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Paulke NJ, Fleischhacker C, Wegener JB, Riedemann GC, Cretu C, Mushtaq M, Zaremba N, Möbius W, Zühlke Y, Wedemeyer J, Liebmann L, Gorshkova AA, Kownatzki-Danger D, Wagner E, Kohl T, Wichmann C, Jahn O, Urlaub H, Toischer K, Hasenfuß G, Moser T, Preobraschenski J, Lenz C, Rog-Zielinska EA, Lehnart SE, Brandenburg S. Dysferlin Enables Tubular Membrane Proliferation in Cardiac Hypertrophy. Circ Res 2024; 135:554-574. [PMID: 39011635 DOI: 10.1161/circresaha.124.324588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/17/2024]
Abstract
BACKGROUND Cardiac hypertrophy compensates for increased biomechanical stress of the heart induced by prevalent cardiovascular pathologies but can result in heart failure if left untreated. Here, we hypothesized that the membrane fusion and repair protein dysferlin is critical for the integrity of the transverse-axial tubule (TAT) network inside cardiomyocytes and contributes to the proliferation of TAT endomembranes during pressure overload-induced cardiac hypertrophy. METHODS Stimulated emission depletion and electron microscopy were used to localize dysferlin in mouse and human cardiomyocytes. Data-independent acquisition mass spectrometry revealed the cardiac dysferlin interactome and proteomic changes of the heart in dysferlin-knockout mice. After transverse aortic constriction, we compared the hypertrophic response of wild-type versus dysferlin-knockout hearts and studied TAT network remodeling mechanisms inside cardiomyocytes by live-cell membrane imaging. RESULTS We localized dysferlin in a vesicular compartment in nanometric proximity to contact sites of the TAT network with the sarcoplasmic reticulum, a.k.a. junctional complexes for Ca2+-induced Ca2+ release. Interactome analyses demonstrated a novel protein interaction of dysferlin with the membrane-tethering sarcoplasmic reticulum protein juncophilin-2, a putative interactor of L-type Ca2+ channels and ryanodine receptor Ca2+ release channels in junctional complexes. Although the dysferlin-knockout caused a mild progressive phenotype of dilated cardiomyopathy, global proteome analysis revealed changes preceding systolic failure. Following transverse aortic constriction, dysferlin protein expression was significantly increased in hypertrophied wild-type myocardium, while dysferlin-knockout animals presented markedly reduced left-ventricular hypertrophy. Live-cell membrane imaging showed a profound reorganization of the TAT network in wild-type left-ventricular myocytes after transverse aortic constriction with robust proliferation of axial tubules, which critically depended on the increased expression of dysferlin within newly emerging tubule components. CONCLUSIONS Dysferlin represents a new molecular target in cardiac disease that protects the integrity of tubule-sarcoplasmic reticulum junctional complexes for regulated excitation-contraction coupling and controls TAT network reorganization and tubular membrane proliferation in cardiomyocyte hypertrophy induced by pressure overload.
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Affiliation(s)
- Nora Josefine Paulke
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Carolin Fleischhacker
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Justus B Wegener
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Gabriel C Riedemann
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Constantin Cretu
- Biochemistry of Membrane Dynamics Group, Institute for Auditory Neuroscience and InnerEarLab (C.C., J.P.), University Medical Center Göttingen, Germany
| | - Mufassra Mushtaq
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Nina Zaremba
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Electron Microscopy, City Campus (W.M.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Yannik Zühlke
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Jasper Wedemeyer
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Lorenz Liebmann
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Anastasiia A Gorshkova
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Daniel Kownatzki-Danger
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Now with Institute of Transfusion Medicine, University Hospital Schleswig-Holstein; Kiel, Germany (D.K.-D)
| | - Eva Wagner
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Tobias Kohl
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
| | - Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab and Center for Biostructural Imaging of Neurodegeneration (C.W.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Olaf Jahn
- Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy (O.J.), University Medical Center Göttingen, Germany
- Neuroproteomics Group, Department of Molecular Neurobiology (O.J.)
| | - Henning Urlaub
- Department of Clinical Chemistry (H.U., C.L.), University Medical Center Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany (H.U., C.L.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Karl Toischer
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany (K.T., G.H., S.E.L.)
| | - Gerd Hasenfuß
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany (K.T., G.H., S.E.L.)
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab (T.M.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Julia Preobraschenski
- Biochemistry of Membrane Dynamics Group, Institute for Auditory Neuroscience and InnerEarLab (C.C., J.P.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Christof Lenz
- Department of Clinical Chemistry (H.U., C.L.), University Medical Center Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany (H.U., C.L.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
| | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z.)
| | - Stephan E Lehnart
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany (K.T., G.H., S.E.L.)
| | - Sören Brandenburg
- Department of Cardiology and Pneumology (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., K.T., G.H., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center (N.J.P., C.F., J.B.W., G.C.R., M.M., N.Z., Y.Z., J.W., L.L., A.A.G., D.K.-D., E.W., T.K., S.E.L., S.B.), University Medical Center Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (W.M., C.W., H.U., K.T., G.H., T.M., J.P., C.L., S.E.L., S.B.)
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Schwenzer N, Teiwes NK, Kohl T, Pohl C, Giller MJ, Lehnart SE, Steinem C. Ca V1.3 channel clusters characterized by live-cell and isolated plasma membrane nanoscopy. Commun Biol 2024; 7:620. [PMID: 38783117 PMCID: PMC11116533 DOI: 10.1038/s42003-024-06313-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
A key player of excitable cells in the heart and brain is the L-type calcium channel CaV1.3. In the heart, it is required for voltage-dependent Ca2+-signaling, i.e., for controlling and modulating atrial cardiomyocyte excitation-contraction coupling. The clustering of CaV1.3 in functionally relevant channel multimers has not been addressed due to a lack of stoichiometric labeling combined with high-resolution imaging. Here, we developed a HaloTag-labeling strategy to visualize and quantify CaV1.3 clusters using STED nanoscopy to address the questions of cluster size and intra-cluster channel density. Channel clusters were identified in the plasma membrane of transfected live HEK293 cells as well as in giant plasma membrane vesicles derived from these cells that were spread on modified glass support to obtain supported plasma membrane bilayers (SPMBs). A small fraction of the channel clusters was colocalized with early and recycling endosomes at the membranes. STED nanoscopy in conjunction with live-cell and SPMB imaging enabled us to quantify CaV1.3 cluster sizes and their molecular density revealing significantly lower channel densities than expected for dense channel packing. CaV1.3 channel cluster size and molecular density were increased in SPMBs after treatment of the cells with the sympathomimetic compound isoprenaline, suggesting a regulated channel cluster condensation mechanism.
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Affiliation(s)
- Niko Schwenzer
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert‑Koch‑Str. 42a, 37075, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37073, Göttingen, Germany
| | - Nikolas K Teiwes
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37073, Göttingen, Germany
- Georg-August Universität, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Tobias Kohl
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert‑Koch‑Str. 42a, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Celine Pohl
- Georg-August Universität, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Michelle J Giller
- Georg-August Universität, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Stephan E Lehnart
- Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert‑Koch‑Str. 42a, 37075, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37073, Göttingen, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
- Collaborative Research Center SFB 1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
| | - Claudia Steinem
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37073, Göttingen, Germany.
- Georg-August Universität, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany.
- Max-Planck-Institut für Dynamik und Selbstorganisation, Am Fassberg 17, 37077, Göttingen, Germany.
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Scardigli M, Pásek M, Santini L, Palandri C, Conti E, Crocini C, Campione M, Loew LM, de Vries AAF, Pijnappels DA, Pavone FS, Poggesi C, Cerbai E, Coppini R, Kohl P, Ferrantini C, Sacconi L. Optogenetic confirmation of transverse-tubular membrane excitability in intact cardiac myocytes. J Physiol 2024; 602:791-808. [PMID: 38348881 DOI: 10.1113/jp285202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/17/2024] [Indexed: 03/09/2024] Open
Abstract
T-tubules (TT) form a complex network of sarcolemmal membrane invaginations, essential for well-co-ordinated excitation-contraction coupling (ECC) and thus homogeneous mechanical activation of cardiomyocytes. ECC is initiated by rapid depolarization of the sarcolemmal membrane. Whether TT membrane depolarization is active (local generation of action potentials; AP) or passive (following depolarization of the outer cell surface sarcolemma; SS) has not been experimentally validated in cardiomyocytes. Based on the assessment of ion flux pathways needed for AP generation, we hypothesize that TT are excitable. We therefore explored TT excitability experimentally, using an all-optical approach to stimulate and record trans-membrane potential changes in TT that were structurally disconnected, and hence electrically insulated, from the SS membrane by transient osmotic shock. Our results establish that cardiomyocyte TT can generate AP. These AP show electrical features that differ substantially from those observed in SS, consistent with differences in the density of ion channels and transporters in the two different membrane domains. We propose that TT-generated AP represent a safety mechanism for TT AP propagation and ECC, which may be particularly relevant in pathophysiological settings where morpho-functional changes reduce the electrical connectivity between SS and TT membranes. KEY POINTS: Cardiomyocytes are characterized by a complex network of membrane invaginations (the T-tubular system) that propagate action potentials to the core of the cell, causing uniform excitation-contraction coupling across the cell. In the present study, we investigated whether the T-tubular system is able to generate action potentials autonomously, rather than following depolarization of the outer cell surface sarcolemma. For this purpose, we developed a fully optical platform to probe and manipulate the electrical dynamics of subcellular membrane domains. Our findings demonstrate that T-tubules are intrinsically excitable, revealing distinct characteristics of self-generated T-tubular action potentials. This active electrical capability would protect cells from voltage drops potentially occurring within the T-tubular network.
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Affiliation(s)
- Marina Scardigli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Michal Pásek
- Institute of Thermomechanics, Czech Academy of Science, Prague, Czech Republic
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lorenzo Santini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Chiara Palandri
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Emilia Conti
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Neuroscience Institute, National Research Council, Pisa, Italy
| | - Claudia Crocini
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Max Rubner Center for Cardiovascular Metabolic Renal Research (MRC), Deutsches Herzzentrum der Charité (DHZC), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marina Campione
- Institute of Neuroscience (IN-CNR) and Department of Biomedical Science, University of Padua, Padua, Italy
| | - Leslie M Loew
- Center for Cell Analysis and Modeling, University of Connecticut, Farmington, CT, USA
| | - Antoine A F de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniël A Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Francesco S Pavone
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Elisabetta Cerbai
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Raffaele Coppini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Florence, Italy
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4
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Tolstik E, Lehnart SE, Soeller C, Lorenz K, Sacconi L. Cardiac multiscale bioimaging: from nano- through micro- to mesoscales. Trends Biotechnol 2024; 42:212-227. [PMID: 37806897 DOI: 10.1016/j.tibtech.2023.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 10/10/2023]
Abstract
Cardiac multiscale bioimaging is an emerging field that aims to provide a comprehensive understanding of the heart and its functions at various levels, from the molecular to the entire organ. It combines both physiologically and clinically relevant dimensions: from nano- and micrometer resolution imaging based on vibrational spectroscopy and high-resolution microscopy to assess molecular processes in cardiac cells and myocardial tissue, to mesoscale structural investigations to improve the understanding of cardiac (patho)physiology. Tailored super-resolution deep microscopy with advanced proteomic methods and hands-on experience are thus strategically combined to improve the quality of cardiovascular research and support future medical decision-making by gaining additional biomolecular information for translational and diagnostic applications.
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Affiliation(s)
- Elen Tolstik
- Department of Cardiovascular Pharmacology, Translational Research, Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. Bunsen-Kirchhoff-Strasse 11, 44139 Dortmund, Germany.
| | - Stephan E Lehnart
- Department of Cardiology and Pneumology, Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Strasse 42a, 37075 Göttingen, Germany; Cluster of Excellence Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC2067), University of Göttingen, 37073 Göttingen, Germany; Collaborative Research Center SFB1190 Compartmental Gates and Contact Sites in Cells, University of Göttingen, 37073 Göttingen, Germany
| | - Christian Soeller
- Department of Physiology, University of Bern, Bühlplatz 5, 3012 Bern, Switzerland
| | - Kristina Lorenz
- Department of Cardiovascular Pharmacology, Translational Research, Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. Bunsen-Kirchhoff-Strasse 11, 44139 Dortmund, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Leonardo Sacconi
- Institute of Clinical Physiology, National Research Council, Rome, Italy; Institute for Experimental Cardiovascular Medicine, University Freiburg, Elsässer Strasse 2q, 79110 Freiburg, Germany.
