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Hartmann N, Knierim M, Maurer W, Dybkova N, Hasenfuß G, Sossalla S, Streckfuss-Bömeke K. Molecular and Functional Relevance of Na V1.8-Induced Atrial Arrhythmogenic Triggers in a Human SCN10A Knock-Out Stem Cell Model. Int J Mol Sci 2023; 24:10189. [PMID: 37373335 DOI: 10.3390/ijms241210189] [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: 05/02/2023] [Revised: 05/26/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
In heart failure and atrial fibrillation, a persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. We have recently shown that NaV1.8 contributes to arrhythmogenesis by inducing a INaL. Genome-wide association studies indicate that mutations in the SCN10A gene (NaV1.8) are associated with increased risk for arrhythmias, Brugada syndrome, and sudden cardiac death. However, the mediation of these NaV1.8-related effects, whether through cardiac ganglia or cardiomyocytes, is still a subject of controversial discussion. We used CRISPR/Cas9 technology to generate homozygous atrial SCN10A-KO-iPSC-CMs. Ruptured-patch whole-cell patch-clamp was used to measure the INaL and action potential duration. Ca2+ measurements (Fluo 4-AM) were performed to analyze proarrhythmogenic diastolic SR Ca2+ leak. The INaL was significantly reduced in atrial SCN10A KO CMs as well as after specific pharmacological inhibition of NaV1.8. No effects on atrial APD90 were detected in any groups. Both SCN10A KO and specific blockers of NaV1.8 led to decreased Ca2+ spark frequency and a significant reduction of arrhythmogenic Ca2+ waves. Our experiments demonstrate that NaV1.8 contributes to INaL formation in human atrial CMs and that NaV1.8 inhibition modulates proarrhythmogenic triggers in human atrial CMs and therefore NaV1.8 could be a new target for antiarrhythmic strategies.
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Affiliation(s)
- Nico Hartmann
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
| | - Maria Knierim
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
- Clinic for Cardio-Thoracic and Vascular Surgery, University Medical Center, 37075 Göttingen, Germany
| | - Wiebke Maurer
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
| | - Gerd Hasenfuß
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
| | - Samuel Sossalla
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
- Departments of Cardiology at Kerckhoff Heart and Lung Center, Bad Nauheim and University of Giessen, 61231 Bad Nauheim, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen and Rhein Main, 61231 Bad Nauheim, Germany
- Institute of Pharmacology and Toxicology, University of Würzburg, 97078 Würzburg, Germany
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Pabel S, Knierim M, Stehle T, Alebrand F, Paulus M, Sieme M, Herwig M, Barsch F, Körtl T, Pöppl A, Wenner B, Ljubojevic-Holzer S, Molina CE, Dybkova N, Camboni D, Fischer TH, Sedej S, Scherr D, Schmid C, Brochhausen C, Hasenfuß G, Maier LS, Hamdani N, Streckfuss-Bömeke K, Sossalla S. Effects of Atrial Fibrillation on the Human Ventricle. Circ Res 2022; 130:994-1010. [PMID: 35193397 PMCID: PMC8963444 DOI: 10.1161/circresaha.121.319718] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [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] [Received: 06/21/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 11/16/2022]
Abstract
RATIONALE Atrial fibrillation (AF) and heart failure often coexist, but their interaction is poorly understood. Clinical data indicate that the arrhythmic component of AF may contribute to left ventricular (LV) dysfunction. OBJECTIVE This study investigates the effects and molecular mechanisms of AF on the human LV. METHODS AND RESULTS Ventricular myocardium from patients with aortic stenosis and preserved LV function with sinus rhythm or rate-controlled AF was studied. LV myocardium from patients with sinus rhythm and patients with AF showed no differences in fibrosis. In functional studies, systolic Ca2+ transient amplitude of LV cardiomyocytes was reduced in patients with AF, while diastolic Ca2+ levels and Ca2+ transient kinetics were not statistically different. These results were confirmed in LV cardiomyocytes from nonfailing donors with sinus rhythm or AF. Moreover, normofrequent AF was simulated in vitro using arrhythmic or rhythmic pacing (both at 60 bpm). After 24 hours of AF-simulation, human LV cardiomyocytes from nonfailing donors showed an impaired Ca2+ transient amplitude. For a standardized investigation of AF-simulation, human iPSC-cardiomyocytes were tested. Seven days of AF-simulation caused reduced systolic Ca2+ transient amplitude and sarcoplasmic reticulum Ca2+ load likely because of an increased diastolic sarcoplasmic reticulum Ca2+ leak. Moreover, cytosolic Na+ concentration was elevated and action potential duration was prolonged after AF-simulation. We detected an increased late Na+ current as a potential trigger for the detrimentally altered Ca2+/Na+-interplay. Mechanistically, reactive oxygen species were higher in the LV of patients with AF. CaMKII (Ca2+/calmodulin-dependent protein kinase IIδc) was found to be more oxidized at Met281/282 in the LV of patients with AF leading to an increased CaMKII activity and consequent increased RyR2 phosphorylation. CaMKII inhibition and ROS scavenging ameliorated impaired systolic Ca2+ handling after AF-simulation. CONCLUSIONS AF causes distinct functional and molecular remodeling of the human LV. This translational study provides the first mechanistic characterization and the potential negative impact of AF in the absence of tachycardia on the human ventricle.
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Affiliation(s)
- Steffen Pabel
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Maria Knierim
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
| | - Thea Stehle
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Felix Alebrand
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
| | - Michael Paulus
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Marcel Sieme
- Institut für Forschung und Lehre (IFL), Department of Molecular and Experimental Cardiology and Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Germany (M.S., M.H., N.H.)
| | - Melissa Herwig
- Institut für Forschung und Lehre (IFL), Department of Molecular and Experimental Cardiology and Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Germany (M.S., M.H., N.H.)
| | - Friedrich Barsch
- Institute of Pathology, University Hospital Regensburg, Germany (F.B., C.B.)
| | - Thomas Körtl
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Arnold Pöppl
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Brisca Wenner
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
| | | | - Cristina E. Molina
- Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Germany (C.E.M.)
| | - Nataliya Dybkova
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
| | - Daniele Camboni
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Germany (D.C., C.S.)
| | - Thomas H. Fischer
- Department of Internal Medicine I, University of Würzburg, Germany (T.H.F.)
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Austria (S.L.-H., S. Sedej, D.S.)
- Faculty of Medicine, University of Maribor, Maribor, Slovenia (S. Sedej)
- BioTechMed Graz, Graz, Austria (S. Sedej)
| | - Daniel Scherr
- Department of Cardiology, Medical University of Graz, Austria (S.L.-H., S. Sedej, D.S.)
| | - Christof Schmid
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Germany (D.C., C.S.)
| | | | - Gerd Hasenfuß
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
| | - Lars S. Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
| | - Nazha Hamdani
- Institut für Forschung und Lehre (IFL), Department of Molecular and Experimental Cardiology and Department of Cardiology, St. Josef-Hospital, Ruhr University Bochum, Germany (M.S., M.H., N.H.)
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
- Institute of Pharmacology and Toxicology, University of Würzburg, Germany (K.S.-B.)
| | - Samuel Sossalla
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.P., M.K., T.S., M.P., T.K., A.P., L.S.M., S. Sossalla)
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany (M.K., F.A., B.W., N.D., G.H., K.S.-B., S. Sossalla)
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Pabel S, Mustroph J, Stehle T, Lebek S, Dybkova N, Keyser A, Rupprecht L, Wagner S, Neef S, Maier LS, Sossalla S. Dantrolene reduces CaMKIIδC-mediated atrial arrhythmias. Europace 2021; 22:1111-1118. [PMID: 32413138 DOI: 10.1093/europace/euaa079] [Citation(s) in RCA: 12] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/10/2020] [Accepted: 03/17/2020] [Indexed: 01/29/2023] Open
Abstract
AIMS In atrial fibrillation (AF), an increased diastolic Ca2+ leak from the sarcoplasmic reticulum (SR) mediated by calcium/calmodulin-dependent-protein-kinaseIIδC (CaMKII) can serve as a substrate for arrhythmia induction and persistence. Dantrolene has been shown to stabilize the cardiac ryanodine-receptor. This study investigated the effects of dantrolene on arrhythmogenesis in human and mouse atria with enhanced CaMKII activity. METHODS AND RESULTS Human atrial cardiomyocytes (CMs) were isolated from patients with AF. To investigate CaMKII-mediated arrhythmogenesis, atrial CMs from mice overexpressing CaMKIIδC (TG) and the respective wildtype (WT) were studied using confocal microscopy (Fluo-4), patch-clamp technique, and in vivo atrial catheter-based burst stimulations. Dantrolene potently reduced Ca2+ spark frequency (CaSpF) and diastolic SR Ca2+ leak in AF CMs. Additional CaMKII inhibition did not further reduce CaSpF or leak compared to dantrolene alone. While the increased SR CaSpF and leak in TG mice were reduced by dantrolene, no effects could be detected in WT. Dantrolene also potently reduced the pathologically enhanced frequency of diastolic SR Ca2+ waves in TG without having effects in WT. As an increased diastolic SR Ca2+ release can induce a depolarizing transient inward current, we could demonstrate that the incidence of afterdepolarizations in TG, but not in WT, mice was significantly diminished in the presence of dantrolene. To translate these findings into an in vivo situation we could show that dantrolene strongly suppressed the inducibility of AF in vivo in TG mice. CONCLUSION Dantrolene reduces CaMKII-mediated atrial arrhythmogenesis and may therefore constitute an interesting antiarrhythmic drug for treating patients with atrial arrhythmias driven by an enhanced CaMKII activity, such as AF.
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Affiliation(s)
- Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Julian Mustroph
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Thea Stehle
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Simon Lebek
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Göttingen, DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075 Göttingen, Germany
| | - Andreas Keyser
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Leopold Rupprecht
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Stefan Neef
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.,Clinic for Cardiology & Pneumology, Georg-August University Göttingen, DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075 Göttingen, Germany
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4
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Treu F, Dybkova N, Jung P, Li Y, Huebscher D, Maurer W, Hasenfuss G, Voigt N, Sossalla S, Wollnik B, Streckfuss-Boemeke K. Genetic variants in calcium regulatory cardiac genes and their contribution to Takotsubo syndrome. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.3712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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 and purpose
Takotsubo syndrome (TTS) is characterized by an acute left ventricular dysfunction similar to a myocardial infarction (MI) in the absence of coronary artery stenosis. Patients show symptoms similar to the acute MI with increased biomarkers and blood serum catecholamines. Recently, we developed a patient-specific TTS stem cell model and identified a higher sensitivity to catecholamine-induced stress. Furthermore, familial TTS cases and genetic studies point to a genetic predisposition. The purpose of this study was to analyze a genetic predisposition by characterizing genetic variants in genes associated with cardiac pathologies and their impact on calcium homoeostasis in TTS.
