1
|
Fakuade FE, Hubricht D, Möller V, Sobitov I, Liutkute A, Döring Y, Seibertz F, Gerloff M, Pronto JRD, Haghighi F, Brandenburg S, Alhussini K, Ignatyeva N, Bonhoff Y, Kestel S, El-Essawi A, Jebran AF, Großmann M, Danner BC, Baraki H, Schmidt C, Sossalla S, Kutschka I, Bening C, Maack C, Linke WA, Heijman J, Lehnart SE, Kensah G, Ebert A, Mason FE, Voigt N. Impaired Intracellular Calcium Buffering Contributes to the Arrhythmogenic Substrate in Atrial Myocytes From Patients With Atrial Fibrillation. Circulation 2024; 150:544-559. [PMID: 38910563 PMCID: PMC11319087 DOI: 10.1161/circulationaha.123.066577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 05/31/2024] [Indexed: 06/25/2024]
Abstract
BACKGROUND Alterations in the buffering of intracellular Ca2+, for which myofilament proteins play a key role, have been shown to promote cardiac arrhythmia. It is interesting that although studies report atrial myofibrillar degradation in patients with persistent atrial fibrillation (persAF), the intracellular Ca2+ buffering profile in persAF remains obscure. Therefore, we aimed to investigate the intracellular buffering of Ca2+ and its potential arrhythmogenic role in persAF. METHODS Transmembrane Ca2+ fluxes (patch-clamp) and intracellular Ca2+ signaling (fluo-3-acetoxymethyl ester) were recorded simultaneously in myocytes from right atrial biopsies of sinus rhythm (Ctrl) and patients with persAF, alongside human atrial subtype induced pluripotent stem cell-derived cardiac myocytes (iPSC-CMs). Protein levels were quantified by immunoblotting of human atrial tissue and induced pluripotent stem cell-derived cardiac myocytes. Mouse whole heart and atrial electrophysiology were measured on a Langendorff system. RESULTS Cytosolic Ca2+ buffering was decreased in atrial myocytes of patients with persAF because of a depleted amount of Ca2+ buffers. In agreement, protein levels of selected Ca2+ binding myofilament proteins, including cTnC (cardiac troponin C), a major cytosolic Ca2+ buffer, were significantly lower in patients with persAF. Small interfering RNA (siRNA)-mediated knockdown of cTnC (si-cTNC) in atrial iPSC-CM phenocopied the reduced cytosolic Ca2+ buffering observed in persAF. Si-cTnC treated atrial iPSC-CM exhibited a higher predisposition to spontaneous Ca2+ release events and developed action potential alternans at low stimulation frequencies. Last, indirect reduction of cytosolic Ca2+ buffering using blebbistatin in an ex vivo mouse whole heart model increased vulnerability to tachypacing-induced atrial arrhythmia, validating the direct mechanistic link between impaired cytosolic Ca2+ buffering and atrial arrhythmogenesis. CONCLUSIONS Our findings suggest that loss of myofilament proteins, particularly reduced cTnC protein levels, causes diminished cytosolic Ca2+ buffering in persAF, thereby potentiating the occurrence of spontaneous Ca2+ release events and atrial fibrillation susceptibility. Strategies targeting intracellular buffering may represent a promising therapeutic lead in persAF management.
Collapse
Affiliation(s)
- Funsho E. Fakuade
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Dominik Hubricht
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Vanessa Möller
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Izzatullo Sobitov
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Aiste Liutkute
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Yannic Döring
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Fitzwilliam Seibertz
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Marcus Gerloff
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Julius Ryan D. Pronto
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Fereshteh Haghighi
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Sören Brandenburg
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Cardiology and Pneumology (S.B., N.I., W.A.L., S.E.L., A.E.), Heart Research Center Göttingen, University Medical Center Göttingen, Germany
| | - Khaled Alhussini
- Department of Thoracic and Cardiovascular Surgery (K.A., C.B.), University Clinic Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg (K.A., C.B., C.M.), University Clinic Würzburg, Germany
| | - Nadezda Ignatyeva
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Cardiology and Pneumology (S.B., N.I., W.A.L., S.E.L., A.E.), Heart Research Center Göttingen, University Medical Center Göttingen, Germany
| | - Yara Bonhoff
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Stefanie Kestel
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Aschraf El-Essawi
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
- Department of Thoracic and Cardiovascular Surgery, Klinikum Braunschweig, Germany (A.E.-E.)
| | - Ahmad Fawad Jebran
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Marius Großmann
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Bernhard C. Danner
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Hassina Baraki
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Constanze Schmidt
- Department of Cardiology, University Hospital Heidelberg, Germany (C.S.)
