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Guo J, Tian Q, Barth M, Xian W, Ruppenthal S, Schaefers HJ, Chen Z, Moretti A, Laugwitz KL, Lipp P. Human BIN1 isoforms grow, maintain and regenerate excitation-contraction couplons in adult rat and human stem cell-derived cardiomyocytes. Cardiovasc Res 2021; 118:1479-1491. [PMID: 34152414 DOI: 10.1093/cvr/cvab195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Indexed: 12/31/2022] Open
Abstract
AIMS In ventricular myocytes, Transverse-tubules (T-tubules) are instrumental for excitation-contraction (EC) coupling and their disarray is a hallmark of cardiac diseases. BIN1 is a key contributor to their biogenesis. Our study set out to investigate the role of human BIN1 splice variants in the maintenance and regeneration of EC-coupling in rat adult ventricular myocytes and human induced pluripotent stem cell-derived cardiac myocytes (hiPS-CMs). METHODS AND RESULTS In heart samples from healthy human donors expression patterns of 5 BIN1 splice variants were identified. Following viral transduction of human BIN1 splice variants in cellular models of T-tubular disarray we employed high-speed confocal calcium imaging and Ca-CLEAN analysis to identify functional EC-coupling sites and T-tubular architecture. Adult rat ventricular myocytes were used to investigate the regeneration after loss and maintenance of EC-coupling while we studied the enhancement of EC-coupling in hiPS-CMs. All five human BIN1 splice variants induced de novo generation of T-tubules in both cell types. Isoforms with the phosphoinositide binding motif (PI) were most potent in maintenance and regeneration of T-tubules and functional EC-coupling in adult rat myocytes. In hiPSC-CMs, BIN1 variants with PI motiv induced de-novo generation of T-tubules, functional EC-coupling sites and enhanced calcium handling. CONCLUSION(S) BIN1 is essential for the maintenance, regeneration, and de-novo generation of functional T-tubules, especially isoforms with PI motifs. These T-tubules trigger the development of functional EC couplons resulting in enhanced calcium handling. TRANSLATIONAL PERSPECTIVE Cardiomyopathy and heart failure are among the most frequent causes of death in modern societies. Gene therapies and hiPSC technology are becoming increasingly promising, both for treatment and therapy development. On the cellular level, one of the common denominators of cardiac diseases is the concurrent loss of T-tubules essential for efficient EC-coupling. While initial approaches in animal models employing gene therapy with BIN1 have depicted encouraging improvements the expression pattern of BIN1 isoforms in the human heart is still elusive. The present study identifies a unique set of five distinct BIN1 isoforms in healthy human hearts and demonstrates their potency in both, T-tubule maintenance and re-generation after loss resulting in efficient EC-coupling. Noteworthy, PI-motif containing isoforms were potent trigger of de-novo generation of T-tubules and establishment of efficient EC-coupling in hiPSC-CMs. Therefore, the expression of BIN1 might be novel and promising for pharmaceutical treatment and gene therapy.
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Affiliation(s)
- Jia Guo
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Qinghai Tian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Monika Barth
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Wenying Xian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Sandra Ruppenthal
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Hans-Joachim Schaefers
- Department of Thoracic and Cardiovascular Surgery, Saarland University Medical Center, Homburg/Saar, Germany
| | - Zhifen Chen
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Alessandra Moretti
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Karl-Ludwig Laugwitz
- I. Department of Medicine, Klinikum rechts der Isar, Technische Universität München, 81675, München, Germany.,DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany
| | - Peter Lipp
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421, Homburg, Germany
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Wang J, Hertz L, Ruppenthal S, El Nemer W, Connes P, Goede JS, Bogdanova A, Birnbaumer L, Kaestner L. Lysophosphatidic Acid-Activated Calcium Signaling Is Elevated in Red Cells from Sickle Cell Disease Patients. Cells 2021; 10:456. [PMID: 33672679 PMCID: PMC7924404 DOI: 10.3390/cells10020456] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 12/15/2022] Open
Abstract
(1) Background: It is known that sickle cells contain a higher amount of Ca2+ compared to healthy red blood cells (RBCs). The increased Ca2+ is associated with the most severe symptom of sickle cell disease (SCD), the vaso-occlusive crisis (VOC). The Ca2+ entry pathway received the name of Psickle but its molecular identity remains only partly resolved. We aimed to map the involved Ca2+ signaling to provide putative pharmacological targets for treatment. (2) Methods: The main technique applied was Ca2+ imaging of RBCs from healthy donors, SCD patients and a number of transgenic mouse models in comparison to wild-type mice. Life-cell Ca2+ imaging was applied to monitor responses to pharmacological targeting of the elements of signaling cascades. Infection as a trigger of VOC was imitated by stimulation of RBCs with lysophosphatidic acid (LPA). These measurements were complemented with biochemical assays. (3) Results: Ca2+ entry into SCD RBCs in response to LPA stimulation exceeded that of healthy donors. LPA receptor 4 levels were increased in SCD RBCs. Their activation was followed by the activation of Gi protein, which in turn triggered opening of TRPC6 and CaV2.1 channels via a protein kinase Cα and a MAP kinase pathway, respectively. (4) Conclusions: We found a new Ca2+ signaling cascade that is increased in SCD patients and identified new pharmacological targets that might be promising in addressing the most severe symptom of SCD, the VOC.
