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Lu F, Liou C, Ma Q, Wu Z, Xue B, Xia Y, Xia S, Trembley MA, Ponek A, Xie W, Shani K, Bortolin RH, Prondzynski M, Berkson P, Zhang X, Naya FJ, Bedi KC, Margulies KB, Zhang D, Parker KK, Pu WT. Virally delivered CMYA5 enhances the assembly of cardiac dyads. Nat Biomed Eng 2024:10.1038/s41551-024-01253-z. [PMID: 39237710 DOI: 10.1038/s41551-024-01253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/09/2024] [Indexed: 09/07/2024]
Abstract
Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) lack nanoscale structures essential for efficient excitation-contraction coupling. Such nanostructures, known as dyads, are frequently disrupted in heart failure. Here we show that the reduced expression of cardiomyopathy-associated 5 (CMYA5), a master protein that establishes dyads, contributes to dyad disorganization in heart failure and to impaired dyad assembly in hiPSC-CMs, and that a miniaturized form of CMYA5 suitable for delivery via an adeno-associated virus substantially improved dyad architecture and normalized cardiac function under pressure overload. In hiPSC-CMs, the miniaturized form of CMYA5 increased contractile forces, improved Ca2+ handling and enhanced the alignment of sarcomere Z-lines with ryanodine receptor 2, a protein that mediates the sarcoplasmic release of stored Ca2+. Our findings clarify the mechanisms responsible for impaired dyad structure in diseased cardiomyocytes, and suggest strategies for promoting dyad assembly and stability in heart disease and during the derivation of hiPSC-CMs.
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Affiliation(s)
- Fujian Lu
- Institutes of Biomedical Sciences, Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China.
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA.
| | - Carter Liou
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Qing Ma
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Zexuan Wu
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Bingqing Xue
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | - Yu Xia
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | - Shutao Xia
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | | | - Anna Ponek
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Wenjun Xie
- Department of Cardiology, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Kevin Shani
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, USA
| | - Raul H Bortolin
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | | | - Paul Berkson
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Xiaoran Zhang
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - Francisco J Naya
- Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, MA, USA
| | - Kenneth C Bedi
- Department of Medicine, Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth B Margulies
- Department of Medicine, Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Donghui Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | - Kevin K Parker
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
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2
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Leemann S, Schneider-Warme F, Kleinlogel S. Cardiac optogenetics: shining light on signaling pathways. Pflugers Arch 2023; 475:1421-1437. [PMID: 38097805 PMCID: PMC10730638 DOI: 10.1007/s00424-023-02892-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023]
Abstract
In the early 2000s, the field of neuroscience experienced a groundbreaking transformation with the advent of optogenetics. This innovative technique harnesses the properties of naturally occurring and genetically engineered rhodopsins to confer light sensitivity upon target cells. The remarkable spatiotemporal precision offered by optogenetics has provided researchers with unprecedented opportunities to dissect cellular physiology, leading to an entirely new level of investigation. Initially revolutionizing neuroscience, optogenetics quickly piqued the interest of the wider scientific community, and optogenetic applications were expanded to cardiovascular research. Over the past decade, researchers have employed various optical tools to observe, regulate, and steer the membrane potential of excitable cells in the heart. Despite these advancements, achieving control over specific signaling pathways within the heart has remained an elusive goal. Here, we review the optogenetic tools suitable to control cardiac signaling pathways with a focus on GPCR signaling, and delineate potential applications for studying these pathways, both in healthy and diseased hearts. By shedding light on these exciting developments, we hope to contribute to the ongoing progress in basic cardiac research to facilitate the discovery of novel therapeutic possibilities for treating cardiovascular pathologies.
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Affiliation(s)
- Siri Leemann
- Institute of Physiology, University of Bern, Bern, Switzerland.
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Sonja Kleinlogel
- Institute of Physiology, University of Bern, Bern, Switzerland
- F. Hoffmann-La Roche, Translational Medicine Neuroscience, Basel, Switzerland
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3
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Dries E, Gilbert G, Roderick HL, Sipido KR. The ryanodine receptor microdomain in cardiomyocytes. Cell Calcium 2023; 114:102769. [PMID: 37390591 DOI: 10.1016/j.ceca.2023.102769] [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: 05/02/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 07/02/2023]
Abstract
The ryanodine receptor type 2 (RyR) is a key player in Ca2+ handling during excitation-contraction coupling. During each heartbeat, RyR channels are responsible for linking the action potential with the contractile machinery of the cardiomyocyte by releasing Ca2+ from the sarcoplasmic reticulum. RyR function is fine-tuned by associated signalling molecules, arrangement in clusters and subcellular localization. These parameters together define RyR function within microdomains and are subject to disease remodelling. This review describes the latest findings on RyR microdomain organization, the alterations with disease which result in increased subcellular heterogeneity and emergence of microdomains with enhanced arrhythmogenic potential, and presents novel technologies that guide future research to study and target RyR channels within specific microdomains.
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Affiliation(s)
- Eef Dries
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium.
| | - Guillaume Gilbert
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium; Laboratoire ORPHY EA 4324, Université de Brest, Brest, France
| | - H Llewelyn Roderick
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Karin R Sipido
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
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4
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Wang X, Dupont C, Grant D, Voss AA, Rich MM. Plateau potentials contribute to myotonia in mouse models of myotonia congenita. Exp Neurol 2023; 361:114303. [PMID: 36563835 PMCID: PMC9892346 DOI: 10.1016/j.expneurol.2022.114303] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/12/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
It has long been accepted that myotonia (muscle stiffness) in patients with muscle channelopathies is due to myotonic discharges (involuntary firing of action potentials). In a previous study, we identified a novel phenomenon in myotonic muscle: development of plateau potentials, transient depolarizations to near -35 mV lasting for seconds to minutes. In the current study we examined whether plateau potentials contribute to myotonia. A recessive genetic model (ClCadr mice) with complete loss of muscle chloride channel (ClC-1) function was used to model severe myotonia congenita with complete loss of ClC-1 function and a pharmacologic model using anthracene-9-carboxylic acid (9 AC) was used to model milder myotonia congenita with incomplete loss of ClC-1 function. Simultaneous measurements of action potentials and myoplasmic Ca2+ from individual muscle fibers were compared to recordings of whole muscle force generation. In ClCadr muscle both myotonia and plateau potentials lasted 10s of seconds to minutes. During plateau potentials lasting 1-2 min, there was a gradual transition from high to low intracellular Ca2+, suggesting a transition in individual fibers from myotonia to flaccid paralysis in severe myotonia congenita. In 9 AC-treated muscles, both myotonia and plateau potentials lasted only a few seconds and Ca2+ remained elevated during the plateau potentials, suggesting plateau potentials contribute to myotonia without causing weakness. We propose, that in myotonic muscle, there is a novel state in which there is contraction in the absence of action potentials. This discovery provides a mechanism to explain reports of patients with myotonia who suffer from electrically silent muscle contraction lasting minutes.
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Affiliation(s)
- Xueyong Wang
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Chris Dupont
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Delaney Grant
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Andrew A Voss
- Department of Biology, Wright State University, Dayton, OH 45435, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA.
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5
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Zheng Q, Chen Y, Chen D, Zhao H, Feng Y, Meng Q, Zhao Y, Zhang H. Calcium transients on the ER surface trigger liquid-liquid phase separation of FIP200 to specify autophagosome initiation sites. Cell 2022; 185:4082-4098.e22. [PMID: 36198318 DOI: 10.1016/j.cell.2022.09.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/20/2022] [Accepted: 08/30/2022] [Indexed: 02/06/2023]
Abstract
The mechanism that initiates autophagosome formation on the ER in multicellular organisms is elusive. Here, we showed that autophagy stimuli trigger Ca2+ transients on the outer surface of the ER membrane, whose amplitude, frequency, and duration are controlled by the metazoan-specific ER transmembrane autophagy protein EPG-4/EI24. Persistent Ca2+ transients/oscillations on the cytosolic ER surface in EI24-depleted cells cause accumulation of FIP200 autophagosome initiation complexes on the ER. This defect is suppressed by attenuating ER Ca2+ transients. Multi-modal SIM analysis revealed that Ca2+ transients on the ER trigger the formation of dynamic and fusion-prone liquid-like FIP200 puncta. Starvation-induced Ca2+ transients on lysosomes also induce FIP200 puncta that further move to the ER. Multiple FIP200 puncta on the ER, whose association depends on the ER proteins VAPA/B and ATL2/3, assemble into autophagosome formation sites. Thus, Ca2+ transients are crucial for triggering phase separation of FIP200 to specify autophagosome initiation sites in metazoans.
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Affiliation(s)
- Qiaoxia Zheng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Di Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Feng
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Quan Meng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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6
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Xu B, Wang Y, Bahriz SMFM, Zhao M, Zhu C, Xiang YK. Probing spatiotemporal PKA activity at the ryanodine receptor and SERCA2a nanodomains in cardomyocytes. Cell Commun Signal 2022; 20:143. [PMID: 36104752 PMCID: PMC9472443 DOI: 10.1186/s12964-022-00947-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/23/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractSpatiotemporal regulation of subcellular protein kinase A (PKA) activity for precise substrate phosphorylation is essential for cellular responses to hormonal stimulation. Ryanodine receptor 2 (RyR2) and (sarco)endoplasmic reticulum calcium ATPase 2a (SERCA2a) represent two critical targets of β adrenoceptor (βAR) signaling on the sarcoplasmic reticulum membrane for cardiac excitation and contraction coupling. Using novel biosensors, we show that cardiac β1AR signals to both RyR2 and SERCA2a nanodomains in cardiomyocytes from mice, rats, and rabbits, whereas the β2AR signaling is restricted from these nanodomains. Phosphodiesterase 4 (PDE4) and PDE3 control the baseline PKA activity and prevent β2AR signaling from reaching the RyR2 and SERCA2a nanodomains. Moreover, blocking inhibitory G protein allows β2AR signaling to the RyR2 but not the SERCA2a nanodomains. This study provides evidence for the differential roles of inhibitory G protein and PDEs in controlling the adrenergic subtype signaling at the RyR2 and SERCA2a nanodomains in cardiomyocytes.