- German Center for Cardiovascular Research Partner Site Heidelberg/Mannheim, Heidelberg University (C.S.)
| | - Samuel Sossalla
- Department of Cardiology, University Hospital Giessen & Kerckhoff Clinic, Germany (S.S.)
- Department of Cardiology, Bad Nauheim & German Center for Cardiovascular Research Partner Site Rhine-Main, Germany (S.S.)
| | - Ingo Kutschka
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Constanze Bening
- Department of Thoracic and Cardiovascular Surgery (K.A., C.B.), University Clinic Würzburg, Germany
- Comprehensive Heart Failure Center Würzburg (K.A., C.B., C.M.), University Clinic Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center Würzburg (K.A., C.B., C.M.), University Clinic Würzburg, Germany
| | - Wolfgang A. Linke
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Cardiology and Pneumology (S.B., N.I., W.A.L., S.E.L., A.E.), Heart Research Center Göttingen, University Medical Center Göttingen, Germany
- Institute of Physiology II, University of Münster, Germany (W.A.L.)
| | - Jordi Heijman
- Gottfried Schatz Research Center, Division of Medical Physics and Biophysics, Medical University of Graz, Austria (J.H.)
- Department of Cardiology, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands (J.H.)
| | - Stephan E. Lehnart
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Cardiology and Pneumology (S.B., N.I., W.A.L., S.E.L., A.E.), Heart Research Center Göttingen, University Medical Center Göttingen, Germany
| | - George Kensah
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Thoracic and Cardiovascular Surgery (F.H., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., G.K.), University Medical Center Göttingen, Germany
| | - Antje Ebert
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Department of Cardiology and Pneumology (S.B., N.I., W.A.L., S.E.L., A.E.), Heart Research Center Göttingen, University Medical Center Göttingen, Germany
| | - Fleur E. Mason
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| | - Niels Voigt
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (F.E.F., A.L., F.S., F.H., S.E.L., A.E., N.V.), Georg-August-University Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Lower Saxony, Germany (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., F.H., S.B., N.I., Y.B., S.K., A.E.-E., A.F.J., M. Großmann, B.C.D., H.B., I.K., W.A.L., S.E.L., G.K., A.E., F.E.M., N.V.)
- Institute of Pharmacology and Toxicology (F.E.F., D.H., V.M., I.S., A.L., Y.D., F.S., M. Gerloff, J.R.D.P., Y.B., S.K., F.E.M., N.V.), University Medical Center Göttingen, Germany
| |
Collapse
|
2
|
Burnham HV, Cizauskas HE, Barefield DY. Fine tuning contractility: atrial sarcomere function in health and disease. Am J Physiol Heart Circ Physiol 2024; 326:H568-H583. [PMID: 38156887 PMCID: PMC11221815 DOI: 10.1152/ajpheart.00252.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.
