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Zhao S, Hulsurkar MM, Lahiri SK, Aguilar-Sanchez Y, Munivez E, Müller FU, Jain A, Malovannaya A, Yiu CHK, Reilly S, Wehrens XHT. Atrial proteomic profiling reveals a switch towards profibrotic gene expression program in CREM-IbΔC-X mice with persistent atrial fibrillation. J Mol Cell Cardiol 2024; 190:1-12. [PMID: 38514002 DOI: 10.1016/j.yjmcc.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/19/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
BACKGROUND Overexpression of the CREM (cAMP response element-binding modulator) isoform CREM-IbΔC-X in transgenic mice (CREM-Tg) causes the age-dependent development of spontaneous AF. PURPOSE To identify key proteome signatures and biological processes accompanying the development of persistent AF through integrated proteomics and bioinformatics analysis. METHODS Atrial tissue samples from three CREM-Tg mice and three wild-type littermates were subjected to unbiased mass spectrometry-based quantitative proteomics, differential expression and pathway enrichment analysis, and protein-protein interaction (PPI) network analysis. RESULTS A total of 98 differentially expressed proteins were identified. Gene ontology analysis revealed enrichment for biological processes regulating actin cytoskeleton organization and extracellular matrix (ECM) dynamics. Changes in ITGAV, FBLN5, and LCP1 were identified as being relevant to atrial fibrosis and structural based on expression changes, co-expression patterns, and PPI network analysis. Comparative analysis with previously published datasets revealed a shift in protein expression patterns from ion-channel and metabolic regulators in young CREM-Tg mice to profibrotic remodeling factors in older CREM-Tg mice. Furthermore, older CREM-Tg mice exhibited protein expression patterns reminiscent of those seen in humans with persistent AF. CONCLUSIONS This study uncovered distinct temporal changes in atrial protein expression patterns with age in CREM-Tg mice consistent with the progressive evolution of AF. Future studies into the role of the key differentially abundant proteins identified in this study in AF progression may open new therapeutic avenues to control atrial fibrosis and substrate development in AF.
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Affiliation(s)
- Shuai Zhao
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mohit M Hulsurkar
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Satadru K Lahiri
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuriana Aguilar-Sanchez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elda Munivez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Antrix Jain
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA
| | - Anna Malovannaya
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA; Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chi Him Kendrick Yiu
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, NIHR Oxford BRC, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, NIHR Oxford BRC, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Medicine (in Cardiology), Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics (in Cardiology), Baylor College of Medicine, Houston, TX 77030, USA; Center for Space Medicine, Baylor College of Medicine, Houston, USA.
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Zhao S, Hulsurkar MM, Lahiri SK, Aguilar-Sanchez Y, Munivez E, Müller FU, Jain A, Malovannaya A, Yiu K, Reilly S, Wehrens XH. Atrial Proteomic Profiling Reveals a Switch Towards Profibrotic Gene Expression Program in CREM-IbΔC-X Mice with Persistent Atrial Fibrillation. bioRxiv 2024:2024.01.10.575097. [PMID: 38260363 PMCID: PMC10802622 DOI: 10.1101/2024.01.10.575097] [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] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Background Overexpression of the CREM (cAMP response element-binding modulator) isoform CREM-IbΔC-X in transgenic mice (CREM-Tg) causes the age-dependent development of spontaneous AF. Purpose To identify key proteome signatures and biological processes accompanying the development of persistent AF through integrated proteomics and bioinformatics analysis. Methods Atrial tissue samples from three CREM-Tg mice and three wild-type littermates were subjected to unbiased mass spectrometry-based quantitative proteomics, differential expression and pathway enrichment analysis, and protein-protein interaction (PPI) network analysis. Results A total of 98 differentially expressed proteins were identified. Gene ontology analysis revealed enrichment for biological processes regulating actin cytoskeleton organization and extracellular matrix (ECM) dynamics. Changes in ITGAV, FBLN5, and LCP1 were identified as being relevant to atrial fibrosis and remodeling based on expression changes, co-expression patterns, and PPI network analysis. Comparative analysis with previously published datasets revealed a shift in protein expression patterns from ion-channel and metabolic regulators in young CREM-Tg mice to profibrotic remodeling factors in older CREM-Tg mice. Furthermore, older CREM-Tg mice exhibited protein expression patterns that resembled those of humans with persistent AF. Conclusions This study uncovered distinct temporal changes in atrial protein expression patterns with age in CREM-Tg mice consistent with the progressive evolution of AF. Future studies into the role of the key differentially abundant proteins identified in this study in AF progression may open new therapeutic avenues to control atrial fibrosis and substrate development in AF.
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Affiliation(s)
- Shuai Zhao
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mohit M. Hulsurkar
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Satadru K. Lahiri
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuriana Aguilar-Sanchez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elda Munivez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Antrix Jain
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA
| | - Anna Malovannaya
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA
- Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kendrick Yiu
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, NIHR Oxford BRC, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, NIHR Oxford BRC, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Xander H.T. Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Medicine (in Cardiology), Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics (in Cardiology), Baylor College of Medicine, Houston, TX 77030, USA
- Center for Space Medicine, Baylor College of Medicine, Houston, USA
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Rohrbeck M, Hoerr V, Piccini I, Greber B, Schulte JS, Hübner SS, Jeworutzki E, Theiss C, Matschke V, Stypmann J, Unger A, Ho HT, Disse P, Strutz-Seebohm N, Faber C, Müller FU, Ludwig S, Rescher U, Linke WA, Klingel K, Busch K, Peischard S, Seebohm G. Pathophysiological Mechanisms of Cardiac Dysfunction in Transgenic Mice with Viral Myocarditis. Cells 2023; 12:cells12040550. [PMID: 36831217 PMCID: PMC9954433 DOI: 10.3390/cells12040550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/21/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Viral myocarditis is pathologically associated with RNA viruses such as coxsackievirus B3 (CVB3), or more recently, with SARS-CoV-2, but despite intensive research, clinically proven treatment is limited. Here, by use of a transgenic mouse strain (TG) containing a CVB3ΔVP0 genome we unravel virus-mediated cardiac pathophysiological processes in vivo and in vitro. Cardiac function, pathologic ECG alterations, calcium homeostasis, intracellular organization and gene expression were significantly altered in transgenic mice. A marked alteration of mitochondrial structure and gene expression indicates mitochondrial impairment potentially contributing to cardiac contractile dysfunction. An extended picture on viral myocarditis emerges that may help to develop new treatment strategies and to counter cardiac failure.
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Affiliation(s)
- Matthias Rohrbeck
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Verena Hoerr
- Translational Research Imaging Center, Clinic of Radiology, University Hospital Münster, D-48149 Münster, Germany
| | - Ilaria Piccini
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Boris Greber
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
- Chemical Genomics Centre of the Max Planck Society, 44227 Dortmund, Germany
| | - Jan Sebastian Schulte
- Institute of Pharmacology and Toxicology, University Hospital Münster, D-48149 Münster, Germany
| | - Sara-Sophie Hübner
- Translational Research Imaging Center, Clinic of Radiology, University Hospital Münster, D-48149 Münster, Germany
| | - Elena Jeworutzki
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Veronika Matschke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Jörg Stypmann
- Department of Cardiovascular Medicine, Division of Cardiology, University Clinic Münster, 48149 Münster, Germany
| | - Andreas Unger
- Institute of Physiology II, Faculty of Medicine, University of Münster, D-48149 Münster, Germany
| | - Huyen Tran Ho
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Paul Disse
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Nathalie Strutz-Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Clinic of Radiology, University Hospital Münster, D-48149 Münster, Germany
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University Hospital Münster, D-48149 Münster, Germany
| | - Stephan Ludwig
- Institute of Virology Münster (IVM), Centre for Molecular Biology of Inflammation (ZMBE), University of Münster, D-48149 Münster, Germany
| | - Ursula Rescher
- Research Group Regulatory Mechanisms of Inflammation, Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation, University of Muenster, 48149 Muenster, Germany
| | - Wolfgang A. Linke
- Institute of Physiology II, Faculty of Medicine, University of Münster, D-48149 Münster, Germany
| | - Karin Klingel
- Cardiopathology, Institute for Pathology and Neuropathology, University Hospital of Tübingen, D-72076 Tübingen, Germany
| | - Karin Busch
- Institute of Integrative Cell Biology and Physiology, Faculty of Biology, University of Muenster, Schlossplatz 5, 48149 Muenster, Germany
| | - Stefan Peischard
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
- Correspondence: (S.P.); (G.S.); Tel.: +49-(0)-251/83-58255 (S.P.); +49-(0)-251/83-58251 (G.S.); Fax: +49-(0)-251/83-58257 (S.P. & G.S.)
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
- Correspondence: (S.P.); (G.S.); Tel.: +49-(0)-251/83-58255 (S.P.); +49-(0)-251/83-58251 (G.S.); Fax: +49-(0)-251/83-58257 (S.P. & G.S.)
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Ludwig S, Blass-Kampmann S, Müller FU. Molecular determinants of health and disease. Biol Chem 2021; 402:1479. [PMID: 34700365 DOI: 10.1515/hsz-2021-0390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Stephan Ludwig
- Institute of Virology, University of Münster, Centre for Molecular Biology of Inflammation (ZMBE), Von-Esmarch-Straße 56, Münster, Germany.,Interdisciplinary Centre for Clinical Research (IZKF), Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, Building D3, 48149 Münster, Germany
| | - Sabine Blass-Kampmann
- Interdisciplinary Centre for Clinical Research (IZKF), Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, Building D3, 48149 Münster, Germany
| | - Frank Ulrich Müller
- Deanery of the Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, Münster, Germany
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Ni L, Lahiri SK, Nie J, Pan X, Abu-Taha I, Reynolds JO, Campbell HM, Wang H, Kamler M, Schmitz W, Müller FU, Li N, Wei X, Wang DW, Dobrev D, Wehrens XHT. Genetic inhibition of Nuclear Factor of Activated T-cell c2 (NFATc2) prevents atrial fibrillation in CREM transgenic mice. Cardiovasc Res 2021; 118:2805-2818. [PMID: 34648001 PMCID: PMC9586567 DOI: 10.1093/cvr/cvab325] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 10/11/2021] [Indexed: 11/14/2022] Open
Abstract
AIMS Abnormal intracellular calcium handling contributes to the progressive nature of atrial fibrillation (AF), the most common sustained cardiac arrhythmia. Evidence in mouse models suggests that activation of the nuclear factor of activated T-cell (NFAT) signaling pathway contributes to atrial remodeling. Our aim was to determine the role of NFATc2 in AF in humans and mouse models. METHODS AND RESULTS Expression levels of NFATc1-c4 isoforms were assessed by quantitative reverse transcription-polymerase chain reaction in right atrial appendages from patients with chronic AF. NFATc1 and NFATc2 mRNA levels were elevated in chronic AF (cAF) patients compared with those in sinus rhythm (SR). Western blotting revealed increased cytosolic and nuclear levels of NFATc2 in AF patients. Similar findings were obtained in CREM-IbΔC-X transgenic (CREM) mice, a model of progressive AF. Telemetry ECG recordings revealed age-dependent spontaneous AF in CREM mice, which was prevented by NFATc2 knockout in CREM: NFATc2-/- mice. Programmed electrical stimulation revealed that CREM: NFATc2-/- mice lacked an AF substrate. Morphometric analysis and histology revealed increased atrial weight and atrial fibrosis in CREM mice compared with WT controls, which was reversed in CREM: NFATc2-/- mice. Confocal microscopy showed an increased Ca2+ spark frequency despite a reduced sarcoplasmic reticulum (SR) Ca2+ load in CREM mice compared with controls, whereas these abnormalities were normalized in CREM: NFATc2-/- mice. Western blotting revealed that genetic inhibition of Ca2+/calmodulin-dependent protein kinase II-mediated phosphorylation of S2814 on RyR2 in CREM: RyR2-S2814A mice suppressed NFATc2 activation observed in CREM mice, suggesting that NFATc2 is activated by excessive SR Ca2+ leak via RyR2. Finally, chromatin immunoprecipitation sequencing from AF patients identified Ras And EF-Hand Domain-Containing Protein (RASEF) as a direct target of NFATc2 mediated transcription. CONCLUSION Our findings reveal activation of the NFAT signaling pathway in patients of Chinese and European descent. NFATc2 knockout prevents the progression of AF in the CREM mouse model. TRANSLATIONAL PERSPECTIVE Atrial fibrillation (AF) is a progressive disease characterized by electrical and structural remodeling which promotes atrial arrhythmias. This study provides evidence for increased 'nuclear factor of activated T-cell' (NFAT) signaling in patients with chronic AF. Studies in the CREM transgenic model of progressive AF revealed that the NFATc2 isoform mediates atrial remodeling associated with AF substrate development. Chromatin immunoprecipitation sequencing of atrial biopsies from AF patients identified 'Ras And EF-Hand Domain-Containing Protein' (RASEF) as a downstream target of NFATc2-mediated transcription, suggesting that targeting these factors might be beneficial for curtailing AF progression.