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5
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Sanders KM, Drumm BT, Cobine CA, Baker SA. Ca 2+ dynamics in interstitial cells: foundational mechanisms for the motor patterns in the gastrointestinal tract. Physiol Rev 2024; 104:329-398. [PMID: 37561138 PMCID: PMC11281822 DOI: 10.1152/physrev.00036.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/29/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023] Open
Abstract
The gastrointestinal (GI) tract displays multiple motor patterns that move nutrients and wastes through the body. Smooth muscle cells (SMCs) provide the forces necessary for GI motility, but interstitial cells, electrically coupled to SMCs, tune SMC excitability, transduce inputs from enteric motor neurons, and generate pacemaker activity that underlies major motor patterns, such as peristalsis and segmentation. The interstitial cells regulating SMCs are interstitial cells of Cajal (ICC) and PDGF receptor (PDGFR)α+ cells. Together these cells form the SIP syncytium. ICC and PDGFRα+ cells express signature Ca2+-dependent conductances: ICC express Ca2+-activated Cl- channels, encoded by Ano1, that generate inward current, and PDGFRα+ cells express Ca2+-activated K+ channels, encoded by Kcnn3, that generate outward current. The open probabilities of interstitial cell conductances are controlled by Ca2+ release from the endoplasmic reticulum. The resulting Ca2+ transients occur spontaneously in a stochastic manner. Ca2+ transients in ICC induce spontaneous transient inward currents and spontaneous transient depolarizations (STDs). Neurotransmission increases or decreases Ca2+ transients, and the resulting depolarizing or hyperpolarizing responses conduct to other cells in the SIP syncytium. In pacemaker ICC, STDs activate voltage-dependent Ca2+ influx, which initiates a cluster of Ca2+ transients and sustains activation of ANO1 channels and depolarization during slow waves. Regulation of GI motility has traditionally been described as neurogenic and myogenic. Recent advances in understanding Ca2+ handling mechanisms in interstitial cells and how these mechanisms influence motor patterns of the GI tract suggest that the term "myogenic" should be replaced by the term "SIPgenic," as this review discusses.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada-Reno, Reno, Nevada, United States
| | - Bernard T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Caroline A Cobine
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Salah A Baker
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada-Reno, Reno, Nevada, United States
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6
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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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Lother A, Kohl P. The heterocellular heart: identities, interactions, and implications for cardiology. Basic Res Cardiol 2023; 118:30. [PMID: 37495826 PMCID: PMC10371928 DOI: 10.1007/s00395-023-01000-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023]
Abstract
The heterocellular nature of the heart has been receiving increasing attention in recent years. In addition to cardiomyocytes as the prototypical cell type of the heart, non-myocytes such as endothelial cells, fibroblasts, or immune cells are coming more into focus. The rise of single-cell sequencing technologies enables identification of ever more subtle differences and has reignited the question of what defines a cell's identity. Here we provide an overview of the major cardiac cell types, describe their roles in homeostasis, and outline recent findings on non-canonical functions that may be of relevance for cardiology. We highlight modes of biochemical and biophysical interactions between different cardiac cell types and discuss the potential implications of the heterocellular nature of the heart for basic research and therapeutic interventions.
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Affiliation(s)
- Achim Lother
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Albertstr. 25, 79104, Freiburg, Germany.
- Interdisciplinary Medical Intensive Care, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany.
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, Faculty of Medicine, University Heart Center, University of Freiburg, Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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8
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Dai Y, Ignatyeva N, Xu H, Wali R, Toischer K, Brandenburg S, Lenz C, Pronto J, Fakuade FE, Sossalla S, Zeisberg EM, Janshoff A, Kutschka I, Voigt N, Urlaub H, Rasmussen TB, Mogensen J, Lehnart SE, Hasenfuss G, Ebert A. An Alternative Mechanism of Subcellular Iron Uptake Deficiency in Cardiomyocytes. Circ Res 2023; 133:e19-e46. [PMID: 37313752 DOI: 10.1161/circresaha.122.321157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 05/26/2023] [Indexed: 06/15/2023]
Abstract
BACKGROUND Systemic defects in intestinal iron absorption, circulation, and retention cause iron deficiency in 50% of patients with heart failure. Defective subcellular iron uptake mechanisms that are independent of systemic absorption are incompletely understood. The main intracellular route for iron uptake in cardiomyocytes is clathrin-mediated endocytosis. METHODS We investigated subcellular iron uptake mechanisms in patient-derived and CRISPR/Cas-edited induced pluripotent stem cell-derived cardiomyocytes as well as patient-derived heart tissue. We used an integrated platform of DIA-MA (mass spectrometry data-independent acquisition)-based proteomics and signaling pathway interrogation. We employed a genetic induced pluripotent stem cell model of 2 inherited mutations (TnT [troponin T]-R141W and TPM1 [tropomyosin 1]-L185F) that lead to dilated cardiomyopathy (DCM), a frequent cause of heart failure, to study the underlying molecular dysfunctions of DCM mutations. RESULTS We identified a druggable molecular pathomechanism of impaired subcellular iron deficiency that is independent of systemic iron metabolism. Clathrin-mediated endocytosis defects as well as impaired endosome distribution and cargo transfer were identified as a basis for subcellular iron deficiency in DCM-induced pluripotent stem cell-derived cardiomyocytes. The clathrin-mediated endocytosis defects were also confirmed in the hearts of patients with DCM with end-stage heart failure. Correction of the TPM1-L185F mutation in DCM patient-derived induced pluripotent stem cells, treatment with a peptide, Rho activator II, or iron supplementation rescued the molecular disease pathway and recovered contractility. Phenocopying the effects of the TPM1-L185F mutation into WT induced pluripotent stem cell-derived cardiomyocytes could be ameliorated by iron supplementation. CONCLUSIONS Our findings suggest that impaired endocytosis and cargo transport resulting in subcellular iron deficiency could be a relevant pathomechanism for patients with DCM carrying inherited mutations. Insight into this molecular mechanism may contribute to the development of treatment strategies and risk management in heart failure.
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Affiliation(s)
- Yuanyuan Dai
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Nadezda Ignatyeva
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Hang Xu
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Ruheen Wali
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Karl Toischer
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Sören Brandenburg
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Christof Lenz
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Department of Clinical Chemistry, University Medical Center Goettingen, (C.L., H.U.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Goettingen (C.L., H.U.)
| | - Julius Pronto
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
| | - Funsho E Fakuade
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Samuel Sossalla
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
- Department for Internal Medicine II, University Medical Center Regensburg (S.S.)
| | - Elisabeth M Zeisberg
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
| | - Andreas Janshoff
- Institute for Physical Chemistry (A.J.), University of Goettingen, Germany
| | - Ingo Kutschka
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Göttingen (I.K.)
| | - Niels Voigt
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Institute of Pharmacology and Toxicology, University Medical Center Goettingen, (J.P., F.E.F., N.V.), University of Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Henning Urlaub
- Department of Clinical Chemistry, University Medical Center Goettingen, (C.L., H.U.), University of Goettingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Goettingen (C.L., H.U.)
| | | | - Jens Mogensen
- Department of Cardiology, Aalborg University Hospital, Denmark (J.M.)
| | - Stephan E Lehnart
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC; C.L., F.E.F., N.V., S.E.L.), University of Goettingen, Germany
| | - Gerd Hasenfuss
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
- Heart Center, Clinic for Cardiology and Pneumology, University Medical Center Goettingen (K.T., S.B., S.S., G.H.), University of Goettingen, Germany
| | - Antje Ebert
- Heart Research Center Goettingen, Clinic for Cardiology and Pneumology, University Medical Center Goettingen, Georg-August University of Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., S.S., E.M.Z., S.E.L., G.H., A.E.)
- DZHK (German Center for Cardiovascular Research), partner site Goettingen, Germany (Y.D., N.I., H.X., R.W., K.T., S.B., C.L., J.P., F.E.F., E.M.Z., I.K., N.V., S.E.L., G.H., A.E.)
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9
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Zhang X, Smith CER, Morotti S, Edwards AG, Sato D, Louch WE, Ni H, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: II. Ca 2+ -handling protein variation. J Physiol 2023; 601:2685-2710. [PMID: 36114707 PMCID: PMC10017376 DOI: 10.1113/jp283602] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Disruption of the transverse-axial tubule system (TATS) in diseases such as heart failure and atrial fibrillation occurs in combination with changes in the expression and distribution of key Ca2+ -handling proteins. Together this ultrastructural and ionic remodelling is associated with aberrant Ca2+ cycling and electrophysiological instabilities that underlie arrhythmic activity. However, due to the concurrent changes in TATs and Ca2+ -handling protein expression and localization that occur in disease it is difficult to distinguish their individual contributions to the arrhythmogenic state. To investigate this, we applied our novel 3D human atrial myocyte model with spatially detailed Ca2+ diffusion and TATS to investigate the isolated and interactive effects of changes in expression and localization of key Ca2+ -handling proteins and variable TATS density on Ca2+ -handling abnormality driven membrane instabilities. We show that modulating the expression and distribution of the sodium-calcium exchanger, ryanodine receptors and the sarcoplasmic reticulum (SR) Ca2+ buffer calsequestrin have varying pro- and anti-arrhythmic effects depending on the balance of opposing influences on SR Ca2+ leak-load and Ca2+ -voltage relationships. Interestingly, the impact of protein remodelling on Ca2+ -driven proarrhythmic behaviour varied dramatically depending on TATS density, with intermediately tubulated cells being more severely affected compared to detubulated and densely tubulated myocytes. This work provides novel mechanistic insight into the distinct and interactive consequences of TATS and Ca2+ -handling protein remodelling that underlies dysfunctional Ca2+ cycling and electrophysiological instability in disease. KEY POINTS: In our companion paper we developed a 3D human atrial myocyte model, coupling electrophysiology and Ca2+ handling with subcellular spatial details governed by the transverse-axial tubule system (TATS). Here we utilize this model to mechanistically examine the impact of TATS loss and changes in the expression and distribution of key Ca2+ -handling proteins known to be remodelled in disease on Ca2+ homeostasis and electrophysiological stability. We demonstrate that varying the expression and localization of these proteins has variable pro- and anti-arrhythmic effects with outcomes displaying dependence on TATS density. Whereas detubulated myocytes typically appear unaffected and densely tubulated cells seem protected, the arrhythmogenic effects of Ca2+ handling protein remodelling are profound in intermediately tubulated cells. Our work shows the interaction between TATS and Ca2+ -handling protein remodelling that underlies the Ca2+ -driven proarrhythmic behaviour observed in atrial fibrillation and may help to predict the effects of antiarrhythmic strategies at varying stages of ultrastructural remodelling.
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Affiliation(s)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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10
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Zhang X, Ni H, Morotti S, Smith C, Sato D, Louch W, Edwards A, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: I. Transverse-axial tubule variation. J Physiol 2023; 601:2655-2683. [PMID: 36094888 PMCID: PMC10008525 DOI: 10.1113/jp283363] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Intracellular calcium (Ca2+ ) cycling is tightly regulated in the healthy heart ensuring effective contraction. This is achieved by transverse (t)-tubule membrane invaginations that facilitate close coupling of key Ca2+ -handling proteins such as the L-type Ca2+ channel and Na+ -Ca2+ exchanger (NCX) on the cell surface with ryanodine receptors (RyRs) on the intracellular Ca2+ store. Although less abundant and regular than in the ventricle, t-tubules also exist in atrial myocytes as a network of transverse invaginations with axial extensions known as the transverse-axial tubule system (TATS). In heart failure and atrial fibrillation, there is TATS remodelling that is associated with aberrant Ca2+ -handling and Ca2+ -induced arrhythmic activity; however, the mechanism underlying this is not fully understood. To address this, we developed a novel 3D human atrial myocyte model that couples electrophysiology and Ca2+ -handling with variable TATS organization and density. We extensively parameterized and validated our model against experimental data to build a robust tool examining TATS regulation of subcellular Ca2+ release. We found that varying TATS density and thus the localization of key Ca2+ -handling proteins has profound effects on Ca2+ handling. Following TATS loss, there is reduced NCX that results in increased cleft Ca2+ concentration through decreased Ca2+ extrusion. This elevated Ca2+ increases RyR open probability causing spontaneous Ca2+ releases and the promotion of arrhythmogenic waves (especially in the cell interior) leading to voltage instabilities through delayed afterdepolarizations. In summary, the present study demonstrates a mechanistic link between TATS remodelling and Ca2+ -driven proarrhythmic behaviour that probably reflects the arrhythmogenic state observed in disease. KEY POINTS: Transverse-axial tubule systems (TATS) modulate Ca2+ handling and excitation-contraction coupling in atrial myocytes, with TATS remodelling in heart failure and atrial fibrillation being associated with altered Ca2+ cycling and subsequent arrhythmogenesis. To investigate the poorly understood mechanisms linking TATS variation and spontaneous Ca2+ release, we built, parameterized and validated a 3D human atrial myocyte model coupling electrophysiology and spatially-detailed subcellular Ca2+ handling governed by the TATS. Simulated TATS loss causes diastolic Ca2+ and voltage instabilities through reduced Na+ -Ca2+ exchanger-mediated Ca2+ removal, cleft Ca2+ accumulation and increased ryanodine receptor open probability, resulting in spontaneous Ca2+ release and promotion of arrhythmogenic waves and delayed afterdepolarizations. At fast electrical rates typical of atrial tachycardia/fibrillation, spontaneous Ca2+ releases are larger and more frequent in the cell interior than at the periphery. Our work provides mechanistic insight into how atrial TATS remodelling can lead to Ca2+ -driven instabilities that may ultimately contribute to the arrhythmogenic state in disease.
