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Perdreau-Dahl H, Lipsett DB, Frisk M, Kermani F, Carlson CR, Brech A, Shen X, Bergan-Dahl A, Hou Y, Tuomainen T, Tavi P, Jones PP, Lunde M, Wasserstrom JA, Laporte J, Ullrich ND, Christensen G, Morth JP, Louch WE. BIN1, Myotubularin, and Dynamin-2 Coordinate T-Tubule Growth in Cardiomyocytes. Circ Res 2023; 132:e188-e205. [PMID: 37139790 DOI: 10.1161/circresaha.122.321732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
BACKGROUND Transverse tubules (t-tubules) form gradually in the developing heart, critically enabling maturation of cardiomyocyte Ca2+ homeostasis. The membrane bending and scaffolding protein BIN1 (amphiphysin-2) has been implicated in this process. However, it is unclear which of the various reported BIN1 isoforms are involved, and whether BIN1 function is regulated by its putative binding partners MTM1 (myotubularin), a phosphoinositide 3'-phosphatase, and DNM2 (dynamin-2), a GTPase believed to mediate membrane fission. METHODS We investigated the roles of BIN1, MTM1, and DNM2 in t-tubule formation in developing mouse cardiomyocytes, and in gene-modified HL-1 and human-induced pluripotent stem cell-derived cardiomyocytes. T-tubules and proteins of interest were imaged by confocal and Airyscan microscopy, and expression patterns were examined by RT-qPCR and Western blotting. Ca2+ release was recorded using Fluo-4. RESULTS We observed that in the postnatal mouse heart, BIN1 localizes along Z-lines from early developmental stages, consistent with roles in initial budding and scaffolding of t-tubules. T-tubule proliferation and organization were linked to a progressive and parallel increase in 4 detected BIN1 isoforms. All isoforms were observed to induce tubulation in cardiomyocytes but produced t-tubules with differing geometries. BIN1-induced tubulations contained the L-type Ca2+ channel, were colocalized with caveolin-3 and the ryanodine receptor, and effectively triggered Ca2+ release. BIN1 upregulation during development was paralleled by increasing expression of MTM1. Despite no direct binding between MTM1 and murine cardiac BIN1 isoforms, which lack exon 11, high MTM1 levels were necessary for BIN1-induced tubulation, indicating a central role of phosphoinositide homeostasis. In contrast, the developing heart exhibited declining levels of DNM2. Indeed, we observed that high levels of DNM2 are inhibitory for t-tubule formation, although this protein colocalizes with BIN1 along Z-lines, and binds all 4 isoforms. CONCLUSIONS These findings indicate that BIN1, MTM1, and DNM2 have balanced and collaborative roles in controlling t-tubule growth in cardiomyocytes.
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Affiliation(s)
- Harmonie Perdreau-Dahl
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership University of Oslo, Norway (H.P.-D., J.P.M.)
- Institut MitoVasc, CNRS UMR 6015, INSERM U1083, Université d'Angers, France (H.P.-D.)
| | - David B Lipsett
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - Michael Frisk
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - Fatemeh Kermani
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Germany (F.K., N.D.U.)
| | - Cathrine R Carlson
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
| | - Andreas Brech
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, Norway (A.B.)
| | - Xin Shen
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - Anna Bergan-Dahl
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - Yufeng Hou
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - Tomi Tuomainen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland (T.T., P.T.)
| | - Pasi Tavi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland (T.T., P.T.)
| | - Peter P Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand (P.P.J.)
| | - Marianne Lunde
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | | | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS UMR7104, Strasbourg University, Illkirch, France (J.L.)
| | - Nina D Ullrich
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Germany (F.K., N.D.U.)
- German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Germany (N.D.U.)
| | - Geir Christensen
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
| | - J Preben Morth
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership University of Oslo, Norway (H.P.-D., J.P.M.)
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark (J.P.M.)
| | - William E Louch
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital and University of Oslo, Norway (H.P.-D., D.B.L., M.F., C.R.C., X.S., A.B.-D., Y.H., M.L., G.C., J.P.M., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (H.P.-D., D.B.L., M.F., X.S., A.B.-D., Y.H., M.L., G.C., W.E.L.)
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Edwards AG, Mørk H, Stokke MK, Lipsett DB, Sjaastad I, Richard S, Sejersted OM, Louch WE. Sarcoplasmic Reticulum Calcium Release Is Required for Arrhythmogenesis in the Mouse. Front Physiol 2021; 12:744730. [PMID: 34712150 PMCID: PMC8546347 DOI: 10.3389/fphys.2021.744730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/20/2021] [Indexed: 11/23/2022] Open
Abstract
Dysfunctional sarcoplasmic reticulum Ca2+ handling is commonly observed in heart failure, and thought to contribute to arrhythmogenesis through several mechanisms. Some time ago we developed a cardiomyocyte-specific inducible SERCA2 knockout mouse, which is remarkable in the degree to which major adaptations to sarcolemmal Ca2+ entry and efflux overcome the deficit in SR reuptake to permit relatively normal contractile function. Conventionally, those adaptations would also be expected to dramatically increase arrhythmia susceptibility. However, that susceptibility has never been tested, and it is possible that the very rapid repolarization of the murine action potential (AP) allows for large changes in sarcolemmal Ca2+ transport without substantially disrupting electrophysiologic stability. We investigated this hypothesis through telemetric ECG recording in the SERCA2-KO mouse, and patch-clamp electrophysiology, Ca2+ imaging, and mathematical modeling of isolated SERCA2-KO myocytes. While the SERCA2-KO animals exhibit major (and unique) electrophysiologic adaptations at both the organ and cell levels, they remain resistant to arrhythmia. A marked increase in peak L-type calcium (ICaL) current and slowed ICaL decay elicited pronounced prolongation of initial repolarization, but faster late repolarization normalizes overall AP duration. Early afterdepolarizations were seldom observed in KO animals, and those that were observed exhibited a mechanism intermediate between murine and large mammal dynamical properties. As expected, spontaneous SR Ca2+ sparks and waves were virtually absent. Together these findings suggest that intact SR Ca2+ handling is an absolute requirement for triggered arrhythmia in the mouse, and that in its absence, dramatic changes to the major inward currents can be resisted by the substantial K+ current reserve, even at end-stage disease.
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Affiliation(s)
- Andrew G Edwards
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Halvor Mørk
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - David B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Sylvain Richard
- Université de Montpellier, INSERM, CNRS, PhyMedExp, Montpellier, France
| | - Ole M Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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Tazmini K, Frisk M, Lewalle A, Laasmaa M, Morotti S, Lipsett DB, Manfra O, Skogestad J, Aronsen JM, Sejersted OM, Sjaastad I, Edwards AG, Grandi E, Niederer SA, Øie E, Louch WE. Hypokalemia Promotes Arrhythmia by Distinct Mechanisms in Atrial and Ventricular Myocytes. Circ Res 2020; 126:889-906. [PMID: 32070187 PMCID: PMC7098435 DOI: 10.1161/circresaha.119.315641] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Hypokalemia occurs in up to 20% of hospitalized patients and is associated with increased incidence of ventricular and atrial fibrillation. It is unclear whether these differing types of arrhythmia result from direct and perhaps distinct effects of hypokalemia on cardiomyocytes. OBJECTIVE To investigate proarrhythmic mechanisms of hypokalemia in ventricular and atrial myocytes. METHODS AND RESULTS Experiments were performed in isolated rat myocytes exposed to simulated hypokalemia conditions (reduction of extracellular [K+] from 5.0 to 2.7 mmol/L) and supported by mathematical modeling studies. Ventricular cells subjected to hypokalemia exhibited Ca2+ overload and increased generation of both spontaneous Ca2+ waves and delayed afterdepolarizations. However, similar Ca2+-dependent spontaneous activity during hypokalemia was only observed in a minority of atrial cells that were observed to contain t-tubules. This effect was attributed to close functional pairing of the Na+-K+ ATPase and Na+-Ca2+ exchanger proteins within these structures, as reduction in Na+ pump activity locally inhibited Ca2+ extrusion. Ventricular myocytes and tubulated atrial myocytes additionally exhibited early afterdepolarizations during hypokalemia, associated with Ca2+ overload. However, early afterdepolarizations also occurred in untubulated atrial cells, despite Ca2+ quiescence. These phase-3 early afterdepolarizations were rather linked to reactivation of nonequilibrium Na+ current, as they were rapidly blocked by tetrodotoxin. Na+ current-driven early afterdepolarizations in untubulated atrial cells were enabled by membrane hyperpolarization during hypokalemia and short action potential configurations. Brief action potentials were in turn maintained by ultra-rapid K+ current (IKur); a current which was found to be absent in tubulated atrial myocytes and ventricular myocytes. CONCLUSIONS Distinct mechanisms underlie hypokalemia-induced arrhythmia in the ventricle and atrium but also vary between atrial myocytes depending on subcellular structure and electrophysiology.
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Affiliation(s)
- Kiarash Tazmini
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway (K.T., E.Ø.)
| | - Michael Frisk
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Alexandre Lewalle
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, United Kingdom (A.L., S.A.N.)
| | - Martin Laasmaa
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - David B. Lipsett
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Ornella Manfra
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Jonas Skogestad
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Jan M. Aronsen
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- Bjørknes College, Oslo, Norway (J.M.A.)
| | - Ole M. Sejersted
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Ivar Sjaastad
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Andrew G. Edwards
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - Steven A. Niederer
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, United Kingdom (A.L., S.A.N.)
| | - Erik Øie
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway (K.T., E.Ø.)
| | - William E. Louch
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
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Tazmini K, Frisk M, Laasmaa M, Lewalle A, Morotti S, Lipsett DB, Manfra O, Skogested J, Magnus Aronsen J, Sjaastad I, Edwards AG, Grandi E, Niederer SA, Øie E, Louch WE. Hypokalemia Promotes Arrhythmia by Distinct Mechanisms in Atrial and Ventricular Myocytes. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Frisk M, Lipsett DB, Louch WE. Reply from M. Frisk, D. B. Lipsett and W. E. Louch. J Physiol 2019; 597:2967-2968. [PMID: 31021407 DOI: 10.1113/jp278067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- M Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, NO-0424, Oslo, Norway.,KG Jebsen Centre for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - D B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, NO-0424, Oslo, Norway.,KG Jebsen Centre for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - W E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, NO-0424, Oslo, Norway.,KG Jebsen Centre for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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Lipsett DB, Frisk M, Aronsen JM, Nordén ES, Buonarati OR, Cataliotti A, Hell JW, Sjaastad I, Christensen G, Louch WE. Cardiomyocyte substructure reverts to an immature phenotype during heart failure. J Physiol 2019; 597:1833-1853. [PMID: 30707448 PMCID: PMC6441900 DOI: 10.1113/jp277273] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/28/2019] [Indexed: 12/16/2022] Open
Abstract
Key points As reactivation of the fetal gene program has been implicated in pathological remodelling during heart failure (HF), we examined whether cardiomyocyte subcellular structure and function revert to an immature phenotype during this disease. Surface and internal membrane structures appeared gradually during development, and returned to a juvenile state during HF. Similarly, dyadic junctions between the cell membrane and sarcoplasmic reticulum were progressively ‘packed’ with L‐type Ca2+ channels and ryanodine receptors during development, and ‘unpacked’ during HF. Despite similarities in subcellular structure, dyads were observed to be functional from early developmental stages, but exhibited an impaired ability to release Ca2+ in failing cardiomyocytes. Thus, while immature and failing cardiomyocytes share similarities in subcellular structure, these do not fully account for the marked impairment of Ca2+ homeostasis observed in HF.
Abstract Reactivation of the fetal gene programme has been implicated as a driver of pathological cardiac remodelling. Here we examined whether pathological remodelling of cardiomyocyte substructure and function during heart failure (HF) reflects a reversion to an immature phenotype. Using scanning electron microscopy, we observed that Z‐grooves and t‐tubule openings at the cell surface appeared gradually during cardiac development, and disappeared during HF. Confocal and super‐resolution imaging within the cell interior revealed similar structural parallels; disorganization of t‐tubules in failing cells was strikingly reminiscent of the late stages of postnatal development, with fewer transverse elements and a high proportion of longitudinal tubules. Ryanodine receptors (RyRs) were observed to be laid down in advance of developing t‐tubules and similarly ‘orphaned’ in HF, although RyR distribution along Z‐lines was relatively sparse. Indeed, nanoscale imaging revealed coordinated packing of L‐type Ca2+ channels and RyRs into dyadic junctions during development, and orderly unpacking during HF. These findings support a ‘last in, first out’ paradigm, as the latest stages of dyadic structural development are reversed during disease. Paired imaging of t‐tubules and Ca2+ showed that the disorganized arrangement of dyads in immature and failing cells promoted desynchronized and slowed Ca2+ release in these two states. However, while developing cells exhibited efficient triggering of Ca2+ release at newly formed dyads, dyadic function was impaired in failing cells despite similar organization of Ca2+ handling proteins. Thus, pathologically deficient Ca2+ homeostasis during HF is only partly linked to the re‐emergence of immature subcellular structure, and additionally reflects lost dyadic functionality. As reactivation of the fetal gene program has been implicated in pathological remodelling during heart failure (HF), we examined whether cardiomyocyte subcellular structure and function revert to an immature phenotype during this disease. Surface and internal membrane structures appeared gradually during development, and returned to a juvenile state during HF. Similarly, dyadic junctions between the cell membrane and sarcoplasmic reticulum were progressively ‘packed’ with L‐type Ca2+ channels and ryanodine receptors during development, and ‘unpacked’ during HF. Despite similarities in subcellular structure, dyads were observed to be functional from early developmental stages, but exhibited an impaired ability to release Ca2+ in failing cardiomyocytes. Thus, while immature and failing cardiomyocytes share similarities in subcellular structure, these do not fully account for the marked impairment of Ca2+ homeostasis observed in HF.
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Affiliation(s)
- D B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - M Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - J M Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - E S Nordén
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - O R Buonarati
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - A Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - J W Hell
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - I Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - G Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - W E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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Abstract
During the past few decades, gene delivery using recombinant virus has made tremendous progress. With a higher than 80 % transduction efficiency, even in non-dividing cells, viral transduction has become the method of choice for efficient gene transfer into cardiomyocytes. However, in vitro gene delivery is dependent on a robust cell isolation protocol, as prolonged cultivation is needed to initiate gene expression and target specific cellular processes. This chapter describes some of the important steps that need to be considered for successful in vitro gene transfer into adult cardiomyocytes. Included are detailed protocols for isolating cells, maintaining rod shaped cardiomyocytes in culture over several days, and employing adenovirus for gene transduction.
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Affiliation(s)
- Kjetil Hodne
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - David B Lipsett
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Ullevål, Kirkeveien 166, 0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Ullevål, Kirkeveien 166, 0407, Oslo, Norway.
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway.
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Lipsett DB, Frisk M, Singh N, Aronsen JM, Marszalec W, Sejersted OM, Sjaastad I, Wasserstrom JA, Christensen G, Louch WE. Bridging Integrator 1 (BIN1) Initiates T-Tubule Growth during Cardiac Development and Disease. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Lipsett DB, Singh N, Frisk M, Aronsen JM, Sejersted OM, Sjaastad I, Wasserstrom JA, Christensen G, Louch WE. Bridging Integrator 1 (BIN1)-Induced T-Tubule Formation in Cardiomyocytes. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.4238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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