Methods and results
Whole exome sequencing analysis of a TTS patient discovered 2 missense AHNAK variants in its C-terminal domain and in addition the missense variant F189L in the calcium buffering calsequestrin 2 gene (CASQ2). AHNAK is a 700kDa big nucleoprotein and is involved in the β-adrenergic regulation of the cardiac calcium channel Cav1.2. 3-month old TTS-iPSC-derived cardiomyocytes (CM) were generated and the variants were confirmed by sequencing. We found AHNAK higher expressed in TTS-iPSC-CMs compared to control, whereas no expression alteration was observed for Cav1.2. Since AHNAK is described to act as a repressor towards Cav1.2, which is relieved under β-adrenergic stimulation, we analyzed the effect of AHNAK variants on a potential co-localization and interaction between both proteins. AHNAK and Cav1.2 were shown to co-localize in the cytoplasm as well as the membranes and co-immunoprecipitation experiments confirmed an interaction of AHNAK and Cav1.2 in all tested control- and TTS-iPSC-CMs. On a functional level, we were able to show by patch clamp analysis that Cav1.2 calcium currents are significantly increased in TTS-iPSC-CMs compared to control. The influence of CASQ2-F189L on sarcomeric reticulum (SR) calcium load was analyzed by epifluorescence microscopy using FURA4 and caffeine-applications. We found significantly decreased SR calcium content with an increased fractional release during systole in TTS-iPSC-CMs. To test, whether these variants are the main reason for altered interaction of AHNAK and Cav1.2, calcium currents or SR calcium load in TTS need to be proven in the future by using CRISPR/Cas9-rescued AHNAK/CASQ2 lines.
Conclusion
Here we show the cardiac functional consequences of AHNAK and CASQ2 missense mutations in TTS-iPSC-CMs with regard to calcium currents and SR calcium load. These results show that AHNAK and CASQ2 variants may predispose to TTS and enable a new therapeutic option for TTS.
Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Else Kröner-Fresenius Foundation
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Affiliation(s)
- F Treu
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - N Dybkova
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - P Jung
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - Y Li
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - D Huebscher
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - W Maurer
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - G Hasenfuss
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - N Voigt
- University Medical Center of Gottingen (UMG), Goettingen, Germany
| | - S Sossalla
- University hospital Regensburg, Regensburg, Germany
| | - B Wollnik
- University Medical Center of Gottingen (UMG), Goettingen, Germany
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Dybkova N, Ahmad S, Tirilomis P, Bengel P, Pabel S, Maier L, Hasenfuss G, Sossalla S. CaMKII delta interaction with neuronal sodium channel Nav1.8 contributes to arrhythmogenic triggers in failing human and mouse cardiomyocytes. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.3693] [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
In heart failure, enhanced persistent current through neuronal sodium channel NaV1.8 (INaL) may induce influx of Na+ into cardiomyocytes. This may cause Ca2+ influx via the Na+/Ca2+ exchanger leading to increased proarrhythmogenic diastolic sarcoplasmic reticulum (SR) Ca2+ leak. This Ca2+ may activate Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) which can induce INaL augmentation by phosphorylating NaV1.5 channels leading to a vicious cycle between INaL and CaMKIIδ.
Here, we examined whether CaMKIIδ associates with NaV1.8 in human and mouse cardiomyocytes thereby regulating its function. Interaction and co-localisation of CaMKIIδ and NaV1.8 were confirmed by co-immunoprecipitation and immunocytochemistry. Whole-cell patch clamp showed a potent reduction of INaL after addition of novel specific Nav1.8 blockers, either A-803467 (30 nmol/L) or PF-01247324 (1 μmol/L) in failing mouse cardiomyocytes overexpressing CaMKIIδc (CaMKIIδc+/T: −109.4±10.6 vs A-803467: −56.9±11.7 and PF-01247324:−-69.9±8.6 A*ms*F-1). In failing human cardiomyocytes inhibition of either NaV1.8 or CaMKIIδ using AIP (1 μmol/L) or AIP and PF-01247324 together led to a significant and comparable decrease of INaL (control: −93.7±7.1 vs PF-01247324: −56.8±6.6; AIP: −44.2±6.6; AIP+PF-01247324: −39.8±5.4 A*ms*F-1). Furthermore, to confirm whether observed alterations in INaL after inhibition of NaV1.8 are not due to an overall reduction in peak sodium current (INa) we measured INa properties in mouse cardiomyocytes. Importantly, we observed no difference neither in the peak nor in inactivation between wild type (WT), WT with PF-01247324 and in mice lacking NaV1.8. Using confocal microscopy we investigated whether inhibition of the NaV1.8-mediated INaL could attenuate the increase of proarrhythmogenic SR Ca2+ spark frequency (CaSpF) caused by overexpression of CaMKIIδ in mice. We observed a significant reduction of CaSpF in both NaV1.8 inhibitor groups (PF-01247324: 0.51±0.08 and A-803467: 0.57±0.08 μm–1 s–1) compared to control (1.00±0.13 μm–1 s–1). Incubation of human failing cardiomyocytes with either AIP (0.35±0.06 μm–1 s–1) or PF-01247324 (0.44±0.11 μm–1 s–1), or blocking CaMKIIδ and NaV1.8 together (0.30±0.08 μm–1 s–1) resulted in significant decrease of CaSpF compared to control (0.89±0.13 μm–1 s–1).
In conclusion, we show for the first time subcellular localisation of the neuronal sodium channel NaV1.8 and its interaction with CaMKIIδ in both human and mouse ventricular cardiomyocytes. Moreover, pharmacological inhibition of NaV1.8 caused a reduction of the augmented INaL and spontaneous diastolic SR-Ca2+ release in both failing human and mouse cardiomyocytes. NaV1.8 and CaMKIIδ interaction seem to play a relevant role for the generation of arrhythmogenic triggers (INaL & spontaneous diastolic SR-Ca2+ release) in both human and mouse cardiomyocytes from failing hearts.
Funding Acknowledgement
Type of funding source: None
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Affiliation(s)
- N Dybkova
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S Ahmad
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - P Tirilomis
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - P Bengel
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S Pabel
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
| | - L.S Maier
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
| | - G Hasenfuss
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S Sossalla
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
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6
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Bengel P, Krekeler C, Ahmad S, Hartmann N, Tirilomis P, Maurer W, Toischer K, Maier L, Hasenfuss G, Streckfuss-Boemeke K, Dybkova N, Sossalla S. SCN10A-knock-out improves survival and proarrhythmia in a transgenic heart failure mouse model. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.0877] [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
In heart failure (HF) both Ca2+/Calmodulin-dependent protein-kinase II (CaMKII) and late sodium current (INaL) are known to contribute to arrhythmogenesis as they contribute to action-potential (AP) prolongation and the occurrence of early- (EADs) and delayed afterdepolarizations (DADs). Further, augmented CaMKII and INaL maintain a vicious cycle as they both can activate each other. We recently found that the sodium channel isoform NaV1.8 is upregulated in HF and hypertrophy and that it is involved in INaL-generation. In the current study we investigated the effects of NaV1.8-knock-out (KO) on HF-progression and arrhythmogenesis in a CaMKII-overexpressing HF mouse model.
Methods/Results
CaMKII overexpressing mice (CaMKII+/T) were crossbred with NaV1.8-KO mice (SCN10A−/−). To our surprise knock-out of NaV1.8 in CaMKII+/T mice (SCN10A−/−/CaMKII+/T) significantly improved survival (median survival 103 days vs 74.5 CaMKII+/T, p<0.01). CaMKII+/T mice exhibited a strong HF phenotype compared to WT with increased heart-weight to tibia length ratio as well as reduced ejection fraction and left-ventricular end-diastolic diameter obtained by echocardiography. However, these structural parameters did not differ between SCN10A−/−/CaMKII+/T and CaMKII+/T. Therefore, cellular electrophysiology experiments were performed in isolated cardiomyocytes for a better understanding of the observed improvement in survival. INaL, measured by patch-clamp technique, was significantly augmented in CaMKII+/T vs WT and SCN10A−/−, while SCN10A−/−/CaMKII+/T showed significantly less INaL than CaMKII+/T alone. Further, AP-duration (APD) was significantly reduced in SCN10A−/−/CaMKII+/T vs CaMKII+/T while AP-amplitude, resting membrane-potential and upstroke velocity (dv/dtmax) remained unchanged. In addition, the occurrence of afterdepolarizations was significantly lower in SCN10A−/−/ CaMKII+/T vs CaMKII+/T. Confocal microscopy using the dye Fluo-4AM was performed and significantly less diastolic Ca2+-waves occurred in SCN10A−/−/CaMKII+/T compared to CaMKII+/T. In order to analyze an organ-specific SCN10A-KO, we generated homozygous SCN10A-KO lines of induced pluripotent stem cells by using CRISPR/Cas9 technology. 2-month old iPSC-cardiomyocytes lacking NaV1.8 were treated with low dose isoprenaline and showed significantly less INaL, thereby serving as a final proof of the relevant role of this Na+-channel on INaL-generation in the cardiomyocyte.
Conclusion
We found a survival benefit by selective knock-out of the neuronal sodium channel isoform NaV1.8 in a proarrhythmic HF mouse model with augmented CaMKII expression. However, in our model NaV1.8-knock-out showed no effects on HF progression, while cellular proarrhythmic triggers were attenuated. Taken together with our findings in IPS-cardiomyocytes treated with the CRSIPR/Cas9 technology NaV1.8 plays a significant role for the generation of INaL and cellular arrhythmogenic triggers in the cardiomyocyte.
Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Deutsche Stiftung für Herzforschung
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Affiliation(s)
- P.R.F Bengel
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - C Krekeler
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - S Ahmad
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - N Hartmann
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - P Tirilomis
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - W Maurer
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - K Toischer
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - L.S Maier
- University Hospital Regensburg, Clinic and Polyclinic for Internal Medicine II, Regensburg, Germany
| | - G Hasenfuss
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - K Streckfuss-Boemeke
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - N Dybkova
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - S Sossalla
- University Hospital Regensburg, Clinic and Polyclinic for Internal Medicine II, Regensburg, Germany
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7
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Pabel S, Reetz F, Dybkova N, Shomroni O, Salinas G, Mustroph J, Hammer KP, Hasenfuss G, Hamdani N, Maier LS, Streckfuss-Bömeke K, Sossalla S. Long-term effects of empagliflozin on excitation-contraction-coupling in human induced pluripotent stem cell cardiomyocytes. J Mol Med (Berl) 2020; 98:1689-1700. [PMID: 33034709 PMCID: PMC7679329 DOI: 10.1007/s00109-020-01989-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 05/13/2020] [Revised: 09/11/2020] [Accepted: 10/01/2020] [Indexed: 12/18/2022]
Abstract
Abstract The SGLT2 inhibitor empagliflozin improved cardiovascular outcomes in patients with diabetes. As the cardiac mechanisms remain elusive, we investigated the long-term effects (up to 2 months) of empagliflozin on excitation-contraction (EC)-coupling in human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CM) in a blinded manner. IPSC from 3 donors, differentiated into pure iPSC-CM (4 differentiations), were treated with a clinically relevant concentration of empagliflozin (0.5 μmol/l) or vehicle control. Treatment, data acquisition, and analysis were conducted externally blinded. Epifluorescence microscopy measurements in iPSC-CM showed that empagliflozin has neutral effects on Ca2+ transient amplitude, diastolic Ca2+ levels, Ca2+ transient kinetics, or sarcoplasmic Ca2+ load after 2 weeks or 8 weeks of treatment. Confocal microscopy determining possible effects on proarrhythmogenic diastolic Ca2+ release events showed that in iPSC-CM, Ca2+ spark frequency and leak was not altered after chronic treatment with empagliflozin. Finally, in patch-clamp experiments, empagliflozin did not change action potential duration, amplitude, or resting membrane potential compared with vehicle control after long-term treatment. Next-generation RNA sequencing (NGS) and mapped transcriptome profiles of iPSC-CMs untreated and treated with empagliflozin for 8 weeks showed no differentially expressed EC-coupling genes. In line with NGS data, Western blots indicate that empagliflozin has negligible effects on key EC-coupling proteins. In this blinded study, direct treatment of iPSC-CM with empagliflozin for a clinically relevant duration of 2 months did not influence cardiomyocyte EC-coupling and electrophysiology. Therefore, it is likely that other mechanisms independent of cardiomyocyte EC-coupling are responsible for the beneficial treatment effect of empagliflozin. Key messages This blinded study investigated the clinically relevant long-term effects (up to 2 months) of empagliflozin on cardiomyocyte excitation-contraction (EC)-coupling. Human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CM) were used to study a human model including a high repetition number of experiments. Empagliflozin has neutral effects on cardiomyocyte Ca2+ transients, sarcoplasmic Ca2+ load, and diastolic sarcoplasmic Ca2+ leak. In patch-clamp experiments, empagliflozin did not change the action potential. Next-generation RNA sequencing, mapped transcriptome profiles, and Western blots of iPSC-CM untreated and treated with empagliflozin showed no differentially expressed EC-coupling candidates.
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Affiliation(s)
- Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Florian Reetz
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, and DZHK (German Center for Cardiovascular Research), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Orr Shomroni
- NGS-Integrative Genomics (NIG) Institute Human Genetics (O.S., G.S.), University Medical Center Goettingen, Georg-August University, Goettingen, Germany
| | - Gabriela Salinas
- NGS-Integrative Genomics (NIG) Institute Human Genetics (O.S., G.S.), University Medical Center Goettingen, Georg-August University, Goettingen, Germany
| | - Julian Mustroph
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Karin P Hammer
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, and DZHK (German Center for Cardiovascular Research), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Nazha Hamdani
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, and DZHK (German Center for Cardiovascular Research), Robert-Koch-Str. 40, 37075, Goettingen, Germany.
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, and DZHK (German Center for Cardiovascular Research), Robert-Koch-Str. 40, 37075, Goettingen, Germany.
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8
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Pabel S, Ahmad S, Tirilomis P, Stehle T, Mustroph J, Knierim M, Dybkova N, Bengel P, Holzamer A, Hilker M, Streckfuss-Bömeke K, Hasenfuss G, Maier LS, Sossalla S. Inhibition of Na V1.8 prevents atrial arrhythmogenesis in human and mice. Basic Res Cardiol 2020; 115:20. [PMID: 32078054 PMCID: PMC7033079 DOI: 10.1007/s00395-020-0780-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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] [Received: 12/26/2019] [Accepted: 02/10/2020] [Indexed: 12/19/2022]
Abstract
Pharmacologic approaches for the treatment of atrial arrhythmias are limited due to side effects and low efficacy. Thus, the identification of new antiarrhythmic targets is of clinical interest. Recent genome studies suggested an involvement of SCN10A sodium channels (NaV1.8) in atrial electrophysiology. This study investigated the role and involvement of NaV1.8 (SCN10A) in arrhythmia generation in the human atria and in mice lacking NaV1.8. NaV1.8 mRNA and protein were detected in human atrial myocardium at a significant higher level compared to ventricular myocardium. Expression of NaV1.8 and NaV1.5 did not differ between myocardium from patients with atrial fibrillation and sinus rhythm. To determine the electrophysiological role of NaV1.8, we investigated isolated human atrial cardiomyocytes from patients with sinus rhythm stimulated with isoproterenol. Inhibition of NaV1.8 by A-803467 or PF-01247324 showed no effects on the human atrial action potential. However, we found that NaV1.8 significantly contributes to late Na+ current and consequently to an increased proarrhythmogenic diastolic sarcoplasmic reticulum Ca2+ leak in human atrial cardiomyocytes. Selective pharmacological inhibition of NaV1.8 potently reduced late Na+ current, proarrhythmic diastolic Ca2+ release, delayed afterdepolarizations as well as spontaneous action potentials. These findings could be confirmed in murine atrial cardiomyocytes from wild-type mice and also compared to SCN10A-/- mice (genetic ablation of NaV1.8). Pharmacological NaV1.8 inhibition showed no effects in SCN10A-/- mice. Importantly, in vivo experiments in SCN10A-/- mice showed that genetic ablation of NaV1.8 protects against atrial fibrillation induction. This study demonstrates that NaV1.8 is expressed in the murine and human atria and contributes to late Na+ current generation and cellular arrhythmogenesis. Blocking NaV1.8 selectively counteracts this pathomechanism and protects against atrial arrhythmias. Thus, our translational study reveals a new selective therapeutic target for treating atrial arrhythmias.
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Affiliation(s)
- Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Shakil Ahmad
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Petros Tirilomis
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Thea Stehle
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Julian Mustroph
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Maria Knierim
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Philipp Bengel
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Andreas Holzamer
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Michael Hilker
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
- Clinic for Cardiology and Pneumology, Georg-August University Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany.
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany.
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9
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Dybkova N, Ahmad S, Pabel S, Tirilomis P, Hartmann N, Fischer TH, Bengel P, Tirilomis T, Ljubojevic S, Renner A, Gummert J, Ellenberger D, Wagner S, Frey N, Maier LS, Streckfuss-Bömeke K, Hasenfuss G, Sossalla S. Differential regulation of sodium channels as a novel proarrhythmic mechanism in the human failing heart. Cardiovasc Res 2019; 114:1728-1737. [PMID: 29931291 DOI: 10.1093/cvr/cvy152] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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] [Received: 11/06/2017] [Accepted: 06/15/2018] [Indexed: 12/18/2022] Open
Abstract
Aims In heart failure (HF), enhanced persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. However, the underlying regulatory mechanisms remain unclear. Our aim was to potentially investigate the regulation and electrophysiological contribution of neuronal sodium channel NaV1.8 in failing human heart and eventually to reveal a novel anti-arrhythmic therapy. Methods and results By western blot, we found that NaV1.8 protein expression is significantly up-regulated, while of the predominant cardiac isoform NaV1.5 is inversely reduced in human HF. Furthermore, to investigate the relation of NaV1.8 regulation with the cellular proarrhythmic events, we performed comprehensive electrophysiology recordings and explore the effect of NaV1.8 on INaL, action potential duration (APD), Ca2+ spark frequency, and arrhythmia induction in human failing cardiomyocytes. NaV1.8 inhibition with the specific blockers A-803467 and PF-01247324 decreased INaL, abbreviated APD and reduced cellular-spontaneous Ca2+-release and proarrhythmic events in human failing cardiomyocytes. Consistently, in mouse cardiomyocytes stressed with isoproterenol, pharmacologic inhibition and genetically knockout of NaV1.8 (SCN10A-/-), were associated with reduced INaL and abbreviated APD. Conclusion We provide first evidence of differential regulation of NaV1.8 and NaV1.5 in the failing human myocardium and their contribution to arrhythmogenesis due to generation of INaL. We propose inhibition of NaV1.8 thus constitutes a promising novel approach for selective anti-arrhythmic therapy in HF.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Shakil Ahmad
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Steffen Pabel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Petros Tirilomis
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Nico Hartmann
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Thomas H Fischer
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Philipp Bengel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, Georg-August University Goettingen, Germany
| | | | - André Renner
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - Jan Gummert
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - David Ellenberger
- Department of Medical Statistics, University Medical Center Goettingen, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Campus Kiel, Schleswig-Holstein, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Samuel Sossalla
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
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10
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Tirilomis P, Ahmad S, Bengel P, Pabel S, Maier L, Hasenfuss G, Dybkova N, Sossalla ST. P1596Interaction of CaMKII and NaV1.8 modulates cardiac electrophysiology in human heart failure. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0355] [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
Introduction
In human heart failure, electrical remodeling contributes to the risk of arrhythmia generation. Increased expression of Ca/Calmodulin-dependent protein kinase IIδ (CaMKIIδ) and an enhanced persistent Na current (INaL) have been linked to arrhythmogenesis. CaMKIIδ increases INaL via regulation of sodium channels thereby contributing to arrhythmias through early- and delayed-afterdepolarizations (EADs and DADs). Genome-wide association studies (GWAS) have described the implication of the neuronal sodium channel isoform NaV1.8 (SCN10A) in cardiac electrophysiology showing modulation in cardiac conduction. We showed that the expression of the isoform Nav1.8 is significantly increased in human failing cardiomyocytes and contributes substantially to the enhanced INaL.
Purpose
We investigated a potential interaction of CaMKIIδ and NaV1.8 and thereby its role in arrhythmia generation and electrophysiology in human and murine failing hearts.