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7
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Serotonin Receptor 5-HT2A Regulates TrkB Receptor Function in Heteroreceptor Complexes. Cells 2022; 11:cells11152384. [PMID: 35954229 PMCID: PMC9368268 DOI: 10.3390/cells11152384] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/22/2022] [Accepted: 07/29/2022] [Indexed: 02/04/2023] Open
Abstract
Serotonin receptor 5-HT2A and tropomyosin receptor kinase B (TrkB) strongly contribute to neuroplasticity regulation and are implicated in numerous neuronal disorders. Here, we demonstrate a physical interaction between 5-HT2A and TrkB in vitro and in vivo using co-immunoprecipitation and biophysical and biochemical approaches. Heterodimerization decreased TrkB autophosphorylation, preventing its activation with agonist 7,8-DHF, even with low 5-HT2A receptor expression. A blockade of 5-HT2A receptor with the preferential antagonist ketanserin prevented the receptor-mediated downregulation of TrkB phosphorylation without restoring the TrkB response to its agonist 7,8-DHF in vitro. In adult mice, intraperitoneal ketanserin injection increased basal TrkB phosphorylation in the frontal cortex and hippocampus, which is in accordance with our findings demonstrating the prevalence of 5-HT2A–TrkB heteroreceptor complexes in these brain regions. An expression analysis revealed strong developmental regulation of 5-HT2A and TrkB expressions in the cortex, hippocampus, and especially the striatum, demonstrating that the balance between TrkB and 5-HT2A may shift in certain brain regions during postnatal development. Our data reveal the functional role of 5-HT2A–TrkB receptor heterodimerization and suggest that the regulated expression of 5-HT2A and TrkB is a molecular mechanism for the brain-region-specific modulation of TrkB functions during development and under pathophysiological conditions.
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8
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Lu F, Ma Q, Xie W, Liou CL, Zhang D, Sweat ME, Jardin BD, Naya FJ, Guo Y, Cheng H, Pu WT. CMYA5 establishes cardiac dyad architecture and positioning. Nat Commun 2022; 13:2185. [PMID: 35449169 PMCID: PMC9023524 DOI: 10.1038/s41467-022-29902-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 04/05/2022] [Indexed: 11/18/2022] Open
Abstract
Cardiac excitation-contraction coupling requires dyads, the nanoscopic microdomains formed adjacent to Z-lines by apposition of transverse tubules and junctional sarcoplasmic reticulum. Disruption of dyad architecture and function are common features of diseased cardiomyocytes. However, little is known about the mechanisms that modulate dyad organization during cardiac development, homeostasis, and disease. Here, we use proximity proteomics in intact, living hearts to identify proteins enriched near dyads. Among these proteins is CMYA5, an under-studied striated muscle protein that co-localizes with Z-lines, junctional sarcoplasmic reticulum proteins, and transverse tubules in mature cardiomyocytes. During cardiac development, CMYA5 positioning adjacent to Z-lines precedes junctional sarcoplasmic reticulum positioning or transverse tubule formation. CMYA5 ablation disrupts dyad architecture, dyad positioning at Z-lines, and junctional sarcoplasmic reticulum Ca2+ release, leading to cardiac dysfunction and inability to tolerate pressure overload. These data provide mechanistic insights into cardiomyopathy pathogenesis by demonstrating that CMYA5 anchors junctional sarcoplasmic reticulum to Z-lines, establishes dyad architecture, and regulates dyad Ca2+ release.
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Affiliation(s)
- Fujian Lu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Qing Ma
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Wenjun Xie
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, 710049, Xi'an, Shanxi, China
| | - Carter L Liou
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Donghui Zhang
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, 430062, Wuhan, Hubei, China
| | - Mason E Sweat
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Blake D Jardin
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Francisco J Naya
- Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, MA, 02215, USA
| | - Yuxuan Guo
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- Peking University Health Science Center, School of Basic Medical Sciences, The Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Science of Ministry of Education, 100191, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
- Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA.
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9
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Demydenko K, Roderick HL. The cardiomyocyte firestarter-RyR clusters ignite their neighbours after augmentation of Ca 2+ release by β-stimulation. Acta Physiol (Oxf) 2022; 234:e13798. [PMID: 35147280 DOI: 10.1111/apha.13798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Kateryna Demydenko
- Laboratory of Experimental Cardiology Department of Cardiovascular Sciences KU Leuven Leuven Belgium
| | - H. Llewelyn Roderick
- Laboratory of Experimental Cardiology Department of Cardiovascular Sciences KU Leuven Leuven Belgium
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10
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Iaparov B, Baglaeva I, Zahradník I, Zahradníková A. Magnesium Ions Moderate Calcium-Induced Calcium Release in Cardiac Calcium Release Sites by Binding to Ryanodine Receptor Activation and Inhibition Sites. Front Physiol 2022; 12:805956. [PMID: 35145426 PMCID: PMC8821920 DOI: 10.3389/fphys.2021.805956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022] Open
Abstract
Ryanodine receptor channels at calcium release sites of cardiac myocytes operate on the principle of calcium-induced calcium release. In vitro experiments revealed competition of Ca2+ and Mg2+ in the activation of ryanodine receptors (RyRs) as well as inhibition of RyRs by Mg2+. The impact of RyR modulation by Mg2+ on calcium release is not well understood due to the technical limitations of in situ experiments. We turned instead to an in silico model of a calcium release site (CRS), based on a homotetrameric model of RyR gating with kinetic parameters determined from in vitro measurements. We inspected changes in the activity of the CRS model in response to a random opening of one of 20 realistically distributed RyRs, arising from Ca2+/Mg2+ interactions at RyR channels. Calcium release events (CREs) were simulated at a range of Mg2+-binding parameters at near-physiological Mg2+ and ATP concentrations. Facilitation of Mg2+ binding to the RyR activation site inhibited the formation of sparks and slowed down their activation. Impeding Mg-binding to the RyR activation site enhanced spark formation and speeded up their activation. Varying Mg2+ binding to the RyR inhibition site also dramatically affected calcium release events. Facilitation of Mg2+ binding to the RyR inhibition site reduced the amplitude, relative occurrence, and the time-to-end of sparks, and vice versa. The characteristics of CREs correlated dose-dependently with the effective coupling strength between RyRs, defined as a function of RyR vicinity, single-channel calcium current, and Mg-binding parameters of the RyR channels. These findings postulate the role of Mg2+ in calcium release as a negative modulator of the coupling strength among RyRs in a CRS, translating to damping of the positive feedback of the calcium-induced calcium-release mechanism.
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Affiliation(s)
| | | | | | - Alexandra Zahradníková
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
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11
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Wang X, Nawaz M, DuPont C, Myers JH, Burke SR, Bannister RA, Foy BD, Voss AA, Rich MM. The role of action potential changes in depolarization-induced failure of excitation contraction coupling in mouse skeletal muscle. eLife 2022; 11:71588. [PMID: 34985413 PMCID: PMC8730720 DOI: 10.7554/elife.71588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 12/24/2021] [Indexed: 12/24/2022] Open
Abstract
Excitation-contraction coupling (ECC) is the process by which electrical excitation of muscle is converted into force generation. Depolarization of skeletal muscle resting potential contributes to failure of ECC in diseases such as periodic paralysis, intensive care unit acquired weakness and possibly fatigue of muscle during vigorous exercise. When extracellular K+ is raised to depolarize the resting potential, failure of ECC occurs suddenly, over a narrow range of resting potentials. Simultaneous imaging of Ca2+ transients and recording of action potentials (APs) demonstrated failure to generate Ca2+ transients when APs peaked at potentials more negative than -30mV. An AP property that closely correlated with failure of the Ca2+ transient was the integral of AP voltage with respect to time. Simultaneous recording of Ca2+ transients and APs with electrodes separated by 1.6mm revealed AP conduction fails when APs peak below -21mV. We hypothesize propagation of APs and generation of Ca2+ transients are governed by distinct AP properties: AP conduction is governed by AP peak, whereas Ca2+ release from the sarcoplasmic reticulum is governed by AP integral. The reason distinct AP properties may govern distinct steps of ECC is the kinetics of the ion channels involved. Na channels, which govern propagation, have rapid kinetics and are insensitive to AP width (and thus AP integral) whereas Ca2+ release is governed by gating charge movement of Cav1.1 channels, which have slower kinetics such that Ca2+ release is sensitive to AP integral. The quantitative relationships established between resting potential, AP properties, AP conduction and Ca2+ transients provide the foundation for future studies of failure of ECC induced by depolarization of the resting potential.
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Affiliation(s)
- Xueyong Wang
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Murad Nawaz
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Chris DuPont
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Jessica H Myers
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Steve Ra Burke
- Wright State University, Department of Biological Sciences, Dayton, United States
| | - Roger A Bannister
- University of Maryland School of Medicine, Departments of Pathology/Biochemistry & Molecular Biology, Baltimore, United States
| | - Brent D Foy
- Wright State University, Department of Physics, Dayton, United States
| | - Andrew A Voss
- Wright State University, Department of Biological Sciences, Dayton, United States
| | - Mark M Rich
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
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12
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Lu F, Li Y, Lin S, Cheng H, Yang S. Spatiotemporal regulation of store-operated calcium entry in cancer metastasis. Biochem Soc Trans 2021; 49:2581-2589. [PMID: 34854917 PMCID: PMC9436031 DOI: 10.1042/bst20210307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 01/08/2023]
Abstract
The store-operated calcium (Ca2+) entry (SOCE) is the Ca2+ entry mechanism used by cells to replenish depleted Ca2+ store. The dysregulation of SOCE has been reported in metastatic cancer. It is believed that SOCE promotes migration and invasion by remodeling the actin cytoskeleton and cell adhesion dynamics. There is recent evidence supporting that SOCE is critical for the spatial and the temporal coding of Ca2+ signals in the cell. In this review, we critically examined the spatiotemporal control of SOCE signaling and its implication in the specificity and robustness of signaling events downstream of SOCE, with a focus on the spatiotemporal SOCE signaling during cancer cell migration, invasion and metastasis. We further discuss the limitation of our current understanding of SOCE in cancer metastasis and potential approaches to overcome such limitation.
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Affiliation(s)
- Fujian Lu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
- Department of Cardiology, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Yunzhan Li
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA, 17033, United States
| | - Shengchen Lin
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA, 17033, United States
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Shengyu Yang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA, 17033, United States
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13
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Sipido KR, Eisner DA. Edward Carmeliet: his contributions and scientific legacy. J Physiol 2021; 599:4727-4729. [PMID: 34533837 DOI: 10.1113/jp282357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Karin R Sipido
- Department of Cardiovascular Sciences, Experimental Cardiology, Leuven, Belgium
| | - David A Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
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14
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Zhang JF, Mehta S, Zhang J. Signaling Microdomains in the Spotlight: Visualizing Compartmentalized Signaling Using Genetically Encoded Fluorescent Biosensors. Annu Rev Pharmacol Toxicol 2021; 61:587-608. [PMID: 33411579 DOI: 10.1146/annurev-pharmtox-010617-053137] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
How cells muster a network of interlinking signaling pathways to faithfully convert diverse external cues to specific functional outcomes remains a central question in biology. Through their ability to convert dynamic biochemical activities to rapid and precise optical readouts, genetically encoded fluorescent biosensors have become instrumental in unraveling the molecular logic controlling the specificity of intracellular signaling. In this review, we discuss how the use of genetically encoded fluorescent biosensors to visualize dynamic signaling events within their native cellular context is elucidating the different strategies employed by cells to organize signaling activities into discrete compartments, or signaling microdomains, to ensure functional specificity.