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Affiliation(s)
- Jue Wang
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX 75708, USA;
| | - Laura Hertz
- Theoretical Medicine and Biosciences, Saarland University, 66421 Homburg, Germany;
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
| | - Sandra Ruppenthal
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
- Gynaecology, Obstetrics and Reproductive Medicine, Saarland University Hospital, 66421 Homburg, Germany
| | - Wassim El Nemer
- Etablissement Français du Sang PACA-Corse, Aix Marseille Université, EFS, CNRS, ADES, 13005 Marseille, France;
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France;
| | - Philippe Connes
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France;
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Teal, University Claude Bernard Lyon 1, 69008 Lyon, France
| | - Jeroen S. Goede
- Division of Oncology and Hematology, Kantonsspital Winterthur, CH-8401 Winterthur, Switzerland;
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, University of Zürich, CH-8057 Zürich, Switzerland;
| | - Lutz Birnbaumer
- Institute of Biomedical Research (BIOMED), Catholic University of Argentina, C1107AFF Buenos Aires, Argentina;
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, 66421 Homburg, Germany;
- Experimental Physics, Dynamics of Fluids, Saarland University, 66123 Saarbrücken, Germany;
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3
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Kaiser E, Tian Q, Wagner M, Barth M, Xian W, Schröder L, Ruppenthal S, Kaestner L, Boehm U, Wartenberg P, Lu H, McMillin SM, Bone DBJ, Wess J, Lipp P. DREADD technology reveals major impact of Gq signalling on cardiac electrophysiology. Cardiovasc Res 2020; 115:1052-1066. [PMID: 30321287 DOI: 10.1093/cvr/cvy251] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 06/02/2018] [Accepted: 10/11/2018] [Indexed: 02/04/2023] Open
Abstract
AIMS Signalling via Gq-coupled receptors is of profound importance in many cardiac diseases such as hypertrophy and arrhythmia. Nevertheless, owing to their widespread expression and the inability to selectively stimulate such receptors in vivo, their relevance for cardiac function is not well understood. We here use DREADD technology to understand the role of Gq-coupled signalling in vivo in cardiac function. METHODS AND RESULTS We generated a novel transgenic mouse line that expresses a Gq-coupled DREADD (Dq) in striated muscle under the control of the muscle creatine kinase promotor. In vivo injection of the DREADD agonist clozapine-N-oxide (CNO) resulted in a dose-dependent, rapid mortality of the animals. In vivo electrocardiogram data revealed severe cardiac arrhythmias including lack of P waves, atrioventricular block, and ventricular tachycardia. Following Dq activation, electrophysiological malfunction of the heart could be recapitulated in the isolated heart ex vivo. Individual ventricular and atrial myocytes displayed a positive inotropic response and arrhythmogenic events in the absence of altered action potentials. Ventricular tissue sections revealed a strong co-localization of Dq with the principal cardiac connexin CX43. Western blot analysis with phosphor-specific antibodies revealed strong phosphorylation of a PKC-dependent CX43 phosphorylation site following CNO application in vivo. CONCLUSION Activation of Gq-coupled signalling has a major impact on impulse generation, impulse propagation, and coordinated impulse delivery in the heart. Thus, Gq-coupled signalling does not only modulate the myocytes' Ca2+ handling but also directly alters the heart's electrophysiological properties such as intercellular communication. This study greatly advances our understanding of the plethora of modulatory influences of Gq signalling on the heart in vivo.
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Affiliation(s)
- Elisabeth Kaiser
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Qinghai Tian
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Michael Wagner
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Monika Barth
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Wenying Xian
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Laura Schröder
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Sandra Ruppenthal
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Lars Kaestner
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
| | - Ulrich Boehm
- Center for Molecular Signaling (PZMS), Institute for Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, Saarland University, Homburg, Germany
| | - Philipp Wartenberg
- Center for Molecular Signaling (PZMS), Institute for Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, Saarland University, Homburg, Germany
| | - Huiyan Lu
- Mouse Transgenic Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Sara M McMillin
- Molecular Signaling Section, Lab. of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Derek B J Bone
- Molecular Signaling Section, Lab. of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Jürgen Wess
- Molecular Signaling Section, Lab. of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Peter Lipp
- Center for Molecular Signaling (PZMS), Institute for Molecular Cell Biology; Medical Faculty, Saarland University, Homburg, Germany
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4
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Lipp P, Guo J, Tian Q, Barth M, Xian W, Ruppenthal S, Schaefers HJ, Chen Z, Moretti A, Laugwitz KL. Human BIN1 Isoforms Maintain, Regenerate and Elicit Functional EC-coupling and Couplons in Adult Rat and Human Induced Pluripotent Stem Cell-derived Cardiomyocytes. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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5
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Xian W, Hui X, Tian Q, Wang H, Moretti A, Laugwitz KL, Flockerzi V, Ruppenthal S, Lipp P. Aberrant Deactivation-Induced Gain of Function in TRPM4 Mutant Is Associated with Human Cardiac Conduction Block. Cell Rep 2019; 24:724-731. [PMID: 30021168 DOI: 10.1016/j.celrep.2018.06.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/27/2018] [Accepted: 06/07/2018] [Indexed: 02/04/2023] Open
Abstract
A gain-of-function mutation in the Ca2+-activated transient receptor potential melastatin member 4 (TRPM4A432T) is linked to life-threatening cardiac conduction disturbance, but the underlying mechanism is unclear. For deeper insights, we used photolysis of caged Ca2+, quantitative Ca2+, and electrophysiological measurements. TRPM4A432T's 2-fold larger membrane current was associated with 50% decreased plasma membrane expression. Kinetic analysis unveiled 4-fold slower deactivation that was responsible for the augmented membrane current progressively rising during repetitive human cardiac action potentials. Rational mutagenesis of TRPM4 at position 432 revealed that the bulkiness of the amino acid was key to TRPM4A432T's aberrant gating. Charged amino acids rendered the channel non-functional. The slow deactivation caused by an amino acid substitution at position 432 from alanine to the bulkier threonine represents a key contributor to the gain of function in TRPM4A432T. Thus, our results add a mechanism in the etiology of TRP channel-linked human cardiac channelopathies.
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Affiliation(s)
- Wenying Xian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Xin Hui
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Qinghai Tian
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Hongmei Wang
- Experimental and Clinical Pharmacology and Toxicology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Alessandra Moretti
- Department of Medicine I (Cardiology and Angiology), Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Karl-Ludwig Laugwitz
- Department of Medicine I (Cardiology and Angiology), Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Veit Flockerzi
- Experimental and Clinical Pharmacology and Toxicology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Sandra Ruppenthal
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Peter Lipp
- Molecular Cell Biology, Centre for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany.