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Affiliation(s)
- X. Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - H. Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - S. Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - C.E.R. Smith
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - D. Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - W.E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo Norway
| | - A.G. Edwards
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Simula Research Laboratory, Lysaker, Norway
| | - E. Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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11
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Martin KE, Ravisankar P, Beerens M, MacRae CA, Waxman JS. Nr2f1a maintains atrial nkx2.5 expression to repress pacemaker identity within venous atrial cardiomyocytes of zebrafish. eLife 2023; 12:e77408. [PMID: 37184369 PMCID: PMC10185342 DOI: 10.7554/elife.77408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Maintenance of cardiomyocyte identity is vital for normal heart development and function. However, our understanding of cardiomyocyte plasticity remains incomplete. Here, we show that sustained expression of the zebrafish transcription factor Nr2f1a prevents the progressive acquisition of ventricular cardiomyocyte (VC) and pacemaker cardiomyocyte (PC) identities within distinct regions of the atrium. Transcriptomic analysis of flow-sorted atrial cardiomyocytes (ACs) from nr2f1a mutant zebrafish embryos showed increased VC marker gene expression and altered expression of core PC regulatory genes, including decreased expression of nkx2.5, a critical repressor of PC differentiation. At the arterial (outflow) pole of the atrium in nr2f1a mutants, cardiomyocytes resolve to VC identity within the expanded atrioventricular canal. However, at the venous (inflow) pole of the atrium, there is a progressive wave of AC transdifferentiation into PCs across the atrium toward the arterial pole. Restoring Nkx2.5 is sufficient to repress PC marker identity in nr2f1a mutant atria and analysis of chromatin accessibility identified an Nr2f1a-dependent nkx2.5 enhancer expressed in the atrial myocardium directly adjacent to PCs. CRISPR/Cas9-mediated deletion of the putative nkx2.5 enhancer leads to a loss of Nkx2.5-expressing ACs and expansion of a PC reporter, supporting that Nr2f1a limits PC differentiation within venous ACs via maintaining nkx2.5 expression. The Nr2f-dependent maintenance of AC identity within discrete atrial compartments may provide insights into the molecular etiology of concurrent structural congenital heart defects and associated arrhythmias.
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Affiliation(s)
- Kendall E Martin
- Molecular Genetics, Biochemistry, and Microbiology Graduate Program, University of Cincinnati College of MedicineCincinnatiUnited States
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Padmapriyadarshini Ravisankar
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Manu Beerens
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Calum A MacRae
- Divisions of Cardiovascular Medicine, Genetics and Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical SchoolBostonUnited States
| | - Joshua S Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Department of Pediatrics, University of Cincinnati College of MedicineCincinnatiUnited States
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12
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Regional Differences in Ca 2+ Signaling and Transverse-Tubules across Left Atrium from Adult Sheep. Int J Mol Sci 2023; 24:ijms24032347. [PMID: 36768669 PMCID: PMC9916916 DOI: 10.3390/ijms24032347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Cardiac excitation-contraction coupling can be different between regions of the heart. Little is known at the atria level, specifically in different regions of the left atrium. This is important given the role of cardiac myocytes from the pulmonary vein sleeves, which are responsible for ectopic activity during atrial fibrillation. In this study, we present a new method to isolate atrial cardiac myocytes from four different regions of the left atrium of a large animal model, sheep, highly relevant to humans. Using collagenase/protease we obtained calcium-tolerant atrial cardiac myocytes from the epicardium, endocardium, free wall and pulmonary vein regions. Calcium transients were slower (time to peak and time to decay) in free wall and pulmonary vein myocytes compared to the epicardium and endocardium. This is associated with lower t-tubule density. Overall, these results suggest regional differences in calcium transient and t-tubule density across left atria, which may play a major role in the genesis of atrial fibrillation.
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13
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Abstract
Cardiac alternans arises from dynamical instabilities in the electrical and calcium cycling systems of the heart, and often precedes ventricular arrhythmias and sudden cardiac death. In this review, we integrate clinical observations with theory and experiment to paint a holistic portrait of cardiac alternans: the underlying mechanisms, arrhythmic manifestations and electrocardiographic signatures. We first summarize the cellular and tissue mechanisms of alternans that have been demonstrated both theoretically and experimentally, including 3 voltage-driven and 2 calcium-driven alternans mechanisms. Based on experimental and simulation results, we describe their relevance to mechanisms of arrhythmogenesis under different disease conditions, and their link to electrocardiographic characteristics of alternans observed in patients. Our major conclusion is that alternans is not only a predictor, but also a causal mechanism of potentially lethal ventricular and atrial arrhythmias across the full spectrum of arrhythmia mechanisms that culminate in functional reentry, although less important for anatomic reentry and focal arrhythmias.
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Affiliation(s)
- Zhilin Qu
- Departments of Medicine (Cardiology), Physiology, and Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - James N. Weiss
- Departments of Medicine (Cardiology), Physiology, and Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
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14
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Keefe JA, Moore OM, Ho KS, Wehrens XHT. Role of Ca 2+ in healthy and pathologic cardiac function: from normal excitation-contraction coupling to mutations that cause inherited arrhythmia. Arch Toxicol 2023; 97:73-92. [PMID: 36214829 PMCID: PMC10122835 DOI: 10.1007/s00204-022-03385-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 01/19/2023]
Abstract
Calcium (Ca2+) ions are a key second messenger involved in the rhythmic excitation and contraction of cardiomyocytes throughout the heart. Proper function of Ca2+-handling proteins is required for healthy cardiac function, whereas disruption in any of these can cause cardiac arrhythmias. This comprehensive review provides a broad overview of the roles of Ca2+-handling proteins and their regulators in healthy cardiac function and the mechanisms by which mutations in these proteins contribute to inherited arrhythmias. Major Ca2+ channels and Ca2+-sensitive regulatory proteins involved in cardiac excitation-contraction coupling are discussed, with special emphasis on the function of the RyR2 macromolecular complex. Inherited arrhythmia disorders including catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, Brugada syndrome, short QT syndrome, and arrhythmogenic right-ventricular cardiomyopathy are discussed with particular emphasis on subtypes caused by mutations in Ca2+-handling proteins.
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Affiliation(s)
- Joshua A Keefe
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Oliver M Moore
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kevin S Ho
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA. .,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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15
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Liu L, Zhou K, Liu X, Hua Y, Wang H, Li Y. The interplay between cardiac dyads and mitochondria regulated the calcium handling in cardiomyocytes. Front Physiol 2022; 13:1013817. [PMID: 36531185 PMCID: PMC9755166 DOI: 10.3389/fphys.2022.1013817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 11/24/2022] [Indexed: 11/15/2023] Open
Abstract
Calcium mishandling and mitochondrial dysfunction have been increasingly recognized as significant factors involved in the progression procedure of cardiomyopathy. Ca2+ mishandling could cause calcium-triggered arrhythmias, which could enhance force development and ATP consumption. Mitochondrial disorganization and dysfunction in cardiomyopathy could disturb the balance of energy catabolic and anabolic procedure. Close spatial localization and arrangement of structural among T-tubule, sarcoplasmic reticulum, mitochondria are important for Ca2+ handling. So that, we illustrate the regulating network between calcium handling and mitochondrial homeostasis, as well as its intracellular mechanisms in this review, which would be worthy to develop novel therapeutic strategy and restore the function of injured cardiomyocytes.
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Affiliation(s)
| | | | | | | | - Hua Wang
- 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, 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, China
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16
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Smith CER, Pinali C, Eisner DA, Trafford AW, Dibb KM. Enhanced calcium release at specialised surface sites compensates for reduced t-tubule density in neonatal sheep atrial myocytes. J Mol Cell Cardiol 2022; 173:61-70. [PMID: 36038009 DOI: 10.1016/j.yjmcc.2022.08.360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/07/2022] [Accepted: 08/23/2022] [Indexed: 01/06/2023]
Abstract
Cardiac myocytes rely on transverse (t)-tubules to facilitate a rapid rise in calcium throughout the cell. However, despite their importance in triggering synchronous Ca2+ release, t-tubules are highly labile structures. They develop postnatally, increase in density during exercise training and are lost in diseases such as heart failure (HF). In the majority of settings, an absence of t-tubules decreases function. Here we show that despite reduced t-tubule density due to immature t-tubules, the newborn atrium is highly specialised to maintain Ca2+ release. To compensate for fewer t-tubules triggering a central rise in Ca2+, Ca2+ release at sites on the cell surface is enhanced in the newborn, exceeding that at all Ca2+ release sites in the adult. Using electron and super resolution microscopy to investigate myocyte ultrastructure, we found that newborn atrial cells had enlarged surface sarcoplasmic reticulum and larger, more closely spaced surface and central ryanodine receptor clusters. We suggest that these adaptations mediate enhanced Ca2+ release at the sarcolemma and aid propagation to compensate for reduced t-tubule density in the neonatal atrium.
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Affiliation(s)
- Charlotte E R Smith
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Christian Pinali
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - David A Eisner
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom.
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17
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Tarifa C, Vallmitjana A, Jiménez-Sábado V, Marchena M, Llach A, Herraiz-Martínez A, Godoy-Marín H, Nolla-Colomer C, Ginel A, Viñolas X, Montiel J, Ciruela F, Echebarria B, Benítez R, Cinca J, Hove-Madsen L. Spatial Distribution of Calcium Sparks Determines Their Ability to Induce Afterdepolarizations in Human Atrial Myocytes. JACC. BASIC TO TRANSLATIONAL SCIENCE 2022; 8:1-15. [PMID: 36777175 PMCID: PMC9911326 DOI: 10.1016/j.jacbts.2022.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022]
Abstract
Analysis of the spatio-temporal distribution of calcium sparks showed a preferential increase in sparks near the sarcolemma in atrial myocytes from patients with atrial fibrillation (AF), linked to higher ryanodine receptor (RyR2) phosphorylation at s2808 and lower calsequestrin-2 levels. Mathematical modeling, incorporating modulation of RyR2 gating, showed that only the observed combinations of RyR2 phosphorylation and calsequestrin-2 levels can account for the spatio-temporal distribution of sparks in patients with and without AF. Furthermore, we demonstrate that preferential calcium release near the sarcolemma is key to a higher incidence and amplitude of afterdepolarizations in atrial myocytes from patients with AF.
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Affiliation(s)
- Carmen Tarifa
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alexander Vallmitjana
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Verónica Jiménez-Sábado
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain
| | - Miquel Marchena
- Department Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Anna Llach
- IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Adela Herraiz-Martínez
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Héctor Godoy-Marín
- Department Pathology and Experimental Therapeutics, IDIBELL, University of Barcelona, Barcelona, Spain,Neuroscience Institute, University of Barcelona, Barcelona, Spain
| | - Carme Nolla-Colomer
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Antonino Ginel
- Servicio de Cirugía Cardiaca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Xavier Viñolas
- Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - José Montiel
- Servicio de Cirugía Cardiaca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Francisco Ciruela
- Department Pathology and Experimental Therapeutics, IDIBELL, University of Barcelona, Barcelona, Spain,Neuroscience Institute, University of Barcelona, Barcelona, Spain
| | - Blas Echebarria
- Department Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Raúl Benítez
- Department d’Enginyeria de Sistemes, Automàtica i Informàtica Industrial, Universitat Politècnica de Catalunya, Spain
| | - Juan Cinca
- IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain,Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Leif Hove-Madsen
- Instituto de Investigaciones Biomédicas de Barcelona, IIBB-CSIC, Barcelona, Spain,IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares, Madrid, Spain,Address for correspondence: Dr Leif Hove-Madsen, Cardiac Rhythm and Contraction Group, Biomedical Research Institute Barcelona, Hospital de la Santa Creu i Sant Pau, St Antoni Ma Claret 167, 08025 Barcelona, Spain.
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18
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Qu Z, Yan D, Song Z. Modeling Calcium Cycling in the Heart: Progress, Pitfalls, and Challenges. Biomolecules 2022; 12:1686. [PMID: 36421700 PMCID: PMC9687412 DOI: 10.3390/biom12111686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/08/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Intracellular calcium (Ca) cycling in the heart plays key roles in excitation-contraction coupling and arrhythmogenesis. In cardiac myocytes, the Ca release channels, i.e., the ryanodine receptors (RyRs), are clustered in the sarcoplasmic reticulum membrane, forming Ca release units (CRUs). The RyRs in a CRU act collectively to give rise to discrete Ca release events, called Ca sparks. A cell contains hundreds to thousands of CRUs, diffusively coupled via Ca to form a CRU network. A rich spectrum of spatiotemporal Ca dynamics is observed in cardiac myocytes, including Ca sparks, spark clusters, mini-waves, persistent whole-cell waves, and oscillations. Models of different temporal and spatial scales have been developed to investigate these dynamics. Due to the complexities of the CRU network and the spatiotemporal Ca dynamics, it is challenging to model the Ca cycling dynamics in the cardiac system, particularly at the tissue sales. In this article, we review the progress of modeling of Ca cycling in cardiac systems from single RyRs to the tissue scale, the pros and cons of the current models and different modeling approaches, and the challenges to be tackled in the future.