Methods
Cardiomyocytes were isolated from explanted failing hearts and CaMKIIδ transgenic (TG) mice. We performed immunostainings and co-immunoprecipitation (Co-IP) to show interactions of CaMKIIδ and Nav1.8 in isolated cardiomyocytes and homogenates. Whole-cell patch clamp experiments were conducted in isolated human and murine ventricular cardiomyocytes. Additionally, Ca2+ transients were measured using epifluorescence microscopy with the Ca2+ dye fura-2 (10μmol/L) whereas Ca2+ sparks measurements were performed by using confocal microscopy with the Ca2+ dye fluo-4 (10μmol/L). PF-01247324 is a novel specific NaV1.8 inhibitor (orally bioavailable; 1 μmol/L) and autocamtide inhibitory peptide (AIP, 1 μmol/L) was used to inhibit CaMKIIδ.
Results
Co-immunoprecipitation experiments revealed an association of CaMKIIδ and Nav1.8 in human homogenates compared to healthy controls. Furthermore, immunohistochemistry stainings in isolated human cardiomyocytes showed a co-localization of CaMKIIδ and NaV1.8 at the intercalated disc and t-tubules. We observed a significant reduction of INaL integral and proarrhythmic SR-Ca2+ spark frequency (CaSpF) after addition of either PF-01247324 or the CaMKIIδ inhibitor AIP in failing human and murine ventricular cardiomyocytes. When PF-01247324 and AIP were added together, the decrease in INaL integral and CaSpF was comparable to PF-01247324 alone in human failing cardiomyocytes. Inhibition of NaV1.8 did not show an effect on Ca2+ transient amplitude or Ca2+ transient decay at different stimulation frequencies in CaMKIIδ TG cardiomyocytes.
Conclusion
Our results demonstrate the significance of both CaMKIIδ and NaV1.8 in INaL generation and their detrimental interaction. This data suggest that increased CaMKIIδ activity plays a substantial role for the activation of NaV1.8-mediated late sodium current and SR-Ca2+ leak.
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Affiliation(s)
- P Tirilomis
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S Ahmad
- University Hospital Regensburg, 2nd Department of Medicine, Regensburg, Germany
| | - P Bengel
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S Pabel
- University Hospital Regensburg, 2nd Department of Medicine, Regensburg, Germany
| | - L Maier
- University Hospital Regensburg, 2nd Department of Medicine, Regensburg, Germany
| | - G Hasenfuss
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - N Dybkova
- University Medical Center of Gottingen (UMG), Gottingen, Germany
| | - S T Sossalla
- University Hospital Regensburg, 2nd Department of Medicine, Regensburg, Germany
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11
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Bengel P, Krekeler C, Ahmad S, Tirilomis P, Toischer K, Dybkova N, Maier LS, Hasenfuss G, Sossalla S. 4966Targeting INaL by a neuronal sodium channel isoform improves survival in a CaMKII-transgenic heart failure mouse model. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz746.0025] [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: 11/12/2022] Open
Abstract
Abstract
Background
Cardiac pathologies like hypertrophy and heart failure are known to be associated with proarrhythmogenic triggers like early- (EADs) and delayed afterdepolarizations (DADs) that can be partly attributed to an augmentation of late sodium current (INaL). Enhanced INaL is closely connected with increased activity of Ca2+/calmodulin dependent-kinase II (CaMKII) in pathology as it is enhanced by CaMKII on the one hand but can also indirectly increase CaMKII-activity on the other. We recently found neuronal sodium channel NaV1.8 to be involved in INaL-augmentation in heart failure and cardiac hypertrophy. Here, we studied possible antiarrhythmic effects of NaV1.8-inhibition in a transgenic mouse model with enhanced CaMKII-expression by selectively knocking out NaV1.8.
Methods/Results
To investigate antiarrhythmic effects of NaV1.8-depletion in-vivo and in-vitro we crossbred CaMKII-transgenic mice (CaMKII+/T) with NaV1.8-knock-out mice (SCN10A−/−). Surprisingly, CaMKII+/T-mice lacking NaV1.8 (CaMKII+/T & SCN10A−/−) showed a significantly improved survival compared to CaMKII+/T alone (97.5 vs 72.0 days, p<0.05). Heart weight to tibia length ratio was significantly increased in CaMKII+/T-mice compared to wild-type, without any differences between CaMKII+/T and CaMKII+/T & SCN10A−/−. To investigate the underlying mechanisms out of this observation we isolated single cardiomyocytes and performed patch-clamp experiments as well as confocal microscopy to measure Ca2+-transients and diastolic Ca2+-waves. INaL-integral was significantly smaller in cardiomyocytes from CaMKII+/T & SCN10A−/−-mice compared to CaMKII+/T alone. During action potential recordings, significantly less afterdepolarizations occurred in CaMKII+/T & SCN10A−/− compared to cardiomyocytes from CaMKII+/T -mice (16.7/min vs 34.9/min, p<0.05). There was a trend of less cells exhibiting diastolic Ca2+-waves in Ca2+-measurements from CaMKII+/T & SCN10A−/− compared to CaMKII+/T (15% vs 25%, p=0.09). As some cells showed more than one event, we calculated the frequency of Ca2+-waves and found a significant reduction of Ca2+-waves in CaMKII+/T & SCN10A−/− vs. CaMKII+/T (22.8/min vs 43.0/min, p<0.05). Moreover, the time to the first event was significantly longer in CaMKII+/T & SCN10A−/−. Ca2+-transient amplitude (F/F0) was significantly lower in CaMKII+/T compared to CaMKII+/T & SCN10A−/− (4.6 vs. 5.3, p=0.05). Further, Ca2+-extrusion from the cytosol was significantly faster in CaMKII+/T & SCN10A−/−.
Conclusion
Our data demonstrates, that inhibition of INaL by targeting NaV1.8 has a potent antiarrhythmic potential as we found a reduction of EADs, DADs and diastolic Ca2+-waves in CaMKII+/T & SCN10A−/−-cardiomyocytes. This antiarrhythmic potential appears to be potent enough to improve survival and to rescue the proarrhythmogenic phenotype of CaMKII-overexpression. However, further in-vivo experiments are necessary to investigate NaV1.8-inhibition for a possible therapeutic approach.
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Affiliation(s)
- P Bengel
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - C Krekeler
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - S Ahmad
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - P Tirilomis
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - K Toischer
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - N Dybkova
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - L S Maier
- University Hospital Regensburg, Clinic and Polyclinic for internal medicine II, Regensburg, Germany
| | - G Hasenfuss
- University Medical Center Gottingen (UMG), Department for Cardiology and Pneumology, Gottingen, Germany
| | - S Sossalla
- University Hospital Regensburg, Clinic and Polyclinic for internal medicine II, Regensburg, Germany
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12
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Ahmad S, Tirilomis P, Pabel S, Dybkova N, Hartmann N, Molina CE, Tirilomis T, Kutschka I, Frey N, Maier LS, Hasenfuss G, Streckfuss-Bömeke K, Sossalla S. The functional consequences of sodium channel Na V 1.8 in human left ventricular hypertrophy. ESC Heart Fail 2018; 6:154-163. [PMID: 30378291 PMCID: PMC6352890 DOI: 10.1002/ehf2.12378] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [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: 06/07/2018] [Revised: 09/18/2018] [Accepted: 10/10/2018] [Indexed: 01/15/2023] Open
Abstract
Aims In hypertrophy and heart failure, the proarrhythmic persistent Na+ current (INaL) is enhanced. We aimed to investigate the electrophysiological role of neuronal sodium channel NaV1.8 in human hypertrophied myocardium. Methods and results Myocardial tissue of 24 patients suffering from symptomatic severe aortic stenosis and concomitant significant afterload‐induced hypertrophy with preserved ejection fraction was used and compared with 12 healthy controls. We performed quantitative real‐time PCR and western blot and detected a significant up‐regulation of NaV1.8 mRNA (2.34‐fold) and protein expression (1.96‐fold) in human hypertrophied myocardium compared with healthy hearts. Interestingly, NaV1.5 protein expression was significantly reduced in parallel (0.60‐fold). Using whole‐cell patch‐clamp technique, we found that the prominent INaL was significantly reduced after addition of novel NaV1.8‐specific blockers either A‐803467 (30 nM) or PF‐01247324 (1 μM) in human hypertrophic cardiomyocytes. This clearly demonstrates the relevant contribution of NaV1.8 to this proarrhythmic current. We observed a significant action potential duration shortening and performed confocal microscopy, demonstrating a 50% decrease in proarrhythmic diastolic sarcoplasmic reticulum (SR)‐Ca2+ leak and SR‐Ca2+ spark frequency after exposure to both NaV1.8 inhibitors. Conclusions We show for the first time that the neuronal sodium channel NaV1.8 is up‐regulated on mRNA and protein level in the human hypertrophied myocardium. Furthermore, inhibition of NaV1.8 reduced augmented INaL, abbreviated the action potential duration, and decreased the SR‐Ca2+ leak. The findings of our study suggest that NaV1.8 could be a promising antiarrhythmic therapeutic target and merits further investigation.
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Affiliation(s)
- Shakil Ahmad
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany.,Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Petros Tirilomis
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Nataliya Dybkova
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Nico Hartmann
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Cristina E Molina
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Georg-August University Goettingen, Goettingen, Germany
| | - Ingo Kutschka
- Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Georg-August University Goettingen, Goettingen, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Katrin Streckfuss-Bömeke
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany.,Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
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13
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Fischer TH, Eiringhaus J, Dybkova N, Saadatmand A, Pabel S, Weber S, Wang Y, Köhn M, Tirilomis T, Ljubojevic S, Renner A, Gummert J, Maier LS, Hasenfuß G, El-Armouche A, Sossalla S. Activation of protein phosphatase 1 by a selective phosphatase disrupting peptide reduces sarcoplasmic reticulum Ca 2+ leak in human heart failure. Eur J Heart Fail 2018; 20:1673-1685. [PMID: 30191648 DOI: 10.1002/ejhf.1297] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [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] [Received: 09/12/2017] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Disruption of Ca2+ homeostasis is a key pathomechanism in heart failure. CaMKII-dependent hyperphosphorylation of ryanodine receptors in the sarcoplasmic reticulum (SR) increases the arrhythmogenic SR Ca2+ leak and depletes SR Ca2+ stores. The contribution of conversely acting serine/threonine phosphatases [protein phosphatase 1 (PP1) and 2A (PP2A)] is largely unknown. METHODS AND RESULTS Human myocardium from three groups of patients was investigated: (i) healthy controls (non-failing, NF, n = 8), (ii) compensated hypertrophy (Hy, n = 16), and (iii) end-stage heart failure (HF, n = 52). Expression of PP1 was unchanged in Hy but greater in HF compared to NF while its endogenous inhibitor-1 (I-1) was markedly lower expressed in both compared to NF, suggesting increased total PP1 activity. In contrast, PP2A expression was lower in Hy and HF compared to NF. Ca2+ homeostasis was severely disturbed in HF compared to Hy signified by a higher SR Ca2+ leak, lower systolic Ca2+ transients as well as a decreased SR Ca2+ load. Inhibition of PP1/PP2A by okadaic acid increased SR Ca2+ load and systolic Ca2+ transients but severely aggravated diastolic SR Ca2+ leak and cellular arrhythmias in Hy. Conversely, selective activation of PP1 by a PP1-disrupting peptide (PDP3) in HF potently reduced SR Ca2+ leak as well as cellular arrhythmias and, importantly, did not compromise systolic Ca2+ release and SR Ca2+ load. CONCLUSION This study is the first to functionally investigate the role of PP1/PP2A for Ca2+ homeostasis in diseased human myocardium. Our data indicate that a modulation of phosphatase activity potently impacts Ca2+ cycling properties. An activation of PP1 counteracts increased kinase activity in heart failure and successfully seals the arrhythmogenic SR Ca2+ leak. It may thus represent a promising future antiarrhythmic therapeutic approach.