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6
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Hertz L, Ruppenthal S, Simionato G, Quint S, Kihm A, Abay A, Petkova-Kirova P, Boehm U, Weissgerber P, Wagner C, Laschke MW, Kaestner L. The Evolution of Erythrocytes Becoming Red in Respect to Fluorescence. Front Physiol 2019; 10:753. [PMID: 31275166 PMCID: PMC6593091 DOI: 10.3389/fphys.2019.00753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/31/2019] [Indexed: 11/13/2022] Open
Abstract
Very young red blood cells, namely reticulocytes, can be quite easily recognized and labeled by cluster of differentiation antibodies (CD71, transferrin receptor) or by staining remnant RNA with thiazol orange. In contrast, age specific erythrocyte labeling is more difficult in later periods of their life time. While erythrocytes contain band 4.1 protein, a molecular clock, so far it has not been possible to read this clock on individual cells. One concept to track erythrocytes during their life time is to mark them when they are young, either directly in vivo or ex vivo followed by a transfusion. Several methods like biotinylation, use of isotopes or fluorescent labeling have proved to be useful experimental approaches but also have several inherent disadvantages. Genetic engineering of mice provides additional options to express fluorescent proteins in erythrocytes. To allow co-staining with popular green fluorescent dyes like Fluo-4 or other fluorescein-based dyes, we bred a mouse line expressing a tandem red fluorescent protein (tdRFP). Within this Brief Research Report, we provide the initial characterisation of this mouse line and show application examples ranging from transfusion experiments and intravital microscopy to multicolour flow cytometry and confocal imaging. We provide a versatile new tool for erythrocyte research and discuss a range of experimental opportunities to study membrane processes and other aspects of erythrocyte development and aging with help of these animals.
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Affiliation(s)
- Laura Hertz
- Institute for Molecular and Cell Biology, Saarland University, Homburg, Germany
| | - Sandra Ruppenthal
- Institute for Molecular and Cell Biology, Saarland University, Homburg, Germany
| | - Greta Simionato
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Stephan Quint
- Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Alexander Kihm
- Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Asena Abay
- Experimental Physics, Saarland University, Saarbrücken, Germany
| | | | - Ulrich Boehm
- Center for Molecular Signaling (PZMS), Institute for Pharmacology, Saarland University, Homburg, Germany
| | - Petra Weissgerber
- Center for Molecular Signaling (PZMS), Institute for Pharmacology, Saarland University, Homburg, Germany
| | - Christian Wagner
- Experimental Physics, Saarland University, Saarbrücken, Germany.,Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg City, Luxembourg
| | - Matthias W Laschke
- Institute for Clinical and Experimental Surgery, Saarland University, Homburg, Germany
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
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7
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Danielczok J, Hertz L, Ruppenthal S, Kaiser E, Petkova-Kirova P, Bogdanova A, Krause E, Lipp P, Freichel M, Kaestner L, Birnbaumer L. Does Erythropoietin Regulate TRPC Channels in Red Blood Cells? Cell Physiol Biochem 2017; 41:1219-1228. [PMID: 28268218 DOI: 10.1159/000464384] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 12/15/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cation channels play an essential role in red blood cells (RBCs) ion homeostasis. One set of ion channels are the transient receptor potential channels of canonical type (TRPC channels). The abundance of these channels in primary erythroblasts, erythroid cell lines and RBCs was associated with an increase in intracellular Ca2+ upon stimulation with Erythropoietin (Epo). In contrast two independent studies on Epo-treated patients revealed diminished basal Ca2+ concentration or reduced phosphatidylserine exposure to the outer membrane leaflet. METHODS To resolve the seemingly conflicting reports we challenged mature human and mouse RBCs of several genotypes with Epo and Prostaglandin E2 (PGE2) and recorded the intracellular Ca2+ content. Next Generation Sequencing was utilised to approach a molecular analysis of reticulocytes. RESULTS/CONCLUSIONS Our results allow concluding that Epo and PGE2 regulation of the Ca2+ homeostasis is distinctly different between murine and human RBCs and that changes in intracellular Ca2+ upon Epo treatment is a primary rather than a compensatory effect. In human RBCs, Epo itself has no effect on Ca2+ fluxes but inhibits the PGE2-induced Ca2+ entry. In murine mature RBCs functional evidence indicates TRPC4/C5 mediated Ca2+ entry activated by Epo whereas PGE2 leads to a TRPC independent Ca2+ entry.
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Scharhag-Rosenberger F, Meyer T, Wegmann M, Ruppenthal S, Kaestner L, Morsch A, Hecksteden A. Irisin does not mediate resistance training-induced alterations in resting metabolic rate. Med Sci Sports Exerc 2015; 46:1736-43. [PMID: 24566753 DOI: 10.1249/mss.0000000000000286] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE This study aimed to investigate the effects of a 6-month preventive resistance training program on resting metabolic rate (RMR) and its associations with fat-free mass (FFM) and the newly described myokine irisin as two potential mechanistic links between exercise training and RMR. METHODS In a randomized controlled trial, 74 sedentary healthy male and female participants either completed 6 months of high-repetition resistance training 3 d·wk in accordance with the American College of Sports Medicine recommendations (RT: n = 37; 47 ± 7 yr; body mass index, 25.0 ± 3.4 kg·m) or served as controls (CO: n = 37; 50 ± 7 yr; body mass index, 24.2 ± 3.2 kg·m). Strength (one-repetition maximum), RMR (indirect calorimetry), body fat (caliper method), and serum irisin concentration (enzyme-linked immunosorbent assay) were measured before and after 6 months of training. RESULTS Training led to an increase in strength (one-repetition maximum leg press, 16% ± 7%; P < 0.001). RMR increased in RT (1671 ± 356 vs 1843 ± 385 kcal·d, P < 0.001) but not in CO (1587 ± 285 vs 1602 ± 294 kcal·d, P = 0.97; group-time interaction, P < 0.01). Body weight (RT, -0.5 ± 2.4 kg; CO, 0.1 ± 2.3 kg), body fat percentage (RT, -1.1% ± 2.5%; CO, -0.7% ± 2.9%), and FFM (RT, 0.4 ± 2.1 kg; CO, 0.6 ± 1.9 kg) did not develop differently between groups (group-time interaction: P = 0.29, P = 0.54, and P = 0.59, respectively). Serum irisin concentration increased in CO (70.8 ± 83.4 ng·mL, P < 0.001) but not in RT (22.4 ± 92.6 ng·mL, P = 0.67; group-time interaction, P < 0.01). The change in RMR was not associated with the change in FFM (r = -0.11, P = 0.36) or irisin (r = -0.004, P = 0.97). CONCLUSIONS Preventive resistance training elicits an increase in RMR. However, in contrast to currently discussed hypotheses, this increase does not seem to be mediated by training-induced changes in FFM or circulating irisin concentration, which casts doubt in the meaning of irisin for human energy balance.