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Affiliation(s)
- Jin-Fan Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA;
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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15
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Hurley ME, Sheard TMD, Norman R, Kirton HM, Shah SS, Pervolaraki E, Yang Z, Gamper N, White E, Steele D, Jayasinghe I. A correlative super-resolution protocol to visualise structural underpinnings of fast second-messenger signalling in primary cell types. Methods 2021; 193:27-37. [PMID: 33059034 DOI: 10.1016/j.ymeth.2020.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/28/2020] [Accepted: 10/07/2020] [Indexed: 10/24/2022] Open
Abstract
Nanometre-scale cellular information obtained through super-resolution microscopies are often unaccompanied by functional information, particularly transient and diffusible signals through which life is orchestrated in the nano-micrometre spatial scale. We describe a correlative imaging protocol which allows the ubiquitous intracellular second messenger, calcium (Ca2+), to be directly visualised against nanoscale patterns of the ryanodine receptor (RyR) Ca2+ channels which give rise to these Ca2+ signals in wildtype primary cells. This was achieved by combining total internal reflection fluorescence (TIRF) imaging of the elementary Ca2+ signals, with the subsequent DNA-PAINT imaging of the RyRs. We report a straightforward image analysis protocol of feature extraction and image alignment between correlative datasets and demonstrate how such data can be used to visually identify the ensembles of Ca2+ channels that are locally activated during the genesis of cytoplasmic Ca2+ signals.
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Affiliation(s)
- Miriam E Hurley
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Thomas M D Sheard
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Ruth Norman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Hannah M Kirton
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Shihab S Shah
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Eleftheria Pervolaraki
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Zhaokang Yang
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Ed White
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Derek Steele
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Izzy Jayasinghe
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Department of Molecular Biology and Biotechnology, Faculty of Science, The University of Sheffield, S10 2TN, UK.
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16
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Dunn TW, Sossin WS. Excitatory postsynaptic calcium transients at Aplysia sensory-motor neuron synapses allow for quantal examination of synaptic strength over multiple days in culture. ACTA ACUST UNITED AC 2021; 28:277-290. [PMID: 34400529 PMCID: PMC8372562 DOI: 10.1101/lm.052639.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/26/2021] [Indexed: 12/21/2022]
Abstract
A more thorough description of the changes in synaptic strength underlying synaptic plasticity may be achieved with quantal resolution measurements at individual synaptic sites. Here, we demonstrate that by using a membrane targeted genetic calcium sensor, we can measure quantal synaptic events at the individual synaptic sites of Aplysia sensory neuron to motor neuron synaptic connections. These results show that synaptic strength is not evenly distributed between all contacts in these cultures, but dominated by multiquantal sites of synaptic contact, likely clusters of individual synaptic sites. Surprisingly, most synaptic contacts were not found opposite presynaptic varicosities, but instead at areas of pre- and postsynaptic contact with no visible thickening of membranes. The release probability, quantal size, and quantal content can be measured over days at individual synaptic contacts using this technique. Homosynaptic depression was accompanied by a reduction in release site probability, with no evidence of individual synaptic site silencing over the course of depression. This technique shows promise in being able to address outstanding questions in this system, including determining the synaptic changes that maintain long-term alterations in synaptic strength that underlie memory.
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Affiliation(s)
- Tyler W Dunn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
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17
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Guo J, Tian Q, Barth M, Xian W, Ruppenthal S, Schaefers HJ, Chen Z, Moretti A, Laugwitz KL, Lipp P. Human BIN1 isoforms grow, maintain and regenerate excitation-contraction couplons in adult rat and human stem cell-derived cardiomyocytes. Cardiovasc Res 2021; 118:1479-1491. [PMID: 34152414 DOI: 10.1093/cvr/cvab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Indexed: 12/31/2022] Open
Abstract
AIMS In ventricular myocytes, Transverse-tubules (T-tubules) are instrumental for excitation-contraction (EC) coupling and their disarray is a hallmark of cardiac diseases. BIN1 is a key contributor to their biogenesis. Our study set out to investigate the role of human BIN1 splice variants in the maintenance and regeneration of EC-coupling in rat adult ventricular myocytes and human induced pluripotent stem cell-derived cardiac myocytes (hiPS-CMs). METHODS AND RESULTS In heart samples from healthy human donors expression patterns of 5 BIN1 splice variants were identified. Following viral transduction of human BIN1 splice variants in cellular models of T-tubular disarray we employed high-speed confocal calcium imaging and Ca-CLEAN analysis to identify functional EC-coupling sites and T-tubular architecture. Adult rat ventricular myocytes were used to investigate the regeneration after loss and maintenance of EC-coupling while we studied the enhancement of EC-coupling in hiPS-CMs. All five human BIN1 splice variants induced de novo generation of T-tubules in both cell types. Isoforms with the phosphoinositide binding motif (PI) were most potent in maintenance and regeneration of T-tubules and functional EC-coupling in adult rat myocytes. In hiPSC-CMs, BIN1 variants with PI motiv induced de-novo generation of T-tubules, functional EC-coupling sites and enhanced calcium handling. CONCLUSION(S) BIN1 is essential for the maintenance, regeneration, and de-novo generation of functional T-tubules, especially isoforms with PI motifs. These T-tubules trigger the development of functional EC couplons resulting in enhanced calcium handling. TRANSLATIONAL PERSPECTIVE Cardiomyopathy and heart failure are among the most frequent causes of death in modern societies. Gene therapies and hiPSC technology are becoming increasingly promising, both for treatment and therapy development. On the cellular level, one of the common denominators of cardiac diseases is the concurrent loss of T-tubules essential for efficient EC-coupling. While initial approaches in animal models employing gene therapy with BIN1 have depicted encouraging improvements the expression pattern of BIN1 isoforms in the human heart is still elusive. The present study identifies a unique set of five distinct BIN1 isoforms in healthy human hearts and demonstrates their potency in both, T-tubule maintenance and re-generation after loss resulting in efficient EC-coupling. Noteworthy, PI-motif containing isoforms were potent trigger of de-novo generation of T-tubules and establishment of efficient EC-coupling in hiPSC-CMs. Therefore, the expression of BIN1 might be novel and promising for pharmaceutical treatment and gene therapy.
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Affiliation(s)
- Jia Guo
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Qinghai Tian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Monika Barth
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Wenying Xian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Sandra Ruppenthal
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Hans-Joachim Schaefers
- Department of Thoracic and Cardiovascular Surgery, Saarland University Medical Center, Homburg/Saar, Germany
| | - Zhifen Chen
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Alessandra Moretti
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Karl-Ludwig Laugwitz
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Peter Lipp
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
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18
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Simultaneous detection of reciprocal interactions between calmodulin, Ca2+ and molecular targets: a focus on the calmodulin-RyR2 complex. Biochem J 2021; 478:487-491. [PMID: 33544125 DOI: 10.1042/bcj20200818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 01/22/2023]
Abstract
In a recent issue of Biochemical Journal, Brohus et al. (Biochem. J.476, 193-209) investigated the interaction between the ubiquitous intracellular Ca2+-sensor calmodulin (CaM) and peptides that mimic different structural regions of the cardiac ryanodine receptor (RyR2) at different Ca2+ concentrations. For the purpose, a novel bidimensional titration assay based on changes in fluorescence anisotropy was designed. The study identified the CaM domains that selectively bind to a specific CaM-binding domain in RyR2 and demonstrated that the interaction occurs essentially under Ca2+-saturating conditions. This study provides an elegant and experimentally accessible framework for detailed molecular investigations of the emerging life-threatening arrhythmia diseases associated with mutations in the genes encoding CaM. Furthermore, by allowing the measurement of the equilibrium dissociation constant in a protein-protein complex as a function of [Ca2+], the methodology presented by Brohus et al. may have broad applicability to the study of Ca2+ signalling.
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19
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Liu X, Wang S, Guo X, Li Y, Ogurlu R, Lu F, Prondzynski M, Buzon SDLS, Ma Q, Zhang D, Wang G, Cotton J, Guo Y, Xiao L, Milan DJ, Xu Y, Schlame M, Bezzerides VJ, Pu WT. Increased Reactive Oxygen Species-Mediated Ca 2+/Calmodulin-Dependent Protein Kinase II Activation Contributes to Calcium Handling Abnormalities and Impaired Contraction in Barth Syndrome. Circulation 2021; 143:1894-1911. [PMID: 33793303 PMCID: PMC8691127 DOI: 10.1161/circulationaha.120.048698] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Mutations in tafazzin (TAZ), a gene required for biogenesis of cardiolipin, the signature phospholipid of the inner mitochondrial membrane, causes Barth syndrome (BTHS). Cardiomyopathy and risk of sudden cardiac death are prominent features of BTHS, but the mechanisms by which impaired cardiolipin biogenesis causes cardiac muscle weakness and arrhythmia are poorly understood. METHODS We performed in vivo electrophysiology to define arrhythmia vulnerability in cardiac-specific TAZ knockout mice. Using cardiomyocytes derived from human induced pluripotent stem cells and cardiac-specific TAZ knockout mice as model systems, we investigated the effect of TAZ inactivation on Ca2+ handling. Through genome editing and pharmacology, we defined a molecular link between TAZ mutation and abnormal Ca2+ handling and contractility. RESULTS A subset of mice with cardiac-specific TAZ inactivation developed arrhythmias, including bidirectional ventricular tachycardia, atrial tachycardia, and complete atrioventricular block. Compared with wild-type controls, BTHS-induced pluripotent stem cell-derived cardiomyocytes had increased diastolic Ca2+ and decreased Ca2+ transient amplitude. BTHS-induced pluripotent stem cell-derived cardiomyocytes had higher levels of mitochondrial and cellular reactive oxygen species than wild-type controls, which activated CaMKII (Ca2+/calmodulin-dependent protein kinase II). Activated CaMKII phosphorylated the RYR2 (ryanodine receptor 2) on serine 2814, increasing Ca2+ leak through RYR2. Inhibition of this reactive oxygen species-CaMKII-RYR2 pathway through pharmacological inhibitors or genome editing normalized aberrant Ca2+ handling in BTHS-induced pluripotent stem cell-derived cardiomyocytes and improved their contractile function. Murine Taz knockout cardiomyocytes also exhibited elevated diastolic Ca2+ and decreased Ca2+ transient amplitude. These abnormalities were ameliorated by Ca2+/calmodulin-dependent protein kinase II or reactive oxygen species inhibition. CONCLUSIONS This study identified a molecular pathway that links TAZ mutation with abnormal Ca2+ handling and decreased cardiomyocyte contractility. This pathway may offer therapeutic opportunities to treat BTHS and potentially other diseases with elevated mitochondrial reactive oxygen species production.