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Affiliation(s)
- Zhilin Qu
- Department of Medicine, David Geffen School of Medicine, University of California, A2-237 CHS, 650 Charles E. Young Drive South, Los Angeles, CA 90095, USA
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Dasen Yan
- Peng Cheng Laboratory, Shenzhen 518066, China
| | - Zhen Song
- Peng Cheng Laboratory, Shenzhen 518066, China
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19
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Leowattana W, Leowattana T, Leowattana P. Human-induced pluripotent stem cell-atrial-specific cardiomyocytes and atrial fibrillation. World J Clin Cases 2022; 10:9588-9601. [PMID: 36186184 PMCID: PMC9516943 DOI: 10.12998/wjcc.v10.i27.9588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/22/2022] [Accepted: 08/16/2022] [Indexed: 02/05/2023] Open
Abstract
Patient-specific human-induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCMs) may be produced, genome-edited, and differentiated into multiple cell types for regenerative medicine, disease modeling, drug testing, toxicity screening, and three-dimensional tissue fabrication. There is presently no complete model of atrial fibrillation (AF) available for studying human pharmacological responses and evaluating the toxicity of potential medication candidates. It has been demonstrated that hiPSC-aCMs can replicate the electrophysiological disease phenotype and genotype of AF. The hiPSC-aCMs, however, are immature and do not reflect the maturity of aCMs in the native myocardium. Numerous laboratories utilize a variety of methodologies and procedures to improve and promote aCM maturation, including electrical stimulation, culture duration, biophysical signals, and changes in metabolic variables. This review covers the current methods being explored for use in the maturation of patient-specific hiPSC-aCMs and their application towards a personalized approach to the pharmacologic therapy of AF.
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Affiliation(s)
- Wattana Leowattana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Tawithep Leowattana
- Department of Medicine, Faculty of Medicine, Srinakharinwirot University, Bangkok 10110, Thailand
| | - Pathomthep Leowattana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
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20
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Barefield DY, Yamakawa S, Tahtah I, Sell JJ, Broman M, Laforest B, Harris S, Alvarez AA, Araujo KN, Puckelwartz MJ, Wasserstrom JA, Fishman GI, McNally EM. Partial and complete loss of myosin binding protein H-like cause cardiac conduction defects. J Mol Cell Cardiol 2022; 169:28-40. [PMID: 35533732 PMCID: PMC9329245 DOI: 10.1016/j.yjmcc.2022.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 03/25/2022] [Accepted: 04/15/2022] [Indexed: 02/04/2023]
Abstract
A premature truncation of MYBPHL in humans and a loss of Mybphl in mice is associated with dilated cardiomyopathy, atrial and ventricular arrhythmias, and atrial enlargement. MYBPHL encodes myosin binding protein H-like (MyBP-HL). Prior work in mice indirectly identified Mybphl expression in the atria and in small puncta throughout the ventricle. Because of its genetic association with human and mouse cardiac conduction system disease, we evaluated the anatomical localization of MyBP-HL and the consequences of loss of MyBP-HL on conduction system function. Immunofluorescence microscopy of normal adult mouse ventricles identified MyBP-HL-positive ventricular cardiomyocytes that co-localized with the ventricular conduction system marker contactin-2 near the atrioventricular node and in a subset of Purkinje fibers. Mybphl heterozygous ventricles had a marked reduction of MyBP-HL-positive cells compared to controls. Lightsheet microscopy of normal perinatal day 5 mouse hearts showed enrichment of MyBP-HL-positive cells within and immediately adjacent to the contactin-2-positive ventricular conduction system, but this association was not apparent in Mybphl heterozygous hearts. Surface telemetry of Mybphl-null mice revealed atrioventricular block and atrial bigeminy, while intracardiac pacing revealed a shorter atrial relative refractory period and atrial tachycardia. Calcium transient analysis of isolated Mybphl-null atrial cardiomyocytes demonstrated an increased heterogeneity of calcium release and faster rates of calcium release compared to wild type controls. Super-resolution microscopy of Mybphl heterozygous and homozygous null atrial cardiomyocytes showed ryanodine receptor disorganization compared to wild type controls. Abnormal calcium release, shorter atrial refractory period, and atrial dilation seen in Mybphl null, but not wild type control hearts, agree with the observed atrial arrhythmias, bigeminy, and atrial tachycardia, whereas the proximity of MyBP-HL-positive cells with the ventricular conduction system provides insight into how a predominantly atrial expressed gene contributes to ventricular arrhythmias and ventricular dysfunction.
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Affiliation(s)
- David Y. Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL;,Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL;,Correspondence to: David Y. Barefield, PhD, Department of Cell and Molecular Physiology Loyola University Chicago, 2160 S. 1st Ave. Maywood, IL 60153,
| | - Sean Yamakawa
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Ibrahim Tahtah
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Jordan J. Sell
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Michael Broman
- Section of Cardiology, Department of Medicine, University of Chicago, Chicago, IL
| | - Brigitte Laforest
- Section of Cardiology, Department of Medicine, University of Chicago, Chicago, IL
| | - Sloane Harris
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Alejandro A. Alvarez
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Kelly N. Araujo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Megan J. Puckelwartz
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - J. Andrew Wasserstrom
- Department of Medicine and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Glenn I. Fishman
- Division of Cardiology, NYU Grossman School of Medicine, New York, New York
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL;,Correspondence to: Elizabeth McNally, MD, PhD, Center for Genetic Medicine, Northwestern University, 303 E. Superior St. Chicago, IL 60611,
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21
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Weninger G, Pochechueva T, El Chami D, Luo X, Kohl T, Brandenburg S, Urlaub H, Guan K, Lenz C, Lehnart SE. Calpain cleavage of Junctophilin-2 generates a spectrum of calcium-dependent cleavage products and DNA-rich NT 1-fragment domains in cardiomyocytes. Sci Rep 2022; 12:10387. [PMID: 35725601 PMCID: PMC9209451 DOI: 10.1038/s41598-022-14320-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Calpains are calcium-activated neutral proteases involved in the regulation of key signaling pathways. Junctophilin-2 (JP2) is a Calpain-specific proteolytic target and essential structural protein inside Ca2+ release units required for excitation-contraction coupling in cardiomyocytes. While downregulation of JP2 by Calpain cleavage in heart failure has been reported, the precise molecular identity of the Calpain cleavage sites and the (patho-)physiological roles of the JP2 proteolytic products remain controversial. We systematically analyzed the JP2 cleavage fragments as function of Calpain-1 versus Calpain-2 proteolytic activities, revealing that both Calpain isoforms preferentially cleave mouse JP2 at R565, but subsequently at three additional secondary Calpain cleavage sites. Moreover, we identified the Calpain-specific primary cleavage products for the first time in human iPSC-derived cardiomyocytes. Knockout of RyR2 in hiPSC-cardiomyocytes destabilized JP2 resulting in an increase of the Calpain-specific cleavage fragments. The primary N-terminal cleavage product NT1 accumulated in the nucleus of mouse and human cardiomyocytes in a Ca2+-dependent manner, closely associated with euchromatic chromosomal regions, where NT1 is proposed to function as a cardio-protective transcriptional regulator in heart failure. Taken together, our data suggest that stabilizing NT1 by preventing secondary cleavage events by Calpain and other proteases could be an important therapeutic target for future studies.
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Affiliation(s)
- Gunnar Weninger
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Tatiana Pochechueva
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany
| | - Dana El Chami
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany
| | - Xiaojing Luo
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, 01307, Dresden, Germany
| | - Tobias Kohl
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany
| | - Sören Brandenburg
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany
| | - Henning Urlaub
- Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Proteomanalyse, Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.,Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, 01307, Dresden, Germany
| | - Christof Lenz
- Proteomanalyse, Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. .,Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany.
| | - Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany. .,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany. .,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany. .,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany.
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22
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Colman MA, Alvarez-Lacalle E, Echebarria B, Sato D, Sutanto H, Heijman J. Multi-Scale Computational Modeling of Spatial Calcium Handling From Nanodomain to Whole-Heart: Overview and Perspectives. Front Physiol 2022; 13:836622. [PMID: 35370783 PMCID: PMC8964409 DOI: 10.3389/fphys.2022.836622] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Regulation of intracellular calcium is a critical component of cardiac electrophysiology and excitation-contraction coupling. The calcium spark, the fundamental element of the intracellular calcium transient, is initiated in specialized nanodomains which co-locate the ryanodine receptors and L-type calcium channels. However, calcium homeostasis is ultimately regulated at the cellular scale, by the interaction of spatially separated but diffusively coupled nanodomains with other sub-cellular and surface-membrane calcium transport channels with strong non-linear interactions; and cardiac electrophysiology and arrhythmia mechanisms are ultimately tissue-scale phenomena, regulated by the interaction of a heterogeneous population of coupled myocytes. Recent advances in imaging modalities and image-analysis are enabling the super-resolution reconstruction of the structures responsible for regulating calcium homeostasis, including the internal structure of nanodomains themselves. Extrapolating functional and imaging data from the nanodomain to the whole-heart is non-trivial, yet essential for translational insight into disease mechanisms. Computational modeling has important roles to play in relating structural and functional data at the sub-cellular scale and translating data across the scales. This review covers recent methodological advances that enable image-based modeling of the single nanodomain and whole cardiomyocyte, as well as the development of multi-scale simulation approaches to integrate data from nanometer to whole-heart. Firstly, methods to overcome the computational challenges of simulating spatial calcium dynamics in the nanodomain are discussed, including image-based modeling at this scale. Then, recent whole-cell models, capable of capturing a range of different structures (such as the T-system and mitochondria) and cellular heterogeneity/variability are discussed at two different levels of discretization. Novel methods to integrate the models and data across the scales and simulate stochastic dynamics in tissue-scale models are then discussed, enabling elucidation of the mechanisms by which nanodomain remodeling underlies arrhythmia and contractile dysfunction. Perspectives on model differences and future directions are provided throughout.
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Affiliation(s)
- Michael A. Colman
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | | | - Blas Echebarria
- Departament de Fisica, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain
| | - Daisuke Sato
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Henry Sutanto
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY, United States
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
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23
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Lang D, Medvedev RY, Ratajczyk L, Zheng J, Yuan X, Lim E, Han OY, Valdivia HH, Glukhov AV. Region-specific distribution of transversal-axial tubule system organization underlies heterogeneity of calcium dynamics in the right atrium. Am J Physiol Heart Circ Physiol 2022; 322:H269-H284. [PMID: 34951544 PMCID: PMC8782648 DOI: 10.1152/ajpheart.00381.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The atrial myocardium demonstrates the highly heterogeneous organization of the transversal-axial tubule system (TATS), although its anatomical distribution and region-specific impact on Ca2+ dynamics remain unknown. Here, we developed a novel method for high-resolution confocal imaging of TATS in intact live mouse atrial myocardium and applied a custom-developed MATLAB-based computational algorithm for the automated analysis of TATS integrity. We observed a twofold higher (P < 0.01) TATS density in the right atrial appendage (RAA) than in the intercaval regions (ICR, the anatomical region between the superior vena cava and atrioventricular junction and between the crista terminalis and interatrial septum). Whereas RAA predominantly consisted of well-tubulated myocytes, ICR showed partially tubulated/untubulated cells. Similar TATS distribution was also observed in healthy human atrial myocardium sections. In both mouse atrial preparations and isolated mouse atrial myocytes, we observed a strong anatomical correlation between TATS distribution and Ca2+ transient synchronization and rise-up time. This region-specific difference in Ca2+ transient morphology disappeared after formamide-induced detubulation. ICR myocytes showed a prolonged action potential duration at 80% of repolarization as well as a significantly lower expression of RyR2 and Cav1.2 proteins but similar levels of NCX1 and Cav1.3 compared with RAA tissue. Our findings provide a detailed characterization of the region-specific distribution of TATS in mouse and human atrial myocardium, highlighting the structural foundation for anatomical heterogeneity of Ca2+ dynamics and contractility in the atria. These results could indicate different roles of TATS in Ca2+ signaling at distinct anatomical regions of the atria and provide mechanistic insight into pathological atrial remodeling.NEW & NOTEWORTHY Mouse and human atrial myocardium demonstrate high variability in the organization of the transversal-axial tubule system (TATS), with more organized TATS expressed in the right atrial appendage. TATS distribution governs anatomical heterogeneity of Ca2+ dynamics and thus could contribute to integral atrial contractility, mechanics, and arrhythmogenicity.
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Affiliation(s)
- Di Lang
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Roman Y Medvedev
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Lucas Ratajczyk
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Jingjing Zheng
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Xiaoyu Yuan
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Evi Lim
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Owen Y Han
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Hector H Valdivia
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
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24
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Brandenburg S, Pawlowitz J, Steckmeister V, Subramanian H, Uhlenkamp D, Scardigli M, Mushtaq M, Amlaz SI, Kohl T, Wegener JW, Arvanitis DA, Sanoudou D, Sacconi L, Hasenfuss G, Voigt N, Nikolaev VO, Lehnart SE. A junctional cAMP compartment regulates rapid Ca 2+ signaling in atrial myocytes. J Mol Cell Cardiol 2022; 165:141-157. [PMID: 35033544 DOI: 10.1016/j.yjmcc.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 12/15/2021] [Accepted: 01/08/2022] [Indexed: 10/19/2022]
Abstract
Axial tubule junctions with the sarcoplasmic reticulum control the rapid intracellular Ca2+-induced Ca2+ release that initiates atrial contraction. In atrial myocytes we previously identified a constitutively increased ryanodine receptor (RyR2) phosphorylation at junctional Ca2+ release sites, whereas non-junctional RyR2 clusters were phosphorylated acutely following β-adrenergic stimulation. Here, we hypothesized that the baseline synthesis of 3',5'-cyclic adenosine monophosphate (cAMP) is constitutively augmented in the axial tubule junctional compartments of atrial myocytes. Confocal immunofluorescence imaging of atrial myocytes revealed that junctin, binding to RyR2 in the sarcoplasmic reticulum, was densely clustered at axial tubule junctions. Interestingly, a new transgenic junctin-targeted FRET cAMP biosensor was exclusively co-clustered in the junctional compartment, and hence allowed to monitor cAMP selectively in the vicinity of junctional RyR2 channels. To dissect local cAMP levels at axial tubule junctions versus subsurface Ca2+ release sites, we developed a confocal FRET imaging technique for living atrial myocytes. A constitutively high adenylyl cyclase activity sustained increased local cAMP levels at axial tubule junctions, whereas β-adrenergic stimulation overcame this cAMP compartmentation resulting in additional phosphorylation of non-junctional RyR2 clusters. Adenylyl cyclase inhibition, however, abolished the junctional RyR2 phosphorylation and decreased L-type Ca2+ channel currents, while FRET imaging showed a rapid cAMP decrease. In conclusion, FRET biosensor imaging identified compartmentalized, constitutively augmented cAMP levels in junctional dyads, driving both the locally increased phosphorylation of RyR2 clusters and larger L-type Ca2+ current density in atrial myocytes. This cell-specific cAMP nanodomain is maintained by a constitutively increased adenylyl cyclase activity, contributing to the rapid junctional Ca2+-induced Ca2+ release, whereas β-adrenergic stimulation overcomes the junctional cAMP compartmentation through cell-wide activation of non-junctional RyR2 clusters.