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Affiliation(s)
- Friederike Scharhag-Rosenberger
- 1Department of Medical Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, Heidelberg, GERMANY; 2German University of Applied Sciences for Prevention and Health Management, Saarbrücken, GERMANY; 3Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, GERMANY; and 4Institute for Molecular Cell Biology, Saarland University, Homburg, GERMANY
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9
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Wiesen K, Kaiser E, Schröder L, Scholz A, Ruppenthal S, Reil JC, Backes C, Meese E, Meier C, Bogdanova A, Lipp P, Kaestner L. Cardiac remodeling in Gαq and Gα11 knockout mice. Int J Cardiol 2015; 202:836-45. [PMID: 26476043 DOI: 10.1016/j.ijcard.2015.10.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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: 07/11/2015] [Revised: 09/29/2015] [Accepted: 10/03/2015] [Indexed: 01/19/2023]
Abstract
BACKGROUND Although both Gαq- and Gα11-protein signaling are believed to be involved in the regulation of cardiac hypertrophy, their detailed contribution to myocardial function remains elusive. METHODS AND RESULTS We studied remodeling processes in healthy transgenic mice with genetically altered Gαq/Gα11-expression, in particular a global Gα11-knockout and a novel inducible cardiac specific Gαq-knockout, as well as a combined double knockout (dKO) mouse line. Echocardiography and telemetric ECG recordings revealed that compared with wild type mice, hearts of dKO mice showed an increased ejection fraction and a decreased heart rate, irrespective of age resulting in a maintained cardiac output. We attributed these findings to the lack of Gα11, which the absence was associated with a decreased afterload. Histological analysis of the extracellular matrix in the heart depicted a diminished presence of collagen in aging hearts of dKO mice compared to wild-type mice. The results of a transcriptome analysis on isolated ventricular cardiac myocytes revealed alterations of the activity of genes involved in the Gαq/Gα11-dependent regulation of the extracellular matrix, such as the matricellular protein Cyr61. CONCLUSIONS From our data we conclude that Gαq/Gα11 signaling pathways play a pivotal role in maintaining gene activity patterns. For the heart we revealed their importance in modulating the properties of the extracellular matrix, a mechanism that might be an important contributor and mechanistic basis for the development of pressure-overload induced cardiac hypertrophy.
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Affiliation(s)
- Kathrina Wiesen
- Institute of Veterinary Physiology, Vetsuisse Faculty and the Zürich Center for Integrative Human Physiology, University of Zürich, 8057 Zürich, Switzerland; Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany
| | - Elisabeth Kaiser
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany
| | - Laura Schröder
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany
| | - Anke Scholz
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany
| | - Sandra Ruppenthal
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany
| | - Jan-Christian Reil
- Clinic for Internal Medicine III, Saarland University, 66421 Homburg/Saar, Germany
| | - Christina Backes
- Institute for Human Genetics, Saarland University, 66421 Homburg/Saar, Germany
| | - Eckart Meese
- Institute for Human Genetics, Saarland University, 66421 Homburg/Saar, Germany
| | - Carola Meier
- Anatomy, Saarland University, 66421 Homburg/Saar, Germany
| | - Anna Bogdanova
- Institute of Veterinary Physiology, Vetsuisse Faculty and the Zürich Center for Integrative Human Physiology, University of Zürich, 8057 Zürich, Switzerland
| | - Peter Lipp
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany.
| | - Lars Kaestner
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, 66421 Homburg/Saar, Germany.
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Nothdurft FP, Fontana D, Ruppenthal S, May A, Aktas C, Mehraein Y, Lipp P, Kaestner L. Differential Behavior of Fibroblasts and Epithelial Cells on Structured Implant Abutment Materials: A Comparison of Materials and Surface Topographies. Clin Implant Dent Relat Res 2014; 17:1237-49. [PMID: 25066589 DOI: 10.1111/cid.12253] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of this study was to compare the proliferation and attachment behavior of fibroblasts and epithelial cells on differently structured abutment materials. MATERIALS AND METHODS Three different surface topographies were prepared on zirconia and titanium alloy specimens and defined as follows: machined (as delivered without further surface modification), smooth (polished), and rough (sandblasted). Energy-dispersive X-ray spectroscopy, topographical analysis, and water contact angle measurements were used to analyze the surface properties. Fibroblasts (HGF1) and epithelial cells (HNEpC) grown on the specimens were investigated 24 hours and 72 hours after seeding and counted using fluorescence imaging. To investigate adhesion, the abundance and arrangement of the focal adhesion protein vinculin were evaluated by immunocytochemistry. RESULTS Similar surface topographies were created on both materials. Fibroblasts exhibited significant higher proliferation rates on comparable surface topographies of zirconia compared with the titanium alloy. The proliferation of fibroblasts and epithelial cells was optimal on different substrate/topography combinations. Cell spreading was generally higher on polished and machined surfaces than on sandblasted surfaces. Rough surfaces provided favorable properties in terms of cellular adhesion of fibroblasts but not of epithelial cells. CONCLUSIONS Our data support complex soft tissue cell-substrate interactions: the fibroblast and epithelial cell response is influenced by both the material and surface topography.