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Affiliation(s)
- Xujie Liu
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Radiology, Basic Medical School, Chongqing Medical University, Chongqing, 400016, China
| | - Suya Wang
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Xiaoling Guo
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
- Center of Scientific Research, the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Roza Ogurlu
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Fujian Lu
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | | | | | - Qing Ma
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Donghui Zhang
- State key laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, Hubei 430062, China
| | - Gang Wang
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Justin Cotton
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
- Harvard College, Cambridge, MA 02138, USA
| | - Yuxuan Guo
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Ling Xiao
- Department of Cardiology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - David J. Milan
- Department of Cardiology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Yang Xu
- Department of Anesthesiology, New York University School of Medicine, New York, New York
| | - Michael Schlame
- Department of Anesthesiology, New York University School of Medicine, New York, New York
| | | | - William T. Pu
- Department of Cardiology, Boston Children’s Hospital, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
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20
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Iaparov BI, Zahradnik I, Moskvin AS, Zahradníková A. In silico simulations reveal that RYR distribution affects the dynamics of calcium release in cardiac myocytes. J Gen Physiol 2021; 153:211900. [PMID: 33735373 PMCID: PMC7980188 DOI: 10.1085/jgp.202012685] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 02/08/2021] [Indexed: 11/20/2022] Open
Abstract
The dyads of cardiac myocytes contain ryanodine receptors (RYRs) that generate calcium sparks upon activation. To test how geometric factors of RYR distribution contribute to the formation of calcium sparks, which cannot be addressed experimentally, we performed in silico simulations on a large set of models of calcium release sites (CRSs). Our models covered the observed range of RYR number, density, and spatial arrangement. The calcium release function of CRSs was modeled by RYR openings, with an open probability dependent on concentrations of free Ca2+ and Mg2+ ions, in a rapidly buffered system, with a constant open RYR calcium current. We found that simulations of spontaneous sparks by repeatedly opening one of the RYRs in a CRS produced three different types of calcium release events (CREs) in any of the models. Transformation of simulated CREs into fluorescence signals yielded calcium sparks with characteristics close to the observed ones. CRE occurrence varied broadly with the spatial distribution of RYRs in the CRS but did not consistently correlate with RYR number, surface density, or calcium current. However, it correlated with RYR coupling strength, defined as the weighted product of RYR vicinity and calcium current, so that CRE characteristics of all models followed the same state-response function. This finding revealed the synergy between structure and function of CRSs in shaping dyad function. Lastly, rearrangements of RYRs simulating hypothetical experiments on splitting and compaction of a dyad revealed an increased propensity to generate spontaneous sparks and an overall increase in calcium release in smaller and more compact dyads, thus underlying the importance and physiological role of RYR arrangement in cardiac myocytes.
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Affiliation(s)
- Bogdan I Iaparov
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,Research Institute of Physics and Applied Mathematics, and Department of Theoretical and Mathematical Physics, Ural Federal University, Ekaterinburg, Russia
| | - Ivan Zahradnik
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Alexander S Moskvin
- Research Institute of Physics and Applied Mathematics, and Department of Theoretical and Mathematical Physics, Ural Federal University, Ekaterinburg, Russia
| | - Alexandra Zahradníková
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
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21
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Observing and Manipulating Cell-Specific Cardiac Function with Light. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 33398827 DOI: 10.1007/978-981-15-8763-4_24] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
The heart is a complex multicellular organ comprising both cardiomyocytes (CM), which make up the majority of the cardiac volume, and non-myocytes (NM), which represent the majority of cardiac cells. CM drive the pumping action of the heart, triggered via rhythmic electrical activity. NM, on the other hand, have many essential functions including generating extracellular matrix, regulating CM activity, and aiding in repair following injury. NM include neurons and interstitial, immune, and endothelial cells. Understanding the role of specific cell types and their interactions with one another may be key to developing new therapies with minimal side effects to treat cardiac disease. However, assessing cell-type-specific behavior in situ using standard techniques is challenging. Optogenetics enables population-specific observation and control, facilitating studies into the role of specific cell types and subtypes. Optogenetic models targeting the most important cardiac cell types have been generated and used to investigate non-canonical roles of those cell populations, e.g., to better understand how cardiac pacing occurs and to assess potential translational possibilities of optogenetics. So far, cardiac optogenetic studies have primarily focused on validating models and tools in the healthy heart. The field is now in a position where animal models and tools should be utilized to improve our understanding of the complex heterocellular nature of the heart, how this changes in disease, and from there to enable the development of cell-specific therapies and improved treatments.
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22
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Sanchez C, Berthier C, Tourneur Y, Monteiro L, Allard B, Csernoch L, Jacquemond V. Detection of Ca2+ transients near ryanodine receptors by targeting fluorescent Ca2+ sensors to the triad. J Gen Physiol 2021; 153:211757. [PMID: 33538764 PMCID: PMC7868779 DOI: 10.1085/jgp.202012592] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 12/03/2020] [Accepted: 12/23/2020] [Indexed: 11/23/2022] Open
Abstract
In intact muscle fibers, functional properties of ryanodine receptor (RYR)–mediated sarcoplasmic reticulum (SR) Ca2+ release triggered by activation of the voltage sensor CaV1.1 have so far essentially been addressed with diffusible Ca2+-sensitive dyes. Here, we used a domain (T306) of the protein triadin to target the Ca2+-sensitive probe GCaMP6f to the junctional SR membrane, in the immediate vicinity of RYR channels, within the triad region. Fluorescence of untargeted GCaMP6f was distributed throughout the muscle fibers and experienced large Ca2+-dependent changes, with obvious kinetic delays, upon application of voltage-clamp depolarizing pulses. Conversely, T306-GCaMP6f localized to the triad and generated Ca2+-dependent fluorescence transients of lower amplitude and faster kinetics for low and intermediate levels of Ca2+ release than those of untargeted GCaMP6f. By contrast, model simulation of the spatial gradients of Ca2+ following Ca2+ release predicted limited kinetic differences under the assumptions that the two probes were present at the same concentration and suffered from identical kinetic limitations. At the spatial level, T306-GCaMP6f transients within distinct regions of a same fiber yielded a uniform time course, even at low levels of Ca2+ release activation. Similar observations were made using GCaMP6f fused to the γ1 auxiliary subunit of CaV1.1. Despite the probe's limitations, our results point out the remarkable synchronicity of voltage-dependent Ca2+ release activation and termination among individual triads and highlight the potential of the approach to visualize activation or closure of single groups of RYR channels. We anticipate targeting of improved Ca2+ sensors to the triad will provide illuminating insights into physiological normal RYR function and its dysfunction under stress or pathological conditions.
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Affiliation(s)
- Colline Sanchez
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Christine Berthier
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Yves Tourneur
- Departamento Nutrição, Universidade Federal de Pernambuco, Recife, Brazil
| | - Laloé Monteiro
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Bruno Allard
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Laszlo Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Vincent Jacquemond
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
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23
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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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24
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Lu F, Pu WT. The architecture and function of cardiac dyads. Biophys Rev 2020; 12:1007-1017. [PMID: 32661902 PMCID: PMC7429583 DOI: 10.1007/s12551-020-00729-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 07/03/2020] [Indexed: 12/28/2022] Open
Abstract
Cardiac excitation-contraction (EC) coupling, which links plasma membrane depolarization to activation of cardiomyocyte contraction, occurs at dyads, the nanoscopic microdomains formed by apposition of transverse (T)-tubules and junctional sarcoplasmic reticulum (jSR). In a dyadic junction, EC coupling occurs through Ca2+-induced Ca2+ release. Membrane depolarization opens voltage-gated L-type Ca2+ channels (LTCCs) in the T-tubule. The resulting influx of extracellular Ca2+ into the dyadic cleft opens Ca2+ release channels known as ryanodine receptors (RYRs) in the jSR, leading to the rapid increase in cytosolic Ca2+ that triggers sarcomere contraction. The efficacy of LTCC-RYR communication greatly affects a myriad of downstream intracellular signaling events, and it is controlled by many factors, including T-tubule and jSR structure, spatial distribution of ion channels, and regulatory proteins that closely regulate the activities of channels within dyads. Alterations in dyad architecture and/or channel activity are seen in many types of heart disease. This review will focus on the current knowledge regarding cardiac dyad structure and function, their alterations in heart failure, and new approaches to study the composition and function of dyads.
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Affiliation(s)
- Fujian Lu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, USA.
- Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA.
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Liu C, Zhong G, Zhou Y, Yang Y, Tan Y, Li Y, Gao X, Sun W, Li J, Jin X, Cao D, Yuan X, Liu Z, Liang S, Li Y, Du R, Zhao Y, Xue J, Zhao D, Song J, Ling S, Li Y. Alteration of calcium signalling in cardiomyocyte induced by simulated microgravity and hypergravity. Cell Prolif 2020; 53:e12783. [PMID: 32101357 PMCID: PMC7106961 DOI: 10.1111/cpr.12783] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/21/2020] [Accepted: 02/02/2020] [Indexed: 12/14/2022] Open
Abstract
Objectives Cardiac Ca2+ signalling plays an essential role in regulating excitation‐contraction coupling and cardiac remodelling. However, the response of cardiomyocytes to simulated microgravity and hypergravity and the effects on Ca2+ signalling remain unknown. Here, we elucidate the mechanisms underlying the proliferation and remodelling of HL‐1 cardiomyocytes subjected to rotation‐simulated microgravity and 4G hypergravity. Materials and Methods The cardiomyocyte cell line HL‐1 was used in this study. A clinostat and centrifuge were used to study the effects of microgravity and hypergravity, respectively, on cells. Calcium signalling was detected with laser scanning confocal microscopy. Protein and mRNA levels were detected by Western blotting and real‐time PCR, respectively. Wheat germ agglutinin (WGA) staining was used to analyse cell size. Results Our data showed that spontaneous calcium oscillations and cytosolic calcium concentration are both increased in HL‐1 cells after simulated microgravity and 4G hypergravity. Increased cytosolic calcium leads to activation of calmodulin‐dependent protein kinase II/histone deacetylase 4 (CaMKII/HDAC4) signalling and upregulation of the foetal genes ANP and BNP, indicating cardiac remodelling. WGA staining indicated that cell size was decreased following rotation‐simulated microgravity and increased following 4G hypergravity. Moreover, HL‐1 cell proliferation was increased significantly under hypergravity but not rotation‐simulated microgravity. Conclusions Our study demonstrates for the first time that Ca2+/CaMKII/HDAC4 signalling plays a pivotal role in myocardial remodelling under rotation‐simulated microgravity and hypergravity.
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Affiliation(s)
- Caizhi Liu
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Guohui Zhong
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | | | | | - Yingjun Tan
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Yuheng Li
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Xingcheng Gao
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Weijia Sun
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Jianwei Li
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Xiaoyan Jin
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Dengchao Cao
- State Key Laboratory of Agrobiotechnology, College of Life Sciences, China Agricultural University, Beijing, China
| | - Xinxin Yuan
- State Key Laboratory of Agrobiotechnology, College of Life Sciences, China Agricultural University, Beijing, China
| | - Zizhong Liu
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Shuai Liang
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Youyou Li
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Ruikai Du
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Yinlong Zhao
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Jianqi Xue
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Dingsheng Zhao
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Jinping Song
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Shukuan Ling
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Yingxian Li
- State Key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
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Xian Y, Zhou M, Han S, Yang R, Wang Y. A FRET biosensor reveals free zinc deficiency in diabetic beta-cell vesicles. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2019.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dries E, Santiago DJ, Gilbert G, Lenaerts I, Vandenberk B, Nagaraju CK, Johnson DM, Holemans P, Roderick HL, Macquaide N, Claus P, Sipido KR. Hyperactive ryanodine receptors in human heart failure and ischaemic cardiomyopathy reside outside of couplons. Cardiovasc Res 2019; 114:1512-1524. [PMID: 29668881 PMCID: PMC6106102 DOI: 10.1093/cvr/cvy088] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 04/12/2018] [Indexed: 12/26/2022] Open
Abstract
Aims In ventricular myocytes from humans and large mammals, the transverse and axial tubular system (TATS) network is less extensive than in rodents with consequently a greater proportion of ryanodine receptors (RyRs) not coupled to this membrane system. TATS remodelling in heart failure (HF) and after myocardial infarction (MI) increases the fraction of non-coupled RyRs. Here we investigate whether this remodelling alters the activity of coupled and non-coupled RyR sub-populations through changes in local signalling. We study myocytes from patients with end-stage HF, compared with non-failing (non-HF), and myocytes from pigs with MI and reduced left ventricular (LV) function, compared with sham intervention (SHAM). Methods and results Single LV myocytes for functional studies were isolated according to standard protocols. Immunofluorescent staining visualized organization of TATS and RyRs. Ca2+ was measured by confocal imaging (fluo-4 as indicator) and using whole-cell patch-clamp (37°C). Spontaneous Ca2+ release events, Ca2+ sparks, as a readout for RyR activity were recorded during a 15 s period following conditioning stimulation at 2 Hz. Sparks were assigned to cell regions categorized as coupled or non-coupled sites according to a previously developed method. Human HF myocytes had more non-coupled sites and these had more spontaneous activity than in non-HF. Hyperactivity of these non-coupled RyRs was reduced by Ca2+/calmodulin-dependent kinase II (CaMKII) inhibition. Myocytes from MI pigs had similar changes compared with SHAM controls as seen in human HF myocytes. As well as by CaMKII inhibition, in MI, the increased activity of non-coupled sites was inhibited by mitochondrial reactive oxygen species (mito-ROS) scavenging. Under adrenergic stimulation, Ca2+ waves were more frequent and originated at non-coupled sites, generating larger Na+/Ca2+ exchange currents in MI than in SHAM. Inhibition of CaMKII or mito-ROS scavenging reduced spontaneous Ca2+ waves, and improved excitation–contraction coupling. Conclusions In HF and after MI, RyR microdomain re-organization enhances spontaneous Ca2+ release at non-coupled sites in a manner dependent on CaMKII activation and mito-ROS production. This specific modulation generates a substrate for arrhythmia that appears to be responsive to selective pharmacologic modulation.
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Affiliation(s)
- Eef Dries
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Demetrio J Santiago
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Guillaume Gilbert
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Ilse Lenaerts
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Bert Vandenberk
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Chandan K Nagaraju
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Daniel M Johnson
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Patricia Holemans
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - H Llewelyn Roderick
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Niall Macquaide
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Piet Claus
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
| | - Karin R Sipido
- Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg, Herestraat Leuven, Belgium
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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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Bezzerides VJ, Caballero A, Wang S, Ai Y, Hylind RJ, Lu F, Heims-Waldron DA, Chambers KD, Zhang D, Abrams DJ, Pu WT. Gene Therapy for Catecholaminergic Polymorphic Ventricular Tachycardia by Inhibition of Ca 2+/Calmodulin-Dependent Kinase II. Circulation 2019; 140:405-419. [PMID: 31155924 PMCID: PMC7274838 DOI: 10.1161/circulationaha.118.038514] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited cardiac arrhythmia characterized by adrenergically triggered arrhythmias, is inadequately treated by current standard of care. Ca2+/calmodulin-dependent protein kinase II (CaMKII), an adrenergically activated kinase that contributes to arrhythmogenesis in heart disease models, is a candidate therapeutic target in CPVT. However, translation of CaMKII inhibition has been limited by the need for selective CaMKII inhibition in cardiomyocytes. Here, we tested the hypothesis that CaMKII inhibition with a cardiomyocyte-targeted gene therapy strategy would suppress arrhythmia in CPVT mouse models. METHODS We developed AAV9-GFP-AIP, an adeno-associated viral vector in which a potent CaMKII inhibitory peptide, autocamtide-2-related inhibitory peptide [AIP], is fused to green fluorescent protein (GFP) and expressed from a cardiomyocyte selective promoter. The vector was delivered systemically. Arrhythmia burden was evaluated with invasive electrophysiology testing in adult mice. AIP was also tested on induced pluripotent stem cells derived from patients with CPVT with different disease-causing mutations to determine the effectiveness of our proposed therapy on human induced pluripotent stem cell-derived cardiomyocytes and different pathogenic genotypes. RESULTS AAV9-GFP-AIP was robustly expressed in the heart without significant expression in extracardiac tissues, including the brain. Administration of AAV9-GFP-AIP to neonatal mice with a known CPVT mutation (RYR2R176Q/+) effectively suppressed ventricular arrhythmias induced by either β-adrenergic stimulation or programmed ventricular pacing, without significant proarrhythmic effect. Intravascular delivery of AAV9-GFP-AIP to adolescent mice transduced ≈50% of cardiomyocytes and was effective in suppressing arrhythmia in CPVT mice. Induced pluripotent stem cell-derived cardiomyocytes derived from 2 different patients with CPVT with different pathogenic mutations demonstrated increased frequency of abnormal calcium release events, which was suppressed by a cell-permeable form of AIP. CONCLUSIONS This proof-of-concept study showed that AAV-mediated delivery of a CaMKII peptide inhibitor to the heart was effective in suppressing arrhythmias in a murine model of CPVT. CaMKII inhibition also reversed the arrhythmia phenotype in human CPVT induced pluripotent stem cell-derived cardiomyocyte models with different pathogenic mutations.
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Affiliation(s)
- Vassilios J Bezzerides
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Ana Caballero
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Suya Wang
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Yulan Ai
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Robyn J Hylind
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Fujian Lu
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Danielle A Heims-Waldron
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Kristina D Chambers
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Donghui Zhang
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Dominic J Abrams
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - William T Pu
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.).,Harvard Stem Cell Institute, Cambridge, MA (W.T.P.)
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Lu F, Sun J, Zheng Q, Li J, Hu Y, Yu P, He H, Zhao Y, Wang X, Yang S, Cheng H. Imaging elemental events of store-operated Ca 2+ entry in invading cancer cells with plasmalemmal targeted sensors. J Cell Sci 2019; 132:jcs.224923. [PMID: 30814332 DOI: 10.1242/jcs.224923] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/04/2019] [Indexed: 12/14/2022] Open
Abstract
STIM1- and Orai1-mediated store-operated Ca2+ entry (SOCE) constitutes the major Ca2+ influx in almost all electrically non-excitable cells. However, little is known about the spatiotemporal organization at the elementary level. Here, we developed Orai1-tethered or palmitoylated biosensor GCaMP6f to report subplasmalemmal Ca2+ signals. We visualized spontaneous discrete and long-lasting transients ('Ca2+ glows') arising from STIM1-Orai1 in invading melanoma cells. Ca2+ glows occurred preferentially in single invadopodia and at sites near the cell periphery under resting conditions. Re-addition of external Ca2+ after store depletion elicited spatially synchronous Ca2+ glows, followed by high-rate discharge of asynchronous local events. Knockout of STIM1 or expression of the dominant-negative Orai1-E106A mutant markedly decreased Ca2+ glow frequency, diminished global SOCE and attenuated invadopodial formation. Functionally, invadopodial Ca2+ glows provided high Ca2+ microdomains to locally activate Ca2+/calmodulin-dependent Pyk2 (also known as PTK2B), which initiates the SOCE-Pyk2-Src signaling cascade required for invasion. Overall, the discovery of elemental Ca2+ signals of SOCE not only unveils a previously unappreciated gating mode of STIM1-Orai1 channels in situ, but also underscores a critical role of the spatiotemporal dynamics of SOCE in orchestrating complex cell behaviors such as invasion. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Fujian Lu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jianwei Sun
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA 17033, USA.,State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Qiaoxia Zheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jinghang Li
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yuanzhao Hu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Peng Yu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Huifang He
- Department of Tumor Biology, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Yan Zhao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Shengyu Yang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA 17033, USA .,Department of Tumor Biology, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
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George SA, Efimov IR. Optocardiography: A Review of its Past, Present and Future. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019; 9:74-80. [PMID: 31803858 PMCID: PMC6892455 DOI: 10.1016/j.cobme.2019.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cardiac electrophysiology has progressed in great strides since the electrical activity of the heart was first discovered in 1842 and documented using electrocardiography. Optical imaging of cardiac electrophysiology, or optocardiography, has seen many advances in recent years including panoramic imaging of the heart, alternating transillumination to image transmural electrical activity, optogenetic models and customizable 3D printed optical mapping systems. Most of these techniques were adopted from other fields of study and refined for cardiac electrophysiology purposes. The future of this field could see similar adaptations of photoacoustic tomography, structured light technology and optical coherence tomography contributing to optocardiography.
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Affiliation(s)
- Sharon A George
- Department of Biomedical Engineering, The George Washington University, Washington, DC
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC
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Ca 2+-dependent calmodulin binding to cardiac ryanodine receptor (RyR2) calmodulin-binding domains. Biochem J 2019; 476:193-209. [PMID: 30530841 PMCID: PMC6340113 DOI: 10.1042/bcj20180545] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 12/05/2018] [Accepted: 12/10/2018] [Indexed: 12/17/2022]
Abstract
The Ca2+ sensor calmodulin (CaM) regulates cardiac ryanodine receptor (RyR2)-mediated Ca2+ release from the sarcoplasmic reticulum. CaM inhibits RyR2 in a Ca2+-dependent manner and aberrant CaM-dependent inhibition results in life-threatening cardiac arrhythmias. However, the molecular details of the CaM–RyR2 interaction remain unclear. Four CaM-binding domains (CaMBD1a, -1b, -2, and -3) in RyR2 have been proposed. Here, we investigated the Ca2+-dependent interactions between CaM and these CaMBDs by monitoring changes in the fluorescence anisotropy of carboxytetramethylrhodamine (TAMRA)-labeled CaMBD peptides during titration with CaM at a wide range of Ca2+ concentrations. We showed that CaM bound to all four CaMBDs with affinities that increased with Ca2+ concentration. CaM bound to CaMBD2 and -3 with high affinities across all Ca2+ concentrations tested, but bound to CaMBD1a and -1b only at Ca2+ concentrations above 0.2 µM. Binding experiments using individual CaM domains revealed that the CaM C-domain preferentially bound to CaMBD2, and the N-domain to CaMBD3. Moreover, the Ca2+ affinity of the CaM C-domain in complex with CaMBD2 or -3 was so high that these complexes are essentially Ca2+ saturated under resting Ca2+ conditions. Conversely, the N-domain senses Ca2+ exactly in the transition from resting to activating Ca2+ when complexed to either CaMBD2 or -3. Altogether, our results support a binding model where the CaM C-domain is anchored to RyR2 CaMBD2 and saturated with Ca2+ during Ca2+ oscillations, while the CaM N-domain functions as a dynamic Ca2+ sensor that can bridge noncontiguous regions of RyR2 or clamp down onto CaMBD2.
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Chen X, Feng Y, Huo Y, Tan W. The Interplay of Rogue and Clustered Ryanodine Receptors Regulates Ca2+ Waves in Cardiac Myocytes. Front Physiol 2018; 9:393. [PMID: 29755362 PMCID: PMC5932313 DOI: 10.3389/fphys.2018.00393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/03/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Xudong Chen
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Yundi Feng
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Yunlong Huo
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China
- *Correspondence: Yunlong Huo
| | - Wenchang Tan
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China
- Shenzhen Graduate School, Peking University, Shenzhen, China
- Wenchang Tan
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34
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Fast, long-term, super-resolution imaging with Hessian structured illumination microscopy. Nat Biotechnol 2018; 36:451-459. [PMID: 29644998 DOI: 10.1038/nbt.4115] [Citation(s) in RCA: 256] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 03/01/2018] [Indexed: 01/13/2023]
Abstract
To increase the temporal resolution and maximal imaging time of super-resolution (SR) microscopy, we have developed a deconvolution algorithm for structured illumination microscopy based on Hessian matrixes (Hessian-SIM). It uses the continuity of biological structures in multiple dimensions as a priori knowledge to guide image reconstruction and attains artifact-minimized SR images with less than 10% of the photon dose used by conventional SIM while substantially outperforming current algorithms at low signal intensities. Hessian-SIM enables rapid imaging of moving vesicles or loops in the endoplasmic reticulum without motion artifacts and with a spatiotemporal resolution of 88 nm and 188 Hz. Its high sensitivity allows the use of sub-millisecond excitation pulses followed by dark recovery times to reduce photobleaching of fluorescent proteins, enabling hour-long time-lapse SR imaging of actin filaments in live cells. Finally, we observed the structural dynamics of mitochondrial cristae and structures that, to our knowledge, have not been observed previously, such as enlarged fusion pores during vesicle exocytosis.
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35
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Chen X, Feng Y, Huo Y, Tan W. Effects of rogue ryanodine receptors on Ca 2+ sparks in cardiac myocytes. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171462. [PMID: 29515864 PMCID: PMC5830753 DOI: 10.1098/rsos.171462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/17/2018] [Indexed: 06/15/2023]
Abstract
Ca2+ sparks and Ca2+ quarks, arising from clustered and rogue ryanodine receptors (RyRs), are significant Ca2+ release events from the junctional sarcoplasmic reticulum (JSR). Based on the anomalous subdiffusion of Ca2+ in the cytoplasm, a mathematical model was developed to investigate the effects of rogue RyRs on Ca2+ sparks in cardiac myocytes. Ca2+ quarks and sparks from the stochastic opening of rogue and clustered RyRs are numerically reproduced and agree with experimental measurements. It is found that the stochastic opening Ca2+ release units (CRUs) of clustered RyRs are regulated by free Ca2+ concentration in the JSR lumen (i.e. [Ca2+]lumen). The frequency of spontaneous Ca2+ sparks is remarkably increased by the rogue RyRs opening at high [Ca2+]lumen, but not at low [Ca2+]lumen. Hence, the opening of rogue RyRs contributes to the formation of Ca2+ sparks at high [Ca2+]lumen. The interplay of Ca2+ sparks and Ca2+ quarks has been discussed in detail. This work is of significance to provide insight into understanding Ca2+ release mechanisms in cardiac myocytes.
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Affiliation(s)
- Xudong Chen
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China
| | - Yundi Feng
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China
| | - Yunlong Huo
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, People's Republic of China
| | - Wenchang Tan
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, People's Republic of China
- Shenzhen Graduate School, Peking University, Shenzhen, People's Republic of China
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36
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Schneider-Warme F. The power of optogenetics : Potential in cardiac experimental and clinical electrophysiology. Herzschrittmacherther Elektrophysiol 2018; 29:24-29. [PMID: 29305704 DOI: 10.1007/s00399-017-0545-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 11/24/2017] [Indexed: 01/02/2023]
Abstract
Optogenetics is an emerging, interdisciplinary research area which combines genetic and optical technologies to steer and monitor specific biological processes. To this end, light-activated proteins, so-called optogenetic actuators, or fluorescent sensor proteins are genetically targeted to the cells of interest. Light activation can then be used to modulate or record cellular behaviour with high spatiotemporal precision. In cardiac research, optogenetic approaches have been used to unravel heterocellular electrotonic interactions, both in vitro and in situ. Pioneering optogenetic studies with potential relevance for clinical electrophysiology include light-controlled pacing experiments and optical defibrillation studies. However, despite successful implementation in mouse models, clinical applications are not feasible to date; these will require major advances in gene therapy and in optical techniques.
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Affiliation(s)
- Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, University Heart Center, Medical Center - University of Freiburg, and Faculty of Medicine, University of Freiburg, Elsässerstr. 2q, 79110, Freiburg, Germany.
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37
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Johnson TK, Henstridge MA, Warr CG. MACPF/CDC proteins in development: Insights from Drosophila torso-like. Semin Cell Dev Biol 2017; 72:163-170. [DOI: 10.1016/j.semcdb.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 05/01/2017] [Accepted: 05/11/2017] [Indexed: 01/08/2023]
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38
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Tsukamoto S, Fujii T, Oyama K, Shintani SA, Shimozawa T, Kobirumaki-Shimozawa F, Ishiwata S, Fukuda N. Simultaneous imaging of local calcium and single sarcomere length in rat neonatal cardiomyocytes using yellow Cameleon-Nano140. J Gen Physiol 2017; 148:341-55. [PMID: 27670899 PMCID: PMC5037341 DOI: 10.1085/jgp.201611604] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/23/2016] [Indexed: 01/07/2023] Open
Abstract
In cardiac muscle, contraction is triggered by sarcolemmal depolarization, resulting in an intracellular Ca(2+) transient, binding of Ca(2+) to troponin, and subsequent cross-bridge formation (excitation-contraction [EC] coupling). Here, we develop a novel experimental system for simultaneous nano-imaging of intracellular Ca(2+) dynamics and single sarcomere length (SL) in rat neonatal cardiomyocytes. We achieve this by expressing a fluorescence resonance energy transfer (FRET)-based Ca(2+) sensor yellow Cameleon-Nano (YC-Nano) fused to α-actinin in order to localize to the Z disks. We find that, among four different YC-Nanos, α-actinin-YC-Nano140 is best suited for high-precision analysis of EC coupling and α-actinin-YC-Nano140 enables quantitative analyses of intracellular calcium transients and sarcomere dynamics at low and high temperatures, during spontaneous beating and with electrical stimulation. We use this tool to show that calcium transients are synchronized along the length of a myofibril. However, the averaging of SL along myofibrils causes a marked underestimate (∼50%) of the magnitude of displacement because of the different timing of individual SL changes, regardless of the absence or presence of positive inotropy (via β-adrenergic stimulation or enhanced actomyosin interaction). Finally, we find that β-adrenergic stimulation with 50 nM isoproterenol accelerated Ca(2+) dynamics, in association with an approximately twofold increase in sarcomere lengthening velocity. We conclude that our experimental system has a broad range of potential applications for the unveiling molecular mechanisms of EC coupling in cardiomyocytes at the single sarcomere level.
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Affiliation(s)
- Seiichi Tsukamoto
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
| | - Teruyuki Fujii
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
| | - Kotaro Oyama
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
| | - Seine A Shintani
- Department of Physics, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Togo Shimozawa
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Sinjuku-ku, Tokyo 162-8480, Japan
| | - Fuyu Kobirumaki-Shimozawa
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Norio Fukuda
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
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39
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Wang Y, Subramanian M, Yurdagul A, Barbosa-Lorenzi VC, Cai B, de Juan-Sanz J, Ryan TA, Nomura M, Maxfield FR, Tabas I. Mitochondrial Fission Promotes the Continued Clearance of Apoptotic Cells by Macrophages. Cell 2017; 171:331-345.e22. [PMID: 28942921 DOI: 10.1016/j.cell.2017.08.041] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 06/21/2017] [Accepted: 08/23/2017] [Indexed: 12/20/2022]
Abstract
Clearance of apoptotic cells (ACs) by phagocytes (efferocytosis) prevents post-apoptotic necrosis and dampens inflammation. Defective efferocytosis drives important diseases, including atherosclerosis. For efficient efferocytosis, phagocytes must be able to internalize multiple ACs. We show here that uptake of multiple ACs by macrophages requires dynamin-related protein 1 (Drp1)-mediated mitochondrial fission, which is triggered by AC uptake. When mitochondrial fission is disabled, AC-induced increase in cytosolic calcium is blunted owing to mitochondrial calcium sequestration, and calcium-dependent phagosome formation around secondarily encountered ACs is impaired. These defects can be corrected by silencing the mitochondrial calcium uniporter (MCU). Mice lacking myeloid Drp1 showed defective efferocytosis and its pathologic consequences in the thymus after dexamethasone treatment and in advanced atherosclerotic lesions in fat-fed Ldlr-/- mice. Thus, mitochondrial fission in response to AC uptake is a critical process that enables macrophages to clear multiple ACs and to avoid the pathologic consequences of defective efferocytosis in vivo.
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Affiliation(s)
- Ying Wang
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Manikandan Subramanian
- Department of Medicine, Columbia University, New York, NY 10032, USA; CSIR-Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | - Arif Yurdagul
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | | | - Bishuang Cai
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Jaime de Juan-Sanz
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Timothy A Ryan
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Masatoshi Nomura
- Department of Medicine and Bioregulatory Science, Kyushu University, Fukuoka, Japan
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Ira Tabas
- Department of Medicine, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA; Department of Physiology, Columbia University, New York, NY 10032, USA.
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40
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Koopman CD, Zimmermann WH, Knöpfel T, de Boer TP. Cardiac optogenetics: using light to monitor cardiac physiology. Basic Res Cardiol 2017; 112:56. [PMID: 28861604 PMCID: PMC5579185 DOI: 10.1007/s00395-017-0645-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022]
Abstract
Our current understanding of cardiac excitation and its coupling to contraction is largely based on ex vivo studies utilising fluorescent organic dyes to assess cardiac action potentials and signal transduction. Recent advances in optogenetic sensors open exciting new possibilities for cardiac research and allow us to answer research questions that cannot be addressed using the classic organic dyes. Especially thrilling is the possibility to use optogenetic sensors to record parameters of cardiac excitation and contraction in vivo. In addition, optogenetics provide a high spatial resolution, as sensors can be coupled to motifs and targeted to specific cell types and subcellular domains of the heart. In this review, we will give a comprehensive overview of relevant optogenetic sensors, how they can be utilised in cardiac research and how they have been applied in cardiac research up to now.
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Affiliation(s)
- Charlotte D Koopman
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM, Utrecht, The Netherlands.,Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584CT, Utrecht, The Netherlands
| | - Wolfram H Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany.,DHZK (German Center for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Imperial College London, London, UK.,Centre for Neurotechnology, Institute of Biomedical Engineering, Imperial College London, London, UK
| | - Teun P de Boer
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM, Utrecht, The Netherlands.
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41
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Sobie EA, Williams GSB, Lederer WJ. Ambiguous interactions between diastolic and SR Ca 2+ in the regulation of cardiac Ca 2+ release. J Gen Physiol 2017; 149:847-855. [PMID: 28798276 PMCID: PMC5583714 DOI: 10.1085/jgp.201711814] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/21/2017] [Indexed: 01/20/2023] Open
Abstract
Sobie et al. highlight unresolved issues concerning the regulation of sarcoplasmic reticulum calcium release in cardiac myocytes.
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Affiliation(s)
- Eric A Sobie
- Department of Pharmacological Sciences, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - George S B Williams
- BioMET, Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD
| | - W J Lederer
- BioMET, Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD
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42
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Pahlavan S, Morad M. Total internal reflectance fluorescence imaging of genetically engineered ryanodine receptor-targeted Ca 2+ probes in rat ventricular myocytes. Cell Calcium 2017; 66:98-110. [PMID: 28807154 DOI: 10.1016/j.ceca.2017.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 12/11/2022]
Abstract
The details of cardiac Ca2+ signaling within the dyadic junction remain unclear because of limitations in rapid spatial imaging techniques, and availability of Ca2+ probes localized to dyadic junctions. To critically monitor ryanodine receptors' (RyR2) Ca2+ nano-domains, we combined the use of genetically engineered RyR2-targeted pericam probes, (FKBP-YCaMP, Kd=150nM, or FKBP-GCaMP6, Kd=240nM) with rapid total internal reflectance fluorescence (TIRF) microscopy (resolution, ∼80nm). The punctate z-line patterns of FKBP,2-targeted probes overlapped those of RyR2 antibodies and sharply contrasted to the images of probes targeted to sarcoplasmic reticulum (SERCA2a/PLB), or cytosolic Fluo-4 images. FKBP-YCaMP signals were too small (∼20%) and too slow (2-3s) to detect Ca2+ sparks, but the probe was effective in marking where Fluo-4 Ca2+ sparks developed. FKBP-GCaMP6, on the other hand, produced rapidly decaying Ca2+ signals that: a) had faster kinetics and activated synchronous with ICa3 but were of variable size at different z-lines and b) were accompanied by spatially confined spontaneous Ca2+ sparks, originating from a subset of eager sites. The frequency of spontaneously occurring sparks was lower in FKBP-GCaMP6 infected myocytes as compared to Fluo-4 dialyzed myocytes, but isoproterenol enhanced their frequency more effectively than in Fluo-4 dialyzed cells. Nevertheless, isoproterenol failed to dissociate FKBP-GCaMP6 from the z-lines. The data suggests that FKBP-GCaMP6 binds predominantly to junctional RyR2s and has sufficient on-rate efficiency as to monitor the released Ca2+ in individual dyadic clefts, and supports the idea that β-adrenergic agonists may modulate the stabilizing effects of native FKBP on RyR2.
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Affiliation(s)
- Sara Pahlavan
- Cardiac Signaling Center of University of South Carolina, Clemson University and Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Marin Morad
- Cardiac Signaling Center of University of South Carolina, Clemson University and Medical University of South Carolina, Charleston, SC 29425, USA.
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43
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Lu FM, Hilgemann DW. Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes. J Gen Physiol 2017; 149:727-749. [PMID: 28606910 PMCID: PMC5496509 DOI: 10.1085/jgp.201711780] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/23/2017] [Indexed: 11/20/2022] Open
Abstract
The Na/K pump exports cytoplasmic Na ions while importing K ions, and its activity is thought to be affected by restricted intracellular Na diffusion in cardiac myocytes. Lu and Hilgemann find instead that the pump can enter an inactivated state and that inactivation can be relieved by cytoplasmic Na. Decades ago, it was proposed that Na transport in cardiac myocytes is modulated by large changes in cytoplasmic Na concentration within restricted subsarcolemmal spaces. Here, we probe this hypothesis for Na/K pumps by generating constitutive transsarcolemmal Na flux with the Na channel opener veratridine in whole-cell patch-clamp recordings. Using 25 mM Na in the patch pipette, pump currents decay strongly during continuous activation by extracellular K (τ, ∼2 s). In contradiction to depletion hypotheses, the decay becomes stronger when pump currents are decreased by hyperpolarization. Na channel currents are nearly unchanged by pump activity in these conditions, and conversely, continuous Na currents up to 0.5 nA in magnitude have negligible effects on pump currents. These outcomes are even more pronounced using 50 mM Li as a cytoplasmic Na congener. Thus, the Na/K pump current decay reflects mostly an inactivation mechanism that immobilizes Na/K pump charge movements, not cytoplasmic Na depletion. When channel currents are increased beyond 1 nA, models with unrestricted subsarcolemmal diffusion accurately predict current decay (τ ∼15 s) and reversal potential shifts observed for Na, Li, and K currents through Na channels opened by veratridine, as well as for Na, K, Cs, Li, and Cl currents recorded in nystatin-permeabilized myocytes. Ion concentrations in the pipette tip (i.e., access conductance) track without appreciable delay the current changes caused by sarcolemmal ion flux. Importantly, cytoplasmic mixing volumes, calculated from current decay kinetics, increase and decrease as expected with osmolarity changes (τ >30 s). Na/K pump current run-down over 20 min reflects a failure of pumps to recover from inactivation. Simulations reveal that pump inactivation coupled with Na-activated recovery enhances the rapidity and effectivity of Na homeostasis in cardiac myocytes. In conclusion, an autoregulatory mechanism enhances cardiac Na/K pump activity when cytoplasmic Na rises and suppresses pump activity when cytoplasmic Na declines.
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Affiliation(s)
- Fang-Min Lu
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX
| | - Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX
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44
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Reddish FN, Miller CL, Gorkhali R, Yang JJ. Calcium Dynamics Mediated by the Endoplasmic/Sarcoplasmic Reticulum and Related Diseases. Int J Mol Sci 2017; 18:E1024. [PMID: 28489021 PMCID: PMC5454937 DOI: 10.3390/ijms18051024] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 12/17/2022] Open
Abstract
The flow of intracellular calcium (Ca2+) is critical for the activation and regulation of important biological events that are required in living organisms. As the major Ca2+ repositories inside the cell, the endoplasmic reticulum (ER) and the sarcoplasmic reticulum (SR) of muscle cells are central in maintaining and amplifying the intracellular Ca2+ signal. The morphology of these organelles, along with the distribution of key calcium-binding proteins (CaBPs), regulatory proteins, pumps, and receptors fundamentally impact the local and global differences in Ca2+ release kinetics. In this review, we will discuss the structural and morphological differences between the ER and SR and how they influence localized Ca2+ release, related diseases, and the need for targeted genetically encoded calcium indicators (GECIs) to study these events.
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Affiliation(s)
- Florence N Reddish
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Cassandra L Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Rakshya Gorkhali
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Jenny J Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
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45
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Maleckar MM, Edwards AG, Louch WE, Lines GT. Studying dyadic structure-function relationships: a review of current modeling approaches and new insights into Ca 2+ (mis)handling. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2017; 11:1179546817698602. [PMID: 28469494 PMCID: PMC5392018 DOI: 10.1177/1179546817698602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/19/2016] [Indexed: 11/25/2022]
Abstract
Excitation–contraction coupling in cardiac myocytes requires calcium influx through L-type calcium channels in the sarcolemma, which gates calcium release through sarcoplasmic reticulum ryanodine receptors in a process known as calcium-induced calcium release, producing a myoplasmic calcium transient and enabling cardiomyocyte contraction. The spatio-temporal dynamics of calcium release, buffering, and reuptake into the sarcoplasmic reticulum play a central role in excitation–contraction coupling in both normal and diseased cardiac myocytes. However, further quantitative understanding of these cells’ calcium machinery and the study of mechanisms that underlie both normal cardiac function and calcium-dependent etiologies in heart disease requires accurate knowledge of cardiac ultrastructure, protein distribution and subcellular function. As current imaging techniques are limited in spatial resolution, limiting insight into changes in calcium handling, computational models of excitation–contraction coupling have been increasingly employed to probe these structure–function relationships. This review will focus on the development of structural models of cardiac calcium dynamics at the subcellular level, orienting the reader broadly towards the development of models of subcellular calcium handling in cardiomyocytes. Specific focus will be given to progress in recent years in terms of multi-scale modeling employing resolved spatial models of subcellular calcium machinery. A review of the state-of-the-art will be followed by a review of emergent insights into calcium-dependent etiologies in heart disease and, finally, we will offer a perspective on future directions for related computational modeling and simulation efforts.
