Mason, Fleur E.

[["dc.bibliographiccitation.firstpage","95"],["dc.bibliographiccitation.journal","Journal of Molecular and Cellular Cardiology"],["dc.bibliographiccitation.lastpage","106"],["dc.bibliographiccitation.volume","94"],["dc.contributor.author","Hartmann, Nico H."],["dc.contributor.author","Mason, Fleur E."],["dc.contributor.author","Braun, Inga"],["dc.contributor.author","Pabel, Steffen"],["dc.contributor.author","Voigt, Niels"],["dc.contributor.author","Schotola, Hanna"],["dc.contributor.author","Fischer, Thomas H."],["dc.contributor.author","Dobrev, Dobromir"],["dc.contributor.author","Danner, Bernhard C."],["dc.contributor.author","Renner, André"],["dc.contributor.author","Gummert, Jan"],["dc.contributor.author","Belardinelli, Luiz"],["dc.contributor.author","Frey, Norbert"],["dc.contributor.author","Maier, Lars S."],["dc.contributor.author","Hasenfuß, Gerd"],["dc.contributor.author","Sossalla, Samuel"],["dc.date.accessioned","2017-09-07T11:44:54Z"],["dc.date.available","2017-09-07T11:44:54Z"],["dc.date.issued","2016"],["dc.description.abstract","Introduction: Pharmacological rhythm control of atrial fibrillation (AF) in patients with structural heart disease is limited. Ranolazine in combination with low dose dronedarone remarkably reduced AF-burden in the phase II HARMONY trial. We thus aimed to investigate the possible mechanisms underlying these results. Methods and results: Patch clamp experiments revealed that ranolazine (5 mu M), low-dose dronedarone (0.3 mu M), and the combination significantly prolonged action potential duration (APD(90)) in atrial myocytes from patients in sinus rhythm (prolongation by 23.5 +/- 0.1%, 31.7 +/- 0.1% and 25.6 +/- 0.1% respectively). Most importantly, in atrial myocytes from patients with AF ranolazine alone, but more the combination with dronedarone, also prolonged the typically abbreviated APD(90) (prolongation by 21.6 +/- 0.1% and 31.9 +/- 0.1% respectively). It was clearly observed that neither ranolazine, dronedarone nor the combination significantly changed the APD or contractility and twitch force in ventricular myocytes or trabeculae from patients with heart failure (HF). Interestingly ranolazine, and more so the combination, but not dronedarone alone, caused hyperpolarization of the resting membrane potential in cardiomyocytes from AF. As measured by confocal microscopy (Fluo-3), ranolazine, dronedarone and the combination significantly suppressed diastolic sarcoplasmic reticulum (SR) Ca2+ leak in myocytes from sinus rhythm (reduction by ranolazine: 89.0 +/- 30.7%, dronedarone: 75.6 +/- 27.4% and combination: 78.0 +/- 272%), in myocytes from AF (reduction by ranolazine: 67.6 +/- 33.7%, dronedarone: 86.5 +/- 31.7% and combination: 81.0 +/- 33.3%), as well as in myocytes from HF (reduction by ranolazine: 64.8 +/- 26.5% and dronedarone: 65.9 +/- 29.3%). Conclusions: Electrophysiological measurements during exposure to ranolazine alone or in combination with low-dose dronedarone showed APD prolongation, cellular hyperpolarization and reduced SR Ca2+ leak in human atrial myocytes. The combined inhibitory effects on various currents, in particular Na+ and K+ currents, may explain the anti-AF effects observed in the HARMONY trial. Therefore, the combination of ranolazine and dronedarone, but also ranolazine alone, may be promising new treatment options for AF, especially in patients with HF, and merit further clinical investigation. (C) 2016 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.yjmcc.2016.03.012"],["dc.identifier.gro","3141690"],["dc.identifier.isi","000376839000011"],["dc.identifier.pmid","27056421"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8938"],["dc.identifier.url","https://sfb1002.med.uni-goettingen.de/production/literature/publications/146"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation","SFB 1002: Modulatorische Einheiten bei Herzinsuffizienz"],["dc.relation","SFB 1002 | D01: Erholung aus der Herzinsuffizienz – Einfluss von Fibrose und Transkriptionssignatur"],["dc.relation.eissn","1095-8584"],["dc.relation.issn","0022-2828"],["dc.relation.workinggroup","RG Hasenfuß (Transition zur Herzinsuffizienz)"],["dc.relation.workinggroup","RG L. Maier (Experimentelle Kardiologie)"],["dc.relation.workinggroup","RG Sossalla (Kardiovaskuläre experimentelle Elektrophysiologie und Bildgebung)"],["dc.relation.workinggroup","RG T. Fischer"],["dc.relation.workinggroup","RG