Collapse
Affiliation(s)
- Hope V Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - Hannah E Cizauskas
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| | - David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, United States
| |
Collapse
|
3
|
Bening C, Genser B, Keller D, Müller-Altrock S, Radakovic D, Penov K, Hassan M, Aleksic I, Leyh R, Madrahimov N. Impact of estradiol, testosterone and their ratio on left and right auricular myofilament function in male and female patients undergoing coronary artery bypass grafting. BMC Cardiovasc Disord 2023; 23:538. [PMID: 37925416 PMCID: PMC10625250 DOI: 10.1186/s12872-023-03582-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 10/26/2023] [Indexed: 11/06/2023] Open
Abstract
BACKGROUND The impact of sex hormones on right and left auricular contractile apparatus function is largely unknown. We evaluated the impact of sex hormones on left and right heart contractility at the level of myocardial filaments harvested from left and right auricles during elective coronary artery bypass surgery. METHODS 150 patients (132 male; 18 female) were enrolled. Preoperative testosterone and estradiol levels were measured with Immunoassay. Calcium induced force measurements were performed with left- and right auricular myofilaments in a skinned fiber model. Correlation analysis was used for comparison of force values and levels of sex hormones and their ratio. RESULTS Low testosterone was associated with higher top force values in right-sided myofilaments but not in left-sided myofilaments for both sexes (p = 0.000 in males, p = 0.001 in females). Low estradiol levels were associated with higher top force values in right-sided myofilaments (p 0.000) in females and only borderline significantly associated with higher top force values in males (p 0.056). In females, low estradiol levels correlated with higher top force values in left sided myofilaments (p 0.000). In males, higher Estradiol/Testosterone ratio (E/T ratio) was only associated with higher top force values from right auricular myofilaments (p 0.04) In contrast, in females higher E/T ratio was associated with lower right auricular myofilament top force values (p 0.03) and higher top force values in left-sided myofilaments (p 0.000). CONCLUSIONS This study shows that patients' comorbidities influence left and right sided contractility and may blur results concerning influence of sex hormones if not eliminated. A sex hormone dependent influence is obvious with different effects on the left and right ventricle. The E/T ratio and its impact on myofilament top force showed divergent results between genders, and may partially explain gender differences in patients with cardiovascular disease.
Collapse
Affiliation(s)
- C Bening
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany.
| | - B Genser
- Medical Faculty Mannheim, Center for Preventive Medicine, Heidelberg University, Digital Health Baden-Württemberg (CPD-BW), Heidelberg , Germany
| | - D Keller
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - S Müller-Altrock
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - D Radakovic
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - K Penov
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - M Hassan
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - I Aleksic
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - R Leyh
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| | - N Madrahimov
- Department of Thoracic and Cardiovascular Surgery, University Hospital Wuerzburg Zentrum Operative Medizin, Oberduerrbacherstr. 6, 97080, Wuerzburg, Germany
| |
Collapse
|
4
|
Deissler PM, Tran KL, Falk V, Pieske B, Grubitzsch H, Primessnig U, Heinzel FR. Functional reserve and contractile phenotype of atrial myocardium from patients with atrial remodeling without and with atrial fibrillation. Am J Physiol Heart Circ Physiol 2023; 325:H729-H738. [PMID: 37594484 DOI: 10.1152/ajpheart.00355.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/26/2023] [Accepted: 08/04/2023] [Indexed: 08/19/2023]
Abstract
Atrial contractility and functional reserve in atrial remodeling (AR) without (AR/-AF) or with atrial fibrillation (AR/+AF) are not well characterized. In this study, functional measurements were performed in right atrial muscle strips (n = 71) obtained from patients (N = 22) undergoing routine cardiac surgery with either no AR [left atrial (LA) diameter < 40 mm and no history of AF (hAF)], AR/-AF (LA diameter ≥ 40 mm, no hAF), or AR/+AF (hAF and LA diameter ≥ 40 mm or LAEF < 45%). AR/-AF and AR/+AF were associated with a prolongation of half-time-to-peak (HTTP, P < 0.001) and time-to-peak (TTP) contraction (P < 0.01) when compared with no AR. This effect was seen at baseline and during β-adrenergic stimulation with isoproterenol (Iso). Early relaxation assessed by half-relaxation time (HRT) was prolonged in AR/-AF (P = 0.03) but not in AR/+AF when compared with no AR at baseline, but this delay in relaxation in AR/-AF was attenuated with Iso. Late relaxation (τ) did not differ between AR/-AF and no AR but was consistently shorter in AR/+AF than no AR before (P = 0.04) and during Iso (P = 0.01), indicating accelerated late relaxation in AR/+AF. Relative force increase during Iso was higher (P = 0.01) and more dispersed (P = 0.047) in patients with AR/+AF. Relative adrenergic response was unaltered in the myocardium of patients with AR/-AF and AR/+AF. In conclusion, AR/-AF and AR/+AF are associated with changes in myocardial inotropic reserve and contractility. The changes are particularly pronounced in patients with AR/+AF, suggesting that the progression from AR/-AF to AR/+AF is associated with progressive alterations in atrial function that may contribute to arrhythmogenesis.NEW & NOTEWORTHY Mechanical alterations in atrial remodeling without (AR/-AF) and with atrial fibrillation (AR/+AF) have not been studied in detail in human atrial tissue preparations. To our knowledge, this is the first study to compare the mechanical phenotype and inotropic reserve in human atrial myocardial preparations from patients with no atrial remodeling, AR/-AF, and AR/+AF. We identify specific patterns of contractile dysfunction and heterogeneity for both, AR/-AF and AR/+AF, indicating the progression of atrial disease.
