that attenuation issues and patient-specific organ/scar geometry may thwart termination in some cases. Across all models, the mechanism of GtACR1-mediated defibrillation was voltage forcing of illuminated tissue toward the modeled channel reversal potential of −40 mV, which made propagation through affected regions impossible. Thus, our findings suggest GtACR1-based optogenetic defibrillation of the human heart may be feasible with ≈2–3 orders of magnitude less energy than ChR2.
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Affiliation(s)
- Alexander R Ochs
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Thomas V Karathanos
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States.,Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD, United States
| | - Patrick M Boyle
- Department of Bioengineering, University of Washington, Seattle, WA, United States.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, United States.,Center for Cardiovascular Biology, University of Washington, Seattle, WA, United States
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14
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Majumder R, Mohamed Nazer AN, Panfilov AV, Bodenschatz E, Wang Y. Electrophysiological Characterization of Human Atria: The Understated Role of Temperature. Front Physiol 2021; 12:639149. [PMID: 34366877 PMCID: PMC8346027 DOI: 10.3389/fphys.2021.639149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Ambient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favor prolongation of the action potential. However, not much is known about the influence of temperature on other important characterization parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5-50°C). We observe that RMP decreases with increasing temperature. At ~ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ~ 200 ms.
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Affiliation(s)
- Rupamanjari Majumder
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | | | - Alexander V Panfilov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov University, Moscow, Russia.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium.,Laboratory of Computational Biology and Medicine, Ural Federal University, Yekaterinburg, Russia
| | - Eberhard Bodenschatz
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Laboratory of Atomic and Solid-State Physics and Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Yong Wang
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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15
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Storch S, Samantzis M, Balbi M. Driving Oscillatory Dynamics: Neuromodulation for Recovery After Stroke. Front Syst Neurosci 2021; 15:712664. [PMID: 34366801 PMCID: PMC8339272 DOI: 10.3389/fnsys.2021.712664] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/21/2021] [Indexed: 12/18/2022] Open
Abstract
Stroke is a leading cause of death and disability worldwide, with limited treatments being available. However, advances in optic methods in neuroscience are providing new insights into the damaged brain and potential avenues for recovery. Direct brain stimulation has revealed close associations between mental states and neuroprotective processes in health and disease, and activity-dependent calcium indicators are being used to decode brain dynamics to understand the mechanisms underlying these associations. Evoked neural oscillations have recently shown the ability to restore and maintain intrinsic homeostatic processes in the brain and could be rapidly deployed during emergency care or shortly after admission into the clinic, making them a promising, non-invasive therapeutic option. We present an overview of the most relevant descriptions of brain injury after stroke, with a focus on disruptions to neural oscillations. We discuss the optical technologies that are currently used and lay out a roadmap for future studies needed to inform the next generation of strategies to promote functional recovery after stroke.
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Affiliation(s)
- Sven Storch
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Montana Samantzis
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Matilde Balbi
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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16
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Li J, Li H, Rao P, Luo J, Wang X, Wang L. Shining light on cardiac electrophysiology: From detection to intervention, from basic research to translational applications. Life Sci 2021; 274:119357. [PMID: 33737082 DOI: 10.1016/j.lfs.2021.119357] [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: 12/05/2020] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Cardiac arrhythmias are an important group of cardiovascular diseases, which can occur alone or in association with other cardiovascular diseases. The development of cardiac arrhythmias cannot be separated from changes in cardiac electrophysiology, and the investigation and clarification of cardiac electrophysiological changes are beneficial for the treatment of cardiac arrhythmias. However, electrical energy-based pacemakers and defibrillators, which are widely used to treat arrhythmias, still have certain disadvantages. Thereby, optics promises to be used for optical manipulation and its use in biomedicine is increasing. Since visible light is readily absorbed and scattered in living tissues and tissue penetration is shallow, optical modulation for cells and tissues requires conversion media that convert light energy into bioelectrical activity. In this regard, fluorescent dyes, light-sensitive ion channels, and optical nanomaterials can assume this role, the corresponding optical mapping technology, optogenetics technology, and optical systems based on luminescent nanomaterials have been introduced into the research in cardiovascular field and are expected to be new tools for the study and treatment of cardiac arrhythmias. In addition, infrared and near-infrared light has strong tissue penetration, which is one of the excellent options of external trigger for achieving optical modulation, and is also widely used in the study of optical modulation of biological activities. Here, the advantages of optical applications are summarized, the research progresses and emerging applications of optical-based technologies as detection and intervention tools for cardiac electrophysiological are highlighted. Moreover, the prospects for future applications of optics in clinical diagnosis and treatment are discussed.
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Affiliation(s)
- Jianyi Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou 570311, PR China
| | - Panpan Rao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Junmiao Luo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China.
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China; Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China.
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17
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Abstract
The electromechanical function of the heart involves complex, coordinated activity over time and space. Life-threatening cardiac arrhythmias arise from asynchrony in these space-time events; therefore, therapies for prevention and treatment require fundamental understanding and the ability to visualize, perturb and control cardiac activity. Optogenetics combines optical and molecular biology (genetic) approaches for light-enabled sensing and actuation of electrical activity with unprecedented spatiotemporal resolution and parallelism. The year 2020 marks a decade of developments in cardiac optogenetics since this technology was adopted from neuroscience and applied to the heart. In this Review, we appraise a decade of advances that define near-term (immediate) translation based on all-optical electrophysiology, including high-throughput screening, cardiotoxicity testing and personalized medicine assays, and long-term (aspirational) prospects for clinical translation of cardiac optogenetics, including new optical therapies for rhythm control. The main translational opportunities and challenges for optogenetics to be fully embraced in cardiology are also discussed.
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18
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Li W, Han JL, Entcheva E. Syncytium cell growth increases Kir2.1 contribution in human iPSC-cardiomyocytes. Am J Physiol Heart Circ Physiol 2020; 319:H1112-H1122. [PMID: 32986966 PMCID: PMC7789971 DOI: 10.1152/ajpheart.00148.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) enable cardiotoxicity testing and personalized medicine. However, their maturity is of concern, including relatively depolarized resting membrane potential and more spontaneous activity compared with adult cardiomyocytes, implicating low or lacking inward rectifier potassium current (Ik1). Here, protein quantification confirms Kir2.1 expression in hiPSC-CM syncytia, albeit several times lower than in adult heart tissue. We find that hiPSC-CM culture density influences Kir2.1 expression at the mRNA level (potassium inwardly rectifying channel subfamily J member 2) and at the protein level and its associated electrophysiology phenotype. Namely, all-optical cardiac electrophysiology and pharmacological treatments reveal reduction of spontaneous and irregular activity and increase in action potential upstroke in denser cultures. Blocking Ik1-like currents with BaCl2 increased spontaneous frequency and blunted action potential upstrokes during pacing in a dose-dependent manner only in the highest-density cultures, in line with Ik1’s role in regulating the resting membrane potential. Our results emphasize the importance of syncytial growth of hiPSC-CMs for more physiologically relevant phenotype and the power of all-optical electrophysiology to study cardiomyocytes in their multicellular setting. NEW & NOTEWORTHY We identify cell culture density and cell-cell contact as an important factor in determining the expression of a key ion channel at the transcriptional and the protein levels, KCNJ2/Kir2.1, and its contribution to the electrophysiology of human induced pluripotent stem cell-derived cardiomyocytes. Our results indicate that studies on isolated cells, out of tissue context, may underestimate the cellular ion channel properties being characterized.
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Affiliation(s)
- Weizhen Li
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
| | - Julie L Han
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
| | - Emilia Entcheva
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
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19
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Li J, Wang L, Luo J, Li H, Rao P, Cheng Y, Wang X, Huang C. Optical capture and defibrillation in rats with monocrotaline-induced myocardial fibrosis 1 year after a single intravenous injection of adeno-associated virus channelrhodopsin-2. Heart Rhythm 2020; 18:109-117. [PMID: 32781160 DOI: 10.1016/j.hrthm.2020.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/28/2020] [Accepted: 08/04/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Optogenetics uses light to regulate cardiac rhythms and terminate malignant arrhythmias. OBJECTIVE The purpose of this study was to investigate the long-term validity of optical capture properties based on virus-transfected channelrhodopsin-2 (ChR2) and evaluate the effects of optogenetic-based defibrillation in an in vivo rat model of myocardial fibrosis enhanced by monocrotaline (MCT). METHODS Fifteen infant rats received jugular vein injection of adeno-associated virus (AAV). After 8 weeks, 5 rats were randomly selected to verify the effectiveness ChR2 transfection. The remaining rats were administered MCT at 11 months. Four weeks after MCT, the availability of 473-nm blue light to capture heart rhythm in these rats was verified again. Ventricular tachycardia (VT) and ventricular fibrillation (VF) were induced by burst stimulation on the basis of enhanced myocardial fibrosis, and the termination effects of the optical manipulation were tested. RESULTS Eight weeks after AAV injection, there was ChR2 expression throughout the ventricular myocardium as reflected by both fluorescence imaging and optical pacing. Four weeks after MCT, significant myocardial fibrosis was achieved. Light could still trigger the corresponding ectopic heart rhythm, and the pulse width and illumination area could affect the light capture rate. VT/VF was induced successfully in 1-year-observation rats, and the rate of termination of VT/VF under light was much higher than that of spontaneous termination. CONCLUSION Viral ChR2 transfection can play a long-term role in the rat heart, and light can successfully regulate heart rhythm and defibrillate after cardiac fibrosis.