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Affiliation(s)
- Thomas H Fischer
- Klinik für Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Germany.,Medizinische Klinik II, Kardiologie, Angiologie, Pneumologie, Klinikum Coburg, Germany.,Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany
| | - Jörg Eiringhaus
- Klinik für Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Germany.,Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany
| | - Nataliya Dybkova
- Klinik für Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Germany.,Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany
| | - Alireza Saadatmand
- Abt. Molekulare Kardiologie und Epigenetik, Universitätsklinikum Heidelberg, Germany
| | - Steffen Pabel
- Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany.,Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Silvio Weber
- Institut für Pharmakologie, Technische Universität Dresden, Germany
| | - Yansong Wang
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Maja Köhn
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany.,Centre for Biological Signalling Studies (BIOSS) and Faculty of Biology, University of Freiburg, Germany
| | - Theodor Tirilomis
- Klinik für Thorax-, Herz-, Gefäßchirurgie, Georg-August-Universität Göttingen, Germany
| | - Senka Ljubojevic
- Abteilung für Kardiologie, Medizinische Universität Graz, Austria
| | - André Renner
- Abteilung für Herz- und Transplantationschirurgie, Herz- und Diabeteszentrum, Bad Oeynhausen, Germany
| | - Jan Gummert
- Abteilung für Herz- und Transplantationschirurgie, Herz- und Diabeteszentrum, Bad Oeynhausen, Germany
| | - Lars S Maier
- Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
| | - Gerd Hasenfuß
- Klinik für Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Germany.,Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany
| | - Ali El-Armouche
- Institut für Pharmakologie, Technische Universität Dresden, Germany
| | - Samuel Sossalla
- Klinik für Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Germany.,Deutsches Zentrum für Herz-Kreislauf Forschung (DZHK), Standort Göttingen, Germany.,Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany
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14
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Ahmad S, Dybkova N, Tirilomis P, Bengel P, Streckfuss-Boemeke K, Maier LS, Hasenfuss G, Sossalla S. P5697Modulation of CaMKII-dependent proarrhythmias by inhibiting Nav1.8 in failing human and mouse ventricular cardiomyocytes. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p5697] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- S Ahmad
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - N Dybkova
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - P Tirilomis
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - P Bengel
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - K Streckfuss-Boemeke
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - L S Maier
- University Hospital Regensburg, Clinic and Polyclinic for Internal Medicine II, Regensburg, Germany
| | - G Hasenfuss
- University Medical Center Gottingen (UMG), Cardiology and Pneumology, Gottingen, Germany
| | - S Sossalla
- University Hospital Regensburg, Clinic and Polyclinic for Internal Medicine II, Regensburg, Germany
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15
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Eiringhaus J, Fischer TH, Dybkova N, Saadatmand A, Pabel S, Weber S, Wang Y, Koehn M, El-Armouche A, Maier LS, Hasenfuss G, Sossalla S. P5703Selective activation of cardiac protein phosphatase 1 is of antiarrhythmic potential in human diseased myocardium. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p5703] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J Eiringhaus
- University clinic, Dept. of Cardiology & Pneumology, Goettingen, Germany
| | - T H Fischer
- Hospital Coburg, Dept. of Cardiology, Angiology & Pneumology, Coburg, Germany
| | - N Dybkova
- University clinic, Dept. of Cardiology & Pneumology, Goettingen, Germany
| | - A Saadatmand
- University Hospital of Heidelberg, Dept. of Molecular Cardiology & Epigenetics, Heidelberg, Germany
| | - S Pabel
- University Hospital Regensburg, Dept. of Cardiology & Pneumology, Regensburg, Germany
| | - S Weber
- Dresden University of Technology, Dept. of Pharmacology & Toxicology, Dresden, Germany
| | - Y Wang
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - M Koehn
- University of Freiburg, Centre for Biological Signalling Studies (BIOSS) and Faculty of Biology, Freiburg, Germany
| | - A El-Armouche
- Dresden University of Technology, Dept. of Pharmacology & Toxicology, Dresden, Germany
| | - L S Maier
- University Hospital Regensburg, Dept. of Cardiology & Pneumology, Regensburg, Germany
| | - G Hasenfuss
- University clinic, Dept. of Cardiology & Pneumology, Goettingen, Germany
| | - S Sossalla
- University Hospital Regensburg, Dept. of Cardiology & Pneumology, Regensburg, Germany
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16
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Dybkova N, Ahmad S, Pabel S, Hartmann N, Tirilomis P, Streckfuss K, Maier L, Frey N, Hasenfuss G, Sossalla S. P4711Contribution of neuronal sodium channel isoform Nav1.8 to enhanced proarrhythmic late sodium current in the human failing heart. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p4711] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- N Dybkova
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - S Ahmad
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - S Pabel
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
| | - N Hartmann
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - P Tirilomis
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - K Streckfuss
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - L Maier
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
| | - N Frey
- University Medical Center of Schleswig-Holstein, Dept. of Internal Medicine III (Cardiology and Angiology), Kiel, Germany
| | - G Hasenfuss
- Dept. Cardiology, University Medical Center, Goettingen, Germany
| | - S Sossalla
- University, Dept. of Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
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17
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Fahmi M, Richter K, Dybkova N, Vettel C, Dewenter M, Fischmeister R, Piorkowski C, El-Armouche A, Sossalla S, Wagner M. P514Investigating the mechanistic role of PDE2 in cardiac arrhythmia. Cardiovasc Res 2018. [DOI: 10.1093/cvr/cvy060.371] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M Fahmi
- Dresden University of Technology, Integrative Center of Pharmacology and Toxicology, Dresden, Germany
| | - K Richter
- Dresden University of Technology, Integrative Center of Pharmacology and Toxicology, Dresden, Germany
| | - N Dybkova
- University Medical Center Gottingen (UMG), Heart Center Gottingen, Department of Cardiology and Pneumology, Gottingen, Germany
| | - C Vettel
- Institute of Experimental and Clinical Pharmacology and Toxicology, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
| | - M Dewenter
- University Hospital of Heidelberg, Molecular Cardiology and Epigenetics, Heidelberg, Germany
| | - R Fischmeister
- University of Paris-Sud 11, INSERM UMR-S 1180, Chatenay-Malabry, France
| | - C Piorkowski
- Heart Center Dresden, Department of Invasive Electrophysiology, Dresden, Germany
| | - A El-Armouche
- Dresden University of Technology, Integrative Center of Pharmacology and Toxicology, Dresden, Germany
| | - S Sossalla
- University Hospital Regensburg, Clinic and Polyclinic for Internal Medicine, Regensburg, Germany
| | - M Wagner
- Heart Center Dresden, Department of Invasive Electrophysiology, Dresden, Germany
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18
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Dybkova N, Ahmad S, Pabel S, Hartmann N, Tirilomis P, Streckfuss K, Maier L, Frey N, Hasenfuss G, Sossalla S. P5302SCN10A/NaV1.8 channels play a critical role in cellular electrophysiology and arrhythmogenesis of the failing human heart. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx493.p5302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Ahmad S, Tirilomis P, Bengel P, Dybkova N, Hasenfuss G, Maier L, Sossalla S. P6283Inhibition of neuronal Na channel NaV1.8 reduces INaL and SR-Ca leak in isolated failing human and mouse ventricular cardiomyocytes. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx493.p6283] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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20
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Neef S, Mann C, Zwenger A, Dybkova N, Maier LS. Reduction of SR Ca2+ leak and arrhythmogenic cellular correlates by SMP-114, a novel CaMKII inhibitor with oral bioavailability. Basic Res Cardiol 2017; 112:45. [DOI: 10.1007/s00395-017-0637-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 06/09/2017] [Indexed: 01/13/2023]
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21
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Fischer TH, Eiringhaus J, Dybkova N, Förster A, Herting J, Kleinwächter A, Ljubojevic S, Schmitto JD, Streckfuß‐Bömeke K, Renner A, Gummert J, Hasenfuss G, Maier LS, Sossalla S. Ca
2+
/calmodulin‐dependent protein kinase
II
equally induces sarcoplasmic reticulum Ca
2+
leak in human ischaemic and dilated cardiomyopathy. Eur J Heart Fail 2014; 16:1292-300. [DOI: 10.1002/ejhf.163] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/28/2014] [Accepted: 08/01/2014] [Indexed: 11/06/2022] Open
Affiliation(s)
- Thomas H. Fischer
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Jörg Eiringhaus
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Nataliya Dybkova
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Anna Förster
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Jonas Herting
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Astrid Kleinwächter
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - Senka Ljubojevic
- Abteilung Kardiologie Medizinische Universitätsklinik Graz Austria
| | - Jan D. Schmitto
- Abteilung Herz‐, Thorax‐, Gefäß‐ und Transplantationschirurgie Medizinische Hochschule Hannover Germany
| | - Katrin Streckfuß‐Bömeke
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
| | - André Renner
- Abteilung Thorax‐, Herz‐, Gefäßchirurgie Herz‐ und Diabeteszentrum Nordrheinwestfalen Bad Oeynhausen Germany
| | - Jan Gummert
- Abteilung Thorax‐, Herz‐, Gefäßchirurgie Herz‐ und Diabeteszentrum Nordrheinwestfalen Bad Oeynhausen Germany
| | - Gerd Hasenfuss
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Goettingen Germany
| | - Lars S. Maier
- Klinik und Poliklinik für Innere Medizin II Uiversitätsklinikum Regensburg Germany
| | - Samuel Sossalla
- Abteilung Kardiologie und Pneumologie/Herzzentrum Georg‐August‐Universität Göttingen Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Goettingen Germany