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Affiliation(s)
- Sören Brandenburg
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.
| | - Jan Pawlowitz
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Vanessa Steckmeister
- Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Dennis Uhlenkamp
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Marina Scardigli
- Department of Physics and Astronomy, University of Florence, Florence, Italy; European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy
| | - Mufassra Mushtaq
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Saskia I Amlaz
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Tobias Kohl
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Jörg W Wegener
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Demetrios A Arvanitis
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy and National Institute of Optics (INO-CNR), Sesto Fiorentino, Italy; Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Gerd Hasenfuss
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany
| | - Niels Voigt
- DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany; Heart Research Center Göttingen, Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany; BioMET, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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25
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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26
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Müllenbroich MC, Kelly A, Acker C, Bub G, Bruegmann T, Di Bona A, Entcheva E, Ferrantini C, Kohl P, Lehnart SE, Mongillo M, Parmeggiani C, Richter C, Sasse P, Zaglia T, Sacconi L, Smith GL. Novel Optics-Based Approaches for Cardiac Electrophysiology: A Review. Front Physiol 2021; 12:769586. [PMID: 34867476 PMCID: PMC8637189 DOI: 10.3389/fphys.2021.769586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/18/2021] [Indexed: 12/31/2022] Open
Abstract
Optical techniques for recording and manipulating cellular electrophysiology have advanced rapidly in just a few decades. These developments allow for the analysis of cardiac cellular dynamics at multiple scales while largely overcoming the drawbacks associated with the use of electrodes. The recent advent of optogenetics opens up new possibilities for regional and tissue-level electrophysiological control and hold promise for future novel clinical applications. This article, which emerged from the international NOTICE workshop in 2018, reviews the state-of-the-art optical techniques used for cardiac electrophysiological research and the underlying biophysics. The design and performance of optical reporters and optogenetic actuators are reviewed along with limitations of current probes. The physics of light interaction with cardiac tissue is detailed and associated challenges with the use of optical sensors and actuators are presented. Case studies include the use of fluorescence recovery after photobleaching and super-resolution microscopy to explore the micro-structure of cardiac cells and a review of two photon and light sheet technologies applied to cardiac tissue. The emergence of cardiac optogenetics is reviewed and the current work exploring the potential clinical use of optogenetics is also described. Approaches which combine optogenetic manipulation and optical voltage measurement are discussed, in terms of platforms that allow real-time manipulation of whole heart electrophysiology in open and closed-loop systems to study optimal ways to terminate spiral arrhythmias. The design and operation of optics-based approaches that allow high-throughput cardiac electrophysiological assays is presented. Finally, emerging techniques of photo-acoustic imaging and stress sensors are described along with strategies for future development and establishment of these techniques in mainstream electrophysiological research.
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Affiliation(s)
| | - Allen Kelly
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Corey Acker
- Center for Cell Analysis and Modeling, UConn Health, Farmington, CT, United States
| | - Gil Bub
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Tobias Bruegmann
- Institute for Cardiovascular Physiology, University Medical Center Goettingen, Goettingen, Germany
| | - Anna Di Bona
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy
| | - Emilia Entcheva
- Department of Biomedical Engineering, The George Washington University, Washington, DC, United States
| | | | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Stephan E. Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, Göttingen, Germany
- Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | | | - Claudia Richter
- German Primate Center - Leibniz Institute for Primate Research, Göttingen, Germany
| | - Philipp Sasse
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Leonardo Sacconi
- European Laboratory for Nonlinear Spectroscopy, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- National Institute of Optics, National Research Council, Florence, Italy
| | - Godfrey L. Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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27
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Reinhardt F, Beneke K, Pavlidou NG, Conradi L, Reichenspurner H, Hove-Madsen L, Molina CE. Abnormal Calcium Handling in Atrial Fibrillation Is Linked to Changes in Cyclic AMP Dependent Signaling. Cells 2021; 10:cells10113042. [PMID: 34831263 PMCID: PMC8616167 DOI: 10.3390/cells10113042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/22/2021] [Accepted: 11/02/2021] [Indexed: 01/03/2023] Open
Abstract
Both, the decreased L-type Ca2+ current (ICa,L) density and increased spontaneous Ca2+ release from the sarcoplasmic reticulum (SR), have been associated with atrial fibrillation (AF). In this study, we tested the hypothesis that remodeling of 3′,5′-cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) signaling is linked to these compartment-specific changes (up- or down-regulation) in Ca2+-handling. Perforated patch-clamp experiments were performed in atrial myocytes from 53 patients with AF and 104 patients in sinus rhythm (Ctl). A significantly higher frequency of transient inward currents (ITI) activated by spontaneous Ca2+ release was confirmed in myocytes from AF patients. Next, inhibition of PKA by H-89 promoted a stronger effect on the ITI frequency in these myocytes compared to myocytes from Ctl patients (7.6-fold vs. 2.5-fold reduction), while the β-agonist isoproterenol (ISO) caused a greater increase in Ctl patients (5.5-fold vs. 2.1-fold). ICa,L density was larger in myocytes from Ctl patients at baseline (p < 0.05). However, the effect of ISO on ICa,L density was only slightly stronger in AF than in Ctl myocytes (3.6-fold vs. 2.7-fold). Interestingly, a significant reduction of ICa,L and Ca2+ sparks was observed upon Ca2+/Calmodulin-dependent protein kinase II inhibition by KN-93, but this inhibition had no effect on ITI. Fluorescence resonance energy transfer (FRET) experiments showed that although AF promoted cytosolic desensitization to β-adrenergic stimulation, ISO increased cAMP to similar levels in both groups of patients in the L-type Ca2+ channel and ryanodine receptor compartments. Basal cAMP signaling also showed compartment-specific regulation by phosphodiesterases in atrial myocytes from 44 Ctl and 43 AF patients. Our results suggest that AF is associated with opposite changes in compartmentalized PKA/cAMP-dependent regulation of ICa,L (down-regulation) and ITI (up-regulation).
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Affiliation(s)
- Franziska Reinhardt
- Department of Cardiovascular Surgery, University Heart & Vascular Center Hamburg UKE, 20251 Hamburg, Germany; (F.R.); (L.C.); (H.R.)
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany; (K.B.); (N.G.P.)
| | - Kira Beneke
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany; (K.B.); (N.G.P.)
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf (UKE), 20251 Hamburg, Germany
| | - Nefeli Grammatica Pavlidou
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany; (K.B.); (N.G.P.)
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf (UKE), 20251 Hamburg, Germany
| | - Lenard Conradi
- Department of Cardiovascular Surgery, University Heart & Vascular Center Hamburg UKE, 20251 Hamburg, Germany; (F.R.); (L.C.); (H.R.)
| | - Hermann Reichenspurner
- Department of Cardiovascular Surgery, University Heart & Vascular Center Hamburg UKE, 20251 Hamburg, Germany; (F.R.); (L.C.); (H.R.)
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf (UKE), 20251 Hamburg, Germany
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona, IIBB-CSIC and IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, 08025 Barcelona, Spain;
| | - Cristina E. Molina
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20251 Hamburg, Germany; (K.B.); (N.G.P.)
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf (UKE), 20251 Hamburg, Germany
- Correspondence: ; Tel.: +49-407-4105-7095
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28
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Benitah JP, Perrier R, Mercadier JJ, Pereira L, Gómez AM. RyR2 and Calcium Release in Heart Failure. Front Physiol 2021; 12:734210. [PMID: 34690808 PMCID: PMC8533677 DOI: 10.3389/fphys.2021.734210] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/30/2021] [Indexed: 12/24/2022] Open
Abstract
Heart Failure (HF) is defined as the inability of the heart to efficiently pump out enough blood to maintain the body's needs, first at exercise and then also at rest. Alterations in Ca2+ handling contributes to the diminished contraction and relaxation of the failing heart. While most Ca2+ handling protein expression and/or function has been shown to be altered in many models of experimental HF, in this review, we focus in the sarcoplasmic reticulum (SR) Ca2+ release channel, the type 2 ryanodine receptor (RyR2). Various modifications of this channel inducing alterations in its function have been reported. The first was the fact that RyR2 is less responsive to activation by Ca2+ entry through the L-Type calcium channel, which is the functional result of an ultrastructural remodeling of the ventricular cardiomyocyte, with fewer and disorganized transverse (T) tubules. HF is associated with an elevated sympathetic tone and in an oxidant environment. In this line, enhanced RyR2 phosphorylation and oxidation have been shown in human and experimental HF. After several controversies, it is now generally accepted that phosphorylation of RyR2 at the Calmodulin Kinase II site (S2814) is involved in both the depressed contractile function and the enhanced arrhythmic susceptibility of the failing heart. Diminished expression of the FK506 binding protein, FKBP12.6, may also contribute. While these alterations have been mostly studied in the left ventricle of HF with reduced ejection fraction, recent studies are looking at HF with preserved ejection fraction. Moreover, alterations in the RyR2 in HF may also contribute to supraventricular defects associated with HF such as sinus node dysfunction and atrial fibrillation.
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Affiliation(s)
| | | | | | | | - Ana M. Gómez
- Signaling and Cardiovascular Pathophysiology—UMR-S 1180, INSERM, Université Paris-Saclay, Châtenay-Malabry, France
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29
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Borysova L, Ng YYH, Wragg ES, Wallis LE, Fay E, Ascione R, Dora KA. High spatial and temporal resolution Ca 2+ imaging of myocardial strips from human, pig and rat. Nat Protoc 2021; 16:4650-4675. [PMID: 34400840 DOI: 10.1038/s41596-021-00590-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 06/14/2021] [Indexed: 11/09/2022]
Abstract
Ca2+ handling within cardiac myocytes underpins coordinated contractile function within the beating heart. This protocol enables high spatial and temporal Ca2+ imaging of ex vivo multicellular myocardial strips. The endocardial surface is retained, and strips of 150-300-µm thickness are dissected, loaded with Ca2+ indicators and mounted within 1.5 h. A list of the equipment and reagents used and the key methodological aspects allowing the use of this technique on strips from any chamber of the mammalian heart are described. We have successfully used this protocol on human, pig and rat biopsy samples. On use of this protocol with intact endocardial endothelium, we demonstrated that the myocytes develop asynchronous spontaneous Ca2+ events, which can be ablated by electrically evoked Ca2+ transients, and subsequently redevelop spontaneously after cessation of stimulation. This protocol thus offers a rapid and reliable method for studying the Ca2+ signaling underpinning cardiomyocyte contraction, in both healthy and diseased tissue.
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Affiliation(s)
- Lyudmyla Borysova
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Y Y Hanson Ng
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Edward S Wragg
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Lillian E Wallis
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Emily Fay
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Raimondo Ascione
- Bristol Heart Institute, Bristol Royal Infirmary, University of Bristol, Bristol, UK
| | - Kim A Dora
- Vascular Pharmacology Group, Department of Pharmacology, University of Oxford, Oxford, UK.
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30
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Kaplan AD, Joca HC, Boyman L, Greiser M. Calcium Signaling Silencing in Atrial Fibrillation: Implications for Atrial Sodium Homeostasis. Int J Mol Sci 2021; 22:10513. [PMID: 34638854 PMCID: PMC8508839 DOI: 10.3390/ijms221910513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting more than 33 million people worldwide. Despite important advances in therapy, AF's incidence remains high, and treatment often results in recurrence of the arrhythmia. A better understanding of the cellular and molecular changes that (1) trigger AF and (2) occur after the onset of AF will help to identify novel therapeutic targets. Over the past 20 years, a large body of research has shown that intracellular Ca2+ handling is dramatically altered in AF. While some of these changes are arrhythmogenic, other changes counteract cellular arrhythmogenic mechanisms (Calcium Signaling Silencing). The intracellular Na+ concentration ([Na+])i is a key regulator of intracellular Ca2+ handling in cardiac myocytes. Despite its importance in the regulation of intracellular Ca2+ handling, little is known about [Na+]i, its regulation, and how it might be changed in AF. Previous work suggests that there might be increases in the late component of the atrial Na+ current (INa,L) in AF, suggesting that [Na+]i levels might be high in AF. Indeed, a pharmacological blockade of INa,L has been suggested as a treatment for AF. Here, we review calcium signaling silencing and changes in intracellular Na+ homeostasis during AF. We summarize the proposed arrhythmogenic mechanisms associated with increases in INa,L during AF and discuss the evidence from clinical trials that have tested the pharmacological INa,L blocker ranolazine in the treatment of AF.