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Affiliation(s)
- Li Ni
- Division of Cardiology, Department of Internal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China
| | - Satadru K Lahiri
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Jiali Nie
- Division of Cardiology, Department of Internal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China
| | - Xiaolu Pan
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Issam Abu-Taha
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Julia O Reynolds
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Hannah M Campbell
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Haihao Wang
- Division of Cardiovascular Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Markus Kamler
- Cardiac Surgery II Essen-Huttrop, University Hospital, West German Heart Center, University of Essen, Germany
| | - Wilhelm Schmitz
- Institute of Pharmacology and Toxicology, University of Münster, Germany
| | | | - Na Li
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.,Institute of Pharmacology and Toxicology, University of Münster, Germany
| | - Xiang Wei
- Division of Cardiovascular Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.,Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX, 77030 USA.,Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, 77030 USA.,Department of Pediatrics, Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030 USA
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Scholz B, Schulte JS, Hamer S, Himmler K, Pluteanu F, Seidl MD, Stein J, Wardelmann E, Hammer E, Völker U, Müller FU. HDAC (Histone Deacetylase) Inhibitor Valproic Acid Attenuates Atrial Remodeling and Delays the Onset of Atrial Fibrillation in Mice. Circ Arrhythm Electrophysiol 2019; 12:e007071. [PMID: 30879335 PMCID: PMC6426346 DOI: 10.1161/circep.118.007071] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Supplemental Digital Content is available in the text. Background: A structural, electrical and metabolic atrial remodeling is central in the development of atrial fibrillation (AF) contributing to its initiation and perpetuation. In the heart, HDACs (histone deacetylases) control remodeling associated processes like hypertrophy, fibrosis, and energy metabolism. Here, we analyzed, whether the HDAC class I/IIa inhibitor valproic acid (VPA) is able to attenuate atrial remodeling in CREM-IbΔC-X (cAMP responsive element modulator isoform IbΔC-X) transgenic mice, a mouse model of extensive atrial remodeling with age-dependent progression from spontaneous atrial ectopy to paroxysmal and finally long-lasting AF. Methods: VPA was administered for 7 or 25 weeks to transgenic and control mice. Atria were analyzed macroscopically and using widefield and electron microscopy. Action potentials were recorded from atrial cardiomyocytes using patch-clamp technique. ECG recordings documented the onset of AF. A proteome analysis with consecutive pathway mapping identified VPA-mediated proteomic changes and related pathways. Results: VPA attenuated many components of atrial remodeling that are present in transgenic mice, animal AF models, and human AF. VPA significantly (P<0.05) reduced atrial dilatation, cardiomyocyte enlargement, atrial fibrosis, and the disorganization of myocyte’s ultrastructure. It significantly reduced the occurrence of atrial thrombi, reversed action potential alterations, and finally delayed the onset of AF by 4 to 8 weeks. Increased histone H4-acetylation in atria from VPA-treated transgenic mice verified effective in vivo HDAC inhibition. Cardiomyocyte-specific genetic inactivation of HDAC2 in transgenic mice attenuated the ultrastructural disorganization of myocytes comparable to VPA. Finally, VPA restrained dysregulation of proteins in transgenic mice that are involved in a multitude of AF relevant pathways like oxidative phosphorylation or RhoA (Ras homolog gene family, member A) signaling and disease functions like cardiac fibrosis and apoptosis of muscle cells. Conclusions: Our results suggest that VPA, clinically available, well-tolerated, and prescribed to many patients for years, has the therapeutic potential to delay the development of atrial remodeling and the onset of AF in patients at risk.
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Affiliation(s)
- Beatrix Scholz
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Jan Sebastian Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Sabine Hamer
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Kirsten Himmler
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Florentina Pluteanu
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Matthias Dodo Seidl
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Juliane Stein
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
| | - Eva Wardelmann
- Gerhard-Domagk-Institute of Pathology, University Hospital Münster, Germany (E.W.)
| | - Elke Hammer
- Interfaculty Institute of Genetics und Functional Genomics, University Medicine Greifswald, Germany (E.H., U.V.).,DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Germany (E.H., U.V.)
| | - Uwe Völker
- Interfaculty Institute of Genetics und Functional Genomics, University Medicine Greifswald, Germany (E.H., U.V.).,DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Germany (E.H., U.V.)
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Germany (B.S., J.S.S., S.H., K.H., F.P., M.D.S., J.S., F.U.M.)
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7
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Boknik P, Drzewiecki K, Eskandar J, Gergs U, Hofmann B, Treede H, Grote-Wessels S, Fabritz L, Kirchhof P, Fortmüller L, Müller FU, Schmitz W, Zimmermann N, Kirchhefer U, Neumann J. Evidence for Arrhythmogenic Effects of A 2A-Adenosine Receptors. Front Pharmacol 2019; 10:1051. [PMID: 31619997 PMCID: PMC6759833 DOI: 10.3389/fphar.2019.01051] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/20/2019] [Indexed: 12/26/2022] Open
Abstract
Adenosine can be released from the heart and may stimulate four different cardiac adenosine receptors. A receptor subtype that couples to the generation of cyclic adenosine monophosphate (cAMP) is the A2A-adenosine receptor (A2A-AR). To better understand its role in cardiac function, we studied mechanical and electrophysiological effects in transgenic mice that overexpress the human A2A-AR in cardiomyocytes (A2A-TG). We used isolated preparations from the left atrium, the right atrium, isolated perfused hearts with surface electrocardiogram (ECG) recording, and surface body ECG recordings of living mice. The hypothesized arrhythmogenic effects of transgenicity per se and A2A-AR stimulation were studied. We noted an increase in the incidence of supraventricular and ventricular arrhythmias under these conditions in A2A-TG. Moreover, we noted that the A2A-AR agonist CGS 21680 exerted positive inotropic effect in isolated human electrically driven (1 Hz) right atrial trabeculae carneae. We conclude that A2A-ARs are functional not only in A2A-TG but also in isolated human atrial preparations. A2A-ARs in A2A-TG per se and their stimulation can lead to cardiac arrhythmias not only in isolated cardiac preparations from A2A-TG but also in living A2A-TG.
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Affiliation(s)
- Peter Boknik
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Katharina Drzewiecki
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - John Eskandar
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Britt Hofmann
- Klinik für Herzchirurgie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Hendrik Treede
- Klinik für Herzchirurgie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Stephanie Grote-Wessels
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom.,University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom.,University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.,Sandwell and West Birmingham Hospital NHS Trust, Birmingham, United Kingdom
| | - Lisa Fortmüller
- Institute for Human Genetics, Genetic epidemiology, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Frank Ulrich Müller
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Wilhelm Schmitz
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | | | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Westfälische Wilhelms-Universität, Münster, Germany
| | - Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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8
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Wiedmann F, Schulte JS, Gomes B, Zafeiriou MP, Ratte A, Rathjens F, Fehrmann E, Scholz B, Voigt N, Müller FU, Thomas D, Katus HA, Schmidt C. Atrial fibrillation and heart failure-associated remodeling of two-pore-domain potassium (K2P) channels in murine disease models: focus on TASK-1. Basic Res Cardiol 2018; 113:27. [DOI: 10.1007/s00395-018-0687-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 06/04/2018] [Indexed: 12/27/2022]
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9
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Bukowska A, Felgendreher M, Scholz B, Wolke C, Schulte JS, Fehrmann E, Wardelmann E, Seidl MD, Lendeckel U, Himmler K, Gardemann A, Goette A, Müller FU. CREM-transgene mice: An animal model of atrial fibrillation and thrombogenesis. Thromb Res 2017; 163:172-179. [PMID: 28807377 DOI: 10.1016/j.thromres.2017.07.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 07/10/2017] [Accepted: 07/31/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND The molecular pathomechanisms underlying atrial thrombogenesis are multifactorial and still require detailed investigations. Transgenic mice with cardiomyocyte-directed expression of the transcriptional repressor CREM-IbΔC-X (CREM-TG) represent an experimental model of atrial fibrillation (AF) that shows a gradual, age-dependent progression from atrial ectopy to persistent AF. Importantly, this model develops biatrial thrombi. The molecular characteristics related to the thrombogenesis in CREM-TG mice have not been studied, yet. METHODS The inflammatory and prothrombotic state was evaluated at the transcriptional (qRT-PCR) and protein level in the left (LA) and right atria (RA) from CREM-TG mice at the age of 20weeks and compared to wild-type controls. Moreover, histological analyses of atrial thrombi were performed. RESULTS The endocardial dysfunction was mirrored by diminished levels of eNOS-mRNA in both atria (RA: 0.79±0.04, LA: 0.72±0.06; each P<0.05). Moreover, the PAI-1/t-PA mRNA ratio was significantly increased in both atria (RA: 3.6±0.6; P<0.01, LA: 4.0±1.0; P<0.05) indicating a high risk of thrombus formation. However, the inflammatory phenotype was more pronounced in the RA and was reflected by a significant increase in the mRNA levels encoding adhesion molecules ICAM-1 (2.1±0.2; P<0.01), VCAM-1 (2.3±0.5; P<0.05), and selectin P (3.6±0.5: P<0.05). CONCLUSIONS CREM-TG mice represent a valuable model for studying atrial thrombogenesis and assessing therapeutic approaches preventing embolic events in the systemic and pulmonary circulation.
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Affiliation(s)
- A Bukowska
- Working Group of Molecular Electrophysiology, Institute of Clinical Chemistry and Pathobiochemistry, Medical Faculty, Otto von Guericke University Magdeburg, Germany.
| | - M Felgendreher
- Working Group of Molecular Electrophysiology, Institute of Clinical Chemistry and Pathobiochemistry, Medical Faculty, Otto von Guericke University Magdeburg, Germany
| | - B Scholz
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
| | - C Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Germany
| | - J S Schulte
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
| | - E Fehrmann
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
| | - E Wardelmann
- Gerhard-Domagk-Institute of Pathology, University Hospital Münster, Germany
| | - M D Seidl
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
| | - U Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Germany
| | - K Himmler
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
| | - A Gardemann
- Working Group of Molecular Electrophysiology, Institute of Clinical Chemistry and Pathobiochemistry, Medical Faculty, Otto von Guericke University Magdeburg, Germany
| | - A Goette
- Working Group of Molecular Electrophysiology, Institute of Clinical Chemistry and Pathobiochemistry, Medical Faculty, Otto von Guericke University Magdeburg, Germany; St. Vincenz-Hospital, Paderborn, Germany
| | - F U Müller
- Institute of Pharmacology and Toxicology, Westfälische Wilhelms-University Münster, Germany
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10
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Schmidt C, Wiedmann F, Kallenberger SM, Ratte A, Schulte JS, Scholz B, Müller FU, Voigt N, Zafeiriou MP, Ehrlich JR, Tochtermann U, Veres G, Ruhparwar A, Karck M, Katus HA, Thomas D. Stretch-activated two-pore-domain (K 2P) potassium channels in the heart: Focus on atrial fibrillation and heart failure. Prog Biophys Mol Biol 2017; 130:233-243. [PMID: 28526353 DOI: 10.1016/j.pbiomolbio.2017.05.004] [Citation(s) in RCA: 26] [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] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 12/18/2022]
Abstract
Two-pore-domain potassium (K2P) channels modulate cellular excitability. The significance of stretch-activated cardiac K2P channels (K2P2.1, TREK-1, KCNK2; K2P4.1, TRAAK, KCNK4; K2P10.1, TREK-2, KCNK10) in heart disease has not been elucidated in detail. The aim of this work was to assess expression and remodeling of mechanosensitive K2P channels in atrial fibrillation (AF) and heart failure (HF) patients in comparison to murine models. Cardiac K2P channel levels were quantified in atrial (A) and ventricular (V) tissue obtained from patients undergoing open heart surgery. In addition, control mice and mouse models of AF (cAMP-response element modulator (CREM)-IbΔC-X transgenic animals) or HF (cardiac dysfunction induced by transverse aortic constriction, TAC) were employed. Human and murine KCNK2 displayed highest mRNA abundance among mechanosensitive members of the K2P channel family (V > A). Disease-associated K2P2.1 remodeling was studied in detail. In patients with impaired left ventricular function, atrial KCNK2 (K2P2.1) mRNA and protein expression was significantly reduced. In AF subjects, downregulation of atrial and ventricular KCNK2 (K2P2.1) mRNA and protein levels was observed. AF-associated suppression of atrial Kcnk2 (K2P2.1) mRNA and protein was recapitulated in CREM-transgenic mice. Ventricular Kcnk2 expression was not significantly altered in mouse models of disease. In conclusion, mechanosensitive K2P2.1 and K2P10.1 K+ channels are expressed throughout the heart. HF- and AF-associated downregulation of KCNK2 (K2P2.1) mRNA and protein levels suggest a mechanistic contribution to cardiac arrhythmogenesis.
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Affiliation(s)
- Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Felix Wiedmann
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Stefan M Kallenberger
- Department for Bioinformatics and Functional Genomics, Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Antonius Ratte
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Jan S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Beatrix Scholz
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Frank Ulrich Müller
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Maria-Patapia Zafeiriou
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Joachim R Ehrlich
- Department of Cardiology, Internal Medicine III, Goethe University, Frankfurt, Germany; Department of Cardiology, St. Josefs-Hospital, Wiesbaden, Germany
| | - Ursula Tochtermann
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Gábor Veres
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Arjang Ruhparwar
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Matthias Karck
- Department of Cardiac Surgery, University of Heidelberg, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg / Mannheim, University of Heidelberg, Germany.
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11
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Keul P, van Borren MMGJ, Ghanem A, Müller FU, Baartscheer A, Verkerk AO, Stümpel F, Schulte JS, Hamdani N, Linke WA, van Loenen P, Matus M, Schmitz W, Stypmann J, Tiemann K, Ravesloot JH, Alewijnse AE, Hermann S, Spijkers LJA, Hiller KH, Herr D, Heusch G, Schäfers M, Peters SLM, Chun J, Levkau B. Sphingosine-1-Phosphate Receptor 1 Regulates Cardiac Function by Modulating Ca2+ Sensitivity and Na+/H+ Exchange and Mediates Protection by Ischemic Preconditioning. J Am Heart Assoc 2016; 5:JAHA.116.003393. [PMID: 27207969 PMCID: PMC4889204 DOI: 10.1161/jaha.116.003393] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Background Sphingosine‐1‐phosphate plays vital roles in cardiomyocyte physiology, myocardial ischemia–reperfusion injury, and ischemic preconditioning. The function of the cardiomyocyte sphingosine‐1‐phosphate receptor 1 (S1P1) in vivo is unknown. Methods and Results Cardiomyocyte‐restricted deletion of S1P1 in mice (S1P1αMHCCre) resulted in progressive cardiomyopathy, compromised response to dobutamine, and premature death. Isolated cardiomyocytes from S1P1αMHCCre mice revealed reduced diastolic and systolic Ca2+ concentrations that were secondary to reduced intracellular Na+ and caused by suppressed activity of the sarcolemmal Na+/H+ exchanger NHE‐1 in the absence of S1P1. This scenario was successfully reproduced in wild‐type cardiomyocytes by pharmacological inhibition of S1P1 or sphingosine kinases. Furthermore, Sarcomere shortening of S1P1αMHCCre cardiomyocytes was intact, but sarcomere relaxation was attenuated and Ca2+ sensitivity increased, respectively. This went along with reduced phosphorylation of regulatory myofilament proteins such as myosin light chain 2, myosin‐binding protein C, and troponin I. In addition, S1P1 mediated the inhibitory effect of exogenous sphingosine‐1‐phosphate on β‐adrenergic–induced cardiomyocyte contractility by inhibiting the adenylate cyclase. Furthermore, ischemic precondtioning was abolished in S1P1αMHCCre mice and was accompanied by defective Akt activation during preconditioning. Conclusions Tonic S1P1 signaling by endogenous sphingosine‐1‐phosphate contributes to intracellular Ca2+ homeostasis by maintaining basal NHE‐1 activity and controls simultaneously myofibril Ca2+ sensitivity through its inhibitory effect on adenylate cyclase. Cardioprotection by ischemic precondtioning depends on intact S1P1 signaling. These key findings on S1P1 functions in cardiac physiology may offer novel therapeutic approaches to cardiac diseases.
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Affiliation(s)
- Petra Keul
- Institute for Pathophysiology, Westdeutsches Herz- und Gefäßzentrum, Universitätsklinikum Essen, Essen, Germany
| | | | - Alexander Ghanem
- Department of Cardiology, Universitätsklinikum Bonn, Bonn, Germany
| | | | | | - Arie O Verkerk
- Heart Failure Research Center, AMC, University of Amsterdam, The Netherlands
| | - Frank Stümpel
- Institute for Pharmakology und Toxikology, Münster, Germany
| | | | - Nazha Hamdani
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Wolfgang A Linke
- Department of Cardiovascular Physiology, Ruhr University Bochum, Bochum, Germany
| | - Pieter van Loenen
- Department of Pharmacology & Pharmacotherapy, AMC, University of Amsterdam, The Netherlands
| | - Marek Matus
- Institute for Pharmakology und Toxikology, Münster, Germany Department of Pharmacology and Toxicology, Comenius University, Bratislava, Slovakia
| | | | - Jörg Stypmann
- Medizinische Klinik und Poliklinik C, Universitätsklinikum Münster, Münster, Germany
| | - Klaus Tiemann
- Medizinische Klinik und Poliklinik C, Universitätsklinikum Münster, Münster, Germany
| | | | - Astrid E Alewijnse
- Department of Pharmacology & Pharmacotherapy, AMC, University of Amsterdam, The Netherlands
| | - Sven Hermann
- European Institute for Molecular Imaging, Münster, Germany
| | - Léon J A Spijkers
- Department of Pharmacology & Pharmacotherapy, AMC, University of Amsterdam, The Netherlands
| | - Karl-Heinz Hiller
- MRB Forschungszentrum Magnet-Resonanz-Bayern e.V., Würzburg, Germany
| | - Deron Herr
- Department of Molecular Biology, Scripps Research Institute, La Jolla, CA
| | - Gerd Heusch
- Institute for Pathophysiology, Westdeutsches Herz- und Gefäßzentrum, Universitätsklinikum Essen, Essen, Germany
| | | | - Stephan L M Peters
- Department of Pharmacology & Pharmacotherapy, AMC, University of Amsterdam, The Netherlands
| | - Jerold Chun
- Department of Molecular Biology, Scripps Research Institute, La Jolla, CA
| | - Bodo Levkau
- Institute for Pathophysiology, Westdeutsches Herz- und Gefäßzentrum, Universitätsklinikum Essen, Essen, Germany
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12
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Zhang M, Schulte JS, Heinick A, Piccini I, Rao J, Quaranta R, Zeuschner D, Malan D, Kim KP, Röpke A, Sasse P, Araúzo-Bravo M, Seebohm G, Schöler H, Fabritz L, Kirchhof P, Müller FU, Greber B. Universal cardiac induction of human pluripotent stem cells in two and three-dimensional formats: implications for in vitro maturation. Stem Cells 2016; 33:1456-69. [PMID: 25639979 DOI: 10.1002/stem.1964] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 12/26/2014] [Indexed: 12/13/2022]
Abstract
Directed cardiac differentiation of human pluripotent stem cells (hPSCs) enables disease modeling, investigation of human cardiogenesis, as well as large-scale production of cardiomyocytes (CMs) for translational purposes. Multiple CM differentiation protocols have been developed to individually address specific requirements of these diverse applications, such as enhanced purity at a small scale or mass production at a larger scale. However, there is no universal high-efficiency procedure for generating CMs both in two-dimensional (2D) and three-dimensional (3D) culture formats, and undefined or complex media additives compromise functional analysis or cost-efficient upscaling. Using systematic combinatorial optimization, we have narrowed down the key requirements for efficient cardiac induction of hPSCs. This implied differentiation in simple serum and serum albumin-free basal media, mediated by a minimal set of signaling pathway manipulations at moderate factor concentrations. The method was applicable both to 2D and 3D culture formats as well as to independent hPSC lines. Global time-course gene expression analyses over extended time periods and in comparison with human heart tissue were used to monitor culture-induced maturation of the resulting CMs. This suggested that hPSC-CMs obtained with our procedure reach a rather stable transcriptomic state after approximately 4 weeks of culture. The underlying gene expression changes correlated well with a decline of immature characteristics as well as with a gain of structural and physiological maturation features within this time frame. These data link gene expression patterns of hPSC-CMs to functional readouts and thus define the cornerstones of culture-induced maturation.
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Affiliation(s)
- Miao Zhang
- Human Stem Cell Pluripotency Group; Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany
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13
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Schulte JS, Fehrmann E, Tekook MA, Kranick D, Fels B, Li N, Wehrens XHT, Heinick A, Seidl MD, Schmitz W, Müller FU. Cardiac expression of the CREM repressor isoform CREM-IbΔC-X in mice leads to arrhythmogenic alterations in ventricular cardiomyocytes. Basic Res Cardiol 2016; 111:15. [PMID: 26818679 PMCID: PMC4729809 DOI: 10.1007/s00395-016-0532-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 01/08/2016] [Indexed: 12/19/2022]
Abstract
Chronic β-adrenergic stimulation is regarded as a pivotal step in the progression of heart failure which is associated with a high risk for arrhythmia. The cAMP-dependent transcription factors cAMP-responsive element binding protein (CREB) and cAMP-responsive element modulator (CREM) mediate transcriptional regulation in response to β-adrenergic stimulation and CREM repressor isoforms are induced after stimulation of the β-adrenoceptor. Here, we investigate whether CREM repressors contribute to the arrhythmogenic remodeling in the heart by analyzing arrhythmogenic alterations in ventricular cardiomyocytes (VCMs) from mice with transgenic expression of the CREM repressor isoform CREM-IbΔC-X (TG). Patch clamp analyses, calcium imaging, immunoblotting and real-time quantitative RT-PCR were conducted to study proarrhythmic alterations in TG VCMs vs. wild-type controls. The percentage of VCMs displaying spontaneous supra-threshold transient-like Ca(2+) releases was increased in TG accompanied by an enhanced transduction rate of sub-threshold Ca(2+) waves into these supra-threshold events. As a likely cause we discovered enhanced NCX-mediated Ca(2+) transport and NCX1 protein level in TG. An increase in I NCX and decrease in I to and its accessory channel subunit KChIP2 was associated with action potential prolongation and an increased proportion of TG VCMs showing early afterdepolarizations. Finally, ventricular extrasystoles were augmented in TG mice underlining the in vivo relevance of our findings. Transgenic expression of CREM-IbΔC-X in mouse VCMs leads to distinct arrhythmogenic alterations. Since CREM repressors are inducible by chronic β-adrenergic stimulation our results suggest that the inhibition of CRE-dependent transcription contributes to the formation of an arrhythmogenic substrate in chronic heart disease.
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Affiliation(s)
- J S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany.
| | - E Fehrmann
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - M A Tekook
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - D Kranick
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - B Fels
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - N Li
- Department of Molecular Physiology and Biophysics, Medicine (Cardiology), and Pediatrics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - X H T Wehrens
- Department of Molecular Physiology and Biophysics, Medicine (Cardiology), and Pediatrics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - A Heinick
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - M D Seidl
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - W Schmitz
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
| | - F U Müller
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, 48149, Münster, Germany
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14
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Schulte JS, Seidl MD, Müller FU. The role of transcription factors in the formation of an arrhythmogenic substrate in congestive human heart failure. Curr Med Chem 2014; 21:1281-98. [PMID: 23862616 DOI: 10.2174/09298673113209990172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/29/2013] [Accepted: 06/23/2013] [Indexed: 11/22/2022]
Abstract
Human congestive heart failure is accompanied by structural and electrical alterations leading to the development of an arrhythmogenic substrate. This substrate is associated with the "sudden cardiac death" due to ventricular tachycardia or ventricular fibrillation. Multiple studies link distinct transcription factors to the transcriptional regulation of genes related to the formation of an arrhythmogenic substrate. In addition to cardiac hypertrophy the up- or downregulation of ion channels, calcium-handling proteins, and proteins forming gap junctions play a pivotal role in the progression of heart failure. This review summarizes the transcriptional regulation of selected genes implicated in the formation of an arrhythmogenic substrate. In this context we provide an overview of relevant transcription factors, activating stimuli and pathways, the evidence of binding to respective elements in the promoter of target genes and the associated mRNA regulation in animal models. Finally, possible therapeutic consequences are discussed.
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Affiliation(s)
| | | | - F U Müller
- Institute of Pharmacology and Toxicology, University of Munster, Domagkstr. 12, 48149 Munster, Germany.
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15
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Seidl MD, Hildebrandt I, Klugstedt C, Nunes F, Endo S, Kojima N, Schmitz W, Müller FU. The function of cAMP responsive element modulator (CREM) in PDGF induced proliferation of vascular smooth muscle cells. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1139.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Iris Hildebrandt
- Institute of Pharmacology and ToxicologyUniversity of MünsterMünsterGermany
| | | | - Frank Nunes
- Institute of Pharmacology and ToxicologyUniversity of MünsterMünsterGermany
| | - Shogo Endo
- Tokyo Metropolitan Institute of GerontologyTokyoJapan
| | | | - Wilhelm Schmitz
- Institute of Pharmacology and ToxicologyUniversity of MünsterMünsterGermany
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16
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Schulte JS, Fehrmann E, Tekook M, Heinick A, Seidl MD, Schmitz W, Müller FU. Potential proarrhythmic alterations in ventricular cardiomyocytes expressing CREM‐IbΔC‐X, a repressory human cardiac isoform of cAMP response element modulator. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1189.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Edda Fehrmann
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
| | - Marcel Tekook
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
| | - Alexander Heinick
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
| | - Matthias Dodo Seidl
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
| | - Wilhelm Schmitz
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
| | - Frank Ulrich Müller
- Institute of Pharmacology and ToxicologyUniversity of Muenster, UKMMuensterGermany
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17
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Tekook MA, Fabritz L, Kirchhof P, König S, Müller FU, Schmitz W, Tal T, Zlotkin E, Kirchhefer U. Gene construction, expression and functional testing of an inotropic peptide from the venom of the black scorpion Hottentotta judaicus. Toxicon 2012; 60:1415-27. [PMID: 23085191 DOI: 10.1016/j.toxicon.2012.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/06/2012] [Accepted: 10/11/2012] [Indexed: 12/29/2022]
Abstract
Anti-insect depressant toxins represent a subfamily of scorpion venom-derived β-toxins that are polypeptides composed of 61-65 amino acid residues stabilized by four disulfide bridges. These toxins affect the activation of voltage-sensitive sodium channels (NaScTx) and exhibit the preferential ability to induce flaccid paralysis in insect larvae. Here we demonstrate the recombinant expression of the novel cardiac inotropic peptide (Bj-IP) that was classified as an anti-insect depressant βNaScTx isolated from the venom of Hottentotta judaicus. By using "splicing by overlap extension" (SOE)-PCR, allowing for the first time one step de novo synthesis of long-chain scorpion toxin genes, we generated a codon-optimized DNA fragment of Bj-IP for cloning into the Escherichia coli vector pQE30. Moreover, the gene of interest was fused to a 6xHis coding DNA sequence. Subsequent recombinant expression was performed in E. coli KRX. The purification of the polypeptide was achieved by a combination of NiNTA agarose columns and RP (C(18)) high-performance liquid chromatography. The purified fusion protein was digested with factor Xa resulting in the elution of Bj-IP. The yield of recombinant Bj-IP expression was approximately 4.5 mg per liter of culture. Mass spectrometry confirmed the theoretical total mass of Bj-IP (6608 Da). Tag-free Bj-IP was refolded in guanidine chloride buffer with a glutathione redox system which was supplemented with different additives at 16 °C. Supplementation with 10% glycerol produced Bj-IP folding forms that exhibited reproducible biological activity in mouse cardiomyocytes. Cell contractility was increased by almost 3-fold and decay kinetics were hasten by 47% after administration of Bj-IP. Taken together, here we show the recombinant expression of the functionally active cardiac inotropic peptide Bj-IP, a new βNaScTx from H. judaicus, for promising pharmacological applications. Furthermore, our data suggest that the use of SOE-PCR may help to facilitate in future the high throughput of cloning and/or modification of scorpion toxin genes.
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Affiliation(s)
- M A Tekook
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Domagkstr. 12, D-48149 Münster, Germany
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Schulte JS, Seidl MD, Nunes F, Freese C, Schneider M, Schmitz W, Müller FU. CREB critically regulates action potential shape and duration in the adult mouse ventricle. Am J Physiol Heart Circ Physiol 2012; 302:H1998-2007. [PMID: 22427515 DOI: 10.1152/ajpheart.00057.2011] [Citation(s) in RCA: 25] [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] [Indexed: 02/08/2023]
Abstract
The cAMP response element binding protein (CREB) belongs to the CREB/cAMP response element binding modulator/activating transcription factor 1 family of cAMP-dependent transcription factors mediating a regulation of gene transcription in response to cAMP. Chronic stimulation of β-adrenergic receptors and the cAMP-dependent signal transduction pathway by elevated plasma catecholamines play a central role in the pathogenesis of heart failure. Ion channel remodeling, particularly a decreased transient outward current (I(to)), and subsequent action potential (AP) prolongation are hallmarks of the failing heart. Here, we studied the role of CREB for ion channel regulation in mice with a cardiomyocyte-specific knockout of CREB (CREB KO). APs of CREB KO cardiomyocytes were prolonged with increased AP duration at 50 and 70% repolarization and accompanied by a by 51% reduction of I(to) peak amplitude as detected in voltage-clamp measurements. We observed a 29% reduction of Kcnd2/Kv4.2 mRNA in CREB KO cardiomyocytes mice while the other I(to)-related channel subunits Kv4.3 and KChIP2 were not different between groups. Accordingly, Kv4.2 protein was reduced by 37% in CREB KO. However, we were not able to detect a direct regulation of Kv4.2 by CREB. The I(to)-dependent AP prolongation went along with an increase of I(Na) and a decrease of I(Ca,L) associated with an upregulation of Scn8a/Nav1.6 and downregulation of Cacna1c/Cav1.2 mRNA in CREB KO cardiomyocytes. Our results from mice with cardiomyocyte-specific inactivation of CREB definitively indicate that CREB critically regulates the AP shape and duration in the mouse ventricle, which might have an impact on ion channel remodeling in situations of altered cAMP-dependent signaling like heart failure.
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Affiliation(s)
- J S Schulte
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany.
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Kirchhof P, Marijon E, Fabritz L, Li N, Wang W, Wang T, Schulte K, Hanstein J, Schulte JS, Vogel M, Mougenot N, Laakmann S, Fortmueller L, Eckstein J, Verheule S, Kaese S, Staab A, Grote-Wessels S, Schotten U, Moubarak G, Wehrens XHT, Schmitz W, Hatem S, Müller FU. Overexpression of cAMP-response element modulator causes abnormal growth and development of the atrial myocardium resulting in a substrate for sustained atrial fibrillation in mice. Int J Cardiol 2011; 166:366-74. [PMID: 22093963 DOI: 10.1016/j.ijcard.2011.10.057] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [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: 09/21/2011] [Accepted: 10/18/2011] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND METHODS Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. The substrate of AF is composed of a complex interplay between structural and functional changes of the atrial myocardium often preceding the occurrence of persistent AF. However, there are only few animal models reproducing the slow progression of the AF substrate to the spontaneous occurrence of the arrhythmia. Transgenic mice (TG) with cardiomyocyte-directed expression of CREM-IbΔC-X, an isoform of transcription factor CREM, develop atrial dilatation and spontaneous-onset AF. Here we tested the hypothesis that TG mice develop an arrhythmogenic substrate preceding AF using physiological and biochemical techniques. RESULTS Overexpression of CREM-IbΔC-X in young TG mice (<8weeks) led to atrial dilatation combined with distension of myocardium, elongated myocytes, little fibrosis, down-regulation of connexin 40, loss of excitability with a number of depolarized myocytes, atrial ectopies and inducibility of AF. These abnormalities continuously progressed with age resulting in interatrial conduction block, increased atrial conduction heterogeneity, leaky sarcoplasmic reticulum calcium stores and the spontaneous occurrence of paroxysmal and later persistent AF. This distinct atrial remodelling was associated with a pattern of non-regulated and up-regulated marker genes of myocardial hypertrophy and fibrosis. CONCLUSIONS Expression of CREM-IbΔC-X in TG hearts evokes abnormal growth and development of the atria preceding conduction abnormalities and altered calcium homeostasis and the development of spontaneous and persistent AF. We conclude that transcription factor CREM is an important regulator of atrial growth implicated in the development of an arrhythmogenic substrate in TG mice.
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Affiliation(s)
- Paulus Kirchhof
- Department of Cardiology and Angiology, University Hospital Münster, Germany
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20
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Seidl MD, Steingräber AK, Sur H, Schmitz W, Müller FU. Function of the cAMP dependent transcription factors CREM and ATF1 in the vasculature. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1026.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Matthias Dodo Seidl
- Institute of Pharmacology and ToxicologyWestfälische Wilhelms‐Universität MünsterMünsterGermany
| | | | - Huyen Sur
- Institute of Pharmacology and ToxicologyWestfälische Wilhelms‐Universität MünsterMünsterGermany
| | - Wilhelm Schmitz
- Institute of Pharmacology and ToxicologyWestfälische Wilhelms‐Universität MünsterMünsterGermany
| | - Frank Ulrich Müller
- Institute of Pharmacology and ToxicologyWestfälische Wilhelms‐Universität MünsterMünsterGermany
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21
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Chelu MG, Sarma S, Sood S, Wang S, van Oort RJ, Skapura DG, Li N, Santonastasi M, Müller FU, Schmitz W, Schotten U, Anderson ME, Valderrábano M, Dobrev D, Wehrens XHT. Calmodulin kinase II-mediated sarcoplasmic reticulum Ca2+ leak promotes atrial fibrillation in mice. J Clin Invest 2009; 119:1940-51. [PMID: 19603549 DOI: 10.1172/jci37059] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A trial fibrillation (AF), the most common human cardiac arrhythmia, is associated with abnormal intracellular Ca2+ handling. Diastolic Ca2+ release from the sarcoplasmic reticulum via "leaky" ryanodine receptors (RyR2s) is hypothesized to contribute to arrhythmogenesis in AF, but the molecular mechanisms are incompletely understood. Here, we have shown that mice with a genetic gain-of-function defect in Ryr2 (which we termed Ryr2R176Q/+ mice) did not exhibit spontaneous AF but that rapid atrial pacing unmasked an increased vulnerability to AF in these mice compared with wild-type mice. Rapid atrial pacing resulted in increased Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylation of RyR2, while both pharmacologic and genetic inhibition of CaMKII prevented AF inducibility in Ryr2R176Q/+ mice. This result suggests that AF requires both an arrhythmogenic substrate (e.g., RyR2 mutation) and enhanced CaMKII activity. Increased CaMKII phosphorylation of RyR2 was observed in atrial biopsies from mice with atrial enlargement and spontaneous AF, goats with lone AF, and patients with chronic AF. Genetic inhibition of CaMKII phosphorylation of RyR2 in Ryr2S2814A knockin mice reduced AF inducibility in a vagotonic AF model. Together, these findings suggest that increased RyR2-dependent Ca2+ leakage due to enhanced CaMKII activity is an important downstream effect of CaMKII in individuals susceptible to AF induction.
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Affiliation(s)
- Mihail G Chelu
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
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22
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Lewin G, Matus M, Basu A, Frebel K, Rohsbach SP, Safronenko A, Seidl MD, Stümpel F, Buchwalow I, König S, Engelhardt S, Lohse MJ, Schmitz W, Müller FU. Critical role of transcription factor cyclic AMP response element modulator in beta1-adrenoceptor-mediated cardiac dysfunction. Circulation 2008; 119:79-88. [PMID: 19103994 DOI: 10.1161/circulationaha.108.786533] [Citation(s) in RCA: 33] [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] [Indexed: 01/08/2023]
Abstract
BACKGROUND Chronic stimulation of the beta(1)-adrenoceptor (beta(1)AR) plays a crucial role in the pathogenesis of heart failure; however, underlying mechanisms remain to be elucidated. The regulation by transcription factors cAMP response element-binding protein (CREB) and cyclic AMP response element modulator (CREM) represents a fundamental mechanism of cyclic AMP-dependent gene control possibly implicated in beta(1)AR-mediated cardiac deterioration. METHODS AND RESULTS We studied the role of CREM in beta(1)AR-mediated cardiac effects, comparing transgenic mice with heart-directed expression of beta(1)AR in the absence and presence of functional CREM. CREM inactivation protected from cardiomyocyte hypertrophy, fibrosis, and left ventricular dysfunction in beta(1)AR-overexpressing mice. Transcriptome and proteome analysis revealed a set of predicted CREB/CREM target genes including the cardiac ryanodine receptor, tropomyosin 1alpha, and cardiac alpha-actin as altered on the mRNA or protein level along with the improved phenotype in CREM-deficient beta(1)AR-transgenic hearts. CONCLUSIONS The results imply the regulation of genes by CREM as an important mechanism of beta(1)AR-induced cardiac damage in mice.
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Affiliation(s)
- Geertje Lewin
- Institute of Pharmacology and Toxicology, University of Münster, Münster, Germany
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23
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Müller FU, Loser K, Kleideiter U, Neumann J, von Wallbrunn C, Dobner T, Scheld HH, Bantel H, Engels IH, Schulze-Osthoff K, Schmitz W. Transcription factor AP-2alpha triggers apoptosis in cardiac myocytes. Cell Death Differ 2005; 11:485-93. [PMID: 14752511 DOI: 10.1038/sj.cdd.4401383] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Idiopathic-dilated cardiomyopathy (IDC) is a common primary myocardial disease of unknown etiology associated with apoptosis, cardiac dilatation, progressive heart failure and increased mortality. An elevation of the transcription factor activator protein 2alpha (AP-2alpha) is involved in vertebrate embryonic development and oncogenesis. Here, we show that AP-2alpha protein is expressed in the human heart and increased in human failing myocardium with IDC. Adenovirus-mediated overexpression of human AP-2alpha triggered apoptosis and increased mRNA levels of Bcl-2 family members Bax and Bcl-x in rat cardiomyocytes. Immunohistological analysis of human myocardium revealed an increased percentage of AP-2alpha-positive nuclei in IDC and, interestingly, a colocalization of AP-2alpha-positive but not -negative cells with a caspase-cleaved fragment of poly(ADP-ribose)polymerase. We suggest AP-2alpha as a novel cardiac regulator implicated in the activation of apoptosis in IDC.
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Affiliation(s)
- F U Müller
- Institute of Pharmacology and Toxicology, University of Münster, Domagkstr. 12, Münster D-48129, Germany.
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24
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Müller FU. [Can a hydergine therapy lead to damage of the coronary vessels?]. Dtsch Med Wochenschr 2002; 127:1401. [PMID: 12134783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Frank Ulrich Müller
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms Universität, Münster
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25
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Mehrhof FB, Müller FU, Bergmann MW, Li P, Wang Y, Schmitz W, Dietz R, von Harsdorf R. In cardiomyocyte hypoxia, insulin-like growth factor-I-induced antiapoptotic signaling requires phosphatidylinositol-3-OH-kinase-dependent and mitogen-activated protein kinase-dependent activation of the transcription factor cAMP response element-binding protein. Circulation 2001; 104:2088-94. [PMID: 11673351 DOI: 10.1161/hc4201.097133] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [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] [Indexed: 11/16/2022]
Abstract
BACKGROUND A variety of pathologic stimuli lead to apoptosis of cardiomyocytes. Survival factors like insulin-like growth factor-I (IGF-I) exert anti-apoptotic effects in the heart. Yet the underlying signaling pathways are poorly understood. METHODS AND RESULTS In a model of hypoxia-induced apoptosis of cultured neonatal cardiomyocytes, IGF-I prevented cell death in a dose-dependent manner. Antiapoptotic signals induced by IGF-I are mediated by more than one signaling pathway, because pharmacological inhibition of the phosphatidylinositol-3-OH-kinase (PI3K) or the mitogen-activated protein kinase kinase (MEK1) signaling pathway both antagonize the protective effect of IGF-I in an additive manner. IGF-I-stimulation was followed by a PI3K-dependent phosphorylation of AKT and BAD and an MEK1-dependent phosphorylation of extracellular signal-regulated kinase (ERK) 1 and ERK2. IGF-I also induced phosphorylation of cAMP response element-binding protein (CREB) in a PI3K- and MEK1-dependent manner. Ectopic overexpression of a dominant-negative mutant of CREB abolished the antiapoptotic effect of IGF-I. Protein levels of the antiapoptotic factor bcl-2 increased after longer periods of IGF-I-stimulation, which could be reversed by pharmacological inhibition of PI3K as well as MEK1 and also by overexpression of dominant-negative CREB. CONCLUSIONS In summary, our data demonstrate that in cardiomyocytes, the antiapoptotic effect of IGF-I requires both PI3K- and MEK1-dependent pathways leading to the activation of the transcription factor CREB, which then induces the expression of the antiapoptotic factor bcl-2.
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Affiliation(s)
- F B Mehrhof
- Department of Cardiology, Franz Volhard Clinic, Humboldt-University, Berlin, Germany
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26
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Müller FU, Bokník P, Knapp J, Linck B, Lüss H, Neumann J, Schmitz W. Activation and inactivation of cAMP-response element-mediated gene transcription in cardiac myocytes. Cardiovasc Res 2001; 52:95-102. [PMID: 11557237 DOI: 10.1016/s0008-6363(01)00361-3] [Citation(s) in RCA: 29] [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] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVE Chronic beta-adrenergic stimulation of the cAMP-dependent signalling pathway is implicated in functionally relevant expressional changes in congestive heart failure. We studied activation and inactivation of the cardiac gene transcription mediated by the cAMP-response element (CRE) and the CRE-binding protein (CREB) as an important mechanism of a cAMP-dependent gene regulation. METHODS We investigated the transcriptional activation by forskolin, an activator of the adenylyl cyclase, in chick embryonic cardiomyocytes transfected with a CRE-controlled luciferase construct in comparison to the phosphorylation and expression of CREB determined on immunoblots. RESULTS Forskolin (10 micromol/l; 8 h) increased CRE-mediated transcription and phosphorylation of CREB 13- and 1.5-fold, respectively. The phosphorylation was further elevated in combination with cantharidin, an inhibitor of type 1+2A protein phosphatases. The transcriptional response to forskolin was desensitized by pretreatment with forskolin (1 micromol/l; 24 h) while CREB phosphorylation was increased. In forskolin-pretreated cells, total CREB protein levels were decreased. Cantharidin did not restore the attenuated transcriptional response. CONCLUSIONS In cardiomyocytes, there is an activation of the CRE-mediated gene transcription by forskolin that is attenuated after prolonged stimulation, and this attenuation is not dependent from a dephosphorylation of CREB. We suggest that attenuation of the CRE-mediated transcription through chronic stimulation of the cAMP-pathway, e.g. by elevated catecholamines, contributes to the altered expressional regulation in congestive heart failure.
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Affiliation(s)
- F U Müller
- The Institute for Pharmacology and Toxicology, University of Münster, Domagkstr. 12, D-48149, Münster, Germany.
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Linck B, Boknik P, Knapp J, Kikuchi K, Lüss H, Müller FU, Nomoto K, Neumann J, Schmitz W. Functional properties of the rat phosphatase 1alpha promoter. Mol Cell Biochem 2001; 223:123-9. [PMID: 11681713 DOI: 10.1023/a:1017926713989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aim of this study was to investigate the functional properties of the promoter of the protein phosphatase 1alpha catalytic subunit. Luciferase plasmids with different fragments of the rat catalytic subunit of the protein phosphatase 1alpha promoter ranging from -3.7 kbp to -59 bp were transiently transfected into cells by the calcium-phosphate precipitation method. The promoter activity was determined in the absence and presence of inotropic agents which influencing the cAMP-depending pathway. The basal transcriptional activity decreased at fragment -124 bp and shorter fragments. To identify regions of regulatory importance we investigated the cAMP-dependent influence on the transcriptional activity. Stimulation of the complete promoter region with forskolin (1-100 microM) for 6 h led to a concentration-dependent decrease of transcriptional activity. Moreover, regions shorter than 3.7 kbp were inhibited by forskolin (10 microM). Short time stimulation (10 min) with forskolin (10 microM) increased the transcriptional activity of only the 3.7 kbp fragment. The effects were antagonized by Rp-cAMPS, a specific antagonist of protein kinase A, indicating cAMP-dependent effects. The results provide evidence for cAMP-dependent regulation of the protein phosphatase 1alpha promotor.
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Affiliation(s)
- B Linck
- Institut für Pharmakologie und Toxikologie, Universität Münster, Germany
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28
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Bokník P, Khorchidi S, Bodor GS, Huke S, Knapp J, Linck B, Lüss H, Müller FU, Schmitz W, Neumann J. Role of protein phosphatases in regulation of cardiac inotropy and relaxation. Am J Physiol Heart Circ Physiol 2001; 280:H786-94. [PMID: 11158978 DOI: 10.1152/ajpheart.2001.280.2.h786] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [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] [Indexed: 11/22/2022]
Abstract
We studied the effects of the protein phosphatase (PP) inhibitor cantharidin (Cant) on time parameters and force of contraction (FOC) in isometrically contracting electrically driven guinea pig papillary muscles. We correlated the mechanical parameters of contractility with phosphorylation of the inhibitory subunit of troponin (TnI-P) and with the site-specific phosphorylation of phospholamban (PLB) at serine-16 (PLB-Ser-16) and threonine-17 (PLB-Thr-17). Cant (after 30 min) started to increase FOC (112 +/- 4% of control, n = 10) and TnI-P and PLB-Thr-17 (120 +/- 5 and 128 +/- 7% of control) without any alteration of relaxation time. Cant (10 microM) started to increase PLB-Ser-16, but the relaxation was shortened at only 100 microM (from 140 +/- 9 to 116 +/- 12 ms, n = 9). Moreover, 100 microM Cant, 3 min after application, started to increase PLB-Thr-17, TnI-P, and FOC. Cant (100 microM) began to increase PLB-Ser-16 after 20 min. This was accompanied by shortening of relaxation time. Differences in protein kinase activation or different substrate specificities of PP may explain the difference in Cant-induced site-specific phosphorylation of PLB in isometrically contracting papillary muscles. Moreover, PLB-Thr-17 may be important for inotropy, whereas PLB-Ser-16 could be a major determinant of relaxation time.
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Affiliation(s)
- P Bokník
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, D-48129 Münster, Germany.
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29
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Lüss H, Klein-Wiele O, Bokník P, Herzig S, Knapp J, Linck B, Müller FU, Scheld HH, Schmid C, Schmitz W, Neumann J. Regional expression of protein phosphatase type 1 and 2A catalytic subunit isoforms in the human heart. J Mol Cell Cardiol 2000; 32:2349-59. [PMID: 11113010 DOI: 10.1006/jmcc.2000.1265] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [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] [Indexed: 11/22/2022]
Abstract
In mammalian species, including man, the duration of myocardial contraction is shorter in atria than ventricles. Total contraction time depends at least in part on phosphorylation and dephosphorylation of cardiac regulatory proteins. Dephosphorylation reactions are mediated by protein phosphatases. In the mammalian heart more than 90% of the protein phosphatase (PP) activity consists of PP1 and PP2A. Therefore, the aim of this study was to investigate which isoforms of PP1 and PP2A are present in human myocardium and whether their expression is regionally different. RT-PCR and Northern blotting revealed that all isoforms of PP1 and PP2A presently known are expressed in the human heart. Expression levels of PP1 alpha, delta, and gamma as well as 2A alpha were higher in right ventricles than in right atria. However, there was no such difference for PP2A beta. At the protein level PP1 alpha was unchanged, whereas PP2A was by 56% higher in right ventricles compared to atria. The phosphorylation state of TnI was lower in right ventricle than in right atrium. Thus, lower protein expression of PP2A in atrium could contribute to the faster relaxation by increasing the phosphorylation state of TnI. We conclude that expression of PP1 and PP2A isoforms is regionally regulated in the human heart.
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Affiliation(s)
- H Lüss
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany.
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30
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Müller FU, Neumann J, Schmitz W. Transcriptional regulation by cAMP in the heart. Mol Cell Biochem 2000; 212:11-7. [PMID: 11108131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Stimulation of the cAMP-dependent signalling pathway by beta-adrenergic catecholamines is an important physiological mechanism to increase contractile force in the heart. In addition to this, long-term beta-adrenergic stimulation by elevated catecholamines also influences the expressional control of functionally relevant cardiac regulatory proteins in human heart failure. The regulation of transcription by the cAMP-response element (CRE) is an important mechanism for a cAMP-mediated control of gene expression involved e.g. in spermiogenesis and memory/learning processes. This article discusses recent data leading to the hypothesis that this mechanism also contributes to altered gene regulation in heart failure.
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Affiliation(s)
- F U Müller
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, Münster, Germany.
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Bokník P, Fockenbrock M, Herzig S, Knapp J, Linck B, Lüss H, Müller FU, Müller T, Schmitz W, Schröder F, Neumann J. Protein phosphatase activity is increased in a rat model of long-term beta-adrenergic stimulation. Naunyn Schmiedebergs Arch Pharmacol 2000; 362:222-31. [PMID: 10997724 DOI: 10.1007/s002100000283] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We tested the hypothesis that altered phosphorylation of Ca2+ regulatory proteins contributes to contractile anomalies in cardiac hypertrophy. Cardiac hypertrophy was induced in rats by chronic s.c. administration of isoproterenol (Iso, 2.4 mg/kg/day) via osmotic minipumps. On day 2 of Iso treatment the expression of atrial natriuretic factor was increased, time of relaxation in isolated papillary muscles shortened and protein expression of phospholamban (PLB) and sarcoplasmic reticulum Ca2+-ATPase reduced. In addition, the phosphorylation state of PLB at serine-16 and threonine-17 was decreased from (arbitrary units) 2.3+/-0.3 to 1.1+/-0.2 and from 4.1+/-0.6 to 2.1+/-0.2, respectively. This was not accompanied by altered activity of PLB-phosphorylating protein kinases (protein kinase A or Ca2+/calmodulin-dependent protein kinase II), whereas the activity of types 1 and 2A protein phosphatases (PP1 and -2A respectively) was enhanced from 1.1+/-0.08 to 1.71+/-0.13 nmol/mg/min. Iso treatment did not alter the PP1/PP2A activity ratio and 1 nmol/l okadaic acid, a concentration which completely blocks the catalytic subunit of PP2A, inhibited about 40% of total PP activity in all groups studied. These data indicate that the activity of both PP1 and PP2A were increased. All effects of Iso treatment were abolished by co-administration of propranolol (29.7 mg/kg/day). It is concluded that dephosphorylation of PLB is due to enhanced activity of PP1 and PP2A. We suggest that chronic beta-adrenergic stimulation, which occurs in human cardiac hypertrophy and failure, can lead to increased activity of PPs. This may contribute to altered contractile responses in the hypertrophied heart.
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Affiliation(s)
- P Bokník
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany.
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Knapp J, Bokník P, Linck B, Lüss H, Müller FU, Petertönjes L, Schmitz W, Neumann J. Cantharidin enhances norepinephrine-induced vasoconstriction in an endothelium-dependent fashion. J Pharmacol Exp Ther 2000; 294:620-6. [PMID: 10900240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
In this study we characterized the effects of the protein phosphatase (PP) type 1 and type 2A inhibitor cantharidin (Cant) and its structural analogs cantharidic acid and endothall on PP activity, force of contraction, and myosin light chain phosphorylation in rat aorta. All compounds inhibited PP activity in homogenates of rat aorta with a rank order of potency of Cant = cantharidic acid > endothall. However, only Cant increased force of contraction and myosin light chain phosphorylation in intact isolated rat aortic rings. Based on these findings, we investigated the effects of Cant on alpha-adrenoceptor-mediated vasoconstriction. Cant (1 and 3 microM) enhanced norepinephrine-induced contraction in endothelium-intact rat aorta. In contrast, Cant did not affect norepinephrine-induced contraction in endothelium-denuded rat aorta. We suggest that inhibition of PP1 and/or PP2A activities by Cant enhances vascular contractility in endothelium-intact rat aorta by increasing the phosphorylation state of endothelial regulatory proteins.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/enzymology
- Aorta, Thoracic/physiology
- Cantharidin/pharmacology
- Catalysis
- Drug Synergism
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- In Vitro Techniques
- Male
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle Relaxation/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/physiology
- Myosin Light Chains/metabolism
- Myosin-Light-Chain Phosphatase
- Norepinephrine/pharmacology
- Okadaic Acid/pharmacology
- Phosphoprotein Phosphatases/antagonists & inhibitors
- Phosphoprotein Phosphatases/metabolism
- Phosphorylation
- Rats
- Rats, Wistar
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Universität Münster, Germany.
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Linck B, Bokník P, Huke S, Kirchhefer U, Knapp J, Lüss H, Müller FU, Neumann J, Tanriseven Z, Vahlensieck U, Baba HA, Jones LR, Philipson KD, Schmitz W. Functional properties of transgenic mouse hearts overexpressing both calsequestrin and the Na(+)-Ca(2+) exchanger. J Pharmacol Exp Ther 2000; 294:648-57. [PMID: 10900244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Overexpression of calsequestrin (CSQ) induces severe cardiac hypertrophy, whereas overexpression of Na(+)-Ca(2+) exchanger (NCX) does not affect cardiac weight. To investigate a possible beneficial effect of NCX in hypertrophy, we produced transgenic mice overexpressing both NCX and CSQ (NCX/CSQ). Surprisingly, these mice developed severe heart failure. The heart/body weight ratio was enhanced and the mRNA expression of ANF, as a marker of hypertrophy, was highest in double transgenic mice. In isolated muscle strips, the basal relaxation time was prolonged in CSQ and NCX/CSQ mice. Moreover, in the presence of caffeine, force of contraction was increased only in CSQ and NCX/CSQ and was accompanied by elevated diastolic tension. In some respects, however, additional overexpression of NCX altered the CSQ phenotype into the wild-type phenotype. The expression of sarcoplasmic reticulum (SR)-Ca(2+)-ATPase and phospholamban, proteins involved in the Ca(2+) uptake of the SR, were only increased in CSQ, indicating a possible influence of NCX in the regulation of SR-Ca(2+) uptake proteins. The Ca(2+) transients and the L-type Ca(2+) currents in the presence of caffeine were very large in CSQ, but smaller increases were noted in double transgenic mice. Therefore, the successful co-overexpression of CSQ and NCX in these mice provides a novel model in which to investigate the interaction of proteins tightly linked to maintain Ca(2+) homeostasis.
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Affiliation(s)
- B Linck
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, Münster, Germany
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Bokník P, Vahlensieck U, Huke S, Knapp J, Linck B, Lüss H, Müller FU, Neumann J, Schmitz W. On the cardiac contractile, electrophysiological and biochemical effects of endothall, a protein phosphatase inhibitor. Pharmacology 2000; 61:43-50. [PMID: 10895080 DOI: 10.1159/000028379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Protein phosphatase inhibitors, e.g. cantharidin, exert positive inotropic effects in mammalian heart preparations. Endothall, a synthetic herbicide which is chemically related to cantharidin, inhibits protein phosphatase activities in mouse liver preparations. However, the cardiac effects of endothall have hitherto not been studied. In guinea pig papillary muscles, endothall (1-100 micromol/l) failed to affect force of contraction, whereas cantharidin (1-100 micromol/l) increased force of contraction maximally to 313.4 +/- 32% of control at 10 micromol/l. In isolated guinea pig ventricular cardiomyocytes, endothall did neither change the free intracellular calcium concentration nor the amplitude of calcium current nor the phosphorylation state of regulatory phosphoproteins like phospholamban. In contrast, cantharidin (30 micromol/l) increased the free intracellular calcium concentration and the L-type calcium current to 149.6 +/- 9% and to 157.6 +/- 12% of control, respectively. Furthermore, cantharidin (1-100 micromol/l) augmented the phosphorylation of phospholamban maximally to 140.8 +/- 7% of control. Nevertheless, in guinea pig ventricular homogenates, both endothall and cantharidin inhibited phosphatase activity with EC(50) values of 1.92 and 0.32 micromol/l, respectively. Thus, in contrast to cantharidin, endothall failed to increase force of contraction, though it inhibited protein phosphatase activity. Clearly, endothall is not an appropriate tool to study the function of protein phosphatases in the mammalian heart.
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Affiliation(s)
- P Bokník
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Deutschland
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Lüss H, Meissner A, Rolf N, Van Aken H, Bokník P, Kirchhefer U, Knapp J, Läer S, Linck B, Lüss I, Müller FU, Neumann J, Schmitz W. Biochemical mechanism(s) of stunning in conscious dogs. Am J Physiol Heart Circ Physiol 2000; 279:H176-84. [PMID: 10899054 DOI: 10.1152/ajpheart.2000.279.1.h176] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mechanism(s) underlying contractile dysfunction in cardiac stunning is not completely understood. The expression and/or the phosphorylation state of cardiac Ca(2+) homoeostasis-regulating proteins might be altered in stunning. We tested this hypothesis in a well-characterized model of stunning. Conscious dogs were chronically instrumented, and the left anterior descending artery (LAD) was occluded for 10 min. Thereafter, reperfusion of the LAD was initiated. Tissues from reperfused LAD (stunned) and Ramus circumflexus (control) areas were obtained when left ventricular regional wall thickening fraction had recovered by 50%. Northern and Western blotting revealed no differences in the expression of the following genes: phospholamban, calsequestrin, sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a, and the inhibitory subunit of troponin I (TnI). However, the phosphorylation state of TnI and phospholamban were reduced in the LAD area. Fittingly, cAMP levels were reduced by 28% (P < 0.05). It is concluded that the contractile dysfunction in cardiac stunning might be mediated in part by decreased levels of cAMP and subsequently a reduced phosphorylation state of phospholamban and TnI.
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Affiliation(s)
- H Lüss
- Institut für Pharmakologie und Toxikologie, Universität Münster, D-48149 Münster, Germany
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Meissner A, Lüss I, Rolf N, Boknik P, Kirchhefer U, Kehm V, Knapp J, Linck B, Lüss H, Müller FU, Weber T, Schmitz W, Van Aken H, Neumann J. The early response genes c-jun and HSP-70 are induced in regional cardiac stunning in conscious mammals. J Thorac Cardiovasc Surg 2000; 119:820-5. [PMID: 10733775 DOI: 10.1016/s0022-5223(00)70019-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [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] [Indexed: 11/26/2022]
Abstract
OBJECTIVES A reversible contractile dysfunction without necrosis after transient myocardial ischemia has been termed stunning. The molecular mechanisms underlying this phenomenon are only now beginning to be unraveled. It is conceivable that the expression of early-response genes may play a crucial role in stunning. METHODS The expression of HSP-70, c-jun, and GRP-94 was investigated in a chronically instrumented dog model (n = 9). The left anterior descending coronary artery was occluded temporarily for 10 minutes after the animals had fully recovered from instrumentation. The wall thickening fraction was measured in the left anterior descending coronary artery and the nonischemic ramus circumflex of the left coronary artery-perfused region. When the wall thickening fraction of the left anterior descending coronary artery had recovered to 50% of preocclusion values, tissue samples were obtained from the areas perfused by the left anterior descending coronary artery and the nonischemic ramus circumflex of the left coronary artery. RESULTS The messenger RNA of HSP-70 was increased to 214% +/- 26% in the area perfused by the left anterior descending artery compared with that perfused by the nonischemic ramus circumflex of the left coronary artery. There was no difference in the messenger RNA of GRP-94. The HSP-70 content was elevated to 130% +/- 14% in the left anterior descending artery compared with the area perfused by the ramus circumflex of the left coronary artery, and the c-jun protein content was 70% +/- 25% higher in the ischemic area compared with the control area. CONCLUSIONS The induction of early-response genes observed here may indicate that they play an adaptive role in myocardial stunning, even in conscious mammals.
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Affiliation(s)
- A Meissner
- Klinik und Poliklinik für Anästhesiologie und operative Intensivmedizin and the Institut für Pharmakologie und Toxikologie, Universität Münster, Germany.
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Neumann J, Vahlensieck U, Boknik P, Linck B, Lüss H, Müller FU, Matherne GP, Schmitz W. Functional studies in atrium overexpressing A1-adenosine receptors. Br J Pharmacol 1999; 128:1623-9. [PMID: 10602345 PMCID: PMC1571796 DOI: 10.1038/sj.bjp.0702963] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Adenosine and the A1-adenosine receptor agonist R-PIA, exerted a negative inotropic effect in isolated, electrically driven left atria of wild-type mice. 2. In left atria of mice overexpressing the A1-adenosine receptor, adenosine and R-PIA exerted a positive inotropic effect. 3. The positive inotropic effect of adenosine and R-PIA in transgenic atria could be blocked by the A1-adenosine receptor antagonist DPCPX. 4. In the presence of isoprenaline, adenosine exerted a negative inotropic effect in wild-type atria but a positive inotropic effect in atria from A1-adenosine receptor overexpressing mice. 5. The rate of beating in right atria was lower in mice overexpressing A1-adenosine receptors compared with wild-type. 6. Adenosine exerted comparable negative chronotropic effects in right atria from both A1-adenosine receptor overexpressing and wild-type mice. 7. A1-adenosine receptor overexpression in the mouse heart can reverse the inotropic but not the chronotropic effects of adenosine, implying different receptor-effector coupling mechanisms.
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Affiliation(s)
- J Neumann
- Institut für Pharmakologie und Toxikologie, Universität Münster, D-48149 Münster, Germany
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Knapp J, Bokník P, Deng MC, Huke S, Lüss I, Klein-Wiele O, Linck B, Lüss H, Müller FU, Nacke P, Scheld HH, Schmitz W, Vahlensieck U, Neumann J. On the contractile function of protein phosphatases in isolated human coronary arteries. Naunyn Schmiedebergs Arch Pharmacol 1999; 360:464-72. [PMID: 10551284 DOI: 10.1007/s002109900124] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is unknown whether protein phosphatases types 1 and 2A are present in and can regulate the tone of human vascular tissue. The expression and possible function of serine/threonine protein phosphatases (PP) type 1 (PP1) and type 2A (PP2A) were studied in isolated human coronary arteries. Catalytic subunits of PPI and PP2A were identified by means of phosphatase activity measurement in tissue homogenates, by separation of enriched extracts through affinity column chromatography, by immunoblotting with specific antibodies, by hybridization of mRNA with specific DNA probes and PCR of reverse transcribed mRNA. Based on these methods, the catalytic subunits of PP1(alpha,beta,gamma) and PP2A(alpha,beta) were identified. Appropriately, cantharidin, an inhibitor of PP1 and PP2A, increased basal tone of human isolated coronary artery rings with an EC50 of about 16 micromol/l by increasing the phosphorylation state of the regulatory light chains of myosin. In summary, PP1 and PP2A are expressed in human coronary arteries and they can alter vascular tone.
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany.
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Knapp J, Bokník P, Linck B, Läer S, Müller FU, Neumann J, Vahlensieck U, Schlüter H, Zidek W, Schmitz W. Inositol-1,4,5-trisphosphate increase by diadenosine tetraphosphate in preparations from failing human myocardium. Naunyn Schmiedebergs Arch Pharmacol 1999; 360:354-7. [PMID: 10543439 DOI: 10.1007/s002109900076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In human ventricular trabeculae carneae 100 microM AP4A (diadenosine tetraphosphate) increased force of contraction to 162.8+/-15.7% of predrug value (n=9). This positive inotropic effect was accompanied by a prolongation of time parameters: time to peak tension and time of relaxation were prolonged by 7.8+/-1.3% and 14.9+/-3.8%, respectively (P<0.05). In the same trabeculae, AP4A increased IP3 (inositol-1,4,5-trisphosphate) content from 9.0+/-1.3 pmol/mg to 22.9+/-5.4 pmol/mg protein (n=5-9). In conclusion, the positive inotropic effect of AP4A in the human myocardium is likely due to an increase of IP3 mediated probably via Gq-coupled P2Y-purinoceptors. Because of the prominent role of Gq in the development of cardiac disease, these findings may lay the ground to further investigate the possible role of AP4A and/or related ligands (e.g. AP2A and AP3A) in heart failure.
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany.
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Bokník P, Unkel C, Kirchhefer U, Kleideiter U, Klein-Wiele O, Knapp J, Linck B, Lüss H, Müller FU, Schmitz W, Vahlensieck U, Zimmermann N, Jones LR, Neumann J. Regional expression of phospholamban in the human heart. Cardiovasc Res 1999; 43:67-76. [PMID: 10536691 DOI: 10.1016/s0008-6363(99)00053-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [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] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Several independent lines of evidence indicate that phospholamban (PLB) expression correlates positively with depression of force of contraction and duration of contraction in isolated cardiac preparations of several animal species. Here, we studied whether PLB levels correlate with attenuation of contractility and enhancement of contractile time parameters in different parts of the human heart. METHODS Force of contraction was measured in isolated electrically driven atrial and ventricular preparations from human hearts. Ca(2+)-uptake by human atrial and ventricular homogenates was assayed at different ionized Ca(2+)-concentrations. Protein expression of PLB and the sarcoplasmic Ca(2+)-ATPase (SERCA) was measured in homogenates by quantitative immunoblotting using specific antibodies. PLB mRNA expression was quantified in human cardiac preparations by Northern blot analysis. RESULTS The duration of contraction in isolated preparations of human right ventricle (RV) was double that found in right atrial preparations (RA) (620 +/- 25 ms versus 308 +/- 15 ms). In RA, PLB expression was reduced by 44% at the protein level and by 34% at the mRNA level compared to RV. In contrast, the SERCA protein content was increased by 104% in RA compared to RV. Ca(2+)-uptake at low ionized Ca(2+)-concentration, where the inhibiting effect of PLB is maximal, amounted to 1.39 +/- 0.28 nmol Ca2+/mg protein in RA and to 0.62 +/- 0.09 nmol Ca2+/mg protein in RV (n = 6 both). CONCLUSIONS It is suggested that duration of contraction is shorter in human atrium versus ventricle due to the combined effect of decreased PLB levels (which inhibits SERCA function) and increased SERCA levels. The lower relative ratio of PLB to SERCA leads to less inhibition of SERCA and increased Ca(2+)-uptake which enhances relaxation and contraction in human atrium.
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Affiliation(s)
- P Bokník
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, Münster, Germany
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Knapp J, Bokník P, Lüss I, Huke S, Linck B, Lüss H, Müller FU, Müller T, Nacke P, Noll T, Piper HM, Schmitz W, Vahlensieck U, Neumann J. The protein phosphatase inhibitor cantharidin alters vascular endothelial cell permeability. J Pharmacol Exp Ther 1999; 289:1480-6. [PMID: 10336542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
In this study, we characterized the effects of the protein phosphatases type 1 (PP 1) and type 2A (PP 2A) inhibitor cantharidin in endothelial cells. We identified catalytic subunits of PP 1alpha, PP 2Aalpha, and PP 2Abeta immunologically in bovine aortic endothelial cells. Moreover, we detected mRNAs coding for catalytic subunits of PP 1alpha, PP 1beta, and PP 2Aalpha by hybridization with specific DNA probes in total RNA from these cells. Okadaic acid and cantharidin inhibited the activities of catalytic subunits of PP 1 (okadaic acid, 0.01-1 microM; cantharidin, 1-100 microM) and PP 2A (okadaic acid, 0.1 nM to 1 microM; cantharidin, 0.1-100 microM) separated by column chromatography in a concentration-dependent manner. Moreover, cantharidin (1 microM to 1 mM) increased the phosphorylation state of endothelial proteins including the regulatory light chains of myosin without affecting cytosolic calcium concentrations. Cantharidin (5-100 microM) increased the permeability of cultured endothelial cells in a time- and concentration-dependent manner. We suggest that inhibition of PP 1 and PP 2A activities by cantharidin increases endothelial permeability by enhancing the phosphorylation state of endothelial regulatory proteins. Thus, cantharidin might be a useful tool to study the function of protein phosphatases in endothelial barrier function.
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany.
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Lüss I, Boknik P, Jones LR, Kirchhefer U, Knapp J, Linck B, Lüss H, Meissner A, Müller FU, Schmitz W, Vahlensieck U, Neumann J. Expression of cardiac calcium regulatory proteins in atrium v ventricle in different species. J Mol Cell Cardiol 1999; 31:1299-314. [PMID: 10371704 DOI: 10.1006/jmcc.1999.0962] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [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] [Indexed: 11/22/2022]
Abstract
The duration of contraction in isolated electrically driven preparations from atrium and ventricle of mouse, rat, rabbit, guinea-pig and dog was consistently shorter in atrial compared to ventricular preparations. Overexpression of phospholamban (PLB) in transgenic mice prolonged duration of contraction, underscoring the importance of PLB for kinetics of cardiac contractility. The expression of regulatory proteins was studied by Western and Northern blot analysis. In rat myocardium, expression of the sarcoplasmic reticulum Ca2+ ATPase (SERCA) was higher in atrium than in ventricle, as was also observed in the rabbit, guinea-pig and wild-type mouse samples. Canine myocardium, however, had similar levels of SERCA (protein and mRNA) in atrium and ventricle. PLB and calsequestrin on protein and RNA levels were lower in atrium than in ventricle from rat, rabbit, guinea-pig and wild-type mouse. PLB protein and RNA levels were higher in ventricle than in atrium at ages 1 and 5 days postnatally and in adult rats. SERCA protein and RNA levels were higher in ventricle than in atrium at days 1 and 5 after birth, but lower in ventricle than in atrium in adult rats. In dog, the calsequestrin level was identical in atrium and ventricle (protein and mRNA) and PLB did not differ between atrium vs ventricle at the protein level but was lower at the mRNA level. Also, Ca2+ uptake was higher in atrium than in ventricle in the dog samples. The expression of the inhibitory subunit of troponin was unchanged between atrium and ventricle in all species studied (protein and mRNA). In dog, protein expression of triadin and junctin was lower in atrium vs ventricle. Triadin mRNA was not altered in dog atrium vs ventricle. In summary, while the hastened relaxation of atrium vs ventricle correlates in part with the lower expression of PLB and higher expression of SERCA, altered regional expression of other SR proteins handling Ca2+ may also play an important role in some species.
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Affiliation(s)
- I Lüss
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Domagkstrasse, Münster 12, D-48149, Germany
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Knapp J, Bokník P, Gumbinger HG, Linck B, Lüss H, Müller FU, Schmitz W, Vahlensieck U, Neumann J. Quantitation of clobazam in human plasma using high-performance liquid chromatography. J Chromatogr Sci 1999; 37:145-9. [PMID: 10335607 DOI: 10.1093/chromsci/37.5.145] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A rapid and simple reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of clobazam concentrations in human blood samples is developed and validated. Solid-phase column extraction is performed to clean up blood samples before running the analytical HPLC system. The chromatography is isocratic with a mobile phase consisting of acetonitrile (20%, v/v), methanol (23%, v/v), and 0.1 M potassium hydrogen phosphate buffer (pH 3.6; 57%, v/v) at a constant flow rate of 2 mL/min. Clobazam is detected at 226 nm. Chromatography is completed within less than 25 min. The recovery rate is greater than 95% and linear over a wide range of drug concentrations. The intra-assay coefficient of variation percentage varies between 4.3 and 12. This method is used for therapeutic drug monitoring in patients undergoing antiepileptic therapy with clobazam. Plasma levels of clobazam ranged from 21 to 663 ng/mL. Other antiepileptic compounds, such as clonazepam and phenobarbital, did not interfere with the detection of clobazam.
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Universität Münster, Germany
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Flesch M, Kilter H, Cremers B, Laufs U, Südkamp M, Ortmann M, Müller FU, Böhm M. Effects of endotoxin on human myocardial contractility involvement of nitric oxide and peroxynitrite. J Am Coll Cardiol 1999; 33:1062-70. [PMID: 10091837 DOI: 10.1016/s0735-1097(98)00660-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [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] [Indexed: 10/18/2022]
Abstract
OBJECTIVES This study examined the effects of endotoxin on cardiac contractility in human myocardium. BACKGROUND In animal myocardium, endotoxin and cytokine treatment led to enhanced inducible nitric oxide synthase (iNOS) expression and contractile dysfunction. Effects in human myocardium are unknown. METHODS Left ventricular myocardial preparations from failing (n = 18) and nonfailing (n = 5) human hearts were incubated for 6 and 12 h in tyrode solution or in tyrode plus lipopolysaccharides (LPS), with LPS plus N(G)-mono-methyl-L-arginine (L-NMMA), with LPS plus hemoglobin or with LPS plus the superoxide scavenger 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron). Force of contraction in response to isoprenaline (0.001 to 3 micromol/liter) was determined in electrically stimulated muscle preparations. The iNOS mRNA expression was examined by in situ hybridization and by polymerase chain reaction. The cyclic guanosine monophosphate (cGMP) levels were determined by radioimmunoassay. RESULTS Isoprenaline concentration dependently increased force of contraction. Six and 12 hours of LPS treatment of failing myocardium decreased maximum inotropic response to isoprenaline by 54% (p = 0.009) and by 69% (p = 0.0023), respectively. In nonfailing myocardium, 12 h of LPS treatment decreased maximum inotropic effect of isoprenaline by 66% (p < 0.001). The LPS effects were attenuated by L-NMMA, hemoglobin and also Tiron. The iNOS mRNA was expressed in all LPS-treated preparations but also in most control myocardial preparations. In situ hybridization revealed iNOS expression within cardiac myocytes. There was no increase in myocardial cGMP content in response to endotoxin. CONCLUSIONS Endotoxin exposure of human myocardium leads to a depression of cardiac contractility, which is mediated by enhanced iNOS activity and release of nitric oxide (NO). Consecutive reaction of NO with superoxide and formation of peroxynitrite may contribute to the decrease in force of contraction.
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Affiliation(s)
- M Flesch
- Klinik III für Innere Medizin, der Universität zu Köln, Germany.
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Vahlensieck U, Bokník P, Gombosová I, Huke S, Knapp J, Linck B, Lüss H, Müller FU, Neumann J, Deng MC, Scheld HH, Jankowski H, Schlüter H, Zidek W, Zimmermann N, Schmitz W. Inotropic effects of diadenosine tetraphosphate (AP4A) in human and animal cardiac preparations. J Pharmacol Exp Ther 1999; 288:805-13. [PMID: 9918592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
Diadenosine tetraphosphate (AP4A) is an endogenous compound and exerts diverse physiological effects in animal systems. However, the effects of AP4A on inotropy in ventricular cardiac preparations have not yet been studied. The effects of AP4A on force of contraction (FOC) were studied in isolated electrically driven guinea pig and human cardiac preparations. Furthermore, the effects of AP4A on L-type calcium current and [Ca]i were studied in isolated guinea pig ventricular myocytes. In guinea pig left atria, AP4A (0.1-100 microM) reduced FOC maximally by 36.5 +/- 4.3%. In guinea pig papillary muscles, AP4A (100 microM) alone was ineffective, but reduced isoproterenol-stimulated FOC maximally by 29.3 +/- 3.4%. The negative inotropic effects of AP4A in atria and papillary muscles were abolished by the A1-adenosine receptor antagonist 1, 3-dipropyl-cyclopentylxanthine. In guinea pig ventricular myocytes, AP4A (100 microM) attenuated isoproterenol-stimulated L-type calcium current and [Ca]i. In human atrial and ventricular preparations, AP4A (100 microM) alone increased FOC to 158.3 +/- 12.4% and 167.5 +/- 25.1%, respectively. These positive inotropic effects were abolished by the P2-purinoceptor antagonist suramin. On the other hand, AP4A (100 microM) reduced FOC by 27.2 +/- 7.4% in isoproterenol-stimulated human ventricular trabeculae. The latter effect was abolished by 1,3-dipropyl-cyclopentylxanthine. In summary, after beta adrenergic stimulation AP4A exerts negative inotropic effects in animal and human ventricular preparations via stimulation of A1-adenosine receptors. In contrast, AP4A alone can exert positive inotropic effects via P2-purinoceptors in human ventricular myocardium. Thus, P2-purinoceptor stimulation might be a new positive inotropic principle in the human myocardium.
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Affiliation(s)
- U Vahlensieck
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany
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Neumann J, Meissner A, Bokník P, Gombosová I, Knapp J, Lüss H, Müller FU, Schlüter H, Zidek W, Rolf N, Van Aken H, Vahlensieck U, Schmitz W. Inotropic effects of diadenosine tetraphosphate in isolated canine cardiac preparations. J Cardiovasc Pharmacol 1999; 33:151-6. [PMID: 9890411 DOI: 10.1097/00005344-199901000-00023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [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] [Indexed: 11/27/2022]
Abstract
We studied the effects of diadenosine tetraphosphate (AP4A) on the force of contraction in canine preparations. The force of contraction was measured in isolated electrically driven (1 Hz) atrial and ventricular cardiac trabeculae from adult dogs. AP4A (100 microM) alone and after prestimulation with 10 nM isoproterenol reduced force of contraction in atrial preparations by approximately 24%. Moreover, AP4A (100 microM) alone and after prestimulation with 10 nM isoproterenol reduced the force of contraction in ventricular preparations by 29 and 29%, respectively. The negative inotropic effects of AP4A were abolished by the A1-adenosine receptor antagonist 1,3-dipropyl-cyclopentyl-xanthine (DPCPX). In summary, in canine myocardium, AP4A alone and after prestimulation with a beta-adrenoceptor agonist exerts negative inotropic effects, which are probably mediated via A1-adenosine receptors.
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Affiliation(s)
- J Neumann
- Institut für Pharmakologie und Toxikologie, Universität Münster, Germany
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Knapp J, Bokník P, Huke S, Gombosová I, Linck B, Lüss H, Müller FU, Müller T, Nacke P, Schmitz W, Vahlensieck U, Neumann J. Contractility and inhibition of protein phosphatases by cantharidin. Gen Pharmacol 1998; 31:729-33. [PMID: 9809469 DOI: 10.1016/s0306-3623(98)00053-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
1. Cantharidin is a natural defensive toxicant produced by blister beetles. 2. Cantharidin shares structural similarity with highly toxic commercial herbicides (e.g., endothall, endothall anhydride and endothall thioanhydride). 3. Cantharidin inhibits the activity of purified catalytic subunits of serine/threonine protein phosphatases (PP) type 1 and type 2A. 4. Cantharidin increases force of contraction in isolated myocardial and vascular preparations. 5. Cantharidin enhances the phosphorylation state of myocardial and vascular regulatory proteins. 6. Cantharidin is a valuable tool for studying the function of PP in regulatory phosphorylation-dephosphorylation events.
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Affiliation(s)
- J Knapp
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Germany
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Abstract
Abnormal beta-adrenergic signal transduction and intracellular Ca2+ handling appear to be a major cause of systolic and diastolic dysfunction in humans with heart failure. The precise mechanisms which cause an alteration in Ca2+ handling have been a subject of investigation in recent years. Several lines of evidence suggest that activation of neurohormonal systems plays a central role. Altered Ca2+-handling (increased diastolic concentrations, reduced systolic Ca2+ release) have a strong impact on diastolic and systolic performance of failing hearts. Sarcoplasmic reticulum Ca2+ ATPase is reduced in activity and in steady-state mRNA concentration. The Na+-Ca2+ exchanger is upregulated at the mRNA and protein levels. Phospholamban depends strongly on cAMP-dependent phosphorylation. A strong sympathetic activation has been shown to desensitize the cAMP system. At the receptor level, there is downregulation of beta1-adrenergic receptors. An uncoupling of beta2-adrenoceptors has been attributed to an increased activity and gene expression of beta-adrenergic receptor kinase in failing myocardium, leading to phosphorylation and uncoupling of receptors. Finally, recent evidence suggests that cAMP-dependent transcription mechanisms may play a role during beta-adrenergic stimulation and cardiomyopathy with heart failure - by means of altered actions of cAMP response element binding protein, the cAMP response element modulator, or the activating transcription factor 1. The exact characterization of signal transduction defects could offer novel approaches to the pharmacological treatment of heart failure.
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Affiliation(s)
- R J Hajjar
- Harvard Medical School, Massachusetts General Hospital, Cardiovascular Center, Charlestown 02129-2060, USA
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Müller FU, Bokník P, Knapp J, Neumann J, Vahlensieck U, Oetjen E, Scheld HH, Schmitz W. Identification and expression of a novel isoform of cAMP response element modulator in the human heart. FASEB J 1998; 12:1191-9. [PMID: 9737722 DOI: 10.1096/fasebj.12.12.1191] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In end-stage human heart failure, excessive beta-adrenergic stimulation of the cAMP-dependent signaling pathway due to enhanced endogenous catecholamines is hypothesized to contribute to expressional alterations of myocardial regulatory proteins. The cAMP response element modulator (CREM) regulates the transcription of cAMP-responsive genes and might be involved in the regulation of cardiac gene expression. Using the reverse transcription polymerase chain reaction, we identified a novel CREM mRNA, CREM-Ib deltaC-X, in the human heart. Overexpression of CREM-Ib deltaC-X decreased cAMP response element (CRE) -mediated gene transcription in HIT-T15 cells, and this activity was assigned to the part of the sequence encoding putative internally translated proteins. Two of three possible internally translated proteins were immunologically identified in cells overexpressing CREM-Ib deltaC-X tagged with the hemagglutinin epitope of the influenza virus. Both proteins were expressed in bacteria and showed CRE-specific DNA binding, formation of heterodimers with the cAMP response element binding protein (CREB), and inhibition of CREB's binding to the CRE. CREM expression was detected on the mRNA and protein levels in the human heart. We conclude that CREM-Ib deltaC-X generates internally translated repressors of CRE-mediated gene transcription, suggesting the first example for the existence and function of human cardiac CREM.
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Affiliation(s)
- F U Müller
- Institut für Pharmakologie und Toxikologie, Universität Münster, Germany.
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Linck B, Bokník P, Baba HA, Eschenhagen T, Haverkamp U, Jäckel E, Jones LR, Kirchhefer U, Knapp J, Läer S, Müller FU, Schmitz W, Scholz H, Syska A, Vahlensieck U, Neumann J. Long-term beta adrenoceptor-mediated alteration in contractility and expression of phospholamban and sarcoplasmic reticulum Ca(++)-ATPase in mammalian ventricle. J Pharmacol Exp Ther 1998; 286:531-8. [PMID: 9655899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We studied the influence of prolonged administration of the beta adrenoceptor agonist isoproterenol on contractile parameters and expression of sarcoplasmic reticulum (SR) Ca(++)-ATPase and phospholamban, genes important for Ca++ uptake into the SR. Isoproterenol (Iso), 0.9% NaCl (Ctr), propranolol (Prop) or Iso plus Prop were administered to rats by subcutaneous infusion with osmotic minipumps for 1, 2, 3, 4, 8, 13 and 26 days, respectively. The positive inotropic effect of Iso was impaired in rats pretreated with Iso in vivo. Iso pretreatment shortened time to peak tension (TPT) by 28%, time of relaxation (RT) by 27% and total contraction time (TCT) by 27% compared with the appropriate controls (day 2). The shortening of time-dependent contractile indices started after 1 day of Iso pretreatment, reached a maximum after 2 days and remained reduced for 4 days. Longer treatment by Iso failed to affect time parameters, whereas the positive inotropic effect of Iso added to the isolated muscles persisted. The shortened contractile time parameters were accompanied by diminished mRNA and protein expression of phospholamban (PLB) and SR-Ca(++)-ATPase (SERCA). The mRNA levels for PLB and SERCA were maximally reduced by 31 +/- 1.3% and 41 +/- 1.4% in the Isopretreated group (2 days) respectively. The reduced mRNA levels were accompanied by reduced levels of the corresponding proteins. It is concluded that altered levels of PLB and SERCA probably account for the noted changes in contractile time parameters in the mammalian heart.
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Affiliation(s)
- B Linck
- Institut für Pharmakologie und Toxikologie, Westfälischen, Wilhelms-Universität, Münster, Germany
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