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22
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Wagner S, Dantz C, Flebbe H, Azizian A, Sag CM, Engels S, Möllencamp J, Dybkova N, Islam T, Shah AM, Maier LS. NADPH oxidase 2 mediates angiotensin II-dependent cellular arrhythmias via PKA and CaMKII. J Mol Cell Cardiol 2014; 75:206-15. [PMID: 25073061 DOI: 10.1016/j.yjmcc.2014.07.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [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] [Received: 01/30/2014] [Revised: 07/01/2014] [Accepted: 07/18/2014] [Indexed: 12/20/2022]
Abstract
RATIONALE Angiotensin II (Ang II) signaling has been implicated in cardiac arrhythmogenesis, which involves induction of reactive oxygen species (ROS). It was shown that Ang II can activate Ca/Calmodulin kinase II (CaMKII) by oxidation via a NADPH oxidase 2 (NOX2)-dependent pathway leading to increased arrhythmic afterdepolarizations. Interestingly, cAMP-dependent protein kinase A (PKA) which regulates similar targets as CaMKII has recently been shown to be redox-sensitive as well. OBJECTIVE This study aims to investigate the distinct molecular mechanisms underlying Ang II-related cardiac arrhythmias with an emphasis on the individual contribution of PKA vs. CaMKII. METHODS AND RESULTS Isolated ventricular cardiac myocytes from rats and mice were used. Ang II exposure resulted in increased NOX2-dependent ROS generation assessed by expression of redox-sensitive GFP and in myocytes loaded with ROS indicator MitoSOX. Whole cell patch clamp measurements showed that Ang II significantly increased peak Ca and Na current (ICa and INa) possibly by enhancing steady-state activation of ICa and INa. These effects were absent in myocytes lacking functional NOX2 (gp91phox(-/-)). In parallel experiments using PKA inhibitor H89, the Ang II effects on peak INa and ICa were also absent. In contrast, genetic knockout of CaMKIIδ (CaMKIIδ(-/-)) did not influence the Ang II-dependent increase in peak ICa and INa. On the other hand, Ang II enhanced INa inactivation, increased late INa and induced diastolic SR (sarcoplasmic reticulum) Ca leak (confocal Ca spark measurements) in a CaMKIIδ-, but not PKA-dependent manner. Surprisingly, only the increase in diastolic SR Ca leak was absent in gp91phox(-/-)myocytes suggesting that Ang II regulates INa inactivation in a manner dependent on CaMKII- but not on NOX2. Finally, we show that Ang II increased the propensity for cellular arrhythmias, for which PKA and CaMKII contribute, both dependent on NOX2. CONCLUSION Ang II activates PKA and CaMKII via NOX2, which results in disturbed Na and Ca currents (via PKA) and enhanced diastolic SR Ca leakage (via CaMKII). Oxidative activation of PKA and CaMKII via NOX2 may represent important pro-arrhythmogenic pathways in the setting of increased Ang II stimulation, which may be relevant for the treatment of arrhythmias in cardiac disease.
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Affiliation(s)
- Stefan Wagner
- Dept. Internal Medicine II, University Hospital Regensburg, Regensburg, Germany; Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Christian Dantz
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Hannah Flebbe
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Azadeh Azizian
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Can Martin Sag
- Dept. Internal Medicine II, University Hospital Regensburg, Regensburg, Germany; Cardiovascular Division, King's College London British Heart Foundation Centre, UK
| | - Susanne Engels
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Johanna Möllencamp
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Towhidul Islam
- Clinic for Cardiology & Pneumology, Georg-August-University Göttingen, and DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Ajay M Shah
- Cardiovascular Division, King's College London British Heart Foundation Centre, UK
| | - Lars S Maier
- Dept. Internal Medicine II, University Hospital Regensburg, Regensburg, Germany.
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23
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Dybkova N, Wagner S, Backs J, Hund TJ, Mohler PJ, Sowa T, Nikolaev VO, Maier LS. Tubulin polymerization disrupts cardiac β-adrenergic regulation of late INa. Cardiovasc Res 2014; 103:168-77. [PMID: 24812278 DOI: 10.1093/cvr/cvu120] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [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: 12/21/2022] Open
Abstract
AIMS The anticancer drug paclitaxel (TXL) that polymerizes microtubules is associated with arrhythmias and sinus node dysfunction. TXL can alter membrane expression of Na channels (NaV1.5) and Na current (INa), but the mechanisms are unknown. Calcium/calmodulin-dependent protein kinase II (CaMKII) can be activated by β-adrenergic stimulation and regulates INa gating. We tested whether TXL interferes with isoproterenol (ISO)-induced activation of CaMKII and consequent INa regulation. METHODS AND RESULTS In wild-type mouse myocytes, the addition of ISO (1 µmol/L) resulted in increased CaMKII auto-phosphorylation (western blotting). This increase was completely abolished after pre-treatment with TXL (100 µmol/L, 1.5 h). The mechanism was further investigated in human embryonic kidney cells. TXL inhibited the ISO-induced β-arrestin translocation. Interestingly, both knockdown of β-arrestin2 expression using small interfering RNA and inhibition of exchange protein directly activated by cAMP (Epac) blocked the ISO-induced CaMKII auto-phosphorylation similar to TXL. The generation of cAMP, however, was unaltered (Epac1-camps). CaMKII-dependent Na channel function was measured using patch-clamp technique in isolated cardiomyoctes. ISO stimulation failed to induce CaMKII-dependent enhancement of late INa and Na channel inactivation (negative voltage shift in steady-state activation and enhanced intermediate inactivation) after pre-incubation with TXL. Consistent with this, TXL also inhibited ISO-induced CaMKII-specific Na channel phosphorylation (at serine 571 of NaV1.5). CONCLUSION Pre-incubation with TXL disrupts the ISO-dependent CaMKII activation and consequent Na channel regulation. This may be important for patients receiving TXL treatments, but also relevant for conditions of increased CaMKII expression and enhanced β-adrenergic stimulation like in heart failure.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Stefan Wagner
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany Department of Internal Medicine II, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany
| | - Johannes Backs
- Department of Cardiology, Angiology and Pneumology, Ruprecht Karls University Heidelberg, Heidelberg, Germany DZHK, Partner Site Heidelberg, Heidelberg, Germany
| | - Thomas J Hund
- Davis Heart and Lung Research Institute, Department of Internal Medicine and Physiology and Cell Biology, Ohio State University Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Davis Heart and Lung Research Institute, Department of Internal Medicine and Physiology and Cell Biology, Ohio State University Medical Center, Columbus, OH, USA
| | - Thomas Sowa
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Viacheslav O Nikolaev
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany
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24
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Dybkova N, Sedej S, Napolitano C, Neef S, Rokita AG, Hünlich M, Brown JH, Kockskämper J, Priori SG, Pieske B, Maier LS. Overexpression of CaMKIIδc in RyR2R4496C+/- knock-in mice leads to altered intracellular Ca2+ handling and increased mortality. J Am Coll Cardiol 2011; 57:469-79. [PMID: 21251589 DOI: 10.1016/j.jacc.2010.08.639] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [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] [Received: 06/08/2010] [Revised: 08/03/2010] [Accepted: 08/12/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVES We investigated whether increased Ca(2+)/calmodulin-dependent kinase II (CaMKII) activity aggravates defective excitation-contraction coupling and proarrhythmic activity in mice expressing R4496C mutated cardiac ryanodine receptors (RyR2). BACKGROUND RyR2 dysfunction is associated with arrhythmic events in inherited and acquired cardiac disease. METHODS CaMKIIδc transgenic mice were crossbred with RyR2(R4496C+/-) knock-in mice. RESULTS Heart weight-to-body weight ratio in CaMKIIδc/RyR2(R4496C) and CaMKIIδc mice was similarly increased approximately 3-fold versus wild-type mice (p < 0.05). Echocardiographic data showed comparable cardiac dilation and impaired contractility in CaMKIIδc/RyR2(R4496C) and CaMKIIδc mice. Sarcoplasmic reticulum Ca(2+) content in isolated myocytes was decreased to a similar extent in CaMKIIδc/RyR2(R4496C) and CaMKIIδc mice. However, relaxation parameters and Ca(2+) decay at 1 Hz were prolonged significantly in CaMKIIδc mice versus CaMKIIδc/RyR2(R4496C) mice. Sarcoplasmic reticulum Ca(2+) spark frequency and characteristics indicated increased sarcoplasmic reticulum Ca(2+) leak in CaMKIIδc/RyR2(R4496C) versus CaMKIIδc myocytes (p < 0.05), most likely because of increased RyR2 phosphorylation. Delayed afterdepolarizations were significantly more frequent with increased amplitudes in CaMKIIδc/RyR2(R4496C) versus CaMKIIδc mice. Increased arrhythmias in vivo (67% vs. 25%; p < 0.05) may explain the increased mortality in CaMKIIδc/RyR2(R4496C) mice, which died prematurely with only 30% alive (vs. 60% for CaMKIIδc, p < 0.05) after 14 weeks. CONCLUSIONS CaMKIIδc overexpression in RyR2(R4496C+/-) knock-in mice increases the propensity toward triggered arrhythmias, which may impair survival. CaMKII contributes to further destabilization of a mutated RyR2 receptor.
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Affiliation(s)
- Nataliya Dybkova
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
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25
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Neef S, Dybkova N, Sossalla S, Ort KR, Fluschnik N, Neumann K, Seipelt R, Schöndube FA, Hasenfuss G, Maier LS. CaMKII-Dependent Diastolic SR Ca
2+
Leak and Elevated Diastolic Ca
2+
Levels in Right Atrial Myocardium of Patients With Atrial Fibrillation. Circ Res 2010; 106:1134-44. [DOI: 10.1161/circresaha.109.203836] [Citation(s) in RCA: 290] [Impact Index Per Article: 20.7] [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: 11/16/2022]
Abstract
Rationale
:
Although research suggests that diastolic Ca
2+
levels might be increased in atrial fibrillation (AF), this hypothesis has never been tested. Diastolic Ca
2+
leak from the sarcoplasmic reticulum (SR) might increase diastolic Ca
2+
levels and play a role in triggering or maintaining AF by transient inward currents through Na
+
/Ca
2+
exchange. In ventricular myocardium, ryanodine receptor type 2 (RyR2) phosphorylation by Ca
2+
/calmodulin-dependent protein kinase (CaMK)II is emerging as an important mechanism for SR Ca
2+
leak.