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Affiliation(s)
- Jianyi Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China; Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
| | - Junmiao Luo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan Province, People's Republic of China
| | - Panpan Rao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Yue Cheng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China.
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China; Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China; Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China.
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20
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Men J, Li A, Jerwick J, Li Z, Tanzi RE, Zhou C. Non-invasive red-light optogenetic control of Drosophila cardiac function. Commun Biol 2020; 3:336. [PMID: 32601302 PMCID: PMC7324573 DOI: 10.1038/s42003-020-1065-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 06/03/2020] [Indexed: 02/03/2023] Open
Abstract
Drosophila is a powerful genetic model system for cardiovascular studies. Recently, optogenetic pacing tools have been developed to control Drosophila heart rhythm noninvasively with blue light, which has a limited penetration depth. Here we developed both a red-light sensitive opsin expressing Drosophila system and an integrated red-light stimulation and optical coherence microscopy (OCM) imaging system. We demonstrated noninvasive control of Drosophila cardiac rhythms using a single light source, including simulated tachycardia in ReaChR-expressing flies and bradycardia and cardiac arrest in halorhodopsin (NpHR)-expressing flies at multiple developmental stages. By using red excitation light, we were able to pace flies at higher efficiency and with lower power than with equivalent blue light excitation systems. The recovery dynamics after red-light stimulation of NpHR flies were observed and quantified. The combination of red-light stimulation, OCM imaging, and transgenic Drosophila systems provides a promising and easily manipulated research platform for noninvasive cardiac optogenetic studies. Men et al. develop an optogenetic pacing tool to control Drosophila heart rhythm noninvasively with red light. Using optical coherence microscopy imaging, they demonstrate effective light-induced tachypacing, bradypacing, and restorable cardiac arrest in transgenic fly models. This study provides a user-friendly research platform for noninvasive cardiac optogenetic studies.
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Affiliation(s)
- Jing Men
- Department of Bioengineering, Lehigh University, Bethlehem, PA, 18015, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63105, USA
| | - Airong Li
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Jason Jerwick
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63105, USA.,Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA, 18015, USA
| | - Zilong Li
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Chao Zhou
- Department of Bioengineering, Lehigh University, Bethlehem, PA, 18015, USA. .,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63105, USA. .,Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
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21
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Sorrentino A, Michel T. Redox à la carte: Novel chemogenetic models of heart failure. Br J Pharmacol 2020; 177:3162-3167. [PMID: 32368791 DOI: 10.1111/bph.15093] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/12/2020] [Accepted: 03/15/2020] [Indexed: 12/20/2022] Open
Abstract
Many current animal models of heart failure are hampered by intrinsic methodological complexities, while other models yield only a subtle cardiac phenotype even after prolonged in vivo treatments. A new 'chemogenetic' animal model of heart failure reproduces a critical characteristic shared by many disease states that lead to heart failure in humans: an increase in redox stress in the heart. This 'chemogenetic' approach exploits a recombinant yeast enzyme that can be dynamically and specifically activated in vivo to generate the ROS hydrogen peroxide (H2 O2 ) in cardiac myocytes. Redox stress can be rapidly, selectively and reversibly manipulated by chemogenetic generation of ROS in cardiac myocytes, yielding a new model of dilated cardiomyopathy. Treatment of animals with the angiotensin receptor antagonist valsartan promotes recovery of ventricular function and resolution of adverse cardiac remodelling. This mini-review discusses in vivo chemogenetic approaches to manipulate and analyse oxidative stress in the heart.
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Affiliation(s)
- Andrea Sorrentino
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Thomas Michel
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
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22
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Paci M, Passini E, Klimas A, Severi S, Hyttinen J, Rodriguez B, Entcheva E. All-Optical Electrophysiology Refines Populations of In Silico Human iPSC-CMs for Drug Evaluation. Biophys J 2020; 118:2596-2611. [PMID: 32298635 PMCID: PMC7231889 DOI: 10.1016/j.bpj.2020.03.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
High-throughput in vitro drug assays have been impacted by recent advances in human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) technology and by contact-free all-optical systems simultaneously measuring action potentials (APs) and Ca2+ transients (CaTrs). Parallel computational advances have shown that in silico simulations can predict drug effects with high accuracy. We combine these in vitro and in silico technologies and demonstrate the utility of high-throughput experimental data to refine in silico hiPSC-CM populations and to predict and explain drug action mechanisms. Optically obtained hiPSC-CM APs and CaTrs were used from spontaneous activity and under optical pacing in control and drug conditions at multiple doses. An updated version of the Paci2018 model was developed to refine the description of hiPSC-CM spontaneous electrical activity; a population of in silico hiPSC-CMs was constructed and calibrated using simultaneously recorded APs and CaTrs. We tested in silico five drugs (astemizole, dofetilide, ibutilide, bepridil, and diltiazem) and compared the outcomes to in vitro optical recordings. Our simulations showed that physiologically accurate population of models can be obtained by integrating AP and CaTr control records. Thus, constructed population of models correctly predicted the drug effects and occurrence of adverse episodes, even though the population was optimized only based on control data and in vitro drug testing data were not deployed during its calibration. Furthermore, the in silico investigation yielded mechanistic insights; e.g., through simulations, bepridil's more proarrhythmic action in adult cardiomyocytes compared to hiPSC-CMs could be traced to the different expression of ion currents in the two. Therefore, our work 1) supports the utility of all-optical electrophysiology in providing high-content data to refine experimentally calibrated populations of in silico hiPSC-CMs, 2) offers insights into certain limitations when translating results obtained in hiPSC-CMs to humans, and 3) shows the strength of combining high-throughput in vitro and population in silico approaches.
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Affiliation(s)
- Michelangelo Paci
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
| | - Elisa Passini
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Aleksandra Klimas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Stefano Severi
- Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi," University of Bologna, Cesena, Italy
| | - Jari Hyttinen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Emilia Entcheva
- Department of Biomedical Engineering, George Washington University, Washington, D.C
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Joshi J, Rubart M, Zhu W. Optogenetics: Background, Methodological Advances and Potential Applications for Cardiovascular Research and Medicine. Front Bioeng Biotechnol 2020; 7:466. [PMID: 32064254 PMCID: PMC7000355 DOI: 10.3389/fbioe.2019.00466] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/19/2019] [Indexed: 12/27/2022] Open
Abstract
Optogenetics is an elegant approach of precisely controlling and monitoring the biological functions of a cell, group of cells, tissues, or organs with high temporal and spatial resolution by using optical system and genetic engineering technologies. The field evolved with the need to precisely control neurons and decipher neural circuity and has made great accomplishments in neuroscience. It also evolved in cardiovascular research almost a decade ago and has made considerable progress in both in vitro and in vivo animal studies. Thus, this review is written with an objective to provide information on the evolution, background, methodical advances, and potential scope of the field for cardiovascular research and medicine. We begin with a review of literatures on optogenetic proteins related to their origin, structure, types, mechanism of action, methods to improve their performance, and the delivery vehicles and methods to express such proteins on target cells and tissues for cardiovascular research. Next, we reviewed historical and recent literatures to demonstrate the scope of optogenetics for cardiovascular research and regenerative medicine and examined that cardiac optogenetics is vital in mimicking heart diseases, understanding the mechanisms of disease progression and also in introducing novel therapies to treat cardiac abnormalities, such as arrhythmias. We also reviewed optogenetics as promising tools in providing high-throughput data for cardiotoxicity screening in drug development and also in deciphering dynamic roles of signaling moieties in cell signaling. Finally, we put forth considerations on the need of scaling up of the optogenetic system, clinically relevant in vivo and in silico models, light attenuation issues, and concerns over the level, immune reactions, toxicity, and ectopic expression with opsin expression. Detailed investigations on such considerations would accelerate the translation of cardiac optogenetics from present in vitro and in vivo animal studies to clinical therapies.