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Affiliation(s)
- Frank P Nothdurft
- Department of Prosthetic Dentistry and Dental Materials Sciences, Saarland University, Homburg/Saar, Germany
| | - Dorothee Fontana
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Sandra Ruppenthal
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Alexander May
- CVD/Biosurfaces, Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Cenk Aktas
- Division CVD/Biosurfaces, Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Yasmin Mehraein
- Institute of Human Genetics, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Lars Kaestner
- Research Center for Molecular Imaging and Screening, Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
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Kaestner L, Scholz A, Tian Q, Ruppenthal S, Tabellion W, Wiesen K, Katus HA, Müller OJ, Kotlikoff MI, Lipp P. Genetically encoded Ca2+ indicators in cardiac myocytes. Circ Res 2014; 114:1623-39. [PMID: 24812351 DOI: 10.1161/circresaha.114.303475] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genetically encoded Ca(2+) indicators constitute a powerful set of tools to investigate functional aspects of Ca(2+) signaling in isolated cardiomyocytes, cardiac tissue, and whole hearts. Here, we provide an overview of the concepts, experiences, state of the art, and ongoing developments in the use of genetically encoded Ca(2+) indicators for cardiac cells and heart tissue. This review is supplemented with in vivo viral gene transfer experiments and comparisons of available genetically encoded Ca(2+) indicators with each other and with the small molecule dye Fura-2. In the context of cardiac myocytes, we provide guidelines for selecting a genetically encoded Ca(2+) indicator. For future developments, we discuss improvements of a broad range of properties, including photophysical properties such as spectral spread and biocompatibility, as well as cellular and in vivo applications.
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Affiliation(s)
- Lars Kaestner
- From the Institute for Molecular Cell Biology and Research Center for Molecular Imaging and Screening, School of Medicine, Saarland University, Homburg-Saar, Germany (L.K., A.S., Q.T., S.R., W.T., K.W., P.L.); Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany (H.A.K., O.J.M.); DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Germany (H.A.K., O.J.M.); and Biomedical Sciences Department, College of Veterinary Medicine, Cornell University, Ithaca, NY (M.I.K.)
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12
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Hecksteden A, Wegmann M, Steffen A, Kraushaar J, Morsch A, Ruppenthal S, Kaestner L, Meyer T. Irisin and exercise training in humans - results from a randomized controlled training trial. BMC Med 2013; 11:235. [PMID: 24191966 PMCID: PMC4228275 DOI: 10.1186/1741-7015-11-235] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/03/2013] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The recent discovery of a new myokine (irisin) potentially involved in health-related training effects has gained great attention, but evidence for a training-induced increase in irisin remains preliminary. Therefore, the present study aimed to determine whether irisin concentration is increased after regular exercise training in humans. METHODS In a randomized controlled design, two guideline conforming training interventions were studied. Inclusion criteria were age 30 to 60 years, <1 hour/week regular activity, non-smoker, and absence of major diseases. 102 participants could be included in the analysis. Subjects in the training groups exercised 3 times per week for 26 weeks. The minimum compliance was defined at 70%. Aerobic endurance training (AET) consisted of 45 minutes of walking/running at 60% heart rate reserve. Strength endurance training (SET) consisted of 8 machine-based exercises (2 sets of 15 repetitions with 100% of the 20 repetition maximum). Serum irisin concentrations in frozen serum samples were determined in a single blinded measurement immediately after the end of the training study. Physical performance provided positive control for the overall efficacy of training. Differences between groups were tested for significance using analysis of variance. For post hoc comparisons with the control group, Dunnett's test was used. RESULTS Maximum performance increased significantly in the training groups compared with controls (controls: ±0.0 ± 0.7 km/h; AET: 1.1 ± 0.6 km/h, P < 0.01; SET: +0.5 ± 0.7 km/h, P = 0.01). Changes in irisin did not differ between groups (controls: 101 ± 81 ng/ml; AET: 44 ± 93 ng/ml; SET: 60 ± 92 ng/ml; in both cases: P = 0.99 (one-tailed testing), 1-β error probability = 0.7). The general upward trend was mainly accounted for by a negative association of irisin concentration with the storage duration of frozen serum samples (P < 0.01, β = -0.33). After arithmetically eliminating this confounder, the differences between groups remained non-significant. CONCLUSIONS A training-induced increase in circulating irisin could not be confirmed, calling into question its proposed involvement in health-related training effects. Because frozen samples are prone to irisin degradation over time, positive results from uncontrolled trials might exclusively reflect the longer storage of samples from initial tests.
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Affiliation(s)
- Anne Hecksteden
- Institute of Sports and Preventive Medicine, Saarland University, 66123 Saarbrücken, Germany.