Objective
:
We tested the hypothesis that CaMKII-dependent diastolic SR Ca
2+
leak and elevated diastolic Ca
2+
levels occurs in atrial myocardium of patients with AF.
Methods and Results
:
We used isolated human right atrial myocytes from patients with AF versus sinus rhythm and found CaMKII expression to be increased by 40±14% (
P
<0.05), as well as CaMKII phosphorylation by 33±12% (
P
<0.05). This was accompanied by a significantly increased RyR2 phosphorylation at the CaMKII site (Ser2814) by 110±53%. Furthermore, cytosolic Ca
2+
levels were elevated during diastole (229±20 versus 164±8 nmol/L,
P
<0.05). Most likely, this resulted from an increased SR Ca
2+
leak in AF (
P
<0.05), which was not attributable to higher SR Ca
2+
load. Tetracaine experiments confirmed that SR Ca
2+
leak through RyR2 leads to the elevated diastolic Ca
2+
level. CaMKII inhibition normalized SR Ca
2+
leak and cytosolic Ca
2+
levels without changes in L-type Ca
2+
current.
Conclusion
:
Increased CaMKII-dependent phosphorylation of RyR2 leads to increased SR Ca
2+
leak in human AF, causing elevated cytosolic Ca
2+
levels, thereby providing a potential arrhythmogenic substrate that could trigger or maintain AF.
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Affiliation(s)
- Stefan Neef
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Nataliya Dybkova
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Samuel Sossalla
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Katharina R. Ort
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Nina Fluschnik
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Kay Neumann
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Ralf Seipelt
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Friedrich A. Schöndube
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Gerd Hasenfuss
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
| | - Lars S. Maier
- From the Departments of Cardiology and Pneumology (S.N., N.D., S.S., K.R.O., N.F., K.N., G.H., L.S.M.) and Thoracic and Cardiovascular Surgery (R.S., F.A.S.), Georg-August-University, Göttingen, Germany
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26
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Sedej S, Heinzel FR, Walther S, Dybkova N, Wakula P, Groborz J, Gronau P, Maier LS, Vos MA, Lai FA, Napolitano C, Priori SG, Kockskämper J, Pieske B. Na+-dependent SR Ca2+ overload induces arrhythmogenic events in mouse cardiomyocytes with a human CPVT mutation. Cardiovasc Res 2010; 87:50-9. [PMID: 20080988 DOI: 10.1093/cvr/cvq007] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [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
AIMS Mutations in the cardiac ryanodine receptor Ca(2+) release channel, RyR2, underlie catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited life-threatening arrhythmia. CPVT is triggered by spontaneous RyR2-mediated sarcoplasmic reticulum (SR) Ca(2+) release in response to SR Ca(2+) overload during beta-adrenergic stimulation. However, whether elevated SR Ca(2+) content--in the absence of protein kinase A activation--affects RyR2 function and arrhythmogenesis in CPVT remains elusive. METHODS AND RESULTS Isolated murine ventricular myocytes harbouring a human RyR2 mutation (RyR2(R4496C+/-)) associated with CPVT were investigated in the absence and presence of 1 micromol/L JTV-519 (RyR2 stabilizer) followed by 100 micromol/L ouabain intervention to increase cytosolic [Na(+)] and SR Ca(2+) load. Changes in membrane potential and intracellular [Ca(2+)] were monitored with whole-cell patch-clamping and confocal Ca(2+) imaging, respectively. At baseline, action potentials (APs), Ca(2+) transients, fractional SR Ca(2+) release, and SR Ca(2+) load were comparable in wild-type (WT) and RyR2(R4496C+/-) myocytes. Ouabain evoked significant increases in diastolic [Ca(2+)], peak systolic [Ca(2+)], fractional SR Ca(2+) release, and SR Ca(2+) content that were quantitatively similar in WT and RyR2(R4496C+/-) myocytes. Ouabain also induced arrhythmogenic events, i.e. spontaneous Ca(2+) waves, delayed afterdepolarizations and spontaneous APs, in both groups. However, the ouabain-induced increase in the frequency of arrhythmogenic events was dramatically larger in RyR2(R4496C+/-) when compared with WT myocytes. JTV-519 greatly reduced the frequency of ouabain-induced arrhythmogenic events. CONCLUSION The elevation of SR Ca(2+) load--in the absence of beta-adrenergic stimulation--is sufficient to increase the propensity for triggered arrhythmias in RyR2(R4496C+/-) cardiomyocytes. Stabilization of RyR2 by JTV-519 effectively reduces these triggered arrhythmias.
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Affiliation(s)
- Simon Sedej
- Division of Cardiology, Medical University of Graz, Auenbruggerplatz 15, Graz A-8036, Austria
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27
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Wagner S, Hacker E, Grandi E, Weber SL, Dybkova N, Sossalla S, Sowa T, Fabritz L, Kirchhof P, Bers DM, Maier LS. Ca/calmodulin kinase II differentially modulates potassium currents. Circ Arrhythm Electrophysiol 2009; 2:285-94. [PMID: 19808479 DOI: 10.1161/circep.108.842799] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Potassium currents contribute to action potential duration (APD) and arrhythmogenesis. In heart failure, Ca/calmodulin-dependent protein kinase II (CaMKII) is upregulated and can alter ion channel regulation and expression. METHODS AND RESULTS We examine the influence of overexpressing cytoplasmic CaMKIIdelta(C), both acutely in rabbit ventricular myocytes (24-hour adenoviral gene transfer) and chronically in CaMKIIdelta(C)-transgenic mice, on transient outward potassium current (I(to)), and inward rectifying current (I(K1)). Acute and chronic CaMKII overexpression increases I(to,slow) amplitude and expression of the underlying channel protein K(V)1.4. Chronic but not acute CaMKII overexpression causes downregulation of I(to,fast), as well as K(V)4.2 and KChIP2, suggesting that K(V)1.4 expression responds faster and oppositely to K(V)4.2 on CaMKII activation. These amplitude changes were not reversed by CaMKII inhibition, consistent with CaMKII-dependent regulation of channel expression and/or trafficking. CaMKII (acute and chronic) greatly accelerated recovery from inactivation for both I(to) components, but these effects were acutely reversed by AIP (CaMKII inhibitor), suggesting that CaMKII activity directly accelerates I(to) recovery. Expression levels of I(K1) and Kir2.1 mRNA were downregulated by CaMKII overexpression. CaMKII acutely increased I(K1), based on inhibition by AIP (in both models). CaMKII overexpression in mouse prolonged APD (consistent with reduced I(to,fast) and I(K1)), whereas CaMKII overexpression in rabbit shortened APD (consistent with enhanced I(K1) and I(to,slow) and faster I(to) recovery). Computational models allowed discrimination of contributions of different channel effects on APD. CONCLUSIONS CaMKII has both acute regulatory effects and chronic expression level effects on I(to) and I(K1) with complex consequences on APD.
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Affiliation(s)
- Stefan Wagner
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
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28
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Sag CM, Dybkova N, Neef S, Maier LS. Effects on recovery during acidosis in cardiac myocytes overexpressing CaMKII. J Mol Cell Cardiol 2007; 43:696-709. [DOI: 10.1016/j.yjmcc.2007.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 09/07/2007] [Accepted: 09/20/2007] [Indexed: 10/22/2022]
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29
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Zhang T, Kohlhaas M, Backs J, Mishra S, Phillips W, Dybkova N, Chang S, Ling H, Bers DM, Maier LS, Olson EN, Brown JH. CaMKIIdelta isoforms differentially affect calcium handling but similarly regulate HDAC/MEF2 transcriptional responses. J Biol Chem 2007; 282:35078-87. [PMID: 17923476 DOI: 10.1074/jbc.m707083200] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The delta(B) and delta(C) splice variants of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), which differ by the presence of a nuclear localization sequence, are both expressed in cardiomyocytes. We used transgenic (TG) mice and CaMKII expression in cardiomyocytes to test the hypothesis that the CaMKIIdelta(C) isoform regulates cytosolic Ca(2+) handling and the delta(B) isoform, which localizes to the nucleus, regulates gene transcription. Phosphorylation of CaMKII sites on the ryanodine receptor (RyR) and on phospholamban (PLB) were increased in CaMKIIdelta(C) TG. This was associated with markedly enhanced sarcoplasmic reticulum (SR) Ca(2+) spark frequency and decreased SR Ca(2+) content in cardiomyocytes. None of these parameters were altered in TG mice expressing the nuclear-targeted CaMKIIdelta(B). In contrast, cardiac expression of either CaMKIIdelta(B) or delta(C) induced transactivation of myocyte enhancer factor 2 (MEF2) gene expression and up-regulated hypertrophic marker genes. Studies using rat ventricular cardiomyocytes confirmed that CaMKIIdelta(B) and delta(C) both regulate MEF2-luciferase gene expression, increase histone deacetylase 4 (HDAC4) association with 14-3-3, and induce HDAC4 translocation from nucleus to cytoplasm, indicating that either isoform can stimulate HDAC4 phosphorylation. Finally, HDAC4 kinase activity was shown to be increased in cardiac homogenates from either CaMKIIdelta(B) or delta(C) TG mice. Thus CaMKIIdelta isoforms have similar effects on hypertrophic gene expression but disparate effects on Ca(2+) handling, suggesting distinct roles for CaMKIIdelta isoform activation in the pathogenesis of cardiac hypertrophy versus heart failure.
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Affiliation(s)
- Tong Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0636, USA.
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30
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Yurukova S, Kilić A, Völker K, Leineweber K, Dybkova N, Maier LS, Brodde OE, Kuhn M. CaMKII-mediated increased lusitropic responses to β-adrenoreceptor stimulation in ANP-receptor deficient mice. Cardiovasc Res 2007; 73:678-88. [PMID: 17107670 DOI: 10.1016/j.cardiores.2006.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [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: 02/27/2006] [Revised: 09/23/2006] [Accepted: 10/04/2006] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Mice with genetic disruption of the guanylyl cyclase-A (GC-A) receptor for atrial natriuretic peptide (ANP), have chronic arterial hypertension and marked cardiac hypertrophy. Intriguingly, despite pronounced remodeling, cardiac contractile functions and cardiomyocyte Ca(2+)-handling are preserved and even enhanced. The present study aimed to characterize the specific molecular mechanisms preventing cardiac failure. METHODS AND RESULTS Contractile function and expression as well as phosphorylation of regulatory proteins were evaluated in isolated perfused working hearts from wild-type and GC-A KO mice under baseline conditions and during beta(1)-adrenergic stimulation. Ca(i)(2+)-transients were monitored in Indo-1 loaded isolated adult cardiomyocytes. Cardiac contractile, especially lusitropic responsiveness to beta-adrenergic stimulation was significantly increased in GC-A KO mice. This was concomitant to enhanced expression and activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), increased dual-site phosphorylation of phospholamban (PLB) at Ser(16) and Thr(17), enhanced amplitude of Ca(i)(2+) transients, and accelerated Ca(i)(2+) decay. In contrast, the expression of cardiac ryanodine receptors and phosphorylation at Ser(2809) and Ser(2815) was not altered. Pharmacological inhibition of CaMKII-but not of protein kinase A-mediated PLB phosphorylation totally abolished the increased effects of beta-adrenergic stimulation on cardiac contractility and Ca(i)(2+)-handling. Thus, acceleration of sarcoplasmic reticulum Ca(2+)-uptake and increased availability of Ca(2+) for contraction, both secondary to increased CaMKII-mediated PLB phosphorylation, seem to mediate the augmented responsiveness of GC-A KO hearts to catecholamines. CONCLUSION Our observations show that increased CaMKII activity enhances the contractile relaxation response of hypertrophic GC-A KO hearts to beta-adrenergic stimulation and emphasize the critical role of CaMKII-dependent pathways in beta(1)-adrenoreceptor modulation of myocardial Ca(2+)-homeostasis and contractility.
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Affiliation(s)
- Sevdalina Yurukova
- Institute of Physiology, University of Würzburg, Röntgenring 9, D-97070 Würzburg, Germany
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31
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Wagner S, Dybkova N, Rasenack EC, Jacobshagen C, Fabritz L, Kirchhof P, Maier SK, Zhang T, Hasenfuss G, Brown JH, Bers DM, Maier LS. Ca2+/calmodulin-dependent protein kinase II regulates cardiac Na+ channels. J Clin Invest 2006; 116:3127-38. [PMID: 17124532 PMCID: PMC1654201 DOI: 10.1172/jci26620] [Citation(s) in RCA: 400] [Impact Index Per Article: 22.2] [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: 08/18/2005] [Accepted: 10/03/2006] [Indexed: 01/01/2023] Open
Abstract
In heart failure (HF), Ca(2+)/calmodulin kinase II (CaMKII) expression is increased. Altered Na(+) channel gating is linked to and may promote ventricular tachyarrhythmias (VTs) in HF. Calmodulin regulates Na(+) channel gating, in part perhaps via CaMKII. We investigated effects of adenovirus-mediated (acute) and Tg (chronic) overexpression of cytosolic CaMKIIdelta(C) on Na(+) current (I(Na)) in rabbit and mouse ventricular myocytes, respectively (in whole-cell patch clamp). Both acute and chronic CaMKIIdelta(C) overexpression shifted voltage dependence of Na(+) channel availability by -6 mV (P < 0.05), and the shift was Ca(2+) dependent. CaMKII also enhanced intermediate inactivation and slowed recovery from inactivation (prevented by CaMKII inhibitors autocamtide 2-related inhibitory peptide [AIP] or KN93). CaMKIIdelta(C) markedly increased persistent (late) inward I(Na) and intracellular Na(+) concentration (as measured by the Na(+) indicator sodium-binding benzofuran isophthalate [SBFI]), which was prevented by CaMKII inhibition in the case of acute CaMKIIdelta(C) overexpression. CaMKII coimmunoprecipitates with and phosphorylates Na(+) channels. In vivo, transgenic CaMKIIdelta(C) overexpression prolonged QRS duration and repolarization (QT intervals), decreased effective refractory periods, and increased the propensity to develop VT. We conclude that CaMKII associates with and phosphorylates cardiac Na(+) channels. This alters I(Na) gating to reduce availability at high heart rate, while enhancing late I(Na) (which could prolong action potential duration). In mice, enhanced CaMKIIdelta(C) activity predisposed to VT. Thus, CaMKII-dependent regulation of Na(+) channel function may contribute to arrhythmogenesis in HF.
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Affiliation(s)
- Stefan Wagner
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Nataliya Dybkova
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Eva C.L. Rasenack
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Claudius Jacobshagen
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Larissa Fabritz
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Paulus Kirchhof
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Sebastian K.G. Maier
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Tong Zhang
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Joan Heller Brown
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Donald M. Bers
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Lars S. Maier
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany.
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany.
Department of Medicine I, Division of Cardiology, University of Würzburg, Würzburg, Germany.
Department of Pharmacology, UCSD, La Jolla, California, USA.
Department of Physiology, Loyola University Chicago, Chicago, Illinois, USA
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Maier LS, Wahl-Schott C, Horn W, Weichert S, Pagel C, Wagner S, Dybkova N, Müller OJ, Näbauer M, Franz WM, Pieske B. Increased SR Ca2+ cycling contributes to improved contractile performance in SERCA2a-overexpressing transgenic rats. Cardiovasc Res 2006; 67:636-46. [PMID: 15932750 DOI: 10.1016/j.cardiores.2005.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [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: 01/07/2005] [Revised: 04/18/2005] [Accepted: 05/01/2005] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVE Heart failure is associated with reduced function of sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) but increased function of sarcolemmal Na+/Ca2+ exchanger (NCX), leading to decreased SR Ca2+ content and loss of frequency-potentiation of contractile force. We reported that SERCA2a-overexpression in transgenic rat hearts (TG) results in improved contractility. However, it was not clear whether TG have improved contractility due to frequency-dependent improved SR Ca2+ handling. METHODS Therefore, we characterized TG (n=35) vs. wild-type (WT) control rats (n=39) under physiological conditions (37 degrees C, stimulation rate <8 Hz). Twitch force, intracellular Ca2+ transients ([Ca2+]i), and SR Ca2+ content were measured in isolated muscles. The contribution of transsarcolemmal Ca2+ influx (I(Ca)) through L-type Ca2+ channels (LTCC) and reverse mode NCX (I(Na/Ca)) to Ca2+ cycling were studied in isolated myocytes. RESULTS With increasing frequency, force increased in TG muscles by 168+/-35% (8 Hz; P<0.05) and SR Ca2+ content increased by maximally 118+/-31% (4 Hz; P<0.05). In WT, there was a flat force-frequency response without changes in SR Ca2+ content. Relaxation parameters of force and [Ca2+]i decay were accelerated at each frequency in TG vs. WT by approximately 10%. At prolonged rest intervals (<240 s), force and SR Ca2+ content increased significantly more in TG. Consequently, absolute SR Ca2+ content measured in myocytes was increased approximately 2-fold in TG. Transsarcolemmal Ca2+ fluxes estimated by I(Ca) (at 0 mV -10.2+/-1.1 vs. -16.9+/-1.3 pA/pF) and I(Na/Ca) (0.17+/-0.02 vs. 0.46+/-0.05 pA/pF) were decreased in TG vs. WT (P<0.05), whereas NCX and LTCC protein expression was only slightly reduced (P=n.s.). CONCLUSION In summary, SERCA2a-overexpression improved contractility in a frequency-dependent way due to increased SR Ca2+ loading whereas transsarcolemmal Ca2+ fluxes were decreased.
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Affiliation(s)
- Lars S Maier
- Abt. Kardiologie and Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Germany
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33
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Kohlhaas M, Zhang T, Seidler T, Zibrova D, Dybkova N, Steen A, Wagner S, Chen L, Brown JH, Bers DM, Maier LS. Increased Sarcoplasmic Reticulum Calcium Leak but Unaltered Contractility by Acute CaMKII Overexpression in Isolated Rabbit Cardiac Myocytes. Circ Res 2006; 98:235-44. [PMID: 16373600 DOI: 10.1161/01.res.0000200739.90811.9f] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The predominant cardiac Ca
2+
/calmodulin-dependent protein kinase (CaMK) is CaMKIIδ. Here we acutely overexpress CaMKIIδ
C
using adenovirus-mediated gene transfer in adult rabbit ventricular myocytes. This circumvents confounding adaptive effects in CaMKIIδ
C
transgenic mice. CaMKIIδ
C
protein expression and activation state (autophosphorylation) were increased 5- to 6-fold. Basal twitch contraction amplitude and kinetics (1 Hz) were not changed in CaMKIIδ
C
versus LacZ expressing myocytes. However, the contraction–frequency relationship was more negative, frequency-dependent acceleration of relaxation was enhanced (τ
0.5Hz
/τ
3Hz
=2.14±0.10 versus 1.87±0.10), and peak Ca
2+
current (
I
Ca
) was increased by 31% (−7.1±0.5 versus −5.4±0.5 pA/pF,
P
<0.05). Ca
2+
transient amplitude was not significantly reduced (−27%,
P
=0.22), despite dramatically reduced sarcoplasmic reticulum (SR) Ca
2+
content (41%;
P
<0.05). Thus fractional SR Ca
2+
release was increased by 60% (
P
<0.05). Diastolic SR Ca
2+
leak assessed by Ca
2+
spark frequency (normalized to SR Ca
2+
load) was increased by 88% in CaMKIIδ
C
versus LacZ myocytes (
P
<0.05; in an multiplicity-of-infection–dependent manner), an effect blocked by CaMKII inhibitors KN-93 and autocamtide-2–related inhibitory peptide. This enhanced SR Ca
2+
leak may explain reduced SR Ca
2+
content, despite measured levels of SR Ca
2+
-ATPase and Na
+
/Ca
2+
exchange expression and function being unaltered. Ryanodine receptor (RyR) phosphorylation in CaMKIIδ
C
myocytes was increased at both Ser2809 and Ser2815, but FKBP12.6 coimmunoprecipitation with RyR was unaltered. This shows for the first time that acute CaMKIIδ
C
overexpression alters RyR function, leading to enhanced SR Ca
2+
leak and reduced SR Ca
2+
content but without reducing twitch contraction and Ca
2+
transients. We conclude that this is attributable to concomitant enhancement of fractional SR Ca
2+
release in CaMKIIδ
C
myocytes (ie, CaMKII-dependent enhancement of RyR Ca
2+
sensitivity during diastole and systole) and increased
I
Ca
.
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Affiliation(s)
- Michael Kohlhaas
- Abteilung Kardiologie & Pneumologie/Herzzentrum, Georg-August-Universität Göttingen, Germany
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