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Affiliation(s)
- Mary M Maleckar
- Simula Research Laboratory, Center for Cardiological Innovation and Center for Biomedical Computing, Lysaker, Norway
| | - Andrew G Edwards
- Simula Research Laboratory, Center for Cardiological Innovation and Center for Biomedical Computing, Lysaker, Norway.,University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and the University of Oslo, Oslo, Norway
| | - Glenn T Lines
- Simula Research Laboratory, Center for Cardiological Innovation and Center for Biomedical Computing, Lysaker, Norway
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46
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Dempsey GT, Chaudhary KW, Atwater N, Nguyen C, Brown BS, McNeish JD, Cohen AE, Kralj JM. Cardiotoxicity screening with simultaneous optogenetic pacing, voltage imaging and calcium imaging. J Pharmacol Toxicol Methods 2016; 81:240-50. [DOI: 10.1016/j.vascn.2016.05.003] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/02/2016] [Accepted: 05/09/2016] [Indexed: 12/23/2022]
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47
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Suzuki J, Kanemaru K, Iino M. Genetically Encoded Fluorescent Indicators for Organellar Calcium Imaging. Biophys J 2016; 111:1119-1131. [PMID: 27477268 DOI: 10.1016/j.bpj.2016.04.054] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Optical Ca(2+) indicators are powerful tools for investigating intracellular Ca(2+) signals in living cells. Although a variety of Ca(2+) indicators have been developed, deciphering the physiological functions and spatiotemporal dynamics of Ca(2+) in intracellular organelles remains challenging. Genetically encoded Ca(2+) indicators (GECIs) using fluorescent proteins are promising tools for organellar Ca(2+) imaging, and much effort has been devoted to their development. In this review, we first discuss the key points of organellar Ca(2+) imaging and summarize the requirements for optimal organellar Ca(2+) indicators. Then, we highlight some of the recent advances in the engineering of fluorescent GECIs targeted to specific organelles. Finally, we discuss the limitations of currently available GECIs and the requirements for advancing the research on intraorganellar Ca(2+) signaling.
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Affiliation(s)
- Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Physiology, University of California San Francisco, San Francisco, California
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan.
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48
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Horváth B, Váczi K, Hegyi B, Gönczi M, Dienes B, Kistamás K, Bányász T, Magyar J, Baczkó I, Varró A, Seprényi G, Csernoch L, Nánási PP, Szentandrássy N. Sarcolemmal Ca(2+)-entry through L-type Ca(2+) channels controls the profile of Ca(2+)-activated Cl(-) current in canine ventricular myocytes. J Mol Cell Cardiol 2016; 97:125-39. [PMID: 27189885 DOI: 10.1016/j.yjmcc.2016.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 04/20/2016] [Accepted: 05/10/2016] [Indexed: 12/15/2022]
Abstract
Ca(2+)-activated Cl(-) current (ICl(Ca)) mediated by TMEM16A and/or Bestrophin-3 may contribute to cardiac arrhythmias. The true profile of ICl(Ca) during an actual ventricular action potential (AP), however, is poorly understood. We aimed to study the profile of ICl(Ca) systematically under physiological conditions (normal Ca(2+) cycling and AP voltage-clamp) as well as in conditions designed to change [Ca(2+)]i. The expression of TMEM16A and/or Bestrophin-3 in canine and human left ventricular myocytes was examined. The possible spatial distribution of these proteins and their co-localization with Cav1.2 was also studied. The profile of ICl(Ca), identified as a 9-anthracene carboxylic acid-sensitive current under AP voltage-clamp conditions, contained an early fast outward and a late inward component, overlapping early and terminal repolarizations, respectively. Both components were moderately reduced by ryanodine, while fully abolished by BAPTA, but not EGTA. [Ca(2+)]i was monitored using Fura-2-AM. Setting [Ca(2+)]i to the systolic level measured in the bulk cytoplasm (1.1μM) decreased ICl(Ca), while application of Bay K8644, isoproterenol, and faster stimulation rates increased the amplitude of ICl(Ca). Ca(2+)-entry through L-type Ca(2+) channels was essential for activation of ICl(Ca). TMEM16A and Bestrophin-3 showed strong co-localization with one another and also with Cav1.2 channels, when assessed using immunolabeling and confocal microscopy in both canine myocytes and human ventricular myocardium. Activation of ICl(Ca) in canine ventricular cells requires Ca(2+)-entry through neighboring L-type Ca(2+) channels and is only augmented by SR Ca(2+)-release. Substantial activation of ICl(Ca) requires high Ca(2+) concentration in the dyadic clefts which can be effectively buffered by BAPTA, but not EGTA.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary; Faculty of Pharmacy, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Krisztina Váczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Bence Hegyi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Mónika Gönczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary; MTA-DE Momentum, Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary; Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Dóm tér 12, P.O. Box 427, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, H-6720 Szeged, Dóm tér 12, P.O. Box 427, Hungary; MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, H-6720 Szeged, Dóm tér 12, P.O. Box 427, Hungary
| | - György Seprényi
- Department of Medical Biology, Faculty of Medicine, University of Szeged, H-6720 Szeged, Somogyi Béla utca 4, P.O. Box 427, Hungary
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary; Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary; Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, Nagyerdei krt 98, P.O. Box 22, Hungary.
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Popescu I, Galice S, Mohler PJ, Despa S. Elevated local [Ca2+] and CaMKII promote spontaneous Ca2+ release in ankyrin-B-deficient hearts. Cardiovasc Res 2016; 111:287-94. [PMID: 27131508 DOI: 10.1093/cvr/cvw093] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/27/2016] [Indexed: 11/13/2022] Open
Abstract
AIMS Loss-of-function mutations in the cytoskeletal protein ankyrin-B (AnkB) cause ventricular tachyarrhythmias in humans. Previously, we found that a larger fraction of the sarcoplasmic reticulum (SR) Ca(2+) leak occurs through Ca(2+) sparks in AnkB-deficient (AnkB(+/-)) mice, which may contribute to arrhythmogenicity via Ca(2+) waves. Here, we investigated the mechanisms responsible for increased Ca(2+) spark frequency in AnkB(+/-) hearts. METHODS AND RESULTS Using immunoblots and phospho-specific antibodies, we found that phosphorylation of ryanodine receptors (RyRs) by CaMKII is enhanced in AnkB(+/-) hearts. In contrast, the PKA-mediated RyR phosphorylation was comparable in AnkB(+/-) and wild-type (WT) mice. CaMKII inhibition greatly reduced Ca(2+) spark frequency in myocytes from AnkB(+/-) mice but had little effect in the WT. Global activities of the major phosphatases PP1 and PP2A were similar in AnkB(+/-) and WT hearts, while CaMKII autophosphorylation, a marker of CaMKII activation, was increased in AnkB(+/-) hearts. Thus, CaMKII-dependent RyR hyperphosphorylation in AnkB(+/-) hearts is caused by augmented CaMKII activity. Intriguingly, CaMKII activation is limited to the sarcolemma-SR junctions since non-junctional CaMKII targets (phospholamban, HDAC4) are not hyperphosphorylated in AnkB(+/-) myocytes. This local CaMKII activation may be the consequence of elevated [Ca(2+)] in the junctional cleft caused by reduced Na(+)/Ca(2+) exchange activity. Indeed, using the RyR-targeted Ca(2+) sensor GCaMP2.2-FBKP12.6, we found that local junctional [Ca(2+)] is significantly elevated in AnkB(+/-) myocytes. CONCLUSIONS The increased incidence of pro-arrhythmogenic Ca(2+) sparks and waves in AnkB(+/-) hearts is due to enhanced CaMKII-mediated RyR phosphorylation, which is caused by higher junctional [Ca(2+)] and consequent local CaMKII activation.
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Affiliation(s)
- Iuliana Popescu
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, 900 S Limestone, Lexington, KY 40536, USA
| | - Samuel Galice
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Peter J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Sanda Despa
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, 900 S Limestone, Lexington, KY 40536, USA
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Awasthi S, Izu LT, Mao Z, Jian Z, Landas T, Lerner A, Shimkunas R, Woldeyesus R, Bossuyt J, Wood BM, Chen YJ, Matthews DL, Lieu DK, Chiamvimonvat N, Lam KS, Chen-Izu Y, Chan JW. Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes. Circ Res 2015; 118:e19-28. [PMID: 26643875 DOI: 10.1161/circresaha.115.307919] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/07/2015] [Indexed: 01/24/2023]
Abstract
RATIONALE Cardiac myocyte contraction is caused by Ca(2+) binding to troponin C, which triggers the cross-bridge power stroke and myofilament sliding in sarcomeres. Synchronized Ca(2+) release causes whole cell contraction and is readily observable with current microscopy techniques. However, it is unknown whether localized Ca(2+) release, such as Ca(2+) sparks and waves, can cause local sarcomere contraction. Contemporary imaging methods fall short of measuring microdomain Ca(2+)-contraction coupling in live cardiac myocytes. OBJECTIVE To develop a method for imaging sarcomere level Ca(2+)-contraction coupling in healthy and disease model cardiac myocytes. METHODS AND RESULTS Freshly isolated cardiac myocytes were loaded with the Ca(2+)-indicator fluo-4. A confocal microscope equipped with a femtosecond-pulsed near-infrared laser was used to simultaneously excite second harmonic generation from A-bands of myofibrils and 2-photon fluorescence from fluo-4. Ca(2+) signals and sarcomere strain correlated in space and time with short delays. Furthermore, Ca(2+) sparks and waves caused contractions in subcellular microdomains, revealing a previously underappreciated role for these events in generating subcellular strain during diastole. Ca(2+) activity and sarcomere strain were also imaged in paced cardiac myocytes under mechanical load, revealing spontaneous Ca(2+) waves and correlated local contraction in pressure-overload-induced cardiomyopathy. CONCLUSIONS Multimodal second harmonic generation 2-photon fluorescence microscopy enables the simultaneous observation of Ca(2+) release and mechanical strain at the subsarcomere level in living cardiac myocytes. The method benefits from the label-free nature of second harmonic generation, which allows A-bands to be imaged independently of T-tubule morphology and simultaneously with Ca(2+) indicators. Second harmonic generation 2-photon fluorescence imaging is widely applicable to the study of Ca(2+)-contraction coupling and mechanochemotransduction in both health and disease.
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Affiliation(s)
- Samir Awasthi
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Leighton T Izu
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Ziliang Mao
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Zhong Jian
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Trevor Landas
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Aaron Lerner
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Rafael Shimkunas
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Rahwa Woldeyesus
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Julie Bossuyt
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Brent M Wood
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Yi-Je Chen
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Dennis L Matthews
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Deborah K Lieu
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Nipavan Chiamvimonvat
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Kit S Lam
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis
| | - Ye Chen-Izu
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis.
| | - James W Chan
- From the Center for Biophotonics (S.A., Z.M., A.L., D.L.M., J.W.C.), Division of Cardiology (D.K.L., N.C., Y.C.-I.), Division of Hematology/Oncology, Department of Internal Medicine (K.S.L.), and Department of Pathology and Laboratory Medicine (J.W.C.), UC Davis School of Medicine, University of California, Davis, Sacramento; and Departments of Pharmacology (L.T.I., Z.J., T.L., J.B., B.W., Y.-J.C., Y.C.-I.), Biomedical Engineering (S.A., R.S., R.W., Y.C.-I.), Biochemistry and Molecular Medicine (K.S.L.), and Microsurgery Core (Y.-J.C.), University of California, Davis.
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