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Affiliation(s)
- Jyotsna Joshi
- Department of Cardiovascular Medicine, Physiology and Biomedical Engineering, Mayo Clinic, Phoenix, AZ, United States
| | - Michael Rubart
- Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Wuqiang Zhu
- Department of Cardiovascular Medicine, Physiology and Biomedical Engineering, Mayo Clinic, Phoenix, AZ, United States
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24
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Keshmiri Neghab H, Goliaei B, Saboury AA, Esmaeeli Djavid G, Pornour M, Hong J, Grusch M. Modulation of cardiac optogenetics by vitamin A. Biofactors 2019; 45:983-990. [PMID: 31509323 DOI: 10.1002/biof.1564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 08/16/2019] [Indexed: 01/03/2023]
Abstract
Cardiac optogenetics is an emergent research area and refers to the delivery of light-activated proteins to excitable heart tissue and the subsequent use of light for controlling the electrical function with high spatial and temporal resolution. Channelrhodopsin-2 (ChR2) is a light-sensitive ion channel with the chromophore, all trans retinal, derived from vitamin A (all-trans-retinol; retinol). In this study, we explored whether exogenous vitamin A can be a limiting factor in the light responsiveness of cardiomyocytes-expressing ChR2. We showed that in cardiomyocytes virally transduced with ChR2 (H134R)-enhanced yellow fluorescent protein, vitamin A supplements lower than 10 μM significantly increased ChR2 expression. Adding 1 μM vitamin A changed light-induced transmembrane potential difference significantly, whereas 5 μM dramatically induced membrane depolarization and triggered intracellular calcium elevation. We concluded that vitamin A supplementation can modulate the efficiency of ChR2 and provide a complementary strategy for improving the performance of optogenetic tools.
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Affiliation(s)
| | - Bahram Goliaei
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Ali A Saboury
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Gholamreza Esmaeeli Djavid
- Department of Photo Healing and Regeneration, Medical Laser Research Center, Yara Institute Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Majid Pornour
- Department of Photo Healing and Regeneration, Medical Laser Research Center, Yara Institute Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Jun Hong
- School of Life Sciences, Henan University, Kaifeng, China
| | - Michael Grusch
- Department of Medicine I, Comprehensive Cancer Center Vienna, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
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25
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Ferenczi EA, Tan X, Huang CLH. Principles of Optogenetic Methods and Their Application to Cardiac Experimental Systems. Front Physiol 2019; 10:1096. [PMID: 31572204 PMCID: PMC6749684 DOI: 10.3389/fphys.2019.01096] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
Optogenetic techniques permit studies of excitable tissue through genetically expressed light-gated microbial channels or pumps permitting transmembrane ion movement. Light activation of these proteins modulates cellular excitability with millisecond precision. This review summarizes optogenetic approaches, using examples from neurobiological applications, and then explores their application in cardiac electrophysiology. We review the available opsins, including depolarizing and hyperpolarizing variants, as well as modulators of G-protein coupled intracellular signaling. We discuss the biophysical properties that determine the ability of microbial opsins to evoke reliable, precise stimulation or silencing of electrophysiological activity. We also review spectrally shifted variants offering possibilities for enhanced depth of tissue penetration, combinatorial stimulation for targeting different cell subpopulations, or all-optical read-in and read-out studies. Expression of the chosen optogenetic tool in the cardiac cell of interest then requires, at the single-cell level, introduction of opsin-encoding genes by viral transduction, or coupling "spark cells" to primary cardiomyocytes or a stem-cell derived counterpart. At the system-level, this requires construction of transgenic mice expressing ChR2 in their cardiomyocytes, or in vivo injection (myocardial or systemic) of adenoviral expression systems. Light delivery, by laser or LED, with widespread or multipoint illumination, although relatively straightforward in vitro may be technically challenged by cardiac motion and light-scattering in biological tissue. Physiological read outs from cardiac optogenetic stimulation include single cell patch clamp recordings, multi-unit microarray recordings from cell monolayers or slices, and electrical recordings from isolated Langendorff perfused hearts. Optical readouts of specific cellular events, including ion transients, voltage changes or activity in biochemical signaling cascades, using small detecting molecules or genetically encoded sensors now offer powerful opportunities for all-optical control and monitoring of cellular activity. Use of optogenetics has expanded in cardiac physiology, mainly using optically controlled depolarizing ion channels to control heart rate and for optogenetic defibrillation. ChR2-expressing cardiomyocytes show normal baseline and active excitable membrane and Ca2+ signaling properties and are sensitive even to ~1 ms light pulses. They have been employed in studies of the intrinsic cardiac adrenergic system and of cardiac arrhythmic properties.
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Affiliation(s)
- Emily A. Ferenczi
- Department of Neurology, Massachusetts General Hospital and Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Christopher L.-H. Huang
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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26
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Richter C, Bruegmann T. No light without the dark: Perspectives and hindrances for translation of cardiac optogenetics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 154:39-50. [PMID: 31515056 DOI: 10.1016/j.pbiomolbio.2019.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 08/18/2019] [Accepted: 08/27/2019] [Indexed: 12/30/2022]
Abstract
Over the last decade, optogenetic stimulation of the heart and its translational potential for rhythm control attracted more and more interest. Optogenetics allows to stimulate cardiomyocytes expressing the light-gated cation channel Channelrhodopsin 2 (ChR2) with light and thus high spatio-temporal precision. Therefore this new approach can overcome the technical limitations of electrical stimulation. In regard of translational approaches, the prospect of pain-free stimulation, if ChR2 expression is restricted to cardiomyocytes, is especially intriguing and could be highly beneficial for cardioversion and defibrillation. However, there is no light without shadow and cardiac optogenetics has to surmount critical hurdles, namely "how" to inscribe light-sensitivity by expressing ChR2 in a native heart and how to avoid side effects such as possible immune responses against the gene transfer. Furthermore, implantable light devices have to be developed which ensure sufficient illumination in a highly contractile environment. Therefore this article reviews recent advantages in the field of cardiac optogenetics with a special focus on the hindrances for the potential translation of this new approach into clinics and provides an outlook how these have to be carefully investigated and could be solved step by step.
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Affiliation(s)
- Claudia Richter
- RG Biomedical Physics, Max Planck Institute for Dynamics & Self-Organization, Am Fassberg 17, 37077, Goettingen, Germany; Department of Cardiology and Pneumology, University Medical Center, Robert-Koch-Str. 42a, 37075, Goettingen, Germany; DZHK e.V. (German Center for Cardiovascular Research), Partner Site Goettingen, 37075, Goettingen, Germany.
| | - Tobias Bruegmann
- DZHK e.V. (German Center for Cardiovascular Research), Partner Site Goettingen, 37075, Goettingen, Germany; Institute for Cardiovascular Physiology, University Medical Center Goettingen, Humboldtallee 23, 37073, Goettingen, Germany.
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27
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Dong R, Mu-u-min R, Reith AJM, O’Shea C, He S, Duan K, Kou K, Grassam-Rowe A, Tan X, Pavlovic D, Ou X, Lei M. A Protocol for Dual Calcium-Voltage Optical Mapping in Murine Sinoatrial Preparation With Optogenetic Pacing. Front Physiol 2019; 10:954. [PMID: 31456689 PMCID: PMC6698704 DOI: 10.3389/fphys.2019.00954] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/09/2019] [Indexed: 01/08/2023] Open
Abstract
Among the animal models for studying the molecular basis of atrial and sinoatrial node (SAN) biology and disease, the mouse is a widely used species due to its feasibility for genetic modifications in genes encoding ion channels or calcium handling and signaling proteins in the heart. It is therefore highly valuable to develop robust methodologies for studying SAN and atrial electrophysiological function in this species. Here, we describe a protocol for performing dual calcium-voltage optical mapping on mouse sinoatrial preparation (SAP), in combination with an optogenetic approach, for studying SAP membrane potential, intracellular Ca2+ transients, and pacemaker activity. The protocol includes the details for preparing the intact SAP, robust tissue dual-dye loading, light-programmed pacing, and high-resolution optical mapping. Our protocol provides an example of use of the combination of optogenetic and optical mapping techniques for investigating SAP membrane potential and intracellular Ca2+ transients and pacemaker activity with high temporal and spatial resolution in specific cardiac tissues. Thus, our protocol provides a useful tool for studying SAP physiology and pathophysiology in mice.
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Affiliation(s)
- Ruirui Dong
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Razik Mu-u-min
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | | | - Christopher O’Shea
- Institute for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Shicheng He
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Kaizhong Duan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Kun Kou
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | | | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Davor Pavlovic
- Institute for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Xianhong Ou
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Ming Lei
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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Ernst P, Xu N, Qu J, Chen H, Goldberg MS, Darley-Usmar V, Zhang JJ, O'Rourke B, Liu X, Zhou L. Precisely Control Mitochondria with Light to Manipulate Cell Fate Decision. Biophys J 2019; 117:631-645. [PMID: 31400914 DOI: 10.1016/j.bpj.2019.06.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/13/2019] [Accepted: 06/17/2019] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial dysfunction has been implicated in many pathological conditions and diseases. The normal functioning of mitochondria relies on maintaining the inner mitochondrial membrane potential (also known as ΔΨm) that is essential for ATP synthesis, Ca2+ homeostasis, redox balance, and regulation of other key signaling pathways such as mitophagy and apoptosis. However, the detailed mechanisms by which ΔΨm regulates cellular function remain incompletely understood, partially because of the difficulty of manipulating ΔΨm with spatiotemporal resolution, reversibility, or cell type specificity. To address this need, we have developed a next generation optogenetic-based technique for controllable mitochondrial depolarization with light. We demonstrate successful targeting of the heterologous channelrhodopsin-2 fusion protein to the inner mitochondrial membrane and formation of functional cationic channels capable of light-induced selective ΔΨm depolarization and mitochondrial autophagy. Importantly, we for the first time, to our knowledge, show that optogenetic-mediated mitochondrial depolarization can be well controlled to differentially influence the fate of cells expressing mitochondrial channelrhodopsin-2; whereas sustained moderate light illumination induces substantial apoptotic cell death, transient mild light illumination elicits cytoprotection via mitochondrial preconditioning. Finally, we show that Parkin overexpression exacerbates, instead of ameliorating, mitochondrial depolarization-mediated cell death in HeLa cells. In summary, we provide evidence that the described mitochondrial-targeted optogenetics may have a broad application for studying the role of mitochondria in regulating cell function and fate decision.
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Affiliation(s)
- Patrick Ernst
- Departments of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama; Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ningning Xu
- Departments of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jing Qu
- Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Herbert Chen
- Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | - Jianyi J Zhang
- Departments of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Xiaoguang Liu
- Departments of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
| | - Lufang Zhou
- Departments of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama; Medicine, University of Alabama at Birmingham, Birmingham, Alabama.
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29
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Sasse P, Funken M, Beiert T, Bruegmann T. Optogenetic Termination of Cardiac Arrhythmia: Mechanistic Enlightenment and Therapeutic Application? Front Physiol 2019; 10:675. [PMID: 31244670 PMCID: PMC6563676 DOI: 10.3389/fphys.2019.00675] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/13/2019] [Indexed: 01/08/2023] Open
Abstract
Optogenetic methods enable selective de- and hyperpolarization of cardiomyocytes expressing light-sensitive proteins within the myocardium. By using light, this technology provides very high spatial and temporal precision, which is in clear contrast to electrical stimulation. In addition, cardiomyocyte-specific expression would allow pain-free stimulation. In light of these intrinsic technical advantages, optogenetic methods provide an intriguing opportunity to understand and improve current strategies to terminate cardiac arrhythmia as well as for possible pain-free arrhythmia termination in patients in the future. In this review, we give a concise introduction to optogenetic stimulation of cardiomyocytes and the whole heart and summarize the recent progress on optogenetic defibrillation and cardioversion to terminate cardiac arrhythmia. Toward this aim, we specifically focus on the different mechanisms of optogenetic arrhythmia termination and how these might influence the prerequisites for success. Furthermore, we critically discuss the clinical perspectives and potential patient populations, which might benefit from optogenetic defibrillation devices.
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Affiliation(s)
- Philipp Sasse
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany
| | - Maximilian Funken
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany.,Department of Internal Medicine II, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Thomas Beiert
- Department of Internal Medicine II, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Tobias Bruegmann
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany.,Research Training Group 1873, University of Bonn, Bonn, Germany.,Institute of Cardiovascular Physiology, University Medical Center, Georg August University Göttingen, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner site Göttingen, Göttingen, Germany
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30
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O’Shea C, Holmes AP, Winter J, Correia J, Ou X, Dong R, He S, Kirchhof P, Fabritz L, Rajpoot K, Pavlovic D. Cardiac Optogenetics and Optical Mapping - Overcoming Spectral Congestion in All-Optical Cardiac Electrophysiology. Front Physiol 2019; 10:182. [PMID: 30899227 PMCID: PMC6416196 DOI: 10.3389/fphys.2019.00182] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 02/14/2019] [Indexed: 12/30/2022] Open
Abstract
Optogenetic control of the heart is an emergent technology that offers unparalleled spatio-temporal control of cardiac dynamics via light-sensitive ion pumps and channels (opsins). This fast-evolving technique holds broad scope in both clinical and basic research setting. Combination of optogenetics with optical mapping of voltage or calcium fluorescent probes facilitates 'all-optical' electrophysiology, allowing precise optogenetic actuation of cardiac tissue with high spatio-temporal resolution imaging of action potential and calcium transient morphology and conduction patterns. In this review, we provide a synopsis of optogenetics and discuss in detail its use and compatibility with optical interrogation of cardiac electrophysiology. We briefly discuss the benefits of all-optical cardiac control and electrophysiological interrogation compared to traditional techniques, and describe mechanisms, unique features and limitations of optically induced cardiac control. In particular, we focus on state-of-the-art setup design, challenges in light delivery and filtering, and compatibility of opsins with fluorescent reporters used in optical mapping. The interaction of cardiac tissue with light, and physical and computational approaches to overcome the 'spectral congestion' that arises from the combination of optogenetics and optical mapping are discussed. Finally, we summarize recent preclinical work applications of combined cardiac optogenetics and optical mapping approach.
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Affiliation(s)
- Christopher O’Shea
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
- EPSRC Centre for Doctoral Training in Physical Sciences for Health, School of Chemistry, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P. Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Clinical Sciences, University of Birmingham, Birmingham, United Kingdom
| | - James Winter
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Joao Correia
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Xianhong Ou
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Ruirui Dong
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Shicheng He
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Cardiology, UHB NHS Trust, Birmingham, United Kingdom
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Cardiology, UHB NHS Trust, Birmingham, United Kingdom
| | - Kashif Rajpoot
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
| | - Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
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31
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Ambrosi CM, Sadananda G, Han JL, Entcheva E. Adeno-Associated Virus Mediated Gene Delivery: Implications for Scalable in vitro and in vivo Cardiac Optogenetic Models. Front Physiol 2019; 10:168. [PMID: 30890951 PMCID: PMC6412093 DOI: 10.3389/fphys.2019.00168] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/12/2019] [Indexed: 12/12/2022] Open
Abstract
Adeno-associated viruses (AAVs) provide advantages in long-term, cardiac-specific gene expression. However, AAV serotype specificity data is lacking in experimental models relevant to cardiac electrophysiology and cardiac optogenetics. We aimed to identify the optimal AAV serotype (1, 6, or 9) in pursuit of scalable rodent and human models using genetic modifications in cardiac electrophysiology and optogenetics, in particular, as well as to elucidate the mechanism of virus uptake. In vitro syncytia of primary neonatal rat ventricular cardiomyocytes (NRVMs) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were infected with AAVs 1, 6, and 9 containing the transgene for eGFP or channelrhodopsin-2 (ChR2) fused to mCherry. In vivo adult rats were intravenously injected with AAV1 and 9 containing ChR2-mCherry. Transgene expression profiles of rat and human cells in vitro revealed that AAV1 and 6 significantly outperformed AAV9. In contrast, systemic delivery of AAV9 in adult rat hearts yielded significantly higher levels of ChR2-mCherry expression and optogenetic responsiveness. We tracked the mechanism of virus uptake to purported receptor-mediators for AAV1/6 (cell surface sialic acid) and AAV9 (37/67 kDa laminin receptor, LamR). In vitro desialylation of NRVMs and hiPSC-CMs with neuraminidase (NM) significantly decreased AAV1,6-mediated gene expression, but interestingly, desialylation of hiPSC-CMs increased AAV9-mediated expression. In fact, only very high viral doses of AAV9-ChR2-mCherry, combined with NM treatment, yielded consistent optogenetic responsiveness in hiPSC-CMs. Differences between the in vitro and in vivo performance of AAV9 could be correlated to robust LamR expression in the intact heart (neonatal rat hearts as well as adult human and rat hearts), but no expression in vitro in cultured cells (primary rat cells and hiPS-CMs). The dynamic nature of LamR expression and its dependence on environmental factors was further corroborated in intact adult human ventricular tissue. The combined transgene expression and cell surface receptor data may explain the preferential efficiency of AAV1/6 in vitro and AAV9 in vivo for cardiac delivery and mechanistic knowledge of their action can help guide cardiac optogenetic efforts. More broadly, these findings are relevant to future efforts in gene therapy for cardiac electrophysiology abnormalities in vivo as well as for genetic modifications of cardiomyocytes by viral means in vitro applications such as disease modeling or high-throughput drug testing.
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Affiliation(s)
- Christina M Ambrosi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States.,Department of Biomedical Engineering, George Washington University, Washington, DC, United States
| | - Gouri Sadananda
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States
| | - Julie L Han
- Department of Biomedical Engineering, George Washington University, Washington, DC, United States
| | - Emilia Entcheva
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States.,Department of Biomedical Engineering, George Washington University, Washington, DC, United States
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32
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Moreno A, Endicott K, Skancke M, Dwyer MK, Brennan J, Efimov IR, Trachiotis G, Mendelowitz D, Kay MW. Sudden Heart Rate Reduction Upon Optogenetic Release of Acetylcholine From Cardiac Parasympathetic Neurons in Perfused Hearts. Front Physiol 2019; 10:16. [PMID: 30745877 PMCID: PMC6360159 DOI: 10.3389/fphys.2019.00016] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 01/10/2019] [Indexed: 11/13/2022] Open
Abstract
The balance of sympathetic and parasympathetic tone provides exquisite control of heart rate and contractility and has also been shown to modulate coronary flow and inflammation. Understanding how autonomic balance is altered by cardiac disease is an active area of research, and developing new ways to control this balance provides insights into disease therapies. However, achieving acute neuron-specific stimulation of autonomic neurons can be difficult in experiments that measure the acute effects of nerve stimulation on the heart. Conventional electrical and pharmacological approaches can be spatially and temporally non-selective. Cell-specific expression of light-activated channels (channelrhodopsin, ChR2) is a powerful approach that enables control of the timing and distribution of cellular stimulation using light. We present such an optogenetic approach where parasympathetic cardiac neurons are selectively photoactivated at high temporal precision to initiate cholinergic-mediated slowing of heart rate. Mice were crossbred to express ChR2 in peripheral cholinergic neurons using Cre-Lox recombination driven by a choline acetyltransferase (ChAT) promoter. Hearts from adult mice were excised, perfused, and the epicardium was illuminated (peak 460–465 nm) to photoactivate ChR2. In one set of studies, hearts were illuminated using a large-field LED light source. In other studies, a micro LED was placed on the right atrium to selectively illuminate the junction of the superior vena cava (SVC) and right atrium. The ECG was acquired before, during, and after tissue illumination to measure changes in heart rate. Upon illumination, hearts exhibited sudden and dramatic reductions in heart rate with restoration of normal heart rate after cessation of illumination. Delays in atrioventricular conduction were also observed. Heart rate reductions at the highest irradiance levels were similar to heart rate reductions caused by application of bethanechol (10 μM) or acetylcholine (800 μM). Atropine (50 nM) completely blocked the effect of ChR2 photoactivation, confirming cholinergic mediation. Optogenetic activation of intrinsic parasympathetic neurons reduced heart rate in an immediate, dose-dependent fashion, resembling the slowing of sinus rate in response to acetylcholine. Our results demonstrate a new approach for controlling parasympathetic modulation of cardiac function by selectively activating the endogenous release of acetylcholine from intrinsic cardiac cholinergic neurons. Key Message: Optogenetic photoactivation of intrinsic cardiac neurons provides immediate, tissue-specific stimulation with minimal cross-reactivity. Our results demonstrate that selective expression of channelrhodopsin within cardiac cholinergic neurons enables photoactivated release of acetylcholine, thereby instantaneously slowing sinus rate and altering atrioventricular conduction. This provides for in-depth examination of the endogenous interplay between cardiac autonomic neurons and the functional outcomes of downstream post-synaptic receptor activation.
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Affiliation(s)
- Angel Moreno
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Kendal Endicott
- Division of Cardiothoracic Surgery, Veterans Affairs Medical Center, Washington, DC, United States
| | - Matthew Skancke
- Division of Cardiothoracic Surgery, Veterans Affairs Medical Center, Washington, DC, United States
| | - Mary Kate Dwyer
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Jaclyn Brennan
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | - Gregory Trachiotis
- Division of Cardiothoracic Surgery, Veterans Affairs Medical Center, Washington, DC, United States
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, United States
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
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A Software Architecture to Mimic a Ventricular Tachycardia in Intact Murine Hearts by Means of an All-Optical Platform. Methods Protoc 2019; 2:mps2010007. [PMID: 31164591 PMCID: PMC6481051 DOI: 10.3390/mps2010007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/29/2018] [Accepted: 01/04/2019] [Indexed: 11/17/2022] Open
Abstract
Optogenetics is an emerging method that uses light to manipulate electrical activity in excitable cells exploiting the interaction between light and light-sensitive depolarizing ion channels, such as channelrhodopsin-2 (ChR2). Initially used in the neuroscience, it has been adopted in cardiac research where the expression of ChR2 in cardiac preparations allows optical pacing, resynchronization and defibrillation. Recently, optogenetics has been leveraged to manipulate cardiac electrical activity in the intact heart in real-time. This new approach was applied to simulate a re-entrant circuit across the ventricle. In this technical note, we describe the development and the implementation of a new software package for real-time optogenetic intervention. The package consists of a single LabVIEW program that simultaneously captures images at very high frame rates and delivers precisely timed optogenetic stimuli based on the content of the images. The software implementation guarantees closed-loop optical manipulation at high temporal resolution by processing the raw data in workstation memory. We demonstrate that this strategy allows the simulation of a ventricular tachycardia with high stability and with a negligible loss of data with a temporal resolution of up to 1 ms.
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Quach B, Krogh-Madsen T, Entcheva E, Christini DJ. Light-Activated Dynamic Clamp Using iPSC-Derived Cardiomyocytes. Biophys J 2018; 115:2206-2217. [PMID: 30447994 PMCID: PMC6289097 DOI: 10.1016/j.bpj.2018.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 08/23/2018] [Accepted: 10/02/2018] [Indexed: 01/31/2023] Open
Abstract
iPSC-derived cardiomyocytes (iPSC-CMs) are a potentially advantageous platform for drug screening because they provide a renewable source of human cardiomyocytes. One obstacle to their implementation is their immature electrophysiology, which reduces relevance to adult arrhythmogenesis. To address this, dynamic clamp is used to inject current representing the insufficient potassium current, IK1, thereby producing more adult-like electrophysiology. However, dynamic clamp requires patch clamp and is therefore low throughput and ill-suited for large-scale drug screening. Here, we use optogenetics to generate such a dynamic-clamp current. The optical dynamic clamp (ODC) uses outward-current-generating opsin, ArchT, to mimic IK1, resulting in more adult-like action potential morphology, similar to IK1 injection via classic dynamic clamp. Furthermore, in the presence of an IKr blocker, ODC revealed expected action potential prolongation and reduced spontaneous excitation. The ODC presented here still requires an electrode to measure Vm but provides a first step toward contactless dynamic clamp, which will not only enable high-throughput screening but may also allow control within multicellular iPSC-CM formats to better recapitulate adult in vivo physiology.
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Affiliation(s)
- Bonnie Quach
- Cardiovascular Research Institute, New York, New York; Weill Cornell Medicine, New York, New York
| | - Trine Krogh-Madsen
- Cardiovascular Research Institute, New York, New York; Weill Cornell Medicine, New York, New York
| | - Emilia Entcheva
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia
| | - David J Christini
- Cardiovascular Research Institute, New York, New York; Weill Cornell Medicine, New York, New York.
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35
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Krishnamurthy VV, Zhang K. Chemical physics in living cells — Using light to visualize and control intracellular signal transduction. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1806152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Vishnu V. Krishnamurthy
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Kai Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Rorsman NJG, Ta CM, Garnett H, Swietach P, Tammaro P. Defining the ionic mechanisms of optogenetic control of vascular tone by channelrhodopsin-2. Br J Pharmacol 2018; 175:2028-2045. [PMID: 29486056 PMCID: PMC5979753 DOI: 10.1111/bph.14183] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 01/16/2018] [Accepted: 02/14/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Optogenetic control of electromechanical coupling in vascular smooth muscle cells (VSMCs) is emerging as a powerful research tool with potential applications in drug discovery and therapeutics. However, the precise ionic mechanisms involved in this control remain unclear. EXPERIMENTAL APPROACH Cell imaging, patch-clamp electrophysiology and muscle tension recordings were used to define these mechanisms over a wide range of light stimulations. KEY RESULTS Transgenic mice expressing a channelrhodopsin-2 variant [ChR2(H134R)] selectively in VSMCs were generated. Isolated VSMCs obtained from these mice demonstrated blue light-induced depolarizing whole-cell currents. Fine control of artery tone was attained by varying the intensity of the light stimulus. This arterial response was sufficient to overcome the endogenous, melanopsin-mediated, light-evoked, arterial relaxation observed in the presence of contractile agonists. Ca2+ entry through voltage-gated Ca2+ channels, and opening of plasmalemmal depolarizing channels (TMEM16A and TRPM) and intracellular IP3 receptors were involved in the ChR2(H134R)-dependent arterial response to blue light at intensities lower than ~0.1 mW·mm-2 . Light stimuli of greater intensity evoked a significant Ca2+ influx directly through ChR2(H134R) and produced marked intracellular alkalinization of VSMCs. CONCLUSIONS AND IMPLICATIONS We identified the range of light intensity allowing optical control of arterial tone, primarily by means of endogenous channels and without substantial alteration to intracellular pH. Within this range, mice expressing ChR2(H134R) in VSMCs are a powerful experimental model for achieving accurate and tuneable optical voltage-clamp of VSMCs and finely graded control of arterial tone, offering new approaches to the discovery of vasorelaxant drugs.
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Affiliation(s)
- Nils J G Rorsman
- Department of PharmacologyUniversity of OxfordOxfordUK
- OXION Initiative in Ion Channels and DiseaseUniversity of OxfordOxfordUK
| | - Chau M Ta
- Department of PharmacologyUniversity of OxfordOxfordUK
| | | | - Pawel Swietach
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
| | - Paolo Tammaro
- Department of PharmacologyUniversity of OxfordOxfordUK
- OXION Initiative in Ion Channels and DiseaseUniversity of OxfordOxfordUK
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Broyles CN, Robinson P, Daniels MJ. Fluorescent, Bioluminescent, and Optogenetic Approaches to Study Excitable Physiology in the Single Cardiomyocyte. Cells 2018; 7:cells7060051. [PMID: 29857560 PMCID: PMC6028913 DOI: 10.3390/cells7060051] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/22/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
This review briefly summarizes the single cell application of classical chemical dyes used to visualize cardiomyocyte physiology and their undesirable toxicities which have the potential to confound experimental observations. We will discuss, in detail, the more recent iterative development of fluorescent and bioluminescent protein-based indicators and their emerging application to cardiomyocytes. We will discuss the integration of optical control strategies (optogenetics) to augment the standard imaging approach. This will be done in the context of potential applications, and barriers, of these technologies to disease modelling, drug toxicity, and drug discovery efforts at the single-cell scale.
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Affiliation(s)
- Connor N Broyles
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK.
- BHF Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK.
| | - Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK.
- BHF Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK.
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK.
- BHF Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK.
- Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford OX3 9DU, UK.
- BHF Centre of Regenerative Medicine, University of Oxford, Oxford OX3 9DU, UK.
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Mihogaoka 8-1, Ibaraki, 567-0047 Osaka, Japan.
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Conant G, Lai BFL, Lu RXZ, Korolj A, Wang EY, Radisic M. High-Content Assessment of Cardiac Function Using Heart-on-a-Chip Devices as Drug Screening Model. Stem Cell Rev Rep 2018; 13:335-346. [PMID: 28429185 DOI: 10.1007/s12015-017-9736-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Drug discovery and development continues to be a challenge to the pharmaceutical industry despite great advances in cell and molecular biology that allow for the design of better targeted therapeutics. Many potential drug compounds fail during the clinical trial due to inefficacy and toxicity that were not predicted during preclinical stages. The fundamental problem lies with the use of traditional drug screening models that still largely rely on the use of cell lines or animal cell monolayers, which leads to lack of predictive power of human tissue and organ response to the drug candidates. More physiologically relevant systems are therefore critical in relieving the burden of high failure rates. Emerging knowledge and techniques in tissue engineering and microfabrication have enabled the development of micro-engineered systems - collectively known as organs-on-chips - that may lead to a paradigm shift in preclinical drug screening assays. In this review we explore the technological advances and challenges in the development of heart-on-a-chip models, by addressing current assessment methods for drug-induced cardiotoxicity and providing a perspective on the modifications that should be implemented to realize the full potential of this system.
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Affiliation(s)
- Genevieve Conant
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Benjamin Fook Lun Lai
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Rick Xing Ze Lu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Anastasia Korolj
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Erika Yan Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Milica Radisic
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada.
- Toronto General Research Institute, Toronto, ON, Canada.
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Lipovsky CE, Brumback BD, Khandekar A, Rentschler SL. Multi-Scale Assessments of Cardiac Electrophysiology Reveal Regional Heterogeneity in Health and Disease. J Cardiovasc Dev Dis 2018. [PMID: 29517992 PMCID: PMC5872364 DOI: 10.3390/jcdd5010016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The left and right ventricles of the four-chambered heart have distinct developmental origins and functions. Chamber-specific developmental programming underlies the differential gene expression of ion channel subunits regulating cardiac electrophysiology that persists into adulthood. Here, we discuss regional specific electrical responses to genetic mutations and cardiac stressors, their clinical correlations, and describe many of the multi-scale techniques commonly used to analyze electrophysiological regional heterogeneity.
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Affiliation(s)
- Catherine E Lipovsky
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, Campus Box 8103, 660 S Euclid Ave, St. Louis, MO 63110, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Brittany D Brumback
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, Campus Box 8103, 660 S Euclid Ave, St. Louis, MO 63110, USA.
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA.
| | - Aditi Khandekar
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, Campus Box 8103, 660 S Euclid Ave, St. Louis, MO 63110, USA.
| | - Stacey L Rentschler
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, Campus Box 8103, 660 S Euclid Ave, St. Louis, MO 63110, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA.
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40
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Cardiac Optogenetics: 2018. JACC Clin Electrophysiol 2018; 4:155-167. [PMID: 29749932 DOI: 10.1016/j.jacep.2017.12.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/04/2017] [Accepted: 12/14/2017] [Indexed: 01/28/2023]
Abstract
Cardiac optogenetics is an emergent research area involving the delivery of light-sensitive proteins (opsins) to excitable heart tissue to enable optical modulation of cardiac electrical function. Optogenetic stimulation has many noteworthy advantages over conventional electrical methods, including selective electrophysiological modulation in specifically targeted cell subpopulations, high-resolution spatiotemporal control via patterned illumination, and use of different opsins to elicit inward or outward transmembrane current. This review summarizes developments achieved since the inception of cardiac optogenetics research, which has spanned nearly a decade. The authors first provide an overview of recent methodological advances in opsin engineering, light sensitization of cardiac tissue, strategies for illuminating the heart, and frameworks for simulating optogenetics in realistic computational models of patient hearts. They then review recent cardiac optogenetics applications, including: 1) all-optical, high-throughput, contactless assays for quantification of electrophysiological properties; 2) optogenetic perturbation of cardiac tissue to unveil mechanistic insights on the initiation, perpetuation, and termination of arrhythmia; and 3) disruptive translational innovations such as light-based pacemaking and defibrillation.
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41
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Axelsen TM, Woldbye DP. Gene Therapy for Parkinson's Disease, An Update. JOURNAL OF PARKINSON'S DISEASE 2018; 8:195-215. [PMID: 29710735 PMCID: PMC6027861 DOI: 10.3233/jpd-181331] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 03/25/2018] [Indexed: 12/19/2022]
Abstract
The current mainstay treatment of Parkinson's disease (PD) consists of dopamine replacement therapy which, in addition to causing several side effects, does not delay disease progression. The field of gene therapy offers a potential means to improve current therapy. The present review gives an update of the present status of gene therapy for PD. Both non-disease and disease modifying transgenes have been tested for PD gene therapy in animal and human studies. Non-disease modifying treatments targeting dopamine or GABA synthesis have been successful and promising at improving PD symptomatology in randomized clinical studies, but substantial testing remains before these can be implemented in the standard clinical treatment repertoire. As for disease modifying targets that theoretically offer the possibility of slowing the progression of disease, several neurotrophic factors show encouraging results in preclinical models (e.g., neurturin, GDNF, BDNF, CDNF, VEGF-A). However, so far, clinical trials have only tested neurturin, and, unfortunately, no trial has been able to meet its primary endpoint. Future clinical trials with neurotrophic factors clearly deserve to be conducted, considering the still enticing goal of actually slowing the disease process of PD. As alternative types of gene therapy, opto- and chemogenetics might also find future use in PD treatment and novel genome-editing technology could also potentially be applied as individualized gene therapy for genetic types of PD.