Collapse
Affiliation(s)
- Peter M Deissler
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Khai Liem Tran
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Volkmar Falk
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum der Charité, Berlin, Germany
| | | | - Herko Grubitzsch
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum der Charité, Berlin, Germany
| | - Uwe Primessnig
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Frank R Heinzel
- Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité, Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- 2. Medizinische Klinik-Kardiologie, Angiologie, Intensivmedizin, Städtisches Klinikum Dresden, Dresden, Germany
| |
Collapse
|
5
|
Butova X, Myachina T, Simonova R, Kochurova A, Mukhlynina E, Kopylova G, Shchepkin D, Khokhlova A. The inter-chamber differences in the contractile function between left and right atrial cardiomyocytes in atrial fibrillation in rats. Front Cardiovasc Med 2023; 10:1203093. [PMID: 37608813 PMCID: PMC10440706 DOI: 10.3389/fcvm.2023.1203093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/24/2023] [Indexed: 08/24/2023] Open
Abstract
Introduction The left and right atria (LA, RA) work under different mechanical and metabolic environments that may cause an intrinsic inter-chamber diversity in structure and functional properties between atrial cardiomyocytes (CM) in norm and provoke their different responsiveness to pathological conditions. In this study, we assessed a LA vs. RA difference in CM contractility in paroxysmal atrial fibrillation (AF) and underlying mechanisms. Methods We investigated the contractile function of single isolated CM from LA and RA using a 7-day acetylcholine (ACh)-CaCl2 AF model in rats. We compared auxotonic force, sarcomere length dynamics, cytosolic calcium ([Ca2+]i) transients, intracellular ROS and NO production in LA and RA CM, and analyzed the phosphorylation levels of contractile proteins and actin-myosin interaction using an in vitro motility assay. Results AF resulted in more prominent structural and functional changes in LA myocardium, reducing sarcomere shortening amplitude, and velocity of sarcomere relengthening in mechanically non-loaded LA CM, which was associated with the increased ROS production, decreased NO production, reduced myofibrillar content, and decreased phosphorylation of cardiac myosin binding protein C and troponin I. However, in mechanically loaded CM, AF depressed the auxotonic force amplitude and kinetics in RA CM, while force characteristics were preserved in LA CM. Discussion Thus, inter-atrial differences are increased in paroxysmal AF and affected by the mechanical load that may contribute to the maintenance and progression of AF.
Collapse
Affiliation(s)
- Xenia Butova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Tatiana Myachina
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Raisa Simonova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Anastasia Kochurova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Elena Mukhlynina
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russian Federation
| | - Galina Kopylova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
| | - Daniil Shchepkin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russian Federation
| | - Anastasia Khokhlova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation
- Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russian Federation
| |
Collapse
|
6
|
Pioner JM, Vitale G, Gentile F, Scellini B, Piroddi N, Cerbai E, Olivotto I, Tardiff J, Coppini R, Tesi C, Poggesi C, Ferrantini C. Genotype-Driven Pathogenesis of Atrial Fibrillation in Hypertrophic Cardiomyopathy: The Case of Different TNNT2 Mutations. Front Physiol 2022; 13:864547. [PMID: 35514357 PMCID: PMC9062294 DOI: 10.3389/fphys.2022.864547] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/28/2022] [Indexed: 11/25/2022] Open
Abstract
Atrial dilation and atrial fibrillation (AF) are common in Hypertrophic CardioMyopathy (HCM) patients and associated with a worsening of prognosis. The pathogenesis of atrial myopathy in HCM remains poorly investigated and no specific association with genotype has been identified. By re-analysis of our cohort of thin-filament HCM patients (Coppini et al. 2014) AF was identified in 10% of patients with sporadic mutations in the cardiac Troponin T gene (TNNT2), while AF occurrence was much higher (25-75%) in patients carrying specific "hot-spot" TNNT2 mutations. To determine the molecular basis of arrhythmia occurrence, two HCM mouse models expressing human TNNT2 variants (a "hot-spot" one, R92Q, and a "sporadic" one, E163R) were selected according to the different pathophysiological pathways previously demonstrated in ventricular tissue. Echocardiography studies showed a significant left atrial dilation in both models, but more pronounced in the R92Q. In E163R atrial trabeculae, in line with what previously observed in ventricular preparations, the energy cost of tension generation was markedly increased. However, no changes of twitch amplitude and kinetics were observed, and there was no atrial arrhythmic propensity. R92Q atrial trabeculae, instead, displayed normal ATP consumption but markedly increased myofilament calcium sensitivity, as previously observed in ventricular preparations. This was associated with reduced inotropic reserve and slower kinetics of twitch contractions and, importantly, with an increased occurrence of spontaneous beats and triggered contractions that represent an intrinsic arrhythmogenic mechanism promoting AF. The association of specific TNNT2 mutations with AF occurrence depends on the mutation-driven pathomechanism (i.e., increased atrial myofilament calcium sensitivity rather than increased myofilament tension cost) and may influence the individual response to treatment.
Collapse
Affiliation(s)
| | - Giulia Vitale
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Francesca Gentile
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | | | - Iacopo Olivotto
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jil Tardiff
- Department of Medicine and Biomedical Engineering, University of Arizona, Tucson, AZ, United States
| | | | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| |
Collapse
|
7
|
Prodanovic M, Geeves MA, Poggesi C, Regnier M, Mijailovich SM. Effect of Myosin Isoforms on Cardiac Muscle Twitch of Mice, Rats and Humans. Int J Mol Sci 2022; 23:1135. [PMID: 35163054 PMCID: PMC8835009 DOI: 10.3390/ijms23031135] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/16/2022] [Accepted: 01/18/2022] [Indexed: 02/04/2023] Open
Abstract
To understand how pathology-induced changes in contractile protein isoforms modulate cardiac muscle function, it is necessary to quantify the temporal-mechanical properties of contractions that occur under various conditions. Pathological responses are much easier to study in animal model systems than in humans, but extrapolation between species presents numerous challenges. Employing computational approaches can help elucidate relationships that are difficult to test experimentally by translating the observations from rats and mice, as model organisms, to the human heart. Here, we use the spatially explicit MUSICO platform to model twitch contractions from rodent and human trabeculae collected in a single laboratory. This approach allowed us to identify the variations in kinetic characteristics of α- and β-myosin isoforms across species and to quantify their effect on cardiac muscle contractile responses. The simulations showed how the twitch transient varied with the ratio of the two myosin isoforms. Particularly, the rate of tension rise was proportional to the fraction of α-myosin present, while the β-isoform dominated the rate of relaxation unless α-myosin was >50%. Moreover, both the myosin isoform and the Ca2+ transient contributed to the twitch tension transient, allowing two levels of regulation of twitch contraction.
Collapse
Affiliation(s)
- Momcilo Prodanovic
- Institute for Information Technologies, University of Kragujevac, 34000 Kragujevac, Serbia;
- Bioengineering Research and Development Center (BioIRC), 34000 Kragujevac, Serbia
- FilamenTech, Inc., Newtown, MA 02458, USA
| | - Michael A. Geeves
- Department of Biosciences, University of Kent, Canterbury CT2 7NJ, Kent, UK;
| | - Corrado Poggesi
- Department of Experimental & Clinical Medicine, University of Florence, 20134 Florence, Italy;
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA;
| | - Srboljub M. Mijailovich
- FilamenTech, Inc., Newtown, MA 02458, USA
- Department of Biology, Illinois Institute of Technology, Chicago, IL 60616, USA
| |
Collapse
|
8
|
Safabakhsh S, Panwar P, Barichello S, Sangha SS, Hanson PJ, Van Petegem F, Laksman Z. THE ROLE OF PHOSPHORYLATION IN ATRIAL FIBRILLATION: A FOCUS ON MASS SPECTROMETRY APPROACHES. Cardiovasc Res 2021; 118:1205-1217. [PMID: 33744917 DOI: 10.1093/cvr/cvab095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/16/2021] [Indexed: 11/14/2022] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia worldwide. It is associated with significant increases in morbidity in the form of stroke and heart failure, and a doubling in all-cause mortality. The pathophysiology of AF is incompletely understood, and this has contributed to a lack of effective treatments and disease-modifying therapies. An important cellular process that may explain how risk factors give rise to AF includes post-translational modification (PTM) of proteins. As the most commonly occurring PTM, protein phosphorylation is especially relevant. Although many methods exist for studying protein phosphorylation, a common and highly resolute technique is mass spectrometry (MS). This review will discuss recent evidence surrounding the role of protein phosphorylation in the pathogenesis of AF. MS-based technology to study phosphorylation and uses of MS in other areas of medicine such as oncology will also be presented. Based on these data, future goals and experiments will be outlined that utilize MS technology to better understand the role of phosphorylation in AF and elucidate its role in AF pathophysiology. This may ultimately allow for the development of more effective AF therapies.
Collapse
Affiliation(s)
- Sina Safabakhsh
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pankaj Panwar
- AbCellera Biologicals Inc., Vancouver, British Columbia, Canada
| | - Scott Barichello
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarabjit S Sangha
- Cellular and Regenerative Medicine Centre, BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, British Columbia, Canada.,Molecular Cardiac Physiology Group, Departments of Biomedical Physiology and Kinesiology and Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada
| | - Paul J Hanson
- UBC Heart Lung Innovation Centre, Vancouver, British Columbia, Canada.,UBC Department of Pathology and Laboratory Medicine, Vancouver, British Columbia, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zachary Laksman
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
9
|
Alpha and beta myosin isoforms and human atrial and ventricular contraction. Cell Mol Life Sci 2021; 78:7309-7337. [PMID: 34704115 PMCID: PMC8629898 DOI: 10.1007/s00018-021-03971-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 01/15/2023]
Abstract
Human atrial and ventricular contractions have distinct mechanical characteristics including speed of contraction, volume of blood delivered and the range of pressure generated. Notably, the ventricle expresses predominantly β-cardiac myosin while the atrium expresses mostly the α-isoform. In recent years exploration of the properties of pure α- & β-myosin isoforms have been possible in solution, in isolated myocytes and myofibrils. This allows us to consider the extent to which the atrial vs ventricular mechanical characteristics are defined by the myosin isoform expressed, and how the isoform properties are matched to their physiological roles. To do this we Outline the essential feature of atrial and ventricular contraction; Explore the molecular structural and functional characteristics of the two myosin isoforms; Describe the contractile behaviour of myocytes and myofibrils expressing a single myosin isoform; Finally we outline the outstanding problems in defining the differences between the atria and ventricles. This allowed us consider what features of contraction can and cannot be ascribed to the myosin isoforms present in the atria and ventricles.
Collapse
|
10
|
Mikhailov AV, Kalyanasundaram A, Li N, Scott SS, Artiga EJ, Subr MM, Zhao J, Hansen BJ, Hummel JD, Fedorov VV. Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms. J Mol Cell Cardiol 2020; 151:56-71. [PMID: 33130148 DOI: 10.1016/j.yjmcc.2020.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022]
Abstract
Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.
Collapse
Affiliation(s)
- Aleksei V Mikhailov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Arrhythmology Research Department, Almazov National Medical Research Centre, Saint-Petersburg, Russia
| | - Anuradha Kalyanasundaram
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ning Li
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Shane S Scott
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Esthela J Artiga
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Megan M Subr
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Brian J Hansen
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John D Hummel
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| |
Collapse
|
11
|
The relation between sarcomere energetics and the rate of isometric tension relaxation in healthy and diseased cardiac muscle. J Muscle Res Cell Motil 2019; 42:47-57. [PMID: 31745760 PMCID: PMC7932984 DOI: 10.1007/s10974-019-09566-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/13/2019] [Indexed: 12/24/2022]
Abstract
Full muscle relaxation happens when [Ca2+] falls below the threshold for force activation. Several experimental models, from whole muscle organs and intact muscle down to skinned fibers, have been used to explore the cascade of kinetic events leading to mechanical relaxation. The use of single myofibrils together with fast solution switching techniques, has provided new information about the role of cross-bridge (CB) dissociation in the time course of isometric force decay. Myofibril’s relaxation is biphasic starting with a slow seemingly linear phase, with a rate constant, slow kREL, followed by a fast mono-exponential phase. Sarcomeres remain isometric during the slow force decay that reflects CB detachment under isometric conditions while the final fast relaxation phase begins with a sudden give of few sarcomeres and is then dominated by intersarcomere dynamics. Based on a simple two-state model of the CB cycle, myofibril slow kREL represents the apparent forward rate with which CBs leave force generating states (gapp) under isometric conditions and correlates with the energy cost of tension generation (ATPase/tension ratio); in short slow kREL ~ gapp ~ tension cost. The validation of this relationship is obtained by simultaneously measuring maximal isometric force and ATP consumption in skinned myocardial strips that provide an unambiguous determination of the relation between contractile and energetic properties of the sarcomere. Thus, combining kinetic experiments in isolated myofibrils and mechanical and energetic measurements in multicellular cardiac strips, we are able to provide direct evidence for a positive linear correlation between myofibril isometric relaxation kinetics (slow kREL) and the energy cost of force production both measured in preparations from the same cardiac sample. This correlation remains true among different types of muscles with different ATPase activities and also when CB kinetics are altered by cardiomyopathy-related mutations. Sarcomeric mutations associated to hypertrophic cardiomyopathy (HCM), a primary cardiac disorder caused by mutations in genes encoding sarcomeric proteins, have been often found to accelerate CB turnover rate and increase the energy cost of myocardial contraction. Here we review data showing that faster CB detachment results in a proportional increase in the energetic cost of tension generation in heart samples from both HCM patients and mouse models of the disease.
Collapse
|
12
|
Lee SP, Ashley EA, Homburger J, Caleshu C, Green EM, Jacoby D, Colan SD, Arteaga-Fernández E, Day SM, Girolami F, Olivotto I, Michels M, Ho CY, Perez MV. Incident Atrial Fibrillation Is Associated With MYH7 Sarcomeric Gene Variation in Hypertrophic Cardiomyopathy. Circ Heart Fail 2019; 11:e005191. [PMID: 30354366 DOI: 10.1161/circheartfailure.118.005191] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Although atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM) patients, the relationship between genetic variation and AF has been poorly defined. Characterizing genetic subtypes of HCM and their associations with AF may help to improve personalized medical care. We aimed to investigate the link between sarcomeric gene variation and incident AF in HCM patients. Methods and Results Patients from the multinational Sarcomeric Human Cardiomyopathy Registry were followed for incident AF. Those with likely pathogenic or pathogenic variants in sarcomeric genes were included. The AF incidence was ascertained by review of medical records and electrocardiograms at each investigative site. One thousand forty adult HCM patients, without baseline AF and with likely pathogenic or pathogenic variation in either MYH7 (n=296), MYBPC3 (n=659), or thin filament genes (n=85), were included. Compared with patients with variation in other sarcomeric genes, those with MYH7 variants were younger on first clinical encounter at the Sarcomeric Human Cardiomyopathy Registry site and more likely to be probands than the MYBPC3 variants. During an average follow-up of 7.2 years, 198 incident AF events occurred. Patients with likely pathogenic or pathogenic mutations in MYH7 had the highest incidence of AF after adjusting for age, sex, proband status, left atrial size, maximal wall thickness, and peak pressure gradient (hazard ratio, 1.7; 95% CI, 1.1-2.6; P=0.009). Conclusions During a mean follow-up of 7.2 years, new-onset AF developed in 19% of HCM patients with sarcomeric mutations. Compared with other sarcomeric genes, patients with likely pathogenic or pathogenic variation in MYH7 had a higher rate of incident AF independent of clinical and echocardiographic factors.
Collapse
Affiliation(s)
- Seung-Pyo Lee
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, CA (S.-P.L., E.A.A., M.V.P.).,Department of Internal Medicine, Seoul National University Hospital, South Korea (S.-P.L.)
| | - Euan A Ashley
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, CA (S.-P.L., E.A.A., M.V.P.).,Stanford Center for Inherited Cardiovascular Disease, Stanford University, CA (E.A.A., C.C., M.V.P.).,Department of Genetics, Stanford University, CA (E.A.A., J.H.)
| | | | - Colleen Caleshu
- Stanford Center for Inherited Cardiovascular Disease, Stanford University, CA (E.A.A., C.C., M.V.P.)
| | | | - Daniel Jacoby
- Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT (D.J.)
| | - Steven D Colan
- Department of Cardiology, Boston Children's Hospital, MA (S.D.C.)
| | - Edmundo Arteaga-Fernández
- Laboratory of Genetics and Molecular Cardiology and Cardiomyopathies Unit, Heart Institute (InCor), University of São Paulo, Brazil (E.A.-F.)
| | - Sharlene M Day
- Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor (S.M.D.)
| | - Francesca Girolami
- Referral Center for Cardiomyopathies, Careggi University Hospital, Florence, Italy (F.G., I.O.)
| | - Iacopo Olivotto
- Referral Center for Cardiomyopathies, Careggi University Hospital, Florence, Italy (F.G., I.O.)
| | - Michelle Michels
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands (M.M.)
| | - Carolyn Y Ho
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA (C.Y.H.)
| | - Marco V Perez
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, CA (S.-P.L., E.A.A., M.V.P.).,Stanford Center for Inherited Cardiovascular Disease, Stanford University, CA (E.A.A., C.C., M.V.P.)
| | | |
Collapse
|
13
|
Bening C, Mazalu EA, Yaqub J, Alhussini K, Glanowski M, Kottmann T, Leyh R. Atrial contractility and fibrotic biomarkers are associated with atrial fibrillation after elective coronary artery bypass grafting. J Thorac Cardiovasc Surg 2019; 159:515-523. [PMID: 30929988 DOI: 10.1016/j.jtcvs.2019.02.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 02/14/2019] [Accepted: 02/15/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVE New-onset postoperative atrial fibrillation is common after cardiac surgery. Less has been reported about the relationship among fibrosis, inflammation, calcium-induced left atrial and right atrial contractile forces, and postoperative atrial fibrillation. We sought to identify predictors of postoperative atrial fibrillation. METHODS From August 2016 to February 2018, we evaluated 229 patients who had preoperative sinus rhythm before elective primary coronary artery bypass grafting. Of 229 patients, 191 maintained sinus rhythm postoperatively, whereas 38 patients developed atrial fibrillation. Preoperative tissue inhibitor of metalloproteinase-1, pentraxin-3, matrix metallopeptidase-9, galectin-3, high-sensitivity C-reactive protein, growth differentiation factor 15, and transforming growth factor-ß were measured. Clinical and echocardiographic findings (tricuspid annular plane systolic excursion for right heart function) and calcium-induced force measurements from left atrial and right atrial-derived skinned myocardial fibers were recorded. RESULTS Patients with atrial fibrillation were older (P = .001), had enlarged left atrial (P = .0001) and right atrial areas (P = .0001), and had decreased tricuspid annular plane systolic excursion (P = .001). Levels of matrix metallopeptidase-9 and pentraxin-3 were decreased (P < .05), whereas growth differentiation factor 15 was increased (P = .001). We detected lower left atrial force values at calcium-induced force measurements 5.5 (P < .05), 5.4 (P < .01), and 5.3 to 4.52 (P = .0001) and right atrial force values at calcium-induced force measurements 5.0 to 4.52 (P < .05) in patients with postoperative atrial fibrillation. Multivariable analysis showed that advanced age (P = .033), decreased left atrial force value at calcium-induced force measurement of 5.5 (P = .033), enlarged left atrial (P = .013) and right atrial (P = .081) areas, and reduced tricuspid annular plane systolic excursion (P = .010) independently predicted postoperative atrial fibrillation. CONCLUSIONS Advanced age, decreased left atrial force value at calcium-induced force measurement of 5.5, enlarged left atrial and right atrial areas, and reduced tricuspid annular plane systolic excursion were identified as independent predictors for postoperative atrial fibrillation.
Collapse
Affiliation(s)
- Constanze Bening
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany; Comprehensive Heart Failure Centre Würzburg, University of Wuerzburg, Wuerzburg, Germany.
| | - Elena-Aura Mazalu
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany
| | - Jonathan Yaqub
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany
| | - Khaled Alhussini
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany
| | - Michal Glanowski
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany
| | | | - Rainer Leyh
- Department of Thoracic and Cardiovascular Surgery, University of Wuerzburg, Wuerzburg, Germany; Comprehensive Heart Failure Centre Würzburg, University of Wuerzburg, Wuerzburg, Germany
| |
Collapse
|
14
|
van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
Collapse
Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| |
Collapse
|
15
|
Zile MA, Trayanova NA. Increased thin filament activation enhances alternans in human chronic atrial fibrillation. