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Ruud M, Frisk M, Melleby AO, Norseng PA, Mohamed BA, Li J, Aronsen JM, Setterberg IE, Jakubiczka J, van Hout I, Coffey S, Shen X, Nygård S, Lunde IG, Tønnessen T, Jones PP, Sjaastad I, Gullestad L, Toischer K, Dahl CP, Christensen G, Louch WE. Regulation of cardiomyocyte t-tubule structure by preload and afterload: Roles in cardiac compensation and decompensation. J Physiol 2024. [PMID: 38686538 DOI: 10.1113/jp284566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
Mechanical load is a potent regulator of cardiac structure and function. Although high workload during heart failure is associated with disruption of cardiomyocyte t-tubules and Ca2+ homeostasis, it remains unclear whether changes in preload and afterload may promote adaptive t-tubule remodelling. We examined this issue by first investigating isolated effects of stepwise increases in load in cultured rat papillary muscles. Both preload and afterload increases produced a biphasic response, with the highest t-tubule densities observed at moderate loads, whereas excessively low and high loads resulted in low t-tubule levels. To determine the baseline position of the heart on this bell-shaped curve, mice were subjected to mildly elevated preload or afterload (1 week of aortic shunt or banding). Both interventions resulted in compensated cardiac function linked to increased t-tubule density, consistent with ascension up the rising limb of the curve. Similar t-tubule proliferation was observed in human patients with moderately increased preload or afterload (mitral valve regurgitation, aortic stenosis). T-tubule growth was associated with larger Ca2+ transients, linked to upregulation of L-type Ca2+ channels, Na+-Ca2+ exchanger, mechanosensors and regulators of t-tubule structure. By contrast, marked elevation of cardiac load in rodents and patients advanced the heart down the declining limb of the t-tubule-load relationship. This bell-shaped relationship was lost in the absence of electrical stimulation, indicating a key role of systolic stress in controlling t-tubule plasticity. In conclusion, modest augmentation of workload promotes compensatory increases in t-tubule density and Ca2+ cycling, whereas this adaptation is reversed in overloaded hearts during heart failure progression. KEY POINTS: Excised papillary muscle experiments demonstrated a bell-shaped relationship between cardiomyocyte t-tubule density and workload (preload or afterload), which was only present when muscles were electrically stimulated. The in vivo heart at baseline is positioned on the rising phase of this curve because moderate increases in preload (mice with brief aortic shunt surgery, patients with mitral valve regurgitation) resulted in t-tubule growth. Moderate increases in afterload (mice and patients with mild aortic banding/stenosis) similarly increased t-tubule density. T-tubule proliferation was associated with larger Ca2+ transients, with upregulation of the L-type Ca2+ channel, Na+-Ca2+ exchanger, mechanosensors and regulators of t-tubule structure. By contrast, marked elevation of cardiac load in rodents and patients placed the heart on the declining phase of the t-tubule-load relationship, promoting heart failure progression. The dependence of t-tubule structure on preload and afterload thus enables both compensatory and maladaptive remodelling, in rodents and humans.
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Affiliation(s)
- Marianne Ruud
- 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
| | - Michael Frisk
- 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
| | - Arne Olav Melleby
- 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
| | - Per Andreas Norseng
- 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
| | - Belal A Mohamed
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Jia Li
- 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
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Ingunn E Setterberg
- 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
| | - Joanna Jakubiczka
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Isabelle van Hout
- Department of Physiology, School of Biomedical Sciences and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Xin Shen
- 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
| | - Ståle Nygård
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Ida G Lunde
- 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
| | - Theis Tønnessen
- 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
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Peter P Jones
- Department of Physiology, School of Biomedical Sciences and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Ivar Sjaastad
- 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
| | - Lars Gullestad
- Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Karl Toischer
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Cristen P Dahl
- Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Geir Christensen
- 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
| | - 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
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Zhang X, Wu Y, Smith C, Louch WE, Morotti S, Dobrev D, Grandi E, Ni H. Enhanced Ca2+-Driven Arrhythmias in Female Patients with Atrial Fibrillation: Insights from Computational Modeling. bioRxiv 2024:2024.03.04.583217. [PMID: 38496584 PMCID: PMC10942295 DOI: 10.1101/2024.03.04.583217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
BACKGROUND AND AIMS Substantial sex-based differences have been reported in atrial fibrillation (AF), with female patients experiencing worse symptoms, increased complications from drug side effects or ablation, and elevated risk of AF-related stroke and mortality. Recent studies revealed sex-specific alterations in AF-associated Ca2+ dysregulation, whereby female cardiomyocytes more frequently exhibit potentially proarrhythmic Ca2+-driven instabilities compared to male cardiomyocytes. In this study, we aim to gain a mechanistic understanding of the Ca2+-handling disturbances and Ca2+-driven arrhythmogenic events in males vs females and establish their responses to Ca2+-targeted interventions. METHODS AND RESULTS We incorporated known sex differences and AF-associated changes in the expression and phosphorylation of key Ca2+-handling proteins and in ultrastructural properties and dimensions of atrial cardiomyocytes into our recently developed 3D atrial cardiomyocyte model that couples electrophysiology with spatially detailed Ca2+-handling processes. Our simulations of quiescent cardiomyocytes show increased incidence of Ca2+ sparks in female vs male myocytes in AF, in agreement with previous experimental reports. Additionally, our female model exhibited elevated propensity to develop pacing-induced spontaneous Ca2+ releases (SCRs) and augmented beat-to-beat variability in action potential (AP)-elicited Ca2+ transients compared with the male model. Parameter sensitivity analysis uncovered precise arrhythmogenic contributions of each component that was implicated in sex and/or AF alterations. Specifically, increased ryanodine receptor phosphorylation in female AF cardiomyocytes emerged as the major SCR contributor, while reduced L-type Ca2+ current was protective against SCRs for male AF cardiomyocytes. Furthermore, simulations of tentative Ca2+-targeted interventions identified potential strategies to attenuate Ca2+-driven arrhythmogenic events in female atria (e.g., t-tubule restoration, and inhibition of ryanodine receptor and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase), and revealed enhanced efficacy when applied in combination. CONCLUSIONS Our sex-specific computational models of human atrial cardiomyocytes uncover increased propensity to Ca2+-driven arrhythmogenic events in female compared to male atrial cardiomyocytes in AF, and point to combined Ca2+-targeted interventions as promising approaches to treat AF in female patients. Our study establishes that AF treatment may benefit from sex-dependent strategies informed by sex-specific mechanisms.
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Lunde PK, Manfra O, Støle TP, Lunde M, Martinsen M, Carlson CR, Louch WE. Polyarginine Cell-Penetrating Peptides Bind and Inhibit SERCA2. Cells 2023; 12:2358. [PMID: 37830576 PMCID: PMC10571751 DOI: 10.3390/cells12192358] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
Cell-penetrating peptides (CPPs) are short peptide sequences that have the ability to cross the cell membrane and deliver cargo. Although it is critical that CPPs accomplish this task with minimal off-target effects, such actions have in many cases not been robustly screened. We presently investigated whether the commonly used CPPs TAT and the polyarginines Arg9 and Arg11 exert off-target effects on cellular Ca2+ homeostasis. In experiments employing myocytes and homogenates from the cardiac left ventricle or soleus muscle, we observed marked inhibition of Ca2+ recycling into the sarcoplasmic reticulum (SR) following incubation with polyarginine CPPs. In both tissues, the rate of SR Ca2+ leak remained unchanged, indicating that protracted Ca2+ removal from the cytosol stemmed from inhibition of the SR Ca2+ ATPase 2 (SERCA2). No such inhibition occurred following treatment with TAT, or in preparations from the SERCA1-expressing extensor digitorum longus muscle. Experiments in HEK cells overexpressing individual SERCA isoforms confirmed that polyarginine incubation specifically inhibited the activity of SERCA2a and 2b, but not SERCA1 or 3. The attenuation of SERCA2 activity was not dependent on the presence of phospholamban, and ELISA-based analyses rather revealed direct interaction between the polyarginines and the actuator domain of the protein. Surface plasmon resonance experiments confirmed strong binding within this region of SERCA2, and slow dissociation between the two species. Based on these observations, we urge caution when employing polyarginine CPPs. Indeed, as SERCA2 is expressed in diverse cell types, the wide-ranging consequences of SERCA2 binding and inhibition should be anticipated in both experimental and therapeutic settings.
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Affiliation(s)
| | | | | | | | | | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway; (P.K.L.); (O.M.); (T.P.S.); (M.L.); (M.M.); (W.E.L.)
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Li J, Sundnes J, Hou Y, Laasmaa M, Ruud M, Unger A, Kolstad TR, Frisk M, Norseng PA, Yang L, Setterberg IE, Alves ES, Kalakoutis M, Sejersted OM, Lanner JT, Linke WA, Lunde IG, de Tombe PP, Louch WE. Stretch Harmonizes Sarcomere Strain Across the Cardiomyocyte. Circ Res 2023; 133:255-270. [PMID: 37401464 PMCID: PMC10355805 DOI: 10.1161/circresaha.123.322588] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND Increasing cardiomyocyte contraction during myocardial stretch serves as the basis for the Frank-Starling mechanism in the heart. However, it remains unclear how this phenomenon occurs regionally within cardiomyocytes, at the level of individual sarcomeres. We investigated sarcomere contractile synchrony and how intersarcomere dynamics contribute to increasing contractility during cell lengthening. METHODS Sarcomere strain and Ca2+ were simultaneously recorded in isolated left ventricular cardiomyocytes during 1 Hz field stimulation at 37 °C, at resting length and following stepwise stretch. RESULTS We observed that in unstretched rat cardiomyocytes, differential sarcomere deformation occurred during each beat. Specifically, while most sarcomeres shortened during the stimulus, ≈10% to 20% of sarcomeres were stretched or remained stationary. This nonuniform strain was not traced to regional Ca2+ disparities but rather shorter resting lengths and lower force production in systolically stretched sarcomeres. Lengthening of the cell recruited additional shortening sarcomeres, which increased contractile efficiency as less negative, wasted work was performed by stretched sarcomeres. Given the known role of titin in setting sarcomere dimensions, we next hypothesized that modulating titin expression would alter intersarcomere dynamics. Indeed, in cardiomyocytes from mice with titin haploinsufficiency, we observed greater variability in resting sarcomere length, lower recruitment of shortening sarcomeres, and impaired work performance during cell lengthening. CONCLUSIONS Graded sarcomere recruitment directs cardiomyocyte work performance, and harmonization of sarcomere strain increases contractility during cell stretch. By setting sarcomere dimensions, titin controls sarcomere recruitment, and its lowered expression in haploinsufficiency mutations impairs cardiomyocyte contractility.
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Affiliation(s)
- Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | | | - Yufeng Hou
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Martin Laasmaa
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Marianne Ruud
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Andreas Unger
- Institute of Physiology II, University of Münster, Germany (A.U., W.A.L.)
| | - Terje R. Kolstad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Per Andreas Norseng
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
| | | | - Ingunn E. Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Estela S. Alves
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (E.S.A., M.K., J.T.L.)
| | - Michaeljohn Kalakoutis
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (E.S.A., M.K., J.T.L.)
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Johanna T. Lanner
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden (E.S.A., M.K., J.T.L.)
| | - Wolfgang A. Linke
- Institute of Physiology II, University of Münster, Germany (A.U., W.A.L.)
| | - Ida G. Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
| | - Pieter P. de Tombe
- Department of Physiology and Biophysics, University of Illinois at Chicago (P.P.d.T.)
- Phymedexp, Université de Montpellier, INSERM, CNRS, France (P.P.d.T.)
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., P.A.N., I.E.S., O.M.S., I.G.L., W.E.L.)
- KG Jebsen Center for Cardiac Research, University of Oslo, Norway (J.L., Y.H., M.L., M.R., T.R.K., M.F., I.E.S., O.M.S., I.G.L., W.E.L.)
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5
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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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6
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Manfra O, Louey S, Jonker SS, Perdreau-Dahl H, Frisk M, Giraud GD, Thornburg KL, Louch WE. Augmenting workload drives T-tubule assembly in developing cardiomyocytes. J Physiol 2023:10.1113/JP284538. [PMID: 37128962 PMCID: PMC10854476 DOI: 10.1113/jp284538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023] Open
Abstract
Contraction of cardiomyocytes is initiated at subcellular elements called dyads, where L-type Ca2+ channels in t-tubules are located within close proximity to ryanodine receptors in the sarcoplasmic reticulum. While evidence from small rodents indicates that dyads are assembled gradually in the developing heart, it is unclear how this process occurs in large mammals. We presently examined dyadic formation in fetal and newborn sheep (Ovis aries), and the regulation of this process by fetal cardiac workload. By employing advanced imaging methods, we demonstrated that t-tubule growth and dyadic assembly proceed gradually during fetal sheep development, from 93 days of gestational age until birth (147 days). This process parallels progressive increases in fetal systolic blood pressure, and includes step-wise colocalization of L-type Ca2+ channels and the Na+ /Ca2+ exchanger with ryanodine receptors. These proteins are upregulated together with the dyadic anchor junctophilin-2 during development, alongside changes in the expression of amphiphysin-2 (BIN1) and its partner proteins myotubularin and dynamin-2. Increasing fetal systolic load by infusing plasma or occluding the post-ductal aorta accelerated t-tubule growth. Conversely, reducing fetal systolic load with infusion of enalaprilat, an angiotensin converting enzyme inhibitor, blunted t-tubule formation. Interestingly, altered t-tubule densities did not relate to changes in dyadic junctions, or marked changes in the expression of dyadic regulatory proteins, indicating that distinct signals are responsible for maturation of the sarcoplasmic reticulum. In conclusion, augmenting blood pressure and workload during normal fetal development critically promotes t-tubule growth, while additional signals contribute to dyadic assembly. KEY POINTS: T-tubule growth and dyadic assembly proceed gradually in cardiomyocytes during fetal sheep development, from 93 days of gestational age until the post-natal stage. Increasing fetal systolic load by infusing plasma or occluding the post-ductal aorta accelerated t-tubule growth and hypertrophy. In contrast, reducing fetal systolic load by enalaprilat infusion slowed t-tubule development and decreased cardiomyocyte size. Load-dependent modulation of t-tubule maturation was linked to altered expression patterns of the t-tubule regulatory proteins junctophilin-2 and amphiphysin-2 (BIN1) and its protein partners. Altered t-tubule densities did not influence dyadic formation, indicating that distinct signals are responsible for maturation of the sarcoplasmic reticulum.
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Affiliation(s)
- Ornella Manfra
- 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
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, OR, USA
| | - Sonnet S Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, OR, USA
| | - Harmonie Perdreau-Dahl
- 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
| | - Michael Frisk
- 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
| | - George D Giraud
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, OR, USA
- VA Portland Health Care System Portland, OR, USA
| | - Kent L Thornburg
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, OR, 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
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7
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Skogestad J, Albert I, Hougen K, Lothe GB, Lunde M, Eken OS, Veras I, Huynh NTT, Børstad M, Marshall S, Shen X, Louch WE, Robinson EL, Cleveland JC, Ambardekar AV, Schwisow JA, Jonas E, Calejo AI, Morth JP, Taskén K, Melleby AO, Lunde PK, Sjaastad I, Carlson CR, Aronsen JM. Disruption of Phosphodiesterase 3A Binding to SERCA2 Increases SERCA2 Activity and Reduces Mortality in Mice With Chronic Heart Failure. Circulation 2023; 147:1221-1236. [PMID: 36876489 DOI: 10.1161/circulationaha.121.054168] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 02/08/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND Increasing SERCA2 (sarco[endo]-plasmic reticulum Ca2+ ATPase 2) activity is suggested to be beneficial in chronic heart failure, but no selective SERCA2-activating drugs are available. PDE3A (phosphodiesterase 3A) is proposed to be present in the SERCA2 interactome and limit SERCA2 activity. Disruption of PDE3A from SERCA2 might thus be a strategy to develop SERCA2 activators. METHODS Confocal microscopy, 2-color direct stochastic optical reconstruction microscopy, proximity ligation assays, immunoprecipitations, peptide arrays, and surface plasmon resonance were used to investigate colocalization between SERCA2 and PDE3A in cardiomyocytes, map the SERCA2/PDE3A interaction sites, and optimize disruptor peptides that release PDE3A from SERCA2. Functional experiments assessing the effect of PDE3A-binding to SERCA2 were performed in cardiomyocytes and HEK293 vesicles. The effect of SERCA2/PDE3A disruption by the disruptor peptide OptF (optimized peptide F) on cardiac mortality and function was evaluated during 20 weeks in 2 consecutive randomized, blinded, and controlled preclinical trials in a total of 148 mice injected with recombinant adeno-associated virus 9 (rAAV9)-OptF, rAAV9-control (Ctrl), or PBS, before undergoing aortic banding (AB) or sham surgery and subsequent phenotyping with serial echocardiography, cardiac magnetic resonance imaging, histology, and functional and molecular assays. RESULTS PDE3A colocalized with SERCA2 in human nonfailing, human failing, and rodent myocardium. Amino acids 277-402 of PDE3A bound directly to amino acids 169-216 within the actuator domain of SERCA2. Disruption of PDE3A from SERCA2 increased SERCA2 activity in normal and failing cardiomyocytes. SERCA2/PDE3A disruptor peptides increased SERCA2 activity also in the presence of protein kinase A inhibitors and in phospholamban-deficient mice, and had no effect in mice with cardiomyocyte-specific inactivation of SERCA2. Cotransfection of PDE3A reduced SERCA2 activity in HEK293 vesicles. Treatment with rAAV9-OptF reduced cardiac mortality compared with rAAV9-Ctrl (hazard ratio, 0.26 [95% CI, 0.11 to 0.63]) and PBS (hazard ratio, 0.28 [95% CI, 0.09 to 0.90]) 20 weeks after AB. Mice injected with rAAV9-OptF had improved contractility and no difference in cardiac remodeling compared with rAAV9-Ctrl after aortic banding. CONCLUSIONS Our results suggest that PDE3A regulates SERCA2 activity through direct binding, independently of the catalytic activity of PDE3A. Targeting the SERCA2/PDE3A interaction prevented cardiac mortality after AB, most likely by improving cardiac contractility.
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Affiliation(s)
- Jonas Skogestad
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Ingrid Albert
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Karina Hougen
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Gustav B Lothe
- Department of Pharmacology, Oslo University Hospital, Norway (G.B.L.)
- Bjørknes College, Oslo, Norway (G.B.L., J.M.A.)
| | - Marianne Lunde
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Olav Søvik Eken
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
- Department of Molecular Medicine, University of Oslo, Norway (O.S.E., I.V., N.T.T.-H., A.O.M., J.M.A.)
| | - Ioanni Veras
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
- Department of Molecular Medicine, University of Oslo, Norway (O.S.E., I.V., N.T.T.-H., A.O.M., J.M.A.)
| | - Ngoc Trang Thi Huynh
- Department of Molecular Medicine, University of Oslo, Norway (O.S.E., I.V., N.T.T.-H., A.O.M., J.M.A.)
| | - Mira Børstad
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Serena Marshall
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Emma Louise Robinson
- Division of Cardiology, Department of Medicine (E.L.R., A.V.A., J.A.S., E.J.), University of Colorado Anschutz Medical Campus, Aurora
| | - Joseph C Cleveland
- Department of Surgery (J.C.C.), University of Colorado Anschutz Medical Campus, Aurora
| | - Amrut V Ambardekar
- Division of Cardiology, Department of Medicine (E.L.R., A.V.A., J.A.S., E.J.), University of Colorado Anschutz Medical Campus, Aurora
| | - Jessica A Schwisow
- Division of Cardiology, Department of Medicine (E.L.R., A.V.A., J.A.S., E.J.), University of Colorado Anschutz Medical Campus, Aurora
| | - Eric Jonas
- Division of Cardiology, Department of Medicine (E.L.R., A.V.A., J.A.S., E.J.), University of Colorado Anschutz Medical Campus, Aurora
| | - Ana I Calejo
- Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership (A.I.C.C., J.P.M., K.T.), Oslo University Hospital and University of Oslo, Norway
| | - Jens Preben Morth
- Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership (A.I.C.C., J.P.M., K.T.), Oslo University Hospital and University of Oslo, Norway
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby (J.P.M.)
| | - Kjetil Taskén
- Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership (A.I.C.C., J.P.M., K.T.), Oslo University Hospital and University of Oslo, Norway
- Institute for Cancer Research, Oslo University Hospital and Institute for Clinical Medicine, University of Oslo, Norway (K.T.)
| | - Arne Olav Melleby
- Department of Molecular Medicine, University of Oslo, Norway (O.S.E., I.V., N.T.T.-H., A.O.M., J.M.A.)
| | - Per Kristian Lunde
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Cathrine Rein Carlson
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research (J.S., I.A., K.H., M.L., O.S.E., I.V., M.B., S.M., X.S., W.E.L., P.K.L., I.S., C.R.C., J.M.A.), Oslo University Hospital and University of Oslo, Norway
- Bjørknes College, Oslo, Norway (G.B.L., J.M.A.)
- Department of Molecular Medicine, University of Oslo, Norway (O.S.E., I.V., N.T.T.-H., A.O.M., J.M.A.)
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8
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Rypdal KB, Olav Melleby A, Robinson EL, Li J, Palmero S, Seifert DE, Martin D, Clark C, López B, Andreassen K, Dahl CP, Sjaastad I, Tønnessen T, Stokke MK, Louch WE, González A, Heymans S, Christensen G, Apte SS, Lunde IG. ADAMTSL3 knock-out mice develop cardiac dysfunction and dilatation with increased TGFβ signalling after pressure overload. Commun Biol 2022; 5:1392. [PMID: 36539599 PMCID: PMC9767913 DOI: 10.1038/s42003-022-04361-1] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Heart failure is a major cause of morbidity and mortality worldwide, and can result from pressure overload, where cardiac remodelling is characterized by cardiomyocyte hypertrophy and death, fibrosis, and inflammation. In failing hearts, transforming growth factor (TGF)β drives cardiac fibroblast (CFB) to myofibroblast differentiation causing excessive extracellular matrix production and cardiac remodelling. New strategies to target pathological TGFβ signalling in heart failure are needed. Here we show that the secreted glycoprotein ADAMTSL3 regulates TGFβ in the heart. We found that Adamtsl3 knock-out mice develop exacerbated cardiac dysfunction and dilatation with increased mortality, and hearts show increased TGFβ activity and CFB activation after pressure overload by aortic banding. Further, ADAMTSL3 overexpression in cultured CFBs inhibits TGFβ signalling, myofibroblast differentiation and collagen synthesis, suggesting a cardioprotective role for ADAMTSL3 by regulating TGFβ activity and CFB phenotype. These results warrant future investigation of the potential beneficial effects of ADAMTSL3 in heart failure.
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Affiliation(s)
- Karoline B Rypdal
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway. .,Division of Diagnostics and Technology, Akershus University Hospital, Lørenskog, Norway. .,K.G. Jebsen Center for Cardiac Biomarkers, University of Oslo, Oslo, Norway.
| | - A Olav Melleby
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Emma L Robinson
- Department of Cardiology, Maastricht University, CARIM School for Cardiovascular Diseases, Maastricht, Netherlands
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Sheryl Palmero
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Deborah E Seifert
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | - Daniel Martin
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | - Catelyn Clark
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | - Begoña López
- Program of Cardiovascular Diseases, CIMA Universidad de Navarra and IdiSNA, Pamplona, Spain.,CIBERCV, Carlos III Institute of Health, Madrid, Spain
| | - Kristine Andreassen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Christen P Dahl
- Department of Cardiology, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Theis Tønnessen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Department of Cardiothoracic Surgery, Oslo University Hospital Ullevål, Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Arantxa González
- Program of Cardiovascular Diseases, CIMA Universidad de Navarra and IdiSNA, Pamplona, Spain.,CIBERCV, Carlos III Institute of Health, Madrid, Spain
| | - Stephane Heymans
- Department of Cardiology, Maastricht University, CARIM School for Cardiovascular Diseases, Maastricht, Netherlands.,Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Leuven, Belgium
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Suneel S Apte
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | - Ida G Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Division of Diagnostics and Technology, Akershus University Hospital, Lørenskog, Norway.,K.G. Jebsen Center for Cardiac Biomarkers, University of Oslo, Oslo, Norway
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9
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Louch WE, Ullrich ND, Navedo MF, Macquaide N. Editorial: Nanodomain regulation of muscle physiology and alterations in disease. Front Physiol 2022; 13:1092304. [PMID: 36523550 PMCID: PMC9745436 DOI: 10.3389/fphys.2022.1092304] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 09/23/2023] Open
Affiliation(s)
- William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
- K. G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Nina D Ullrich
- Institute of Physiology and Pathophysiology, Division of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg University, Heidelberg, Germany
| | - Manuel F Navedo
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, United States
| | - Niall Macquaide
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
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10
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Frisk M, Norseng PA, Stenersen Espe EK, Louch WE. Tubulator: an automated approach to analysis of t-tubule and dyadic organization in cardiomyocytes. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210468. [PMID: 36189810 PMCID: PMC9527907 DOI: 10.1098/rstb.2021.0468] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During cardiac disease, t-tubules and dyads are remodelled and disrupted within cardiomyocytes, thereby reducing cardiac performance. Given the pathological implications of such dyadic remodelling, robust and versatile tools for characterizing these sub-cellular structures are needed. While analysis programs for continuous and regular structures such as rodent ventricular t-tubules are available, at least in two dimensions, these approaches are less appropriate for assessment of more irregular structures, such as dyadic proteins and non-rodent t-tubules. Here, we demonstrate versatile, easy-to-use software that performs such analyses. This software, called Tubulator, enables automated analysis of t-tubules and dyadic proteins alike, in both tissue sections and isolated myocytes. The program measures densities of subcellular structures and proteins in individual cells, quantifies their distribution into transversely and longitudinally oriented elements, and supports detailed co-localization analyses. Importantly, Tubulator provides tools for three-dimensional assessment and rendering of image stacks, extending examinations from the single plane to the whole-myocyte level. To provide insight into the consequences of dyadic organization for synchrony of Ca2+ handling, Tubulator also creates 'distance maps', by calculating the distance from all cytosolic positions to the nearest t-tubule and/or dyad. In conclusion, this freely accessible program provides detailed automated analysis of the three-dimensional nature of dyadic and t-tubular structures. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Per Andreas Norseng
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Emil Knut Stenersen Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
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11
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Ottesen AH, Raiborg C, Melleby AO, Hansen MSH, Hafver TL, Sandbu RA, Aronsen JM, Etholm L, Stokke MK, Sjaastad I, Louch WE, Carlson CR, Christensen G, Rosjo H. Synapsin 2 regulates NCX1 trafficking and is down-regulated in the failing myocardium, which increases the risk of ventricular arrhythmia and heart failure mortality. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.2974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Synapsin 2 (Syn2) modulates vesicle transport in the post-synaptic terminal in the brain, and has been linked to sudden unexplained death in epilepsy, but has never previously been studied in the myocardium.
Purpose
Given the association of vesicle transport in the brain and the heart, and the similarity of sudden death in epilepsy and cardiac arrhythmias, we have studied the role of Syn2 in the heart.
Methods
We explored left ventricular (LV) Syn2 levels in various experimental heart failure (HF) models and assessed mortality in Syn2 knock out (KO) mice vs. wild type (WT) littermates after pressure-overload induced by aortic banding. We used confocal imaging and virus transduction to characterize Syn2 localization and co-localization with NCX and Rab proteins. We verified Syn2-NCX interaction by immunoprecipitation, mass spectrometry, and surface resonance experiments. We investigated calcium handling in isolated cardiomyocytes. Susceptibility for ventricular arrhythmias was also tested in Langendorff-perfused hearts.
Results
We found Syn2, but not synapsin 1, to be expressed in the myocardium. LV Syn2 levels were markedly downregulated in the failing myocardium after experimental myocardial infarction or aortic banding. Syn2 KO mice had increased mortality compared to WT littermates following aortic banding, but demonstrated no clear clinical or echocardiographic phenotype, except reduced fractional shortening. Given no clear etiology for increased mortality, we next explored the association between Syn2 and ion-channel vesicle transport, calcium handling and ventricular arrhythmias. By confocal imaging and viral transduction, we found Syn2 to localize in vesicles in HL-1 cells, where Syn2 co-localized with Rab2, Rab3, Rab7 and NCX1. Syn2 was also found to interact with NCX1 as tested by immunoprecipitation, mass spectrometry, and surface resonance experiments. NCX1 levels were downregulated in the membrane fraction in the left ventricle of Syn2 KO mice compared to WT littermates following aortic banding. We observed increased frequency of calcium sparks and waves in isolated Syn2 KO cardiomyocytes compared to controls. We found enhanced susceptibility of Syn2 KO mice for ventricular arrhythmias compared to WT littermates mice during ISO stress testing in explanted hearts. Hearts from Syn2 KO mice also demonstrated more severe ventricular arrhythmias compared to hearts from WT littermates controls.
Conclusions
We report for the first time that Syn2 is expressed in the myocardium and that Syn2 seems to regulate NCX1 transport and localization. We also found markedly reduced LV Syn2 levels in HF individuals and mice that lacked Syn2 more frequent displayed severe ventricular arrhythmias and had increased mortality. Hence, our data suggest that reduced Syn2 in the failing myocardium may lead to increased mortality, possibly linked to altered NCX trafficking and subsequent ventricular arrhythmias.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- A H Ottesen
- Akershus University Hospital , Lørenskog , Norway
| | - C Raiborg
- Oslo University Hospital , Oslo , Norway
| | | | | | - T L Hafver
- Oslo University Hospital , Oslo , Norway
| | - R A Sandbu
- Oslo University Hospital , Oslo , Norway
| | | | - L Etholm
- Oslo University Hospital , Oslo , Norway
| | - M K Stokke
- Oslo University Hospital , Oslo , Norway
| | - I Sjaastad
- Oslo University Hospital , Oslo , Norway
| | - W E Louch
- Oslo University Hospital , Oslo , Norway
| | | | | | - H Rosjo
- Akershus University Hospital , Lørenskog , Norway
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12
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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 2022:10.1113/JP283602. [PMID: 36114707 PMCID: PMC10017376 DOI: 10.1113/jp283602] [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] [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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13
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Zhang X, Ni H, Morotti S, Smith CER, Sato D, Louch WE, Edwards AG, 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 2022. [PMID: 36094888 PMCID: PMC10008525 DOI: 10.1113/jp283363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Haibo Ni
- 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
| | - Andrew G Edwards
- Department of Pharmacology, University of California Davis, Davis, CA, USA.,Simula Research Laboratory, Lysaker, Norway
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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14
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Silva GJJ, Parvan R, Shen X, Frisk M, Altara R, Strand ME, Rypdal KB, Lunde IG, Louch WE, Aronsen JM, Stenslokken KO, Stokke MK, Cataliotti A. ProANP31-67 ameliorates adverse cardiac remodeling and improves systolic and diastolic functions in a preclinical model of cardiorenal syndrome. Cardiovasc Res 2022. [DOI: 10.1093/cvr/cvac066.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): South-Eastern Norway Regional Health Authority (HSØ-RHF, Project No. 25674)
Background
The cardiac hormone proANP31-67, a linear fragment of the N-terminal Atrial Natriuretic Peptide, has known enhancing renal effects. More recently, we described the cardio protective effects of this hormone in a model of chronic hypertension. More specifically, independently of the blood pressure level, proANP31-67 improved diastolic function, attenuated cardiac fibrosis, and reduced hypertrophy.
Purpose
The current study was designed to assess the cardiorenal effects of proANP31-67 in a rodent model of hampered renal function, followed by cardiac injury produced by ischemia/reperfusion (I/R).
Methods
Right uninephrectomy (UNX) was performed in Wistar rats (n=28). Sixteen weeks after UNX, rats underwent cardiac I/R injury and randomly assigned to proANP31-67 (50 ng/kg/day s.c., n=15) or Vehicle (n=13) for four weeks post I/R. Echocardiographic examinations were performed at baseline (before UNX), 16 weeks after UNX, and four weeks after I/R. At the end of the study, cardiomyocytes were isolated and tissue samples were collected.
Results
Chronic UNX resulted in diastolic impairment (E/A: 1.47±0.08 at baseline vs 0.98±0.14 at 16 wks post UNX, p=0.0010). I/R further accentuated the development of the cardiorenal syndrome, and induced a mild systolic dysfunction in the placebo treated animals. However, four weeks of treatment with proANP31-67 preserved systolic function (EF: 62±3% placebo vs 74±2% proANP31-67, p<0.0001), and reverted the diastolic dysfunction (E/A: 0.72±0.15 placebo vs 1.24±0.11 proANP31-67, p=0.0134). ProANP31-67 ameliorated the adverse cardiac remodeling (i.e., reduction in the cardiomyocyte cross-sectional area and interstitial fibrosis), enhanced Ca2+ handling, and improved cardiomyocyte t-tubules´ structural changes compared to vehicle. At the cellular level, in vitro experiments demonstrated the direct effect of proANP31-67 on cardiomyocyte hypertrophy (assessed by [3H]-leucine incorporation) induced by endothelin 1 and angiotensin II.
Conclusion
ProANP31-67 has a direct cardiomyocyte protective effect, leading to an improvement in Ca2+ homeostasis and t-tubules´ structures and, prevents the development of systolic and diastolic dysfunction in a pre-clinical model of cardiorenal syndrome.
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Affiliation(s)
- GJJ Silva
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - R Parvan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - X Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - M Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - R Altara
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - ME Strand
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - KB Rypdal
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - IG Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - WE Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - JM Aronsen
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Oslo , Norway
| | - K-O Stenslokken
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Oslo , Norway
| | - MK Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
| | - A Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway , Oslo , Norway
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15
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Hernández Mesa M, van den Brink J, Louch WE, McCabe KJ, Rangamani P. Nanoscale organization of ryanodine receptor distribution and phosphorylation pattern determines the dynamics of calcium sparks. PLoS Comput Biol 2022; 18:e1010126. [PMID: 35666763 PMCID: PMC9203011 DOI: 10.1371/journal.pcbi.1010126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 06/16/2022] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
Super-resolution imaging techniques have provided a better understanding of the relationship between the nanoscale organization and function of ryanodine receptors (RyRs) in cardiomyocytes. Recent data have indicated that this relationship is disrupted in heart failure (HF), as RyRs are dispersed into smaller and more numerous clusters. However, RyRs are also hyperphosphorylated in this condition, and this is reported to occur preferentially within the cluster centre. Thus, the combined impact of RyR relocalization and sensitization on Ca2+ spark generation in failing cardiomyocytes is likely complex and these observations suggest that both the nanoscale organization of RyRs and the pattern of phosphorylated RyRs within clusters could be critical determinants of Ca2+ spark dynamics. To test this hypothesis, we used computational modeling to quantify the relationships between RyR cluster geometry, phosphorylation patterns, and sarcoplasmic reticulum (SR) Ca2+ release. We found that RyR cluster disruption results in a decrease in spark fidelity and longer sparks with a lower amplitude. Phosphorylation of some RyRs within the cluster can play a compensatory role, recovering healthy spark dynamics. Interestingly, our model predicts that such compensation is critically dependent on the phosphorylation pattern, as phosphorylation localized within the cluster center resulted in longer Ca2+ sparks and higher spark fidelity compared to a uniformly distributed phosphorylation pattern. Our results strongly suggest that both the phosphorylation pattern and nanoscale RyR reorganization are critical determinants of Ca2+ dynamics in HF. Ryanodine receptors (RyRs) are ion channels located on the membrane of the sarcoplasmic reticulum that are responsible for an increase in cytosolic Ca2+ during cell excitation. Here, we investigate how the geometry of RyR clusters combined with spatial phosphorylation patterns impacts on Ca2+ spark generation and kinetics. The findings from our study show that phosphorylation pattern and both RyR cluster shape and dispersion have implications on Ca2+ spark activity and provide insights into altered Ca2+ dynamics during HF.
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Affiliation(s)
- María Hernández Mesa
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Jonas van den Brink
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Kimberly J. McCabe
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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16
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Praetorius H, Louch WE. Europhysiology 2022: Let's meet for real. Acta Physiol (Oxf) 2022; 235:e13825. [PMID: 35466542 DOI: 10.1111/apha.13825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 11/26/2022]
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17
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Louch WE, Perdreau-Dahl H, Edwards AG. Image-Driven Modeling of Nanoscopic Cardiac Function: Where Have We Come From, and Where Are We Going? Front Physiol 2022; 13:834211. [PMID: 35356084 PMCID: PMC8959215 DOI: 10.3389/fphys.2022.834211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/31/2022] [Indexed: 11/24/2022] Open
Abstract
Complementary developments in microscopy and mathematical modeling have been critical to our understanding of cardiac excitation–contraction coupling. Historically, limitations imposed by the spatial or temporal resolution of imaging methods have been addressed through careful mathematical interrogation. Similarly, limitations imposed by computational power have been addressed by imaging macroscopic function in large subcellular domains or in whole myocytes. As both imaging resolution and computational tractability have improved, the two approaches have nearly merged in terms of the scales that they can each be used to interrogate. With this review we will provide an overview of these advances and their contribution to understanding ventricular myocyte function, including exciting developments over the last decade. We specifically focus on experimental methods that have pushed back limits of either spatial or temporal resolution of nanoscale imaging (e.g., DNA-PAINT), or have permitted high resolution imaging on large cellular volumes (e.g., serial scanning electron microscopy). We also review the progression of computational approaches used to integrate and interrogate these new experimental data sources, and comment on near-term advances that may unify understanding of the underlying biology. Finally, we comment on several outstanding questions in cardiac physiology that stand to benefit from a concerted and complementary application of these new experimental and computational methods.
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Affiliation(s)
- 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
| | - Harmonie Perdreau-Dahl
- 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
| | - Andrew G. Edwards
- Simula Research Laboratory, Lysaker, Norway
- *Correspondence: Andrew G. Edwards,
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18
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Abstract
In mammalian cardiac myocytes, the plasma membrane includes the surface sarcolemma but also a network of membrane invaginations called transverse (t-) tubules. These structures carry the action potential deep into the cell interior, allowing efficient triggering of Ca2+ release and initiation of contraction. Once thought to serve as rather static enablers of excitation-contraction coupling, recent work has provided a newfound appreciation of the plasticity of the t-tubule network's structure and function. Indeed, t-tubules are now understood to support dynamic regulation of the heartbeat across a range of timescales, during all stages of life, in both health and disease. This review article aims to summarize these concepts, with consideration given to emerging t-tubule regulators and their targeting in future therapies.
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Affiliation(s)
- Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom;
| | - 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
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom;
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19
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Zhang X, Ni H, Morotti S, Smith C, Sato D, Louch WE, Edwards AG, Grandi E. Quantifying the interactive arrhythmogenic effects of cell ultrastructural remodeling and calcium-handling protein redistribution in a three-dimensional model of the human atrial myocyte. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.873] [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: 11/02/2022] Open
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20
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Mesa MH, den Brink JV, Louch WE, McCabe KJ, Rangamani P. Nanoscale organization of ryanodine receptor distribution and phosphorylation pattern determines the dynamics of calcium sparks. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.865] [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: 12/01/2022] Open
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21
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Zhou J, Singh N, Monnier C, Marszalec W, Gao L, Jin J, Frisk M, Louch WE, Verma S, Krishnamurthy P, Nico E, Mulla M, Aistrup GL, Kishore R, Wasserstrom JA. Phosphatidylinositol-4,5-Bisphosphate Binding to Amphiphysin-II Modulates T-Tubule Remodeling: Implications for Heart Failure. Front Physiol 2022; 12:782767. [PMID: 35002765 PMCID: PMC8733645 DOI: 10.3389/fphys.2021.782767] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
BIN1 (amphyphysin-II) is a structural protein involved in T-tubule (TT) formation and phosphatidylinositol-4,5-bisphosphate (PIP2) is responsible for localization of BIN1 to sarcolemma. The goal of this study was to determine if PIP2-mediated targeting of BIN1 to sarcolemma is compromised during the development of heart failure (HF) and is responsible for TT remodeling. Immunohistochemistry showed co-localization of BIN1, Cav1.2, PIP2, and phospholipase-Cβ1 (PLCβ1) in TTs in normal rat and human ventricular myocytes. PIP2 levels were reduced in spontaneously hypertensive rats during HF progression compared to age-matched controls. A PIP Strip assay of two native mouse cardiac-specific isoforms of BIN1 including the longest (cardiac BIN1 #4) and shortest (cardiac BIN1 #1) isoforms as well human skeletal BIN1 showed that all bound PIP2. In addition, overexpression of all three BIN1 isoforms caused tubule formation in HL-1 cells. A triple-lysine motif in a short loop segment between two helices was mutated and replaced by negative charges which abolished tubule formation, suggesting a possible location for PIP2 interaction aside from known consensus binding sites. Pharmacological PIP2 depletion in rat ventricular myocytes caused TT loss and was associated with changes in Ca2+ release typically found in myocytes during HF, including a higher variability in release along the cell length and a slowing in rise time, time to peak, and decay time in treated myocytes. These results demonstrate that depletion of PIP2 can lead to TT disruption and suggest that PIP2 interaction with cardiac BIN1 is required for TT maintenance and function.
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Affiliation(s)
- Junlan Zhou
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Neha Singh
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Chloe Monnier
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - William Marszalec
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Li Gao
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Jing Jin
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Michael Frisk
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital, Oslo, Norway.,K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital, Oslo, Norway.,K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Suresh Verma
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Prasanna Krishnamurthy
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Elsa Nico
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Maaz Mulla
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Gary L Aistrup
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Raj Kishore
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - J Andrew Wasserstrom
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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22
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Carlson CR, Aronsen JM, Bergan-Dahl A, Moutty MC, Lunde M, Lunde PK, Jarstadmarken H, Wanichawan P, Pereira L, Kolstad TRS, Dalhus B, Subramanian H, Hille S, Christensen G, Müller OJ, Nikolaev V, Bers DM, Sjaastad I, Shen X, Louch WE, Klussmann E, Sejersted OM. AKAP18δ Anchors and Regulates CaMKII Activity at Phospholamban-SERCA2 and RYR. Circ Res 2022; 130:27-44. [PMID: 34814703 PMCID: PMC9500498 DOI: 10.1161/circresaha.120.317976] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [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: 01/09/2023]
Abstract
BACKGROUND The sarcoplasmic reticulum (SR) Ca2+-ATPase 2 (SERCA2) mediates Ca2+ reuptake into SR and thereby promotes cardiomyocyte relaxation, whereas the ryanodine receptor (RYR) mediates Ca2+ release from SR and triggers contraction. Ca2+/CaMKII (CaM [calmodulin]-dependent protein kinase II) regulates activities of SERCA2 through phosphorylation of PLN (phospholamban) and RYR through direct phosphorylation. However, the mechanisms for CaMKIIδ anchoring to SERCA2-PLN and RYR and its regulation by local Ca2+ signals remain elusive. The objective of this study was to investigate CaMKIIδ anchoring and regulation at SERCA2-PLN and RYR. METHODS A role for AKAP18δ (A-kinase anchoring protein 18δ) in CaMKIIδ anchoring and regulation was analyzed by bioinformatics, peptide arrays, cell-permeant peptide technology, immunoprecipitations, pull downs, transfections, immunoblotting, proximity ligation, FRET-based CaMKII activity and ELISA-based assays, whole cell and SR vesicle fluorescence imaging, high-resolution microscopy, adenovirus transduction, adenoassociated virus injection, structural modeling, surface plasmon resonance, and alpha screen technology. RESULTS Our results show that AKAP18δ anchors and directly regulates CaMKIIδ activity at SERCA2-PLN and RYR, via 2 distinct AKAP18δ regions. An N-terminal region (AKAP18δ-N) inhibited CaMKIIδ through binding of a region homologous to the natural CaMKII inhibitor peptide and the Thr17-PLN region. AKAP18δ-N also bound CaM, introducing a second level of control. Conversely, AKAP18δ-C, which shares homology to neuronal CaMKIIα activator peptide (N2B-s), activated CaMKIIδ by lowering the apparent Ca2+ threshold for kinase activation and inducing CaM trapping. While AKAP18δ-C facilitated faster Ca2+ reuptake by SERCA2 and Ca2+ release through RYR, AKAP18δ-N had opposite effects. We propose a model where the 2 unique AKAP18δ regions fine-tune Ca2+-frequency-dependent activation of CaMKIIδ at SERCA2-PLN and RYR. CONCLUSIONS AKAP18δ anchors and functionally regulates CaMKII activity at PLN-SERCA2 and RYR, indicating a crucial role of AKAP18δ in regulation of the heartbeat. To our knowledge, this is the first protein shown to enhance CaMKII activity in heart and also the first AKAP (A-kinase anchoring protein) reported to anchor a CaMKII isoform, defining AKAP18δ also as a CaM-KAP.
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Affiliation(s)
- Cathrine R. Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo Norway,Department of Pharmacology, Oslo University Hospital, Norway
| | - Anna Bergan-Dahl
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Marie Christine Moutty
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Marianne Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Hilde Jarstadmarken
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Pimthanya Wanichawan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Laetitia Pereira
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Terje RS Kolstad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Bjørn Dalhus
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, 0424 Oslo, Norway,Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, 0424 Oslo, Norway
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany,German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Susanne Hille
- German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany,Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Oliver J. Müller
- German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany,Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Viacheslav Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany,German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Donald M. Bers
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Enno Klussmann
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany,German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
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23
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Setterberg IE, Le C, Frisk M, Perdreau-Dahl H, Li J, Louch WE. Corrigendum: The Physiology and Pathophysiology of T-Tubules in the Heart. Front Physiol 2021; 12:790227. [PMID: 34764889 PMCID: PMC8576569 DOI: 10.3389/fphys.2021.790227] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Harmonie Perdreau-Dahl
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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24
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Kobirumaki-Shimozawa F, Shimozawa T, Oyama K, Baba S, Li J, Nakanishi T, Terui T, Louch WE, Ishiwata S, Fukuda N. Synchrony of sarcomeric movement regulates left ventricular pump function in the in vivo beating mouse heart. J Gen Physiol 2021; 153:212675. [PMID: 34605861 PMCID: PMC8493835 DOI: 10.1085/jgp.202012860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
Sarcomeric contraction in cardiomyocytes serves as the basis for the heart's pump functions. It has generally been considered that in cardiac muscle as well as in skeletal muscle, sarcomeres equally contribute to myofibrillar dynamics in myocytes at varying loads by producing similar levels of active and passive force. In the present study, we expressed α-actinin-AcGFP in Z-disks to analyze dynamic behaviors of sequentially connected individual sarcomeres along a myofibril in a left ventricular (LV) myocyte of the in vivo beating mouse heart. To quantify the magnitude of the contribution of individual sarcomeres to myofibrillar dynamics, we introduced the novel parameter "contribution index" (CI) to measure the synchrony in movements between a sarcomere and a myofibril (from -1 [complete asynchrony] to 1 [complete synchrony]). First, CI varied markedly between sarcomeres, with an average value of ∼0.3 during normal systole. Second, when the movements between adjacent sarcomeres were asynchronous (CI < 0), a sarcomere and the ones next to the adjacent sarcomeres and farther away moved in synchrony (CI > 0) along a myofibril. Third, when difference in LV pressure in diastole and systole (ΔLVP) was lowered to <10 mm Hg, diastolic sarcomere length increased. Under depressed conditions, the movements between adjacent sarcomeres were in marked asynchrony (CI, -0.3 to -0.4), and, as a result, average CI was linearly decreased in association with a decrease in ΔLVP. These findings suggest that in the left ventricle of the in vivo beating mouse heart, (1) sarcomeres heterogeneously contribute to myofibrillar dynamics due to an imbalance of active and passive force between neighboring sarcomeres, (2) the force imbalance is pronounced under depressed conditions coupled with a marked increase in passive force and the ensuing tug-of-war between sarcomeres, and (3) sarcomere synchrony via the distal intersarcomere interaction regulates the heart's pump function in coordination with myofibrillar contractility.
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Affiliation(s)
| | - Togo Shimozawa
- Technical Division, School of Science, The University of Tokyo, Tokyo, Japan
| | - Kotaro Oyama
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan.,Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Gunma, Japan
| | - Shunsuke Baba
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Tomohiro Nakanishi
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takako Terui
- Department of Anesthesiology, The Jikei University School of Medicine, Tokyo, Japan
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Norio Fukuda
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
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25
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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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26
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Abstract
In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms.
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Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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27
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Rohner E, Witman N, Sohlmer J, De Genst E, Louch WE, Sahara M, Chien KR. An mRNA assay system demonstrates proteasomal-specific degradation contributes to cardiomyopathic phospholamban null mutation. Mol Med 2021; 27:102. [PMID: 34496741 PMCID: PMC8425124 DOI: 10.1186/s10020-021-00362-8] [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: 03/28/2021] [Accepted: 08/24/2021] [Indexed: 01/15/2023] Open
Abstract
Background The human L39X phospholamban (PLN) cardiomyopathic mutant has previously been reported as a null mutation but the detailed molecular pathways that lead to the complete lack of detectable protein remain to be clarified. Previous studies have shown the implication between an impaired cellular degradation homeostasis and cardiomyopathy development. Therefore, uncovering the underlying mechanism responsible for the lack of PLN protein has important implications in understanding the patient pathology, chronic human calcium dysregulation and aid the development of potential therapeutics. Methods A panel of mutant and wild-type reporter tagged PLN modified mRNA (modRNA) constructs were transfected in human embryonic stem cell-derived cardiomyocytes. Lysosomal and proteasomal chemical inhibitors were used together with cell imaging and protein analysis tools in order to dissect degradation pathways associated with expressed PLN constructs. Transcriptional profiling of the cardiomyocytes transfected by wild-type or L39X mutant PLN modRNA was analysed with bulk RNA sequencing. Results Our modRNA assay system revealed that transfected L39X mRNA was stable and actively translated in vitro but with only trace amount of protein detectable. Proteasomal inhibition of cardiomyocytes transfected with L39X mutant PLN modRNA showed a fourfold increase in protein expression levels. Additionally, RNA sequencing analysis of protein degradational pathways showed a significant distinct transcriptomic signature between wild-type and L39X mutant PLN modRNA transfected cardiomyocytes. Conclusion Our results demonstrate that the cardiomyopathic PLN null mutant L39X is rapidly, actively and specifically degraded by proteasomal pathways. Herein, and to the best of our knowledge, we report for the first time the usage of modified mRNAs to screen for and illuminate alternative molecular pathways found in genes associated with inherited cardiomyopathies. Supplementary Information The online version contains supplementary material available at 10.1186/s10020-021-00362-8.
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Affiliation(s)
- Eduarde Rohner
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.,Integrated Cardio Metabolic Center, Department of Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Nevin Witman
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.,Integrated Cardio Metabolic Center, Department of Medicine, Karolinska Institutet, Huddinge, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jesper Sohlmer
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.,Integrated Cardio Metabolic Center, Department of Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Erwin De Genst
- Integrated Cardio Metabolic Center, Department of Medicine, Karolinska Institutet, Huddinge, Sweden
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Makoto Sahara
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden. .,Department of Surgery, Yale University School of Medicine, New Haven, CN, USA.
| | - Kenneth R Chien
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden. .,Integrated Cardio Metabolic Center, Department of Medicine, Karolinska Institutet, Huddinge, Sweden.
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28
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Grote Beverborg N, Später D, Knöll R, Hidalgo A, Yeh ST, Elbeck Z, Silljé HHW, Eijgenraam TR, Siga H, Zurek M, Palmér M, Pehrsson S, Albery T, Bomer N, Hoes MF, Boogerd CJ, Frisk M, van Rooij E, Damle S, Louch WE, Wang QD, Fritsche-Danielson R, Chien KR, Hansson KM, Mullick AE, de Boer RA, van der Meer P. Phospholamban antisense oligonucleotides improve cardiac function in murine cardiomyopathy. Nat Commun 2021; 12:5180. [PMID: 34462437 PMCID: PMC8405807 DOI: 10.1038/s41467-021-25439-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 07/27/2021] [Indexed: 12/20/2022] Open
Abstract
Heart failure (HF) is a major cause of morbidity and mortality worldwide, highlighting an urgent need for novel treatment options, despite recent improvements. Aberrant Ca2+ handling is a key feature of HF pathophysiology. Restoring the Ca2+ regulating machinery is an attractive therapeutic strategy supported by genetic and pharmacological proof of concept studies. Here, we study antisense oligonucleotides (ASOs) as a therapeutic modality, interfering with the PLN/SERCA2a interaction by targeting Pln mRNA for downregulation in the heart of murine HF models. Mice harboring the PLN R14del pathogenic variant recapitulate the human dilated cardiomyopathy (DCM) phenotype; subcutaneous administration of PLN-ASO prevents PLN protein aggregation, cardiac dysfunction, and leads to a 3-fold increase in survival rate. In another genetic DCM mouse model, unrelated to PLN (Cspr3/Mlp-/-), PLN-ASO also reverses the HF phenotype. Finally, in rats with myocardial infarction, PLN-ASO treatment prevents progression of left ventricular dilatation and improves left ventricular contractility. Thus, our data establish that antisense inhibition of PLN is an effective strategy in preclinical models of genetic cardiomyopathy as well as ischemia driven HF.
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Affiliation(s)
- Niels Grote Beverborg
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Daniela Später
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden.
| | - Ralph Knöll
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden
| | - Alejandro Hidalgo
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden
- Murdoch Children's Research Institute (MCRI), Flemington, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | | | - Zaher Elbeck
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden
| | - Herman H W Silljé
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Tim R Eijgenraam
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Humam Siga
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden
| | - Magdalena Zurek
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Malin Palmér
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
- Laboratory of Experimental Biomedicine, Core Facilities, Sahlgrenska Academy, Gothenburg University, Göteborg, Sweden
| | - Susanne Pehrsson
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Tamsin Albery
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Nils Bomer
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Martijn F Hoes
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Cornelis J Boogerd
- Department of Molecular Cardiology, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Eva van Rooij
- Department of Molecular Cardiology, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Qing-Dong Wang
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Regina Fritsche-Danielson
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Kenneth R Chien
- Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet, Huddinge, Sweden
- Department of Cell and Molecular Biology (CMB), Karolinska Institute, Stockholm, Sweden
| | - Kenny M Hansson
- Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | | | - Rudolf A de Boer
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Peter van der Meer
- Department of Cardiology University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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29
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Frisk M, Le C, Shen X, Røe ÅT, Hou Y, Manfra O, Silva GJJ, van Hout I, Norden ES, Aronsen JM, Laasmaa M, Espe EKS, Zouein FA, Lambert RR, Dahl CP, Sjaastad I, Lunde IG, Coffey S, Cataliotti A, Gullestad L, Tønnessen T, Jones PP, Altara R, Louch WE. Etiology-Dependent Impairment of Diastolic Cardiomyocyte Calcium Homeostasis in Heart Failure With Preserved Ejection Fraction. J Am Coll Cardiol 2021; 77:405-419. [PMID: 33509397 PMCID: PMC7840890 DOI: 10.1016/j.jacc.2020.11.044] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/26/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Whereas heart failure with reduced ejection fraction (HFrEF) is associated with ventricular dilation and markedly reduced systolic function, heart failure with preserved ejection fraction (HFpEF) patients exhibit concentric hypertrophy and diastolic dysfunction. Impaired cardiomyocyte Ca2+ homeostasis in HFrEF has been linked to disruption of membrane invaginations called t-tubules, but it is unknown if such changes occur in HFpEF. OBJECTIVES This study examined whether distinct cardiomyocyte phenotypes underlie the heart failure entities of HFrEF and HFpEF. METHODS T-tubule structure was investigated in left ventricular biopsies obtained from HFrEF and HFpEF patients, whereas cardiomyocyte Ca2+ homeostasis was studied in rat models of these conditions. RESULTS HFpEF patients exhibited increased t-tubule density in comparison with control subjects. Super-resolution imaging revealed that higher t-tubule density resulted from both tubule dilation and proliferation. In contrast, t-tubule density was reduced in patients with HFrEF. Augmented collagen deposition within t-tubules was observed in HFrEF but not HFpEF hearts. A causative link between mechanical stress and t-tubule disruption was supported by markedly elevated ventricular wall stress in HFrEF patients. In HFrEF rats, t-tubule loss was linked to impaired systolic Ca2+ homeostasis, although diastolic Ca2+ removal was also reduced. In contrast, Ca2+ transient magnitude and release kinetics were largely maintained in HFpEF rats. However, diastolic Ca2+ impairments, including reduced sarco/endoplasmic reticulum Ca2+-ATPase activity, were specifically observed in diabetic HFpEF but not in ischemic or hypertensive models. CONCLUSIONS Although t-tubule disruption and impaired cardiomyocyte Ca2+ release are hallmarks of HFrEF, such changes are not prominent in HFpEF. Impaired diastolic Ca2+ homeostasis occurs in both conditions, but in HFpEF, this mechanism for diastolic dysfunction is etiology-dependent.
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Affiliation(s)
- Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway. https://twitter.com/IEMRLouch
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Åsmund T Røe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Yufeng Hou
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ornella Manfra
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Gustavo J J Silva
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Einar S Norden
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Bjørknes College, Oslo, Norway
| | - J Magnus Aronsen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Martin Laasmaa
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Emil K S Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Fouad A Zouein
- Department of Pharmacology and Toxicology, American University of Beirut Medical Center, Faculty of Medicine, Riad El-Solh, Beirut, Lebanon
| | - Regis R Lambert
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Christen P Dahl
- Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Ida G Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Alessandro Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Lars Gullestad
- Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Theis Tønnessen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Department of Cardiothoracic Surgery, Oslo University Hospital Ullevål, Oslo, Norway
| | - Peter P Jones
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Raffaele Altara
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway. https://twitter.com/IEMRLouch
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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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] [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: 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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31
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Yamakawa S, Wu D, Dasgupta M, Pedamallu H, Gupta B, Modi R, Mufti M, O'Callaghan C, Frisk M, Louch WE, Arora R, Shiferaw Y, Burrell A, Ryan J, Nelson L, Chow M, Shah SJ, Aistrup G, Zhou J, Marszalec W, Wasserstrom JA. Role of t-tubule remodeling on mechanisms of abnormal calcium release during heart failure development in canine ventricle. Am J Physiol Heart Circ Physiol 2021; 320:H1658-H1669. [PMID: 33635163 PMCID: PMC8260383 DOI: 10.1152/ajpheart.00946.2020] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 11/22/2022]
Abstract
The goal of this work was to investigate the role of t-tubule (TT) remodeling in abnormal Ca2+ cycling in ventricular myocytes of failing dog hearts. Heart failure (HF) was induced using rapid right ventricular pacing. Extensive changes in echocardiographic parameters, including left and right ventricular dilation and systolic dysfunction, diastolic dysfunction, elevated left ventricular filling pressures, and abnormal cardiac mechanics, indicated that severe HF developed. TT loss was extensive when measured as the density of total cell volume, derived from three-dimensional confocal image analysis, and significantly increased the distances in the cell interior to closest cell membrane. Changes in Ca2+ transients indicated increases in heterogeneity of Ca2+ release along the cell length. When critical properties of Ca2+ release variability were plotted as a function of TT organization, there was a complex, nonlinear relationship between impaired calcium release and decreasing TT organization below a certain threshold of TT organization leading to increased sensitivity in Ca2+ release below a TT density threshold of 1.5%. The loss of TTs was also associated with a greater incidence of triggered Ca2+ waves during rapid pacing. Finally, virtually all of these observations were replicated by acute detubulation by formamide treatment, indicating an important role of TT remodeling in impaired Ca2+ cycling. We conclude that TT remodeling itself is a major contributor to abnormal Ca2+ cycling in HF, reducing myocardial performance. The loss of TTs is also responsible for a greater incidence of triggered Ca2+ waves that may play a role in ventricular arrhythmias arising in HF.NEW & NOTEWORTHY Three-dimensional analysis of t-tubule density showed t-tubule disruption throughout the whole myocyte in failing dog ventricle. A double-linear relationship between Ca2+ release and t-tubule density displays a steeper slope at t-tubule densities below a threshold value (∼1.5%) above which there is little effect on Ca2+ release (T-tubule reserve). T-tubule loss increases incidence of triggered Ca2+ waves. Chemically induced t-tubule disruption suggests that t-tubule loss alone is a critical component of abnormal Ca2+ cycling in heart failure.
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Affiliation(s)
- Sean Yamakawa
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Daniel Wu
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Mona Dasgupta
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Havisha Pedamallu
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Binita Gupta
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Rishi Modi
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Maryam Mufti
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Caitlin O'Callaghan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - William E Louch
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Rishi Arora
- California State University Northridge, Los Angeles, California
| | - Yohannes Shiferaw
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Amy Burrell
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Juliet Ryan
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Lauren Nelson
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Madeleine Chow
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Sanjiv J Shah
- The Masonic Medical Research Institute, Utica, New York
| | - Gary Aistrup
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Junlan Zhou
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - William Marszalec
- Feinberg Cardiovascular and Renal Research Institute and Department of Medicine (Cardiology), Northwestern University Feinberg School of Medicine, Chicago, Illinois
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32
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Zhang X, Ni H, Morotti S, Sato D, Louch WE, Edwards AG, Grandi E. Quantifying the Arrhythmogenic Effects of Subcellular Structural Variations in a Three-Dimensional Model of the Human Atrial Myocyte. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.2097] [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: 10/22/2022] Open
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33
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Danielsen TK, Sadredini M, Manotheepan R, Aronsen JM, Frisk M, Hansen MH, Andressen KW, Hougen K, Levy FO, Louch WE, Sejersted OM, Sjaastad I, Stokke MK. Exercise Training Stabilizes RyR2-Dependent Ca 2+ Release in Post-infarction Heart Failure. Front Cardiovasc Med 2021; 7:623922. [PMID: 33569394 PMCID: PMC7868397 DOI: 10.3389/fcvm.2020.623922] [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: 10/30/2020] [Accepted: 12/17/2020] [Indexed: 11/20/2022] Open
Abstract
Aim: Dysfunction of the cardiac ryanodine receptor (RyR2) is an almost ubiquitous finding in animal models of heart failure (HF) and results in abnormal Ca2+ release in cardiomyocytes that contributes to contractile impairment and arrhythmias. We tested whether exercise training (ET), as recommended by current guidelines, had the potential to stabilize RyR2-dependent Ca2+ release in rats with post-myocardial infarction HF. Materials and Methods: We subjected male Wistar rats to left coronary artery ligation or sham operations. After 1 week, animals were characterized by echocardiography and randomized to high-intensity interval ET on treadmills or to sedentary behavior (SED). Running speed was adjusted based on a weekly VO2max test. We repeated echocardiography after 5 weeks of ET and harvested left ventricular cardiomyocytes for analysis of RyR2-dependent systolic and spontaneous Ca2+ release. Phosphoproteins were analyzed by Western blotting, and beta-adrenoceptor density was quantified by radioligand binding. Results: ET increased VO2max in HF-ET rats to 127% of HF-SED (P < 0.05). This coincided with attenuated spontaneous SR Ca2+ release in left ventricular cardiomyocytes from HF-ET but also reduced Ca2+ transient amplitude and slowed Ca2+ reuptake during adrenoceptor activation. However, ventricular diameter and fractional shortening were unaffected by ET. Analysis of Ca2+ homeostasis and major proteins involved in the regulation of SR Ca2+ release and reuptake could not explain the attenuated spontaneous SR Ca2+ release or reduced Ca2+ transient amplitude. Importantly, measurements of beta-adrenoceptors showed a normalization of beta1-adrenoceptor density and beta1:beta2-adrenoceptor ratio in HF-ET. Conclusion: ET increased aerobic capacity in post-myocardial infarction HF rats and stabilized RyR2-dependent Ca2+ release. Our data show that these effects of ET can be gained without major alterations in SR Ca2+ regulatory proteins and indicate that future studies should include upstream parts of the sympathetic signaling pathway.
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Affiliation(s)
- Tore Kristian Danielsen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Mani Sadredini
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ravinea Manotheepan
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Marie Haugsten Hansen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Kjetil Wessel Andressen
- Department of Pharmacology, Institute of Clinical Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Karina Hougen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Finn Olav Levy
- Department of Pharmacology, Institute of Clinical Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ole Mathias Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Mathis Korseberg Stokke
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway.,Kristian Gerhard (KG) Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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34
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Foo KS, Lehtinen ML, Leung CY, Lian X, Xu J, Keung W, Geng L, Kolstad TRS, Thams S, Wong AOT, Wong N, Bylund K, Zhou C, He X, Jin SB, Clarke J, Lendahl U, Li RA, Louch WE, Chien KR. Human ISL1 + Ventricular Progenitors Self-Assemble into an In Vivo Functional Heart Patch and Preserve Cardiac Function Post Infarction. Mol Ther 2021; 29:409. [PMID: 33296664 PMCID: PMC7791073 DOI: 10.1016/j.ymthe.2020.11.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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35
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Masjoan Juncos JX, Shakil S, Bradley WE, Wei CC, Zafar I, Powell P, Mariappan N, Louch WE, Ford DA, Ahmad A, Dell'Italia LJ, Ahmad S. Chronic cardiac structural damage, diastolic and systolic dysfunction following acute myocardial injury due to bromine exposure in rats. Arch Toxicol 2021; 95:179-193. [PMID: 32979061 PMCID: PMC7855670 DOI: 10.1007/s00204-020-02919-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/17/2020] [Indexed: 12/16/2022]
Abstract
Accidental bromine spills are common and its large industrial stores risk potential terrorist attacks. The mechanisms of bromine toxicity and effective therapeutic strategies are unknown. Our studies demonstrate that inhaled bromine causes deleterious cardiac manifestations. In this manuscript we describe mechanisms of delayed cardiac effects in the survivors of a single bromine exposure. Rats were exposed to bromine (600 ppm for 45 min) and the survivors were sacrificed at 14 or 28 days. Echocardiography, hemodynamic analysis, histology, transmission electron microscopy (TEM) and biochemical analysis of cardiac tissue were performed to assess functional, structural and molecular effects. Increases in right ventricular (RV) and left ventricular (LV) end-diastolic pressure and LV end-diastolic wall stress with increased LV fibrosis were observed. TEM images demonstrated myofibrillar loss, cytoskeletal breakdown and mitochondrial damage at both time points. Increases in cardiac troponin I (cTnI) and N-terminal pro brain natriuretic peptide (NT-proBNP) reflected myofibrillar damage and increased LV wall stress. LV shortening decreased as a function of increasing LV end-systolic wall stress and was accompanied by increased sarcoendoplasmic reticulum calcium ATPase (SERCA) inactivation and a striking dephosphorylation of phospholamban. NADPH oxidase 2 and protein phosphatase 1 were also increased. Increased circulating eosinophils and myocardial 4-hydroxynonenal content suggested increased oxidative stress as a key contributing factor to these effects. Thus, a continuous oxidative stress-induced chronic myocardial damage along with phospholamban dephosphorylation are critical for bromine-induced chronic cardiac dysfunction. These findings in our preclinical model will educate clinicians and public health personnel and provide important endpoints to evaluate therapies.
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MESH Headings
- Animals
- Bromine
- Calcium-Binding Proteins/metabolism
- Cardiomegaly/chemically induced
- Cardiomegaly/metabolism
- Cardiomegaly/pathology
- Cardiomegaly/physiopathology
- Cardiotoxicity
- Diastole
- Disease Models, Animal
- Fibrosis
- Male
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/ultrastructure
- Myocardium/metabolism
- Myocardium/ultrastructure
- NADPH Oxidase 2/metabolism
- Natriuretic Peptide, Brain/metabolism
- Oxidative Stress/drug effects
- Peptide Fragments/metabolism
- Phosphorylation
- Protein Phosphatase 1/metabolism
- Rats, Sprague-Dawley
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Systole
- Time Factors
- Troponin I/metabolism
- Ventricular Dysfunction, Left/chemically induced
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Right/chemically induced
- Ventricular Dysfunction, Right/metabolism
- Ventricular Dysfunction, Right/pathology
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Function, Left
- Ventricular Function, Right
- Ventricular Remodeling
- Rats
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Affiliation(s)
- Juan Xavier Masjoan Juncos
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA
| | - Shazia Shakil
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA
| | - Wayne E Bradley
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Veterans Affairs Medical Center, Birmingham, AL, USA
| | - Chih-Chang Wei
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Veterans Affairs Medical Center, Birmingham, AL, USA
| | - Iram Zafar
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA
| | - Pamela Powell
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Veterans Affairs Medical Center, Birmingham, AL, USA
| | - Nithya Mariappan
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- Center for Heart Failure Research, KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - David A Ford
- Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University, St. Louis, MO, USA
| | - Aftab Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA
| | - Louis J Dell'Italia
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Veterans Affairs Medical Center, Birmingham, AL, USA
| | - Shama Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, #322 BMRII, 901 19th St. South, Birmingham, AL, 35294, USA.
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Rubinstein J, Woo JG, Garcia AM, Alsaied T, Li J, Lunde PK, Moore RA, Laasmaa M, Sammons A, Mays WA, Miyamoto SD, Louch WE, Veldtman GR. Probenecid Improves Cardiac Function in Subjects with a Fontan Circulation and Augments Cardiomyocyte Calcium Homeostasis. Pediatr Cardiol 2020; 41:1675-1688. [PMID: 32770262 PMCID: PMC7704717 DOI: 10.1007/s00246-020-02427-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/21/2020] [Indexed: 10/23/2022]
Abstract
Subjects with functionally univentricular circulation who have completed staged single ventricle palliation, with the final stage culminating in the Fontan procedure, are often living into adulthood. However, high morbidity and mortality remain prevalent in these patients, as diastolic and systolic dysfunction of the single systemic ventricle are linked to Fontan circulatory failure. We presently investigated the effects of probenecid in post-Fontan patients. Used for decades for the treatment of gout, probenecid has been shown in recent years to positively influence cardiac function via effects on the Transient Receptor Potential Vanilloid 2 (TRPV2) channel in cardiomyocytes. Indeed, we observed that probenecid improved cardiac function and exercise performance in patients with a functionally univentricular circulation. This was consistent with our findings from a retrospective cohort of patients with single ventricle physiology where TRPV2 expression was increased. Experiments in isolated cardiomyocytes associated these positive actions to augmentation of diastolic calcium homeostasis.
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Affiliation(s)
- Jack Rubinstein
- Department of Internal Medicine, Division of Cardiovascular Health & Disease, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA.
| | - Jessica G Woo
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Anastacia M Garcia
- Department of Pediatrics, Division of Cardiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Tarek Alsaied
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Ryan A Moore
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Martin Laasmaa
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Amanda Sammons
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Wayne A Mays
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Shelley D Miyamoto
- Department of Pediatrics, Division of Cardiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Gruschen R Veldtman
- Adult Congenital Heart Disease Service, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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37
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Louch WE. A horse of a different colour: distinct mechanisms of HFpEF and HFrEF. J Physiol 2020; 598:5005-5006. [PMID: 32985684 PMCID: PMC7756253 DOI: 10.1113/jp280691] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- William 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, Norway
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38
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Longobardi S, Lewalle A, Coveney S, Sjaastad I, Espe EKS, Louch WE, Musante CJ, Sher A, Niederer SA. Predicting left ventricular contractile function via Gaussian process emulation in aortic-banded rats. Philos Trans A Math Phys Eng Sci 2020; 378:20190334. [PMID: 32448071 PMCID: PMC7287330 DOI: 10.1098/rsta.2019.0334] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cardiac contraction is the result of integrated cellular, tissue and organ function. Biophysical in silico cardiac models offer a systematic approach for studying these multi-scale interactions. The computational cost of such models is high, due to their multi-parametric and nonlinear nature. This has so far made it difficult to perform model fitting and prevented global sensitivity analysis (GSA) studies. We propose a machine learning approach based on Gaussian process emulation of model simulations using probabilistic surrogate models, which enables model parameter inference via a Bayesian history matching (HM) technique and GSA on whole-organ mechanics. This framework is applied to model healthy and aortic-banded hypertensive rats, a commonly used animal model of heart failure disease. The obtained probabilistic surrogate models accurately predicted the left ventricular pump function (R2 = 0.92 for ejection fraction). The HM technique allowed us to fit both the control and diseased virtual bi-ventricular rat heart models to magnetic resonance imaging and literature data, with model outputs from the constrained parameter space falling within 2 SD of the respective experimental values. The GSA identified Troponin C and cross-bridge kinetics as key parameters in determining both systolic and diastolic ventricular function. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.
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Affiliation(s)
- S Longobardi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - A Lewalle
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - S Coveney
- Insigneo Institute for in-silico Medicine and Department of Computer Science, University of Sheffield, Sheffield, UK
| | - I Sjaastad
- Institute for Experimental Medical Research and KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - E K S Espe
- Institute for Experimental Medical Research and KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - W E Louch
- Institute for Experimental Medical Research and KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - C J Musante
- Pfizer Worldwide Research, Development and Medical, Cambridge, MA, USA
| | - A Sher
- Pfizer Worldwide Research, Development and Medical, Cambridge, MA, USA
| | - S A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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Røe ÅT, Ruud M, Espe EK, Manfra O, Longobardi S, Aronsen JM, Nordén ES, Husebye T, Kolstad TRS, Cataliotti A, Christensen G, Sejersted OM, Niederer SA, Andersen GØ, Sjaastad I, Louch WE. Regional diastolic dysfunction in post-infarction heart failure: role of local mechanical load and SERCA expression. Cardiovasc Res 2020; 115:752-764. [PMID: 30351410 PMCID: PMC6432054 DOI: 10.1093/cvr/cvy257] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/08/2018] [Accepted: 10/22/2018] [Indexed: 01/08/2023] Open
Abstract
Aims Regional heterogeneities in contraction contribute to heart failure with reduced ejection fraction (HFrEF). We aimed to determine whether regional changes in myocardial relaxation similarly contribute to diastolic dysfunction in post-infarction HFrEF, and to elucidate the underlying mechanisms. Methods and results Using the magnetic resonance imaging phase-contrast technique, we examined local diastolic function in a rat model of post-infarction HFrEF. In comparison with sham-operated animals, post-infarction HFrEF rats exhibited reduced diastolic strain rate adjacent to the scar, but not in remote regions of the myocardium. Removal of Ca2+ within cardiomyocytes governs relaxation, and we indeed found that Ca2+ transients declined more slowly in cells isolated from the adjacent region. Resting Ca2+ levels in adjacent zone myocytes were also markedly elevated at high pacing rates. Impaired Ca2+ removal was attributed to a reduced rate of Ca2+ sequestration into the sarcoplasmic reticulum (SR), due to decreased local expression of the SR Ca2+ ATPase (SERCA). Wall stress was elevated in the adjacent region. Using ex vivo experiments with loaded papillary muscles, we demonstrated that high mechanical stress is directly linked to SERCA down-regulation and slowing of relaxation. Finally, we confirmed that regional diastolic dysfunction is also present in human HFrEF patients. Using echocardiographic speckle-tracking of patients enrolled in the LEAF trial, we found that in comparison with controls, post-infarction HFrEF subjects exhibited reduced diastolic train rate adjacent to the scar, but not in remote regions of the myocardium. Conclusion Our data indicate that relaxation varies across the heart in post-infarction HFrEF. Regional diastolic dysfunction in this condition is linked to elevated wall stress adjacent to the infarction, resulting in down-regulation of SERCA, disrupted diastolic Ca2+ handling, and local slowing of relaxation.
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Affiliation(s)
- Åsmund T Røe
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Marianne Ruud
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Emil K Espe
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ornella Manfra
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Stefano Longobardi
- Biomedical Engineering Department, The Rayne Institute, King's College, London, London, UK
| | - Jan M Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Einar Sjaastad Nordén
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Trygve Husebye
- Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway
| | - Terje R S Kolstad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Alessandro Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ole M Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway
| | - Steven A Niederer
- Biomedical Engineering Department, The Rayne Institute, King's College, London, London, UK
| | | | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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Altara R, da Silva GJJ, Frisk M, Spelta F, Zouein FA, Louch WE, Booz GW, Cataliotti A. Cardioprotective Effects of the Novel Compound Vastiras in a Preclinical Model of End-Organ Damage. Hypertension 2020; 75:1195-1204. [PMID: 32200677 DOI: 10.1161/hypertensionaha.120.14704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cardiac hypertrophy and renal damage associated with hypertension are independent predictors of morbidity and mortality. In a model of hypertensive heart disease and renal damage, we tested the actions of continuous administration of Vastiras, a novel compound derived from the linear fragment of ANP (atrial natriuretic peptide), namely pro-ANP31-67, on blood pressure and associated renal and cardiac function and remodeling. Of note, this peptide, unlike the ring structured forms, does not bind to the classic natriuretic peptide receptors. Dahl/Salt-Sensitive rats fed a 4% NaCl diet for 6 weeks developed hypertension, cardiac hypertrophy, and renal damage. Four weeks of treatment with 50 to 100 ng/kg per day of Vastiras exhibited positive effects on renal function, independent of blood pressure regulation. Treated rats had increased urine excretion, natriuresis, and enhanced glomerular filtration rate. Importantly, these favorable renal effects were accompanied by improved cardiac structure and function, including attenuated cardiac hypertrophy, as indicated by decreased heart weight to body weight ratio, relative wall thickness, and left atrial diameter, as well as reduced fibrosis and normalized ratio of the diastolic mitral inflow E wave to A wave. A renal subtherapeutic dose of Vastiras (25 ng/kg per day) induced similar protective effects on the heart. At the cellular level, cardiomyocyte size and t-tubule density were preserved in Vastiras-treated compared with untreated animals. In conclusion, these data demonstrate the cardiorenal protective actions of chronic supplementation of a first-in-class compound, Vastiras, in a preclinical model of maladaptive cardiac hypertrophy and renal damage induced by hypertension.
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Affiliation(s)
- Raffaele Altara
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,KG Jebsen Center for Cardiac Research, University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,Department of Pathology (R.A.), University of Mississippi Medical Center, Jackson, MS
| | - Gustavo J J da Silva
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,KG Jebsen Center for Cardiac Research, University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.)
| | - Michael Frisk
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,KG Jebsen Center for Cardiac Research, University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.)
| | | | - Fouad A Zouein
- Department of Pharmacology and Toxicology, American University of Beirut Medical Center, Faculty of Medicine, Riad El-Solh, Lebanon (F.A.Z.)
| | - William E Louch
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,KG Jebsen Center for Cardiac Research, University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.)
| | - George W Booz
- Department of Pharmacology and Toxicology, School of Medicine (G.W.B.), University of Mississippi Medical Center, Jackson, MS
| | - Alessandro Cataliotti
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.).,KG Jebsen Center for Cardiac Research, University of Oslo, Norway (R.A., G.J.J.d.S., M.F., W.E.L., A.C.)
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Tazmini K, Fraz MSA, Nymo SH, Stokke MK, Louch WE, Øie E. Potassium infusion increases the likelihood of conversion of recent-onset atrial fibrillation-A single-blinded, randomized clinical trial. Am Heart J 2020; 221:114-124. [PMID: 31986288 DOI: 10.1016/j.ahj.2019.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 12/21/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND The optimal antiarrhythmic management of recent-onset atrial fibrillation (ROAF) or atrial flutter is controversial and there is a considerable variability in clinical treatment strategies. It is not known if potassium infusion has the potential to convert ROAF or atrial flutter to sinus rhythm (SR). Therefore, we aimed to investigate if patients with ROAF or atrial flutter and plasma-potassium levels ≤4.0 mmol/L have increased probability to convert to SR if the plasma-potassium level is increased towards the upper reference range (4.1-5.0 mmol/L). METHODS In a placebo-controlled, single-blinded trial, patients with ROAF or atrial flutter and plasma-potassium ≤4.0 mmol/L presenting between April 2013 and November 2017 were randomized to receive potassium chloride (KCl) infusion (n = 60) or placebo (n = 53). Patients in the KCl group received infusions at one of three different rates: 9.4 mmol/h (n = 11), 12 mmol/h (n = 19), or 15 mmol/h (n = 30). RESULTS There was no statistical difference in the number of conversions to SR between the KCl group and placebo [logrank test, P = .29; hazard ratio (HR) 1.20 (CI 0.72-1.98)]. However, KCl-infused patients who achieved an above-median hourly increase in plasma-potassium (>0.047 mmol/h) exhibited a significantly higher conversion rate compared with placebo [logrank P = .002; HR 2.40 (CI 1.36-4.21)] and KCl patients with below-median change in plasma-potassium [logrank P < .001; HR 4.41 (CI 2.07-9.40)]. Due to pain at the infusion site, the infusion was prematurely terminated in 10 patients (17%). CONCLUSIONS Although increasing plasma-potassium levels did not significantly augment conversion of ROAF or atrial flutter to SR in patients with potassium levels in the lower-normal range, our results indicate that this treatment may be effective when a rapid increase in potassium concentration is tolerated and achieved.
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Affiliation(s)
- Kiarash Tazmini
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway; Institute of Experimental Medical Research, Oslo University Hospital, Ullevål and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway.
| | - Mai S Aa Fraz
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
| | - Ståle H Nymo
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
| | - Mathis K Stokke
- K.G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway; Clinic of Internal Medicine, Lovisenberg Diaconal Hospital, Oslo, Norway
| | - William E Louch
- Institute of Experimental Medical Research, Oslo University Hospital, Ullevål and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Erik Øie
- Department of Internal Medicine, Diakonhjemmet Hospital, 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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Hou Y, Laasmaa M, Li J, Manfra O, Shen X, Jones PP, Soeller C, Louch WE. Correlating Calcium Sparks and Ryanodine Receptor Localization in Live Cardiomyocytes. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3088] [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: 10/25/2022] Open
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Zhang X, Ni H, Morotti S, Louch WE, Edwards AG, Sato D, Grandi E. Effects of Ultrastructural Remodeling on Calcium Signaling and Electrophysiology in a Three-Dimensional Model of the Human Atrial Myocyte. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1490] [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: 10/25/2022] Open
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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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Ottesen AH, Carlson CR, Eken OS, Sadredini M, Myhre PL, Shen X, Dalhus B, Laver DR, Lunde PK, Kurola J, Lunde M, Hoff JE, Godang K, Sjaastad I, Pettilä V, Stridsberg M, Lehnart SE, Edwards AG, Lunde IG, Omland T, Stokke MK, Christensen G, Røsjø H, Louch WE. Secretoneurin Is an Endogenous Calcium/Calmodulin-Dependent Protein Kinase II Inhibitor That Attenuates Ca 2+-Dependent Arrhythmia. Circ Arrhythm Electrophysiol 2020; 12:e007045. [PMID: 30943765 DOI: 10.1161/circep.118.007045] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Circulating SN (secretoneurin) concentrations are increased in patients with myocardial dysfunction and predict poor outcome. Because SN inhibits CaMKIIδ (Ca2+/calmodulin-dependent protein kinase IIδ) activity, we hypothesized that upregulation of SN in patients protects against cardiomyocyte mechanisms of arrhythmia. METHODS Circulating levels of SN and other biomarkers were assessed in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT; n=8) and in resuscitated patients after ventricular arrhythmia-induced cardiac arrest (n=155). In vivo effects of SN were investigated in CPVT mice (RyR2 [ryanodine receptor 2]-R2474S) using adeno-associated virus-9-induced overexpression. Interactions between SN and CaMKIIδ were mapped using pull-down experiments, mutagenesis, ELISA, and structural homology modeling. Ex vivo actions were tested in Langendorff hearts and effects on Ca2+ homeostasis examined by fluorescence (fluo-4) and patch-clamp recordings in isolated cardiomyocytes. RESULTS SN levels were elevated in patients with CPVT and following ventricular arrhythmia-induced cardiac arrest. In contrast to NT-proBNP (N-terminal pro-B-type natriuretic peptide) and hs-TnT (high-sensitivity troponin T), circulating SN levels declined after resuscitation, as the risk of a new arrhythmia waned. Myocardial pro-SN expression was also increased in CPVT mice, and further adeno-associated virus-9-induced overexpression of SN attenuated arrhythmic induction during stress testing with isoproterenol. Mechanistic studies mapped SN binding to the substrate binding site in the catalytic region of CaMKIIδ. Accordingly, SN attenuated isoproterenol induced autophosphorylation of Thr287-CaMKIIδ in Langendorff hearts and inhibited CaMKIIδ-dependent RyR phosphorylation. In line with CaMKIIδ and RyR inhibition, SN treatment decreased Ca2+ spark frequency and dimensions in cardiomyocytes during isoproterenol challenge, and reduced the incidence of Ca2+ waves, delayed afterdepolarizations, and spontaneous action potentials. SN treatment also lowered the incidence of early afterdepolarizations during isoproterenol; an effect paralleled by reduced magnitude of L-type Ca2+ current. CONCLUSIONS SN production is upregulated in conditions with cardiomyocyte Ca2+ dysregulation and offers compensatory protection against cardiomyocyte mechanisms of arrhythmia, which may underlie its putative use as a biomarker in at-risk patients.
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Affiliation(s)
- Anett H Ottesen
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Cathrine R Carlson
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Olav Søvik Eken
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Mani Sadredini
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Peder L Myhre
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Bjørn Dalhus
- Department for Microbiology, Clinic for Laboratory Medicine (B.D.), Oslo University Hospital, Norway.,Department for Medical Biochemistry, Institute for Clinical Medicine (B.D.), University of Oslo, Norway
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (D.R.L.)
| | - Per Kristian Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Jouni Kurola
- Division of Intensive Care Medicine, Kuopio University Hospital, Finland (J.K.)
| | - Marianne Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Jon Erik Hoff
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.)
| | - Kristin Godang
- Section of Specialized Endocrinology, Department of Endocrinology (K.G.), Oslo University Hospital, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
| | - Ville Pettilä
- Division of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki & Helsinki University Hospital, Finland (V.P.)
| | - Mats Stridsberg
- Department of Medical Sciences, Uppsala University, Sweden (M. Stridsberg)
| | - Stephan E Lehnart
- Heart Research Center Goettingen, University Medicine Center Goettingen, Germany (S.E.L.)
| | - Andrew G Edwards
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,Simula Research Laboratory, Fornebu, Norway (A.G.E)
| | - Ida G Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Torbjørn Omland
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
| | - Helge Røsjø
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
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Shiferaw Y, Aistrup GL, Louch WE, Wasserstrom JA. Remodeling Promotes Proarrhythmic Disruption of Calcium Homeostasis in Failing Atrial Myocytes. Biophys J 2019; 118:476-491. [PMID: 31889516 DOI: 10.1016/j.bpj.2019.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/19/2019] [Accepted: 12/09/2019] [Indexed: 01/31/2023] Open
Abstract
It is well known that heart failure (HF) typically coexists with atrial fibrillation (AF). However, until now, no clear mechanism has been established that relates HF to AF. In this study, we apply a multiscale computational framework to establish a mechanistic link between atrial myocyte structural remodeling in HF and AF. Using a spatially distributed model of calcium (Ca) signaling, we show that disruption of the spatial relationship between L-type Ca channels (LCCs) and ryanodine receptors results in markedly increased Ca content of the sarcoplasmic reticulum (SR). This increase in SR load is due to changes in the balance between Ca entry via LCCs and Ca extrusion due to the sodium-calcium exchanger after an altered spatial relationship between these signaling proteins. Next, we show that the increased SR load in atrial myocytes predisposes these cells to subcellular Ca waves that occur during the action potential (AP) and are triggered by LCC openings. These waves are common in atrial cells because of the absence of a well-developed t-tubule system in most of these cells. This distinct spatial architecture allows for the presence of a large pool of orphaned ryanodine receptors, which can fire and sustain Ca waves during the AP. Finally, we incorporate our atrial cell model in two-dimensional tissue simulations and demonstrate that triggered wave generation in cells leads to electrical waves in tissue that tend to fractionate to form wavelets of excitation. This fractionation is driven by the underlying stochasticity of subcellular Ca waves, which perturbs AP repolarization and consequently induces localized conduction block in tissue. We outline the mechanism for this effect and argue that it may explain the propensity for atrial arrhythmias in HF.
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Affiliation(s)
- Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California.
| | - Gary L Aistrup
- Department of Experimental Cardiology, Masonic Medical Research Institute, Utica, New York
| | - William 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
| | - J A Wasserstrom
- Department of Medicine (Cardiology) and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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48
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Laasmaa M, Lu P, Veletić M, Louch WE, Bergsland J, Balasingham I, Vendelin M. Energy-efficiency of Cardiomyocyte Stimulation with Rectangular Pulses. Sci Rep 2019; 9:13307. [PMID: 31527628 PMCID: PMC6746869 DOI: 10.1038/s41598-019-49791-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/30/2019] [Indexed: 11/10/2022] Open
Abstract
In cardiac pacemaker design, energy expenditure is an important issue. This work aims to explore whether varying stimulation pulse configuration is a viable optimization strategy for reducing energy consumption by the pacemaker. A single cardiomyocyte was used as an experimental model. Each cardiomyocyte was stimulated with different stimulation protocols using rectangular waveforms applied in varying number, in short succession. The amplitude, the width of each pulse, and the interval between consecutive pulses were modified. The application of multiple pulses in a short sequence led to a reduction of the threshold voltage required for stimulation when compared to a single pulse. However, none of the employed multi-pulse sequences reduced the overall energy expenditure of cell stimulation when compared to a single pulse stimulation. Among multiple pulse protocols, a combination of two short pulses (1 ms) separated with a short interval (0.5 ms) had the same energy requirements as a single short pulse (1 ms), but required the application of significantly less voltage. While increasing the number of consecutive pulses does not reduce the energy requirements of the pacemaker, the reduction in threshold voltage can be considered in practice if lower stimulation voltages are desired.
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Affiliation(s)
- Martin Laasmaa
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, 12618, Tallinn, Estonia
| | - Pengfei Lu
- Intervention Centre, Oslo University Hospital (OUS), 0372, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo (UiO), 0372, Oslo, Norway
| | - Mladen Veletić
- Intervention Centre, Oslo University Hospital (OUS), 0372, Oslo, Norway.,Faculty of Electrical Engineering, University of Banja Luka (UNIBL), 78000, Banja Luka, Bosnia and Herzegovina
| | - William E Louch
- Institute for Experimental Medical Research, University of Oslo, Oslo, Norway
| | - Jacob Bergsland
- Intervention Centre, Oslo University Hospital (OUS), 0372, Oslo, Norway
| | - Ilangko Balasingham
- Intervention Centre, Oslo University Hospital (OUS), 0372, Oslo, Norway.,Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), 7491, Trondheim, Norway
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, 12618, Tallinn, Estonia.
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49
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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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50
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Tazmini K, Nymo SH, Louch WE, Ranhoff AH, Øie E. Electrolyte imbalances in an unselected population in an emergency department: A retrospective cohort study. PLoS One 2019; 14:e0215673. [PMID: 31022222 PMCID: PMC6483356 DOI: 10.1371/journal.pone.0215673] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 04/05/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although electrolyte imbalances (EIs) are common in the emergency department (ED), few studies have examined the occurrence of such conditions in an unselected population. OBJECTIVES To investigate the frequency of EI among adult patients who present to the ED, with regards to type and severity, and the association with age and sex of the patient, hospital length of stay (LOS), readmission, and mortality. METHODS A retrospective cohort study. All patients ≥18 years referred for any reason to the ED between January 1, 2010, and December 31, 2015, who had measured blood electrolytes were included. In total, 62 991 visits involving 31 966 patients were registered. RESULTS EIs were mostly mild, and the most common EI was hyponatremia (glucose-corrected) (24.6%). Patients with increasing severity of EI had longer LOS compared with patients with normal electrolyte measurements. Among all admitted patients, there were 12928 (20.5%) readmissions within 30 days from discharge during the study period. Hyponatremia (glucose-corrected) was associated with readmission, with an adjusted odds ratio (OR) of 1.25 (95% CI, 1.18-1.32). Hypomagnesemia and hypocalcemia (albumin-corrected) were also associated with readmission, with ORs of 1.25 (95% CI, 1.07-1.45) and 1.22 (95% CI, 1.02-1.46), respectively. Dysnatremia, dyskalemia, hypercalcemia, hypermagnesemia, and hyperphosphatemia were associated with increased in-hospital mortality, whereas all EIs except hypophosphatemia were associated with increased 30-day and 1-year mortality. CONCLUSIONS EIs were common and increasing severity of EIs was associated with longer LOS and increased in-hospital, 30-days and 1-year mortality. EI monitoring is crucial for newly admitted patients, and up-to-date training in EI diagnosis and treatment is essential for ED physicians.
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Affiliation(s)
- Kiarash Tazmini
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
- * E-mail:
| | - Ståle H. Nymo
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
| | - William E. Louch
- Institute of Experimental Medical Research, Oslo University Hospital, Ullevål and University of Oslo, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Anette H. Ranhoff
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Erik Øie
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo, Oslo, Norway
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