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Affiliation(s)
- Aaron D. Kaplan
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Humberto C. Joca
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
| | - Maura Greiser
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.D.K.); (H.C.J.); (L.B.)
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31
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Wright PT, Gorelik J, Harding SE. Electrophysiological Remodeling: Cardiac T-Tubules and ß-Adrenoceptors. Cells 2021; 10:cells10092456. [PMID: 34572106 PMCID: PMC8468945 DOI: 10.3390/cells10092456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 01/09/2023] Open
Abstract
Beta-adrenoceptors (βAR) are often viewed as archetypal G-protein coupled receptors. Over the past fifteen years, investigations in cardiovascular biology have provided remarkable insights into this receptor family. These studies have shifted pharmacological dogma, from one which centralized the receptor to a new focus on structural micro-domains such as caveolae and t-tubules. Important studies have examined, separately, the structural compartmentation of ion channels and βAR. Despite links being assumed, relatively few studies have specifically examined the direct link between structural remodeling and electrical remodeling with a focus on βAR. In this review, we will examine the nature of receptor and ion channel dysfunction on a substrate of cardiomyocyte microdomain remodeling, as well as the likely ramifications for cardiac electrophysiology. We will then discuss the advances in methodologies in this area with a specific focus on super-resolution microscopy, fluorescent imaging, and new approaches involving microdomain specific, polymer-based agonists. The advent of powerful computational modelling approaches has allowed the science to shift from purely empirical work, and may allow future investigations based on prediction. Issues such as the cross-reactivity of receptors and cellular heterogeneity will also be discussed. Finally, we will speculate as to the potential developments within this field over the next ten years.
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Affiliation(s)
- Peter T. Wright
- School of Life & Health Sciences, University of Roehampton, Holybourne Avenue, London SW15 4JD, UK;
- Cardiac Section, National Heart and Lung Institute (NHLI), Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK;
| | - Julia Gorelik
- Cardiac Section, National Heart and Lung Institute (NHLI), Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK;
| | - Sian E. Harding
- Cardiac Section, National Heart and Lung Institute (NHLI), Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK;
- Correspondence:
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32
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Earley S, Lederer WJ. Metabolic Control of Cardiac Pacemaking. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab043. [PMID: 35330951 PMCID: PMC8788821 DOI: 10.1093/function/zqab043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 08/10/2021] [Accepted: 08/19/2021] [Indexed: 01/07/2023]
Affiliation(s)
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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33
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Sadredini M, Haugsten Hansen M, Frisk M, Louch WE, Lehnart SE, Sjaastad I, Stokke MK. CaMKII inhibition has dual effects on spontaneous Ca 2+ release and Ca 2+ alternans in ventricular cardiomyocytes from mice with a gain-of-function RyR2 mutation. Am J Physiol Heart Circ Physiol 2021; 321:H446-H460. [PMID: 34270372 DOI: 10.1152/ajpheart.00011.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In conditions with abnormally increased activity of the cardiac ryanodine receptor (RyR2), Ca2+/calmodulin-dependent protein kinase II (CaMKII) can contribute to a further destabilization of RyR2 that results in triggered arrhythmias. Therefore, inhibition of CaMKII in such conditions has been suggested as a strategy to suppress RyR2 activity and arrhythmias. However, suppression of RyR2 activity can lead to the development of arrhythmogenic Ca2+ alternans. The aim of this study was to test whether the suppression of RyR2 activity caused by inhibition of CaMKII increases propensity for Ca2+ alternans. We studied spontaneous Ca2+ release events and Ca2+ alternans in isolated left ventricular cardiomyocytes from mice carrying the gain-of-function RyR2 mutation RyR2-R2474S and from wild-type mice. CaMKII inhibition by KN-93 effectively decreased the frequency of spontaneous Ca2+ release events in RyR2-R2474S cardiomyocytes exposed to the β-adrenoceptor agonist isoprenaline. However, KN-93-treated RyR2-R2474S cardiomyocytes also showed increased propensity for Ca2+ alternans and increased Ca2+ alternans ratio compared with both an inactive analog of KN-93 and with vehicle-treated controls. This increased propensity for Ca2+ alternans was explained by prolongation of Ca2+ release refractoriness. Importantly, the increased propensity for Ca2+ alternans in KN-93-treated RyR2-R2474S cardiomyocytes did not surpass that of wild type. In conclusion, inhibition of CaMKII efficiently reduces spontaneous Ca2+ release but promotes Ca2+ alternans in RyR2-R2474S cardiomyocytes with a gain-of-function RyR2 mutation. The dominant effect in RyR2-R2474S is to reduce spontaneous Ca2+ release, which supports this intervention as a therapeutic strategy in this specific condition. However, future studies on CaMKII inhibition in conditions with increased propensity for Ca2+ alternans should include investigation of both phenomena.NEW & NOTEWORTHY Genetically increased RyR2 activity promotes arrhythmogenic Ca2+ release. Inhibition of CaMKII suppresses RyR2 activity and arrhythmogenic Ca2+ release. Suppression of RyR2 activity prolongs refractoriness of Ca2+ release. Prolonged refractoriness of Ca2+ release leads to arrhythmogenic Ca2+ alternans. CaMKII inhibition promotes Ca2+ alternans by prolonging Ca2+ release refractoriness.
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Affiliation(s)
- Mani Sadredini
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway
| | - Marie Haugsten Hansen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway
| | - Stephan E Lehnart
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Göttingen, Germany
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway
| | - Mathis Korseberg Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Cardiac Research Centre, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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34
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Gharanei M, Shafaattalab S, Sangha S, Gunawan M, Laksman Z, Hove-Madsen L, Tibbits GF. Atrial-specific hiPSC-derived cardiomyocytes in drug discovery and disease modeling. Methods 2021; 203:364-377. [PMID: 34144175 DOI: 10.1016/j.ymeth.2021.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/08/2021] [Accepted: 06/12/2021] [Indexed: 12/19/2022] Open
Abstract
The discovery and application of human-induced pluripotent stem cells (hiPSCs) have been instrumental in the investigation of the pathophysiology of cardiovascular diseases. Patient-specific hiPSCs can now be generated, genome-edited, and subsequently differentiated into various cell types and used for regenerative medicine, disease modeling, drug testing, toxicity screening, and 3D tissue generation. Modulation of the retinoic acid signaling pathway has been shown to direct cardiomyocyte differentiation towards an atrial lineage. A variety of studies have successfully differentiated patient-specific atrial cardiac myocytes (hiPSC-aCM) and atrial engineered heart tissue (aEHT) that express atrial specific genes (e.g., sarcolipin and ANP) and exhibit atrial electrophysiological and contractility profiles. Identification of protocols to differentiate atrial cells from patients with atrial fibrillation and other inherited diseases or creating disease models using genetic mutation studies has shed light on the mechanisms of atrial-specific diseases and identified the efficacy of atrial-selective pharmacological compounds. hiPSC-aCMs and aEHTs can be used in drug discovery and drug screening studies to investigate the efficacy of atrial selective drugs on atrial fibrillation models. Furthermore, hiPSC-aCMs can be effective tools in studying the mechanism, pathophysiology and treatment options of atrial fibrillation and its genetic underpinnings. The main limitation of using hiPSC-CMs is their immature phenotype compared to adult CMs. A wide range of approaches and protocols are used by various laboratories to optimize and enhance CM maturation, including electrical stimulation, culture time, biophysical cues and changes in metabolic factors.
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Affiliation(s)
- Mayel Gharanei
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; hiPSC-CM Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
| | - Sanam Shafaattalab
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; hiPSC-CM Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
| | - Sarabjit Sangha
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; hiPSC-CM Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
| | - Marvin Gunawan
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; hiPSC-CM Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
| | - Zachary Laksman
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada; School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Leif Hove-Madsen
- Cardiac Rhythm and Contraction Group, IIBB-CSIC, CIBERCV, IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona 08025, Spain
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; hiPSC-CM Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia V5Z 4H4, Canada; School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
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35
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Dai W, Kesaraju S, Weber CR. Transcriptional factors in calcium mishandling and atrial fibrillation development. Pflugers Arch 2021; 473:1177-1197. [PMID: 34003377 DOI: 10.1007/s00424-021-02553-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/19/2021] [Accepted: 02/05/2021] [Indexed: 12/19/2022]
Abstract
Healthy cardiac conduction relies on the coordinated electrical activity of distinct populations of cardiomyocytes. Disruption of cell-cell conduction results in cardiac arrhythmias, a leading cause of morbidity and mortality worldwide. Recent genetic studies have highlighted a major heritable component and identified numerous loci associated with risk of atrial fibrillation, including transcription factor genes, particularly those important in cardiac development, microRNAs, and long noncoding RNAs. Identification of such genetic factors has prompted the search to understand the mechanisms that underlie the genetic component of AF. Recent studies have found several mechanisms by which genetic alterations can result in AF formation via disruption of calcium handling. Loss of developmental transcription factors in adult cardiomyocytes can result in disruption of SR calcium ATPase, sodium calcium exchanger, calcium channels, among other ion channels, which underlie action potential abnormalities and triggered activity that can contribute to AF. This review aims to summarize the complex network of transcription factors and their roles in calcium handling.
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Affiliation(s)
- Wenli Dai
- Department of Pathology, University of Chicago, Chicago, IL, USA
| | - Sneha Kesaraju
- Department of Pathology, University of Chicago, Chicago, IL, USA
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36
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Berisha F, Götz KR, Wegener JW, Brandenburg S, Subramanian H, Molina CE, Rüffer A, Petersen J, Bernhardt A, Girdauskas E, Jungen C, Pape U, Kraft AE, Warnke S, Lindner D, Westermann D, Blankenberg S, Meyer C, Hasenfuß G, Lehnart SE, Nikolaev VO. cAMP Imaging at Ryanodine Receptors Reveals β 2-Adrenoceptor Driven Arrhythmias. Circ Res 2021; 129:81-94. [PMID: 33902292 DOI: 10.1161/circresaha.120.318234] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Filip Berisha
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (F.B., H.S., C.E.M., A.E.K., V.O.N.).,Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Konrad R Götz
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Germany (K.R.G., J.W.W., S. Brandenburg, G.H., S.E.L.)
| | - Jörg W Wegener
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Germany (K.R.G., J.W.W., S. Brandenburg, G.H., S.E.L.).,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (J.W.W., S. Brandenburg, G.H., S.E.L.)
| | - Sören Brandenburg
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Germany (K.R.G., J.W.W., S. Brandenburg, G.H., S.E.L.).,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (J.W.W., S. Brandenburg, G.H., S.E.L.)
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (F.B., H.S., C.E.M., A.E.K., V.O.N.).,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Cristina E Molina
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (F.B., H.S., C.E.M., A.E.K., V.O.N.).,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - André Rüffer
- Department of Cardiovascular Surgery, University Heart and Vascular Center Hamburg, Germany (A.R., J.P., A.B., E.G.)
| | - Johannes Petersen
- Department of Cardiovascular Surgery, University Heart and Vascular Center Hamburg, Germany (A.R., J.P., A.B., E.G.)
| | - Alexander Bernhardt
- Department of Cardiovascular Surgery, University Heart and Vascular Center Hamburg, Germany (A.R., J.P., A.B., E.G.)
| | - Evaldas Girdauskas
- Department of Cardiovascular Surgery, University Heart and Vascular Center Hamburg, Germany (A.R., J.P., A.B., E.G.)
| | - Christiane Jungen
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Cardiology-Electrophysiology, cNEP (Cardiac Neuro- and Electrophysiology Research Group) (C.J., U.P., C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ulrike Pape
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Cardiology-Electrophysiology, cNEP (Cardiac Neuro- and Electrophysiology Research Group) (C.J., U.P., C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Axel E Kraft
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (F.B., H.S., C.E.M., A.E.K., V.O.N.).,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Svenja Warnke
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Diana Lindner
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Dirk Westermann
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Stefan Blankenberg
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
| | - Christian Meyer
- Department of Cardiology (F.B., C.J., U.P., S.W., D.L., D.W., S. Blankenberg, C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Cardiology-Electrophysiology, cNEP (Cardiac Neuro- and Electrophysiology Research Group) (C.J., U.P., C.M.), University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerd Hasenfuß
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Germany (K.R.G., J.W.W., S. Brandenburg, G.H., S.E.L.).,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (J.W.W., S. Brandenburg, G.H., S.E.L.)
| | - Stephan E Lehnart
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany (J.W.W., S. Brandenburg, G.H., S.E.L.)
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Germany (F.B., H.S., C.E.M., A.E.K., V.O.N.).,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (F.B., H.S., C.E.M., A.E., S.W., D.L., D.W., S. Blankenberg, V.O.N.)
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37
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Lang D, Glukhov AV. Cellular and Molecular Mechanisms of Functional Hierarchy of Pacemaker Clusters in the Sinoatrial Node: New Insights into Sick Sinus Syndrome. J Cardiovasc Dev Dis 2021; 8:jcdd8040043. [PMID: 33924321 PMCID: PMC8069964 DOI: 10.3390/jcdd8040043] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/17/2022] Open
Abstract
The sinoatrial node (SAN), the primary pacemaker of the heart, consists of a heterogeneous population of specialized cardiac myocytes that can spontaneously produce action potentials, generating the rhythm of the heart and coordinating heart contractions. Spontaneous beating can be observed from very early embryonic stage and under a series of genetic programing, the complex heterogeneous SAN cells are formed with specific biomarker proteins and generate robust automaticity. The SAN is capable to adjust its pacemaking rate in response to environmental and autonomic changes to regulate the heart's performance and maintain physiological needs of the body. Importantly, the origin of the action potential in the SAN is not static, but rather dynamically changes according to the prevailing conditions. Changes in the heart rate are associated with a shift of the leading pacemaker location within the SAN and accompanied by alterations in P wave morphology and PQ interval on ECG. Pacemaker shift occurs in response to different interventions: neurohormonal modulation, cardiac glycosides, pharmacological agents, mechanical stretch, a change in temperature, and a change in extracellular electrolyte concentrations. It was linked with the presence of distinct anatomically and functionally defined intranodal pacemaker clusters that are responsible for the generation of the heart rhythm at different rates. Recent studies indicate that on the cellular level, different pacemaker clusters rely on a complex interplay between the calcium (referred to local subsarcolemmal Ca2+ releases generated by the sarcoplasmic reticulum via ryanodine receptors) and voltage (referred to sarcolemmal electrogenic proteins) components of so-called "coupled clock pacemaker system" that is used to describe a complex mechanism of SAN pacemaking. In this review, we examine the structural, functional, and molecular evidence for hierarchical pacemaker clustering within the SAN. We also demonstrate the unique molecular signatures of intranodal pacemaker clusters, highlighting their importance for physiological rhythm regulation as well as their role in the development of SAN dysfunction, also known as sick sinus syndrome.
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38
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Rog-Zielinska EA, Moss R, Kaltenbacher W, Greiner J, Verkade P, Seemann G, Kohl P, Cannell MB. Nano-scale morphology of cardiomyocyte t-tubule/sarcoplasmic reticulum junctions revealed by ultra-rapid high-pressure freezing and electron tomography. J Mol Cell Cardiol 2021; 153:86-92. [PMID: 33359037 PMCID: PMC8035077 DOI: 10.1016/j.yjmcc.2020.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 11/27/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022]
Abstract
Detailed knowledge of the ultrastructure of intracellular compartments is a prerequisite for our understanding of how cells function. In cardiac muscle cells, close apposition of transverse (t)-tubule (TT) and sarcoplasmic reticulum (SR) membranes supports stable high-gain excitation-contraction coupling. Here, the fine structure of this key intracellular element is examined in rabbit and mouse ventricular cardiomyocytes, using ultra-rapid high-pressure freezing (HPF, omitting aldehyde fixation) and electron microscopy. 3D electron tomograms were used to quantify the dimensions of TT, terminal cisternae of the SR, and the space between SR and TT membranes (dyadic cleft). In comparison to conventional aldehyde-based chemical sample fixation, HPF-preserved samples of both species show considerably more voluminous SR terminal cisternae, both in absolute dimensions and in terms of junctional SR to TT volume ratio. In rabbit cardiomyocytes, the average dyadic cleft surface area of HPF and chemically fixed myocytes did not differ, but cleft volume was significantly smaller in HPF samples than in conventionally fixed tissue; in murine cardiomyocytes, the dyadic cleft surface area was higher in HPF samples with no difference in cleft volume. In both species, the apposition of the TT and SR membranes in the dyad was more likely to be closer than 10 nm in HPF samples compared to CFD, presumably resulting from avoidance of sample shrinkage associated with conventional fixation techniques. Overall, we provide a note of caution regarding quantitative interpretation of chemically-fixed ultrastructures, and offer novel insight into cardiac TT and SR ultrastructure with relevance for our understanding of cardiac physiology.
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Affiliation(s)
- E A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - R Moss
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - W Kaltenbacher
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - J Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - P Verkade
- School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK
| | - G Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - P Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M B Cannell
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.
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39
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Martin KE, Waxman JS. Atrial and Sinoatrial Node Development in the Zebrafish Heart. J Cardiovasc Dev Dis 2021; 8:jcdd8020015. [PMID: 33572147 PMCID: PMC7914448 DOI: 10.3390/jcdd8020015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/31/2021] [Accepted: 02/04/2021] [Indexed: 12/11/2022] Open
Abstract
Proper development and function of the vertebrate heart is vital for embryonic and postnatal life. Many congenital heart defects in humans are associated with disruption of genes that direct the formation or maintenance of atrial and pacemaker cardiomyocytes at the venous pole of the heart. Zebrafish are an outstanding model for studying vertebrate cardiogenesis, due to the conservation of molecular mechanisms underlying early heart development, external development, and ease of genetic manipulation. Here, we discuss early developmental mechanisms that instruct appropriate formation of the venous pole in zebrafish embryos. We primarily focus on signals that determine atrial chamber size and the specialized pacemaker cells of the sinoatrial node through directing proper specification and differentiation, as well as contemporary insights into the plasticity and maintenance of cardiomyocyte identity in embryonic zebrafish hearts. Finally, we integrate how these insights into zebrafish cardiogenesis can serve as models for human atrial defects and arrhythmias.
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Affiliation(s)
- Kendall E. Martin
- Molecular Genetics, Biochemistry, and Microbiology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joshua S. Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
- Correspondence:
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40
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Wang X, Chen X, Dobrev D, Li N. The crosstalk between cardiomyocyte calcium and inflammasome signaling pathways in atrial fibrillation. Pflugers Arch 2021; 473:389-405. [PMID: 33511453 DOI: 10.1007/s00424-021-02515-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia in adults. The prevalence and incidence of AF is going to increase substantially over the next few decades. Because AF increases the risk of stroke, heart failure, dementia, and others, it severely impacts the quality of life, morbidity, and mortality. Although the pathogenesis of AF is multifaceted and complex, focal ectopic activity and reentry are considered as the fundamental proarrhythmic mechanisms underlying AF development. Over the past 2 decades, large amount of evidence points to the key role of intracellular Ca2+ dysregulation in both initiation and maintenance of AF. More recently, emerging evidence reveal that NLRP3 (NACHT, LRR, PYD domain-containing 3) inflammasome pathway contributes to the substrate of both triggered activity and reentry, ultimately promoting AF. In this article, we review the current state of knowledge on Ca2+ signaling and NLRP3 inflammasome activity in AF. We also discuss the potential crosstalk between these two quintessential contributors to AF promotion.
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Affiliation(s)
- Xiaolei Wang
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
| | - Xiaohui Chen
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Na Li
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA. .,Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.
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41
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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42
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Blatter LA, Kanaporis G, Martinez-Hernandez E, Oropeza-Almazan Y, Banach K. Excitation-contraction coupling and calcium release in atrial muscle. Pflugers Arch 2021; 473:317-329. [PMID: 33398498 DOI: 10.1007/s00424-020-02506-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/16/2020] [Indexed: 01/02/2023]
Abstract
In cardiac muscle, the process of excitation-contraction coupling (ECC) describes the chain of events that links action potential induced myocyte membrane depolarization, surface membrane ion channel activation, triggering of Ca2+ induced Ca2+ release from the sarcoplasmic reticulum (SR) Ca2+ store to activation of the contractile machinery that is ultimately responsible for the pump function of the heart. Here we review similarities and differences of structural and functional attributes of ECC between atrial and ventricular tissue. We explore a novel "fire-diffuse-uptake-fire" paradigm of atrial ECC and Ca2+ release that assigns a novel role to the SR SERCA pump and involves a concerted "tandem" activation of the ryanodine receptor Ca2+ release channel by cytosolic and luminal Ca2+. We discuss the contribution of the inositol 1,4,5-trisphosphate (IP3) receptor Ca2+ release channel as an auxiliary pathway to Ca2+ signaling, and we review IP3 receptor-induced Ca2+ release involvement in beat-to-beat ECC, nuclear Ca2+ signaling, and arrhythmogenesis. Finally, we explore the topic of electromechanical and Ca2+ alternans and its ramifications for atrial arrhythmia.
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Affiliation(s)
- L A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA.
| | - G Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - E Martinez-Hernandez
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - Y Oropeza-Almazan
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - K Banach
- Department of Internal Medicine/Cardiology, Rush University Medical Center, Chicago, IL, 60612, USA
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43
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Rog-Zielinska EA, Scardigli M, Peyronnet R, Zgierski-Johnston CM, Greiner J, Madl J, O'Toole ET, Morphew M, Hoenger A, Sacconi L, Kohl P. Beat-by-Beat Cardiomyocyte T-Tubule Deformation Drives Tubular Content Exchange. Circ Res 2020; 128:203-215. [PMID: 33228470 PMCID: PMC7834912 DOI: 10.1161/circresaha.120.317266] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Supplemental Digital Content is available in the text. The sarcolemma of cardiomyocytes contains many proteins that are essential for electromechanical function in general, and excitation-contraction coupling in particular. The distribution of these proteins is nonuniform between the bulk sarcolemmal surface and membrane invaginations known as transverse tubules (TT). TT form an intricate network of fluid-filled conduits that support electromechanical synchronicity within cardiomyocytes. Although continuous with the extracellular space, the narrow lumen and the tortuous structure of TT can form domains of restricted diffusion. As a result of unequal ion fluxes across cell surface and TT membranes, limited diffusion may generate ion gradients within TT, especially deep within the TT network and at high pacing rates.
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Affiliation(s)
- Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.)
| | - Marina Scardigli
- European Laboratory for Non-Linear Spectroscopy, National Institute of Optics, National Research Council, Sesto Fiorentino (Florence), Italy (M.S., L.S.)
| | - Remi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.)
| | - Callum M Zgierski-Johnston
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.)
| | - Joachim Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.)
| | - Josef Madl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.)
| | - Eileen T O'Toole
- Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder (E.T.O., M.M., A.H.)
| | - Mary Morphew
- Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder (E.T.O., M.M., A.H.)
| | - Andreas Hoenger
- Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder (E.T.O., M.M., A.H.)
| | - Leonardo Sacconi
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.).,European Laboratory for Non-Linear Spectroscopy, National Institute of Optics, National Research Council, Sesto Fiorentino (Florence), Italy (M.S., L.S.)
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, and Faculty of Medicine, University of Freiburg, Germany (E.A.R.-Z., R.P., C.M.Z.-J., J.G., J.M., L.S., P.K.).,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany (P.K.)
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44
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Gunawan MG, Sangha SS, Shafaattalab S, Lin E, Heims-Waldron DA, Bezzerides VJ, Laksman Z, Tibbits GF. Drug screening platform using human induced pluripotent stem cell-derived atrial cardiomyocytes and optical mapping. Stem Cells Transl Med 2020; 10:68-82. [PMID: 32927497 PMCID: PMC7780813 DOI: 10.1002/sctm.19-0440] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 07/13/2020] [Accepted: 08/03/2020] [Indexed: 12/17/2022] Open
Abstract
Current drug development efforts for the treatment of atrial fibrillation are hampered by the fact that many preclinical models have been unsuccessful in reproducing human cardiac physiology and its response to medications. In this study, we demonstrated an approach using human induced pluripotent stem cell-derived atrial and ventricular cardiomyocytes (hiPSC-aCMs and hiPSC-vCMs, respectively) coupled with a sophisticated optical mapping system for drug screening of atrial-selective compounds in vitro. We optimized differentiation of hiPSC-aCMs by modulating the WNT and retinoid signaling pathways. Characterization of the transcriptome and proteome revealed that retinoic acid pushes the differentiation process into the atrial lineage and generated hiPSC-aCMs. Functional characterization using optical mapping showed that hiPSC-aCMs have shorter action potential durations and faster Ca2+ handling dynamics compared with hiPSC-vCMs. Furthermore, pharmacological investigation of hiPSC-aCMs captured atrial-selective effects by displaying greater sensitivity to atrial-selective compounds 4-aminopyridine, AVE0118, UCL1684, and vernakalant when compared with hiPSC-vCMs. These results established that a model system incorporating hiPSC-aCMs combined with optical mapping is well-suited for preclinical drug screening of novel and targeted atrial selective compounds.
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Affiliation(s)
- Marvin G Gunawan
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.,Tibbits Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Sarabjit S Sangha
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.,Tibbits Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Sanam Shafaattalab
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.,Tibbits Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Eric Lin
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | | | - Zachary Laksman
- Division of Cardiology, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.,Tibbits Research Team, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
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45
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Campbell HM, Quick AP, Abu-Taha I, Chiang DY, Kramm CF, Word TA, Brandenburg S, Hulsurkar M, Alsina KM, Liu HB, Martin B, Uhlenkamp D, Moore OM, Lahiri SK, Corradini E, Kamler M, Heck AJR, Lehnart SE, Dobrev D, Wehrens XHT. Loss of SPEG Inhibitory Phosphorylation of Ryanodine Receptor Type-2 Promotes Atrial Fibrillation. Circulation 2020; 142:1159-1172. [PMID: 32683896 DOI: 10.1161/circulationaha.120.045791] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Enhanced diastolic calcium (Ca2+) release through ryanodine receptor type-2 (RyR2) has been implicated in atrial fibrillation (AF) promotion. Diastolic sarcoplasmic reticulum Ca2+ leak is caused by increased RyR2 phosphorylation by PKA (protein kinase A) or CaMKII (Ca2+/calmodulin-dependent kinase-II) phosphorylation, or less dephosphorylation by protein phosphatases. However, considerable controversy remains regarding the molecular mechanisms underlying altered RyR2 function in AF. We thus aimed to determine the role of SPEG (striated muscle preferentially expressed protein kinase), a novel regulator of RyR2 phosphorylation, in AF pathogenesis. METHODS Western blotting was performed with right atrial biopsies from patients with paroxysmal AF. SPEG atrial knockout mice were generated using adeno-associated virus 9. In mice, AF inducibility was determined using intracardiac programmed electric stimulation, and diastolic Ca2+ leak in atrial cardiomyocytes was assessed using confocal Ca2+ imaging. Phosphoproteomics studies and Western blotting were used to measure RyR2 phosphorylation. To test the effects of RyR2-S2367 phosphorylation, knockin mice with an inactivated S2367 phosphorylation site (S2367A) and a constitutively activated S2367 residue (S2367D) were generated by using CRISPR-Cas9. RESULTS Western blotting revealed decreased SPEG protein levels in atrial biopsies from patients with paroxysmal AF in comparison with patients in sinus rhythm. SPEG atrial-specific knockout mice exhibited increased susceptibility to pacing-induced AF by programmed electric stimulation and enhanced Ca2+ spark frequency in atrial cardiomyocytes with Ca2+ imaging, establishing a causal role for decreased SPEG in AF pathogenesis. Phosphoproteomics in hearts from SPEG cardiomyocyte knockout mice identified RyR2-S2367 as a novel kinase substrate of SPEG. Western blotting demonstrated that RyR2-S2367 phosphorylation was also decreased in patients with paroxysmal AF. RyR2-S2367A mice exhibited an increased susceptibility to pacing-induced AF, and aberrant atrial sarcoplasmic reticulum Ca2+ leak, as well. In contrast, RyR2-S2367D mice were resistant to pacing-induced AF. CONCLUSIONS Unlike other kinases (PKA, CaMKII) that increase RyR2 activity, SPEG phosphorylation reduces RyR2-mediated sarcoplasmic reticulum Ca2+ release. Reduced SPEG levels and RyR2-S2367 phosphorylation typified patients with paroxysmal AF. Studies in S2367 knockin mouse models showed a causal relationship between reduced S2367 phosphorylation and AF susceptibility. Thus, modulating SPEG activity and phosphorylation levels of the novel S2367 site on RyR2 may represent a novel target for AF treatment.
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Affiliation(s)
- Hannah M Campbell
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Ann P Quick
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Issam Abu-Taha
- Institute of Pharmacology (I.A.-T., D.D.), University Duisburg-Essen, Germany
| | - David Y Chiang
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Medicine (Cardiovascular Division), Brigham and Women's Hospital, Harvard Medical School, Boston, MA (D.Y.C.)
| | - Carlos F Kramm
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Tarah A Word
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Sören Brandenburg
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Germany (S.B., D.U., S.E.L.)
| | - Mohit Hulsurkar
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Katherina M Alsina
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Hui-Bin Liu
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Institute of Clinical Pharmacy, the Second Affiliated Hospital of Harbin Medical University, China (H.-B.L.)
| | - Brian Martin
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Dennis Uhlenkamp
- Institute of Pharmacology (I.A.-T., D.D.), University Duisburg-Essen, Germany.,Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Germany (S.B., D.U., S.E.L.)
| | - Oliver M Moore
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Neuroscience (O.M.M., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Satadru K Lahiri
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX
| | - Eleonora Corradini
- Biomolecular Mass Spectrometry & Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands (E.C., A.J.R.H.)
| | - Markus Kamler
- Department of Thoracic and Cardiovascular Surgery Huttrop (M.K.), University Duisburg-Essen, Germany
| | - Albert J R Heck
- Biomolecular Mass Spectrometry & Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands (E.C., A.J.R.H.)
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Germany (S.B., D.U., S.E.L.)
| | | | - Xander H T Wehrens
- Cardiovascular Research Institute (H.M.C., A.P.Q., D.Y.C., C.F.K., T.A.W., M.H., K.MA., H.-B.L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Molecular Physiology & Biophysics (H.M.C., A.P.Q., D.Y.C., F.K., T.A.W., M.H., K.M.A., H.-L., B.M., O.M.M., S.K.L., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Neuroscience (O.M.M., X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Medicine (Cardiology) (X.H.T.W.), Baylor College of Medicine, Houston, TX.,Department of Pediatrics (X.H.T.W.), Baylor College of Medicine, Houston, TX.,Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX
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46
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Nattel S, Heijman J, Zhou L, Dobrev D. Molecular Basis of Atrial Fibrillation Pathophysiology and Therapy: A Translational Perspective. Circ Res 2020; 127:51-72. [PMID: 32717172 PMCID: PMC7398486 DOI: 10.1161/circresaha.120.316363] [Citation(s) in RCA: 227] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Atrial fibrillation (AF) is a highly prevalent arrhythmia, with substantial associated morbidity and mortality. There have been significant management advances over the past 2 decades, but the burden of the disease continues to increase and there is certainly plenty of room for improvement in treatment options. A potential key to therapeutic innovation is a better understanding of underlying fundamental mechanisms. This article reviews recent advances in understanding the molecular basis for AF, with a particular emphasis on relating these new insights to opportunities for clinical translation. We first review the evidence relating basic electrophysiological mechanisms to the characteristics of clinical AF. We then discuss the molecular control of factors leading to some of the principal determinants, including abnormalities in impulse conduction (such as tissue fibrosis and other extra-cardiomyocyte alterations, connexin dysregulation and Na+-channel dysfunction), electrical refractoriness, and impulse generation. We then consider the molecular drivers of AF progression, including a range of Ca2+-dependent intracellular processes, microRNA changes, and inflammatory signaling. The concept of key interactome-related nodal points is then evaluated, dealing with systems like those associated with CaMKII (Ca2+/calmodulin-dependent protein kinase-II), NLRP3 (NACHT, LRR, and PYD domains-containing protein-3), and transcription-factors like TBX5 and PitX2c. We conclude with a critical discussion of therapeutic implications, knowledge gaps and future directions, dealing with such aspects as drug repurposing, biologicals, multispecific drugs, the targeting of cardiomyocyte inflammatory signaling and potential considerations in intervening at the level of interactomes and gene-regulation. The area of molecular intervention for AF management presents exciting new opportunities, along with substantial challenges.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
- IHU Liryc and Fondation Bordeaux Université, Bordeaux, France
| | - Jordi Heijman
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Liping Zhou
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
| | - Dobromir Dobrev
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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47
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Fakuade FE, Steckmeister V, Seibertz F, Gronwald J, Kestel S, Menzel J, Pronto JRD, Taha K, Haghighi F, Kensah G, Pearman CM, Wiedmann F, Teske AJ, Schmidt C, Dibb KM, El-Essawi A, Danner BC, Baraki H, Schwappach B, Kutschka I, Mason FE, Voigt N. Altered atrial cytosolic calcium handling contributes to the development of postoperative atrial fibrillation. Cardiovasc Res 2020; 117:1790-1801. [PMID: 32520995 PMCID: PMC8208741 DOI: 10.1093/cvr/cvaa162] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/04/2020] [Accepted: 06/04/2020] [Indexed: 01/14/2023] Open
Abstract
Aims Atrial fibrillation (AF) is a commonly occurring arrhythmia after cardiac surgery (postoperative AF, poAF) and is associated with poorer outcomes. Considering that reduced atrial contractile function is a predictor of poAF and that Ca2+ plays an important role in both excitation–contraction coupling and atrial arrhythmogenesis, this study aims to test whether alterations of intracellular Ca2+ handling contribute to impaired atrial contractility and to the arrhythmogenic substrate predisposing patients to poAF. Methods and results Right atrial appendages were obtained from patients in sinus rhythm undergoing open-heart surgery. Cardiomyocytes were investigated by simultaneous measurement of [Ca2+]i and action potentials (APs, patch-clamp). Patients were followed-up for 6 days to identify those with and without poAF. Speckle-tracking analysis of preoperative echocardiography revealed reduced left atrial contraction strain in poAF patients. At the time of surgery, cellular Ca2+ transients (CaTs) and the sarcoplasmic reticulum (SR) Ca2+ content were smaller in the poAF group. CaT decay was slower in poAF, but the decay of caffeine-induced Ca2+ transients was unaltered, suggesting preserved sodium-calcium exchanger function. In agreement, western blots revealed reduced SERCA2a expression in poAF patients but unaltered phospholamban expression/phosphorylation. Computational modelling indicated that reduced SERCA activity promotes occurrence of CaT and AP alternans. Indeed, alternans of CaT and AP occurred more often and at lower stimulation frequencies in atrial myocytes from poAF patients. Resting membrane potential and AP duration were comparable between both groups at various pacing frequencies (0.25–8 Hz). Conclusions Biochemical, functional, and modelling data implicate reduced SERCA-mediated Ca2+ reuptake into the SR as a major contributor to impaired preoperative atrial contractile function and to the pre-existing arrhythmogenic substrate in patients developing poAF.
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Affiliation(s)
- Funsho E Fakuade
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Vanessa Steckmeister
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Judith Gronwald
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Stefanie Kestel
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Julia Menzel
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Molecular Biology, University Medical Centre, Humboldtallee 23, 37075 Göttingen, Germany
| | - Julius Ryan D Pronto
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Karim Taha
- Department of Cardiology, University Medical Centre, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands.,Netherlands Heart Institute, Holland Heart House, Moreelsepark 1, 3511 EP Utrecht, The Netherlands
| | - Fereshteh Haghighi
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - George Kensah
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Charles M Pearman
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Felix Wiedmann
- Department of Cardiology, University Medical Center Heidelberg, Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Germany
| | - Arco J Teske
- Department of Cardiology, University Medical Centre, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands
| | - Constanze Schmidt
- Department of Cardiology, University Medical Center Heidelberg, Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Germany
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Aschraf El-Essawi
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, Klinikum Braunschweig, Braunschweig, Germany
| | - Bernhard C Danner
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Hassina Baraki
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Blanche Schwappach
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Molecular Biology, University Medical Centre, Humboldtallee 23, 37075 Göttingen, Germany
| | - Ingo Kutschka
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany.,Department of Thoracic and Cardiovascular Surgery, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Fleur E Mason
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Germany
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48
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Lang D, Calaghan SC, Gorelik J, Glukhov AV. Editorial: Cardiomyocyte Microdomains: An Emerging Concept of Local Regulation and Remodeling. Front Physiol 2020; 11:512. [PMID: 32574239 PMCID: PMC7264110 DOI: 10.3389/fphys.2020.00512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 04/27/2020] [Indexed: 11/29/2022] Open
Affiliation(s)
- Di Lang
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
| | - Sarah C. Calaghan
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Julia Gorelik
- Myocardial Function, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Alexey V. Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
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49
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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50
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Marchena M, Echebarria B. Influence of the tubular network on the characteristics of calcium transients in cardiac myocytes. PLoS One 2020; 15:e0231056. [PMID: 32302318 PMCID: PMC7164608 DOI: 10.1371/journal.pone.0231056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/14/2020] [Indexed: 01/09/2023] Open
Abstract
Transverse and axial tubules (TATS) are an essential ingredient of the excitation-contraction machinery that allow the effective coupling of L-type Calcium Channels (LCC) and ryanodine receptors (RyR2). They form a regular network in ventricular cells, while their presence in atrial myocytes is variable regionally and among animal species We have studied the effect of variations in the TAT network using a bidomain computational model of an atrial myocyte with variable density of tubules. At each z-line the t-tubule length is obtained from an exponential distribution, with a given mean penetration length. This gives rise to a distribution of t-tubules in the cell that is characterized by the fractional area (F.A.) occupied by the t-tubules. To obtain consistent results, we average over different realizations of the same mean penetration length. To this, in some simulations we add the effect of a network of axial tubules. Then we study global properties of calcium signaling, as well as regional heterogeneities and local properties of sparks and RyR2 openings. In agreement with recent experiments in detubulated ventricular and atrial cells, we find that detubulation reduces the calcium transient and synchronization in release. However, it does not affect sarcoplasmic reticulum (SR) load, so the decrease in SR calcium release is due to regional differences in Ca2+ release, that is restricted to the cell periphery in detubulated cells. Despite the decrease in release, the release gain is larger in detubulated cells, due to recruitment of orphaned RyR2s, i.e, those that are not confronting a cluster of LCCs. This probably provides a safeguard mechanism, allowing physiological values to be maintained upon small changes in the t-tubule density. Finally, we do not find any relevant change in spark properties between tubulated and detubulated cells, suggesting that the differences found in experiments could be due to differential properties of the RyR2s in the membrane and in the t-tubules, not incorporated in the present model. This work will help understand the effect of detubulation, that has been shown to occur in disease conditions such as heart failure (HF) in ventricular cells, or atrial fibrillation (AF) in atrial cells.
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Affiliation(s)
- Miquel Marchena
- Departament de Física, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Blas Echebarria
- Departament de Física, Universitat Politècnica de Catalunya, Barcelona, Spain
- * E-mail:
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