Voigt (Molecular Pharmacology)"],["dc.title","The combined effects of ranolazine and dronedarone on human atrial and ventricular electrophysiology"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","184"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Cardiovascular Research"],["dc.bibliographiccitation.lastpage","196"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Fischer, Thomas H."],["dc.contributor.author","Herting, Jonas"],["dc.contributor.author","Mason, Fleur E."],["dc.contributor.author","Hartmann, Nico"],["dc.contributor.author","Watanabe, Saera"],["dc.contributor.author","Nikolaev, Viacheslav O."],["dc.contributor.author","Sprenger, Julia U."],["dc.contributor.author","Fan, Peidong"],["dc.contributor.author","Yao, Lina"],["dc.contributor.author","Popov, Aron-Frederik"],["dc.contributor.author","Danner, Bernhard C."],["dc.contributor.author","Schoendube, Friedrich"],["dc.contributor.author","Belardinelli, Luiz"],["dc.contributor.author","Hasenfuss, Gerd"],["dc.contributor.author","Maier, Lars S."],["dc.contributor.author","Sossalla, Samuel"],["dc.date.accessioned","2017-09-07T11:43:42Z"],["dc.date.available","2017-09-07T11:43:42Z"],["dc.date.issued","2015"],["dc.description.abstract","Aims Enhanced cardiac late Na current (late I-Na) and increased sarcoplasmic reticulum (SR)-Ca2+-leak are both highly arrhythmogenic. This study seeks to identify signalling pathways interconnecting late I-Na and SR-Ca2+-leak in atrial cardiomyocytes (CMs). Methods and results In murine atrial CMs, SR-Ca2+-leak was increased by the late I-Na enhancer Anemonia sulcata toxin II (ATX-II). An inhibition of Ca2+/calmodulin-dependent protein kinase II (Autocamide-2-related inhibitory peptide), protein kinase A (H89), or late I-Na (Ranolazine or Tetrodotoxin) all prevented ATX-II-dependent SR-Ca2+-leak. The SR-Ca2+-leak induction by ATX-II was not detected when either the Na+/Ca2+ exchanger was inhibited (KBR) or in CaMKIIdc-knockout mice. FRET measurements revealed increased cAMP levels upon ATX-II stimulation, which could be prevented by inhibition of adenylyl cyclases (ACs) 5 and 6 (NKY 80) but not by inhibition of phosphodiesterases (IBMX), suggesting PKA activation via an AC-dependent increase of cAMP levels. Western blots showed late I-Na-dependent hyperphosphorylation of CaMKII as well as PKA target sites at ryanodine receptor type-2 (-S2814 and -S2808) and phospholamban (-Thr17, -S16). Enhancement of late I-Na did not alter Ca2+-transient amplitude or SR-Ca2+-load. However, upon late I-Na activation and simultaneous CaMKII inhibition, Ca2+-transient amplitude and SR-Ca2+-load were increased, whereas PKA inhibition reduced Ca2+-transient amplitude and load and additionally slowed Ca2+ elimination. In atrial CMs from patients with atrial fibrillation, inhibition of late I-Na, CaMKII, or PKA reduced the SR-Ca2+-leak. Conclusion Late I-Na exerts distinct effects on Ca2+ homeostasis in atrial myocardium through activation of CaMKII and PKA. Inhibition of late I-Na represents a potential approach to attenuate CaMKII activation and decreases SR-Ca2+-leak in atrial rhythm disorders. The interconnection with the cAMP/PKA system further increases the antiarrhythmic potential of late I-Na inhibition."],["dc.identifier.doi","10.1093/cvr/cvv153"],["dc.identifier.gro","3141867"],["dc.identifier.isi","000359088800021"],["dc.identifier.pmid","25990311"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/1956"],["dc.identifier.url","https://sfb1002.med.uni-goettingen.de/production/literature/publications/104"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation","SFB 1002: Modulatorische Einheiten bei Herzinsuffizienz"],["dc.relation","SFB 1002 | A03: Bedeutung CaMKII-abhängiger Mechanismen für die Arrhythmogenese bei Herzinsuffizienz"],["dc.relation.eissn","1755-3245"],["dc.relation.issn","0008-6363"],["dc.relation.issn","1755-3245"],["dc.relation.workinggroup","RG Hasenfuß (Transition zur Herzinsuffizienz)"],["dc.relation.workinggroup","RG L. Maier (Experimentelle Kardiologie)"],["dc.relation.workinggroup","RG Nikolaev (Cardiovascular Research Center)"],["dc.relation.workinggroup","RG Sossalla (Kardiovaskuläre experimentelle Elektrophysiologie und Bildgebung)"],["dc.relation.workinggroup","RG T. Fischer"],["dc.title","Late INa increases diastolic SR-Ca2+-leak in atrial myocardium by activating PKA and CaMKII"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]