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Affiliation(s)
- Tobias M. Axelsen
- Department of Neurology, Herlev University Hospital, Herlev, Denmark
| | - David P.D. Woldbye
- Department of Neuroscience, Panum Institute, Mærsk Tower, University of Copenhagen, Copenhagen N, Denmark
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42
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Boyle PM, Murphy MJ, Karathanos TV, Zahid S, Blake RC, Trayanova NA. Termination of re-entrant atrial tachycardia via optogenetic stimulation with optimized spatial targeting: insights from computational models. J Physiol 2017; 596:181-196. [PMID: 29193078 DOI: 10.1113/jp275264] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/22/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Optogenetics has emerged as a potential alternative to electrotherapy for treating heart rhythm disorders, but its applicability for terminating atrial arrhythmias remains largely unexplored. We used computational models reconstructed from clinical MRI scans of fibrotic patient atria to explore the feasibility of optogenetic termination of atrial tachycardia (AT), comparing two different illumination strategies: distributed vs. targeted. We show that targeted optogenetic stimulation based on automated, non-invasive flow-network analysis of patient-specific re-entry morphology may be a reliable approach for identifying the optimal illumination target in each individual (i.e. the critical AT isthmus). The above-described approach yields very high success rates (up to 100%) and requires dramatically less input power than distributed illumination We conclude that simulations in patient-specific models show that targeted light pulses lasting longer than the AT cycle length can efficiently and reliably terminate AT if the human atria can be successfully light-sensitized via gene delivery of ChR2. ABSTRACT Optogenetics has emerged as a potential alternative to electrotherapy for treating arrhythmia, but feasibility studies have been limited to ventricular defibrillation via epicardial light application. Here, we assess the efficacy of optogenetic atrial tachycardia (AT) termination in human hearts using a strategy that targets for illumination specific regions identified in an automated manner. In three patient-specific models reconstructed from late gadolinium-enhanced MRI scans, we simulated channelrhodopsin-2 (ChR2) expression via gene delivery. In all three models, we attempted to terminate re-entrant AT (induced via rapid pacing) via optogenetic stimulation. We compared two strategies: (1) distributed illumination of the endocardium by multi-optrode grids (number of optrodes, Nopt = 64, 128, 256) and (2) targeted illumination of the critical isthmus, which was identified via analysis of simulated activation patterns using an algorithm based on flow networks. The illuminated area and input power were smaller for the targeted approach (19-57.8 mm2 ; 0.6-1.8 W) compared to the sparsest distributed arrays (Nopt = 64; 124.9 ± 6.3 mm2 ; 3.9 ± 0.2 W). AT termination rates for distributed illumination were low, ranging from <5% for short pulses (1/10 ms long) to ∼20% for longer stimuli (100/1000 ms). When we attempted to terminate the same AT episodes with targeted illumination, outcomes were similar for short pulses (1/10 ms long: 0% success) but improved for longer stimuli (100 ms: 54% success; 1000 ms: 90% success). We conclude that simulations in patient-specific models show that light pulses lasting longer than the AT cycle length can efficiently and reliably terminate AT in atria light-sensitized via gene delivery. We show that targeted optogenetic stimulation based on analysis of AT morphology may be a reliable approach for defibrillation and requires less power than distributed illumination.
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Affiliation(s)
- Patrick M Boyle
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Michael J Murphy
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Thomas V Karathanos
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Sohail Zahid
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Robert C Blake
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Natalia A Trayanova
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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43
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Abstract
This Special Collection will gather all studies highlighting recent advances in theoretical and experimental studies of arrhythmia, with a specific focus on research seeking to elucidate links between calcium homeostasis in cardiac cells and organ-scale disruption of heart rhythm.
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Affiliation(s)
- Makarand Deo
- Department of Engineering, Norfolk State University, Norfolk, VA, USA
| | - Seth H Weinberg
- Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Patrick M Boyle
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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44
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Björk S, Ojala EA, Nordström T, Ahola A, Liljeström M, Hyttinen J, Kankuri E, Mervaala E. Evaluation of Optogenetic Electrophysiology Tools in Human Stem Cell-Derived Cardiomyocytes. Front Physiol 2017; 8:884. [PMID: 29163220 PMCID: PMC5673656 DOI: 10.3389/fphys.2017.00884] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/18/2017] [Indexed: 11/25/2022] Open
Abstract
Current cardiac drug safety assessments focus on hERG channel block and QT prolongation for evaluating arrhythmic risks, whereas the optogenetic approach focuses on the action potential (AP) waveform generated by a monolayer of human cardiomyocytes beating synchronously, thus assessing the contribution of several ion channels on the overall drug effect. This novel tool provides arrhythmogenic sensitizing by light-induced pacing in combination with non-invasive, all-optical measurements of cardiomyocyte APs and will improve assessment of drug-induced electrophysiological aberrancies. With the help of patch clamp electrophysiology measurements, we aimed to investigate whether the optogenetic modifications alter human cardiomyocytes' electrophysiology and how well the optogenetic analyses perform against this gold standard. Patch clamp electrophysiology measurements of non-transduced stem cell-derived cardiomyocytes compared to cells expressing the commercially available optogenetic constructs Optopatch and CaViar revealed no significant changes in action potential duration (APD) parameters. Thus, inserting the optogenetic constructs into cardiomyocytes does not significantly affect the cardiomyocyte's electrophysiological properties. When comparing the two methods against each other (patch clamp vs. optogenetic imaging) we found no significant differences in APD parameters for the Optopatch transduced cells, whereas the CaViar transduced cells exhibited modest increases in APD-values measured with optogenetic imaging. Thus, to broaden the screen, we combined optogenetic measurements of membrane potential and calcium transients with contractile motion measured by video motion tracking. Furthermore, to assess how optogenetic measurements can predict changes in membrane potential, or early afterdepolarizations (EADs), cells were exposed to cumulating doses of E-4031, a hERG potassium channel blocker, and drug effects were measured at both spontaneous and paced beating rates (1, 2 Hz). Cumulating doses of E-4031 produced prolonged APDs, followed by EADs and drug-induced quiescence. These observations were corroborated by patch clamp and contractility measurements. Similar responses, although more modest were seen with the IKs potassium channel blocker JNJ-303. In conclusion, optogenetic measurements of AP waveforms combined with optical pacing compare well with the patch clamp gold standard. Combined with video motion contractile measurements, optogenetic imaging provides an appealing alternative for electrophysiological screening of human cardiomyocyte responses in pharmacological efficacy and safety testings.
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Affiliation(s)
- Susann Björk
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Elina A Ojala
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tommy Nordström
- Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Antti Ahola
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of Technology, Tampere, Finland
| | - Mikko Liljeström
- Department of Anatomy, Faculty of Medicine and HiLIFE, University of Helsinki, Helsinki, Finland
| | - Jari Hyttinen
- BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of Technology, Tampere, Finland
| | - Esko Kankuri
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Eero Mervaala
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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45
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Watanabe M, Feola I, Majumder R, Jangsangthong W, Teplenin AS, Ypey DL, Schalij MJ, Zeppenfeld K, de Vries AAF, Pijnappels DA. Optogenetic manipulation of anatomical re-entry by light-guided generation of a reversible local conduction block. Cardiovasc Res 2017; 113:354-366. [PMID: 28395022 DOI: 10.1093/cvr/cvx003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 01/10/2017] [Indexed: 01/03/2023] Open
Abstract
Aims Anatomical re-entry is an important mechanism of ventricular tachycardia, characterized by circular electrical propagation in a fixed pathway. It's current investigative and therapeutic approaches are non-biological, rather unspecific (drugs), traumatizing (electrical shocks), or irreversible (ablation). Optogenetics is a new biological technique that allows reversible modulation of electrical function with unmatched spatiotemporal precision using light-gated ion channels. We therefore investigated optogenetic manipulation of anatomical re-entry in ventricular cardiac tissue. Methods and results Transverse, 150-μm-thick ventricular slices, obtained from neonatal rat hearts, were genetically modified with lentiviral vectors encoding Ca2+-translocating channelrhodopsin (CatCh), a light-gated depolarizing ion channel, or enhanced yellow fluorescent protein (eYFP) as control. Stable anatomical re-entry was induced in both experimental groups. Activation of CatCh was precisely controlled by 470-nm patterned illumination, while the effects on anatomical re-entry were studied by optical voltage mapping. Regional illumination in the pathway of anatomical re-entry resulted in termination of arrhythmic activity only in CatCh-expressing slices by establishing a local and reversible, depolarization-induced conduction block in the illuminated area. Systematic adjustment of the size of the light-exposed area in the re-entrant pathway revealed that re-entry could be terminated by either wave collision or extinction, depending on the depth (transmurality) of illumination. In silico studies implicated source-sink mismatches at the site of subtransmural conduction block as an important factor in re-entry termination. Conclusions Anatomical re-entry in ventricular tissue can be manipulated by optogenetic induction of a local and reversible conduction block in the re-entrant pathway, allowing effective re-entry termination. These results provide distinctively new mechanistic insight into re-entry termination and a novel perspective for cardiac arrhythmia management.
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Khamo JS, Krishnamurthy VV, Sharum SR, Mondal P, Zhang K. Applications of Optobiology in Intact Cells and Multicellular Organisms. J Mol Biol 2017; 429:2999-3017. [PMID: 28882542 DOI: 10.1016/j.jmb.2017.08.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/26/2017] [Accepted: 08/28/2017] [Indexed: 12/25/2022]
Abstract
Temporal kinetics and spatial coordination of signal transduction in cells are vital for cell fate determination. Tools that allow for precise modulation of spatiotemporal regulation of intracellular signaling in intact cells and multicellular organisms remain limited. The emerging optobiological approaches use light to control protein-protein interaction in live cells and multicellular organisms. Optobiology empowers light-mediated control of diverse cellular and organismal functions such as neuronal activity, intracellular signaling, gene expression, cell proliferation, differentiation, migration, and apoptosis. In this review, we highlight recent developments in optobiology, focusing on new features of second-generation optobiological tools. We cover applications of optobiological approaches in the study of cellular and organismal functions, discuss current challenges, and present our outlook. Taking advantage of the high spatial and temporal resolution of light control, optobiology promises to provide new insights into the coordination of signaling circuits in intact cells and multicellular organisms.
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Affiliation(s)
- John S Khamo
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Savanna R Sharum
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Payel Mondal
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kai Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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47
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Bondarenko VE, Shilnikov AL. Bursting dynamics in the normal and failing hearts. Sci Rep 2017; 7:5927. [PMID: 28725037 PMCID: PMC5517618 DOI: 10.1038/s41598-017-05198-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/15/2017] [Indexed: 01/03/2023] Open
Abstract
A failing heart differs from healthy hearts by an array of symptomatic characteristics, including impaired Ca2+ transients, upregulation of Na+/Ca2+ exchanger function, reduction of Ca2+ uptake to sarcoplasmic reticulum, reduced K+ currents, and increased propensity to arrhythmias. While significant efforts have been made in both experimental studies and model development to display the causes of heart failure, the full process of deterioration from a healthy to a failing heart yet remains deficiently understood. In this paper, we analyze a highly detailed mathematical model of mouse ventricular myocytes to disclose the key mechanisms underlying the continual transition towards a state of heart failure. We argue that such a transition can be described in mathematical terms as a sequence of bifurcations that the healthy cells undergo while transforming into failing cells. They include normal action potentials and [Ca2+]i transients, action potential and [Ca2+]i alternans, and bursting behaviors. These behaviors where supported by experimental studies of heart failure. The analysis of this model allowed us to identify that the slow component of the fast Na+ current is a key determining factor for the onset of bursting activity in mouse ventricular myocytes.
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Affiliation(s)
- Vladimir E Bondarenko
- Department of Mathematics and Statistics and Neuroscience Institute, Georgia State University, 30 Pryor Street, Atlanta, GA 30303, United States.
| | - Andrey L Shilnikov
- Department of Mathematics and Statistics and Neuroscience Institute, Georgia State University, 30 Pryor Street, Atlanta, GA 30303, United States.,Institute for Information Technologies, Mathematics and Mechanics, Nizhni Novgorod State University, Gagarin Av. 23, 606950, Nizhni Novgorod, Russia
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48
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Ccoffinn: Automated Wave Tracking in Cultured Cardiac Monolayers. Biophys J 2017; 111:1595-1599. [PMID: 27760347 DOI: 10.1016/j.bpj.2016.08.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 08/19/2016] [Accepted: 08/26/2016] [Indexed: 11/23/2022] Open
Abstract
Cardiac arrhythmias are one of the most frequent causes of death worldwide. A popular biological model used to study arrhythmogenesis is the cultured cardiac cell monolayer, which provides a good trade-off between physiological relevance and experimental access. Excitation wave patterns are imaged using high-bandwidth detectors, producing large data sets that are typically analyzed manually. To make such analysis less time consuming and less subjective, we have designed and implemented a toolkit for segmentation and tracking of cardiac waves in optical mapping recordings. The toolkit is optimized for high-resolution detectors to accommodate the growing availability of inexpensive high-resolution detectors for life science imaging applications (e.g., scientific CMOS cameras). The software extracts key features of propagating waves, such as wavefront speed and entropy. The methods have been validated using synthetic data, and real-world examples are provided, showing a difference in conduction velocity between two different types of cardiac cell cultures.
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49
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Crocini C, Ferrantini C, Pavone FS, Sacconi L. Optogenetics gets to the heart: A guiding light beyond defibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:132-139. [PMID: 28506694 DOI: 10.1016/j.pbiomolbio.2017.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 01/01/2023]
Abstract
Optogenetics provides a tool for controlling the electrical activity of excitable cells by means of the interaction of light with light-gated ion channels. Despite the fact that optogenetics has been intensively utilized in the neurosciences, it has been more rarely employed as an instrument for studying cardiac pathophysiology. However, the advantages of optical approaches to perturb cardiac electrical activity are numerous, especially when the spatio-temporal qualities of light are utterly exploited. Here, we review the main breakthroughs employing optogenetics to perturb cardiac pathophysiology and attempt a comparison of methods and procedures that have employed optogenetics in the heart. We particularly focus on light-based defibrillation strategies that represent one of the latest achievements in this field. We highlight the important role of advanced optical methods for detecting and stimulating electrical activity for optimizing defibrillation strategies and, more generally, for dissecting novel insights in cardiac physiology. Finally, we discuss the main future perspectives that we envision for optogenetics in the heart, both in terms of translational applications and for addressing fundamental questions of cardiac function.
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Affiliation(s)
- Claudia Crocini
- European Laboratory for Non Linear Spectroscopy (LENS), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, FI, Italy; National Institute of Optic (CNR-INO), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, Italy.
| | - Cecilia Ferrantini
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Francesco S Pavone
- European Laboratory for Non Linear Spectroscopy (LENS), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, FI, Italy; National Institute of Optic (CNR-INO), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, Italy; Department of Physics and Astronomy, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Leonardo Sacconi
- European Laboratory for Non Linear Spectroscopy (LENS), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, FI, Italy; National Institute of Optic (CNR-INO), Via Nello Carrara, 1 - 50019 Sesto Fiorentino, Italy
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Li Q, Ni RR, Hong H, Goh KY, Rossi M, Fast VG, Zhou L. Electrophysiological Properties and Viability of Neonatal Rat Ventricular Myocyte Cultures with Inducible ChR2 Expression. Sci Rep 2017; 7:1531. [PMID: 28484220 PMCID: PMC5431527 DOI: 10.1038/s41598-017-01723-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/03/2017] [Indexed: 11/25/2022] Open
Abstract
Channelrhodopsin-2 (ChR2)-based optogenetic technique has been increasingly applied to cardiovascular research. However, the potential effects of ChR2 protein overexpression on cardiomyocytes are not completely understood. The present work aimed to examine how the doxycycline-inducible lentiviral-mediated ChR2 expression may affect cell viability and electrophysiological property of neonatal rat ventricular myocyte (NRVM) cultures. Primary NVRMs were infected with lentivirus containing ChR2 or YFP gene and subjected to cytotoxicity analysis. ChR2-expressing cultures were then paced electrically or optically with a blue light-emitting diode, with activation spread recorded simultaneously using optical mapping. Results showed that ChR2 could be readily transduced to NRVMs by the doxycycline-inducible lentiviral system; however, high-level ChR2 (but not YFP) expression was associated with substantial cytotoxicity, which hindered optical pacing. Application of bromodeoxyuridine significantly reduced cell damage, allowing stimulation with light. Simultaneous optical Vm mapping showed that conduction velocity, action potential duration, and dVm/dtmax were similar in ChR2-expressing and control cultures. Finally, the ChR2-expressing cultures could be optically paced at multiple sites, with significantly reduced overall activation time. In summary, we demonstrated that inducible lentiviral-mediated ChR2 overexpression might cause cytotoxicity in NRVM cultures, which could be alleviated without impairing electrophysiological function, allowing simultaneous optical pacing and Vm mapping.
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Affiliation(s)
- Qince Li
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, 1900 University Blvd, Birmingham, 35294, Alabama, USA.,Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Rong Ruby Ni
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, 1900 University Blvd, Birmingham, 35294, Alabama, USA.,Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Huixian Hong
- Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Kah Yong Goh
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, 1900 University Blvd, Birmingham, 35294, Alabama, USA.,Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Michael Rossi
- Department of Biomedical Engineering, University of Alabama at Birmingham, 1670 University Blvd, Birmingham, 35294, Alabama, USA
| | - Vladimir G Fast
- Department of Biomedical Engineering, University of Alabama at Birmingham, 1670 University Blvd, Birmingham, 35294, Alabama, USA. .,Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA.
| | - Lufang Zhou
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, 1900 University Blvd, Birmingham, 35294, Alabama, USA. .,Department of Biomedical Engineering, University of Alabama at Birmingham, 1670 University Blvd, Birmingham, 35294, Alabama, USA. .,Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA. .,Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA.
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