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13
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Oberhofer M, Tian Q, Ruppenthal S, Wegener S, Reil JC, Körbel C, Hammer K, Menger M, Neuberger HR, Kaestner L, Lipp P. Calcium dysregulation in ventricular myocytes from mice expressing constitutively active Rac1. Cell Calcium 2013; 54:26-36. [DOI: 10.1016/j.ceca.2013.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/20/2013] [Accepted: 03/30/2013] [Indexed: 10/26/2022]
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14
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Wang J, Wagner-Britz L, Bogdanova A, Ruppenthal S, Wiesen K, Kaiser E, Tian Q, Krause E, Bernhardt I, Lipp P, Philipp SE, Kaestner L. Morphologically homogeneous red blood cells present a heterogeneous response to hormonal stimulation. PLoS One 2013; 8:e67697. [PMID: 23840765 PMCID: PMC3695909 DOI: 10.1371/journal.pone.0067697] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 05/22/2013] [Indexed: 11/19/2022] Open
Abstract
Red blood cells (RBCs) are among the most intensively studied cells in natural history, elucidating numerous principles and ground-breaking knowledge in cell biology. Morphologically, RBCs are largely homogeneous, and most of the functional studies have been performed on large populations of cells, masking putative cellular variations. We studied human and mouse RBCs by live-cell video imaging, which allowed single cells to be followed over time. In particular we analysed functional responses to hormonal stimulation with lysophosphatidic acid (LPA), a signalling molecule occurring in blood plasma, with the Ca2+ sensor Fluo-4. Additionally, we developed an approach for analysing the Ca2+ responses of RBCs that allowed the quantitative characterization of single-cell signals. In RBCs, the LPA-induced Ca2+ influx showed substantial diversity in both kinetics and amplitude. Also the age-classification was determined for each particular RBC and consecutively analysed. While reticulocytes lack a Ca2+ response to LPA stimulation, old RBCs approaching clearance generated robust LPA-induced signals, which still displayed broad heterogeneity. Observing phospatidylserine exposure as an effector mechanism of intracellular Ca2+ revealed an even increased heterogeneity of RBC responses. The functional diversity of RBCs needs to be taken into account in future studies, which will increasingly require single-cell analysis approaches. The identified heterogeneity in RBC responses is important for the basic understanding of RBC signalling and their contribution to numerous diseases, especially with respect to Ca2+ influx and the associated pro-thrombotic activity.
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Affiliation(s)
- Jue Wang
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | | | - Anna Bogdanova
- Institute of Veterinary Physiology, Vetsuisse Faculty and the Zürich Center for Integrative Human Physiology, University of Zürich, Zürich, Switzerland
| | - Sandra Ruppenthal
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | - Kathrina Wiesen
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | - Elisabeth Kaiser
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | - Qinghai Tian
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | - Elmar Krause
- Physiology, Saarland University, Homburg/Saar, Germany
| | - Ingolf Bernhardt
- Biophysics Laboratory, Saarland University, Saarbrücken, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
| | - Stephan E. Philipp
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg/Saar, Germany
| | - Lars Kaestner
- Institute for Molecular Cell Biology and Research Centre for Molecular Imaging and Screening, Saarland University, Homburg/Saar, Germany
- * E-mail:
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15
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Blaich A, Pahlavan S, Tian Q, Oberhofer M, Poomvanicha M, Lenhardt P, Domes K, Wegener JW, Moosmang S, Ruppenthal S, Scholz A, Lipp P, Hofmann F. Mutation of the calmodulin binding motif IQ of the L-type Ca(v)1.2 Ca2+ channel to EQ induces dilated cardiomyopathy and death. J Biol Chem 2012; 287:22616-25. [PMID: 22589547 DOI: 10.1074/jbc.m112.357921] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cardiac excitation-contraction coupling (EC coupling) links the electrical excitation of the cell membrane to the mechanical contractile machinery of the heart. Calcium channels are major players of EC coupling and are regulated by voltage and Ca(2+)/calmodulin (CaM). CaM binds to the IQ motif located in the C terminus of the Ca(v)1.2 channel and induces Ca(2+)-dependent inactivation (CDI) and facilitation (CDF). Mutation of Ile to Glu (Ile1624Glu) in the IQ motif abolished regulation of the channel by CDI and CDF. Here, we addressed the physiological consequences of such a mutation in the heart. Murine hearts expressing the Ca(v)1.2(I1624E) mutation were generated in adult heterozygous mice through inactivation of the floxed WT Ca(v)1.2(L2) allele by tamoxifen-induced cardiac-specific activation of the MerCreMer Cre recombinase. Within 10 days after the first tamoxifen injection these mice developed dilated cardiomyopathy (DCM) accompanied by apoptosis of cardiac myocytes (CM) and fibrosis. In Ca(v)1.2(I1624E) hearts, the activity of phospho-CaM kinase II and phospho-MAPK was increased. CMs expressed reduced levels of Ca(v)1.2(I1624E) channel protein and I(Ca). The Ca(v)1.2(I1624E) channel showed "CDI" kinetics. Despite a lower sarcoplasmic reticulum Ca(2+) content, cellular contractility and global Ca(2+) transients remained unchanged because the EC coupling gain was up-regulated by an increased neuroendocrine activity. Treatment of mice with metoprolol and captopril reduced DCM in Ca(v)1.2(I1624E) hearts at day 10. We conclude that mutation of the IQ motif to IE leads to dilated cardiomyopathy and death.
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Affiliation(s)
- Anne Blaich
- Forschergruppe, Institut für Pharmakologie und Toxikologie, Technische Universität München, 80802 München, Germany
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16
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Pahlavan S, Oberhofer M, Sauer B, Ruppenthal S, Tian Q, Scholz A, Kaestner L, Lipp P. Gαq and Gα11 contribute to the maintenance of cellular electrophysiology and Ca2+ handling in ventricular cardiomyocytes. Cardiovasc Res 2012; 95:48-58. [DOI: 10.1093/cvr/cvs162] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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17
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Jung CB, Moretti A, Mederos y Schnitzler M, Iop L, Storch U, Bellin M, Dorn T, Ruppenthal S, Pfeiffer S, Goedel A, Dirschinger RJ, Seyfarth M, Lam JT, Sinnecker D, Gudermann T, Lipp P, Laugwitz KL. Dantrolene rescues arrhythmogenic RYR2 defect in a patient-specific stem cell model of catecholaminergic polymorphic ventricular tachycardia. EMBO Mol Med 2012; 4:180-91. [PMID: 22174035 PMCID: PMC3376852 DOI: 10.1002/emmm.201100194] [Citation(s) in RCA: 263] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 12/01/2011] [Accepted: 12/05/2011] [Indexed: 12/23/2022] Open
Abstract
Coordinated release of calcium (Ca2+) from the sarcoplasmic reticulum (SR) through cardiac ryanodine receptor (RYR2) channels is essential for cardiomyocyte function. In catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited disease characterized by stress-induced ventricular arrhythmias in young patients with structurally normal hearts, autosomal dominant mutations in RYR2 or recessive mutations in calsequestrin lead to aberrant diastolic Ca2+ release from the SR causing arrhythmogenic delayed after depolarizations (DADs). Here, we report the generation of induced pluripotent stem cells (iPSCs) from a CPVT patient carrying a novel RYR2 S406L mutation. In patient iPSC-derived cardiomyocytes, catecholaminergic stress led to elevated diastolic Ca2+ concentrations, a reduced SR Ca2+ content and an increased susceptibility to DADs and arrhythmia as compared to control myocytes. This was due to increased frequency and duration of elementary Ca2+ release events (Ca2+ sparks). Dantrolene, a drug effective on malignant hyperthermia, restored normal Ca2+ spark properties and rescued the arrhythmogenic phenotype. This suggests defective inter-domain interactions within the RYR2 channel as the pathomechanism of the S406L mutation. Our work provides a new in vitro model to study the pathogenesis of human cardiac arrhythmias and develop novel therapies for CPVT.
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Affiliation(s)
- Christian B Jung
- Klinikum rechts der Isar, Technische Universität München, I. Medizinische Klinik, Kardiologie, München, Germany
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18
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Tian Q, Pahlavan S, Oleinikow K, Jung J, Ruppenthal S, Scholz A, Schumann C, Kraegeloh A, Oberhofer M, Lipp P, Kaestner L. Functional and morphological preservation of adult ventricular myocytes in culture by sub-micromolar cytochalasin D supplement. J Mol Cell Cardiol 2011; 52:113-24. [PMID: 21930133 DOI: 10.1016/j.yjmcc.2011.09.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 08/04/2011] [Accepted: 09/01/2011] [Indexed: 11/25/2022]
Abstract
In cardiac myocytes, cytochalasin D (CytoD) was reported to act as an actin disruptor and mechanical uncoupler. Using confocal and super-resolution STED microscopy, we show that CytoD preserves the actin filament architecture of adult rat ventricular myocytes in culture. Five hundred nanomolar CytoD was the optimal concentration to achieve both preservation of the T-tubular structure during culture periods of 3 days and conservation of major functional characteristics such as action potentials, calcium transients and, importantly, the contractile properties of single myocytes. Therefore, we conclude that the addition of CytoD to the culture of adult cardiac myocytes can indeed be used to generate a solid single-cell model that preserves both morphology and function of freshly isolated cells. Moreover, we reveal a putative link between cytoskeletal and T-tubular remodeling. In the absence of CytoD, we observed a loss of T-tubules that led to significant dyssynchronous Ca(2+)-induced Ca(2+) release (CICR), while in the presence of 0.5 μM CytoD, T-tubules and homogeneous CICR were majorly preserved. Such data suggested a possible link between the actin cytoskeleton, T-tubules and synchronous, reliable excitation-contraction-coupling. Thus, T-tubular re-organization in cell culture sheds some additional light onto similar processes found during many cardiac diseases and might link cytoskeletal alterations to changes in subcellular Ca(2+) signaling revealed under such pathophysiological conditions.
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Affiliation(s)
- Qinghai Tian
- Institute for Molecular Cell Biology, Medical Faculty, Building 61, Saarland University, 66421 Homburg/Saar, Germany
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19
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Meissner M, Weissgerber P, Londoño JEC, Prenen J, Link S, Ruppenthal S, Molkentin JD, Lipp P, Nilius B, Freichel M, Flockerzi V. Moderate calcium channel dysfunction in adult mice with inducible cardiomyocyte-specific excision of the cacnb2 gene. J Biol Chem 2011; 286:15875-82. [PMID: 21357697 DOI: 10.1074/jbc.m111.227819] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The major L-type voltage-gated calcium channels in heart consist of an α1C (Ca(V)1.2) subunit usually associated with an auxiliary β subunit (Ca(V)β2). In embryonic cardiomyocytes, both the complete and the cardiac myocyte-specific null mutant of Ca(V)β2 resulted in reduction of L-type calcium currents by up to 75%, compromising heart function and causing defective remodeling of intra- and extra-embryonic blood vessels followed by embryonic death. Here we conditionally excised the Ca(V)β2 gene (cacnb2) specifically in cardiac myocytes of adult mice (KO). Upon gene deletion, Ca(V)β2 protein expression declined by >96% in isolated cardiac myocytes and by >74% in protein fractions from heart. These latter protein fractions include Ca(V)β2 proteins expressed in cardiac fibroblasts. Surprisingly, mice did not show any obvious impairment, although cacnb2 excision was not compensated by expression of other Ca(V)β proteins or changes of Ca(V)1.2 protein levels. Calcium currents were still dihydropyridine-sensitive, but current density at 0 mV was reduced by <29%. The voltage for half-maximal activation was slightly shifted to more depolarized potentials in KO cardiomyocytes when compared with control cells, but the difference was not significant. In summary, Ca(V)β2 appears to be a much stronger modulator of L-type calcium currents in embryonic than in adult cardiomyocytes. Although essential for embryonic survival, Ca(V)β2 down-regulation in cardiomyocytes is well tolerated by the adult mice.
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Affiliation(s)
- Marcel Meissner
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, Germany
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Kaestner L, Scholz A, Ruppenthal S, Sauer B, Oberhofer M, Lipp P. Improvement of Learning and Teaching Efficiency by Web-Associated Seminars. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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21
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Tian Q, Pahlavan S, Ruppenthal S, Scholz A, Wiesen K, Oberhofer M, Kaestner L, Lipp P. Alterations of Membrane Currents, Contractility and Calcium Signaling in Gq/G11 Single and Double Ko Mice. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.3026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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22
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Kaestner L, Tian Q, Pahlavan S, Oleinikow K, Ruppenthal S, Scholz A, Oberhofer M, Schumann C, Kraegeloh A, Lipp P. The Differential Action of Cytocalasin D in T-tubular Remodelling of Ventricular Myocytes. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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23
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Tian Q, Oberhofer M, Ruppenthal S, Scholz A, Buschmann V, Tsutsui H, Miyawaki A, Zeug A, Lipp P, Kaestner L. Optical Action Potential Screening on Adult Ventricular Myocytes as an Alternative QT-screen. Cell Physiol Biochem 2011; 27:281-90. [DOI: 10.1159/000327954] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2011] [Indexed: 11/19/2022] Open
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Hammer K, Ruppenthal S, Viero C, Scholz A, Edelmann L, Kaestner L, Lipp P. Remodelling of Ca2+ handling organelles in adult rat ventricular myocytes during long term culture. J Mol Cell Cardiol 2010; 49:427-37. [PMID: 20540947 DOI: 10.1016/j.yjmcc.2010.05.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 04/26/2010] [Accepted: 05/19/2010] [Indexed: 11/18/2022]
Abstract
It is well known that for cardiomyocytes, isolation and culturing induce largely unknown remodelling processes. We analysed changes in the structure of cell compartments with optical techniques such as confocal microscopy and fluorescence redistribution after photobleaching employing adenoviral-mediated transduction of targeted fluorescent proteins and small molecule dyes. We identified characteristic remodelling processes: the T-tubular membrane system was gradually lost by a process referred to as "sequential pinching off", in an outward direction. Mitochondria fell in one of three classes, very small (0.9 microm length), medium long (1.8 microm) or extended shape (3.6 microm) organelles. Over the culturing time mitochondria gradually fused. Bleaching of individual mitochondria revealed association between apparently separated mitochondria by "tunnelling" via sub-resolution organelle-tubes. This tunnelling process was increasing over the culturing time. A gradual loss of the cross-striation arrangement in the endoplasmic/sarcoplasmic reticulum was visualised. Analysis of large populations of Ca(2+) sparks by video-rate confocal 2D-scanning revealed significant albeit small changes of these elementary SR-Ca(2+) release events in adult cardiomyocytes that could be related to changes in SR-Ca(2+) content rather than resting Ca(2+) concentration. In conclusion, primary isolated cardiomyocytes from adult hearts undergo a well-defined, but reproducible subcellular remodelling during optimised long term culture.
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Affiliation(s)
- Karin Hammer
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Homburg/Saar, Germany
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25
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Kaestner L, Scholz A, Hammer K, Vecerdea A, Ruppenthal S, Lipp P. Isolation and genetic manipulation of adult cardiac myocytes for confocal imaging. J Vis Exp 2009:1433. [PMID: 19763080 DOI: 10.3791/1433] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cardiac myocytes isolated from adult hearts are widely accepted as a model somewhere half way between embryonic and neonatal muscle cells on one side and a working heart on the other. Thus, cardiomyocytes serve as good models for cardiac cellular physiology and pathophysiology, for pharmaceutical investigations as well as for the exploration of transgenic animal models. Here we describe a method of isolating the cells from the heart. Furthermore we show how a genetic manipulation on cardiac myocytes can be performed without breeding a transgenic animal: This is the combination of long term culture (1 week) and adenoviral gene transfer. The latter one is described from the construction of the virus to the transduction of the cells. It can be used for the expression of genetically encoded biosensors (GEBs), fluorescent fusion proteins, but also for protein over expression and down regulation, e.g. using RNAi. Here we provide an example for the expression of a fusion protein staining a subcellular structure (Golgi). Such protein expression can be visualized by confocal imaging of z-stacks for a 3D-reconstruction of subcellular structures. The protocol comprises state-of-the-art in cell culture, molecular biology and biophysics and thus provides an approach for exploring new horizons in cellular cardiology.
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Affiliation(s)
- Lars Kaestner
- Institute for Molecular Cell Biology, Saarland University.
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26
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Scholz AM, Reither G, Heinz A, Ruppenthal S, Schaefers HJ, Lipp P. Alteration of Gq-signaling in Human Heart Disease. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Hammer KP, Ruppenthal S, Vecerdea A, Kaestner L, Lipp P. Ventricular Myocyte Morphology in Long Term Culture. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.1934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Kaestner L, Müller O, Flockerzi A, Hammer K, Tabellion W, Tian Q, Ruppenthal S, Scholz A, Lipp P. Towards Cardiac Safety Screens by Single Cell Imaging Procedures. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.1474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Viero C, Kraushaar U, Ruppenthal S, Kaestner L, Lipp P. A primary culture system for sustained expression of a calcium sensor in preserved adult rat ventricular myocytes. Cell Calcium 2008; 43:59-71. [PMID: 17822759 DOI: 10.1016/j.ceca.2007.04.001] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 03/27/2007] [Indexed: 11/21/2022]
Abstract
For studying heart pathologies on the cellular level, cultured adult cardiac myocytes represent an important approach. We aimed to explore a novel adult rat ventricular myocyte culture system with minimised dedifferentiation allowing extended experimental manipulation of the cells such as expression of exogenous proteins. Various culture conditions were investigated including medium supplement, substrate coating and electrical pacing for one week. Adult myocytes were probed for (i) viability, (ii) morphology, (iii) frequency dependence of contractions, (iv) Ca(2+) transients, and (v) their tolerance towards adenovirus-mediated expression of the Ca(2+) sensor "inverse pericam". Conventionally, in either serum supplemented or serum-free medium, myocytes dedifferentiated into flat cells within 3 days or cell physiology and morphology were impaired, respectively. In contrast, myocytes cultured in medium supplemented with an insulin-transferrin-selenite mixture on substrates coated with extracellular matrix proteins showed an increased cell attachment and a conserved cross-striation. Moreover, these myocytes displayed optimised preservation of their contractile behaviour and Ca(2+) signalling even under conditions of continuous electrical pacing. Sustained expression of inverse pericam did not alter myocyte function and allowed long lasting high speed Ca(2+) imaging of electrically driven adult myocytes. Our single-cell model thus provides a new advance for high-content screening of these highly specialised cells.
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Affiliation(s)
- Cedric Viero
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Building 61, 66421 Homburg/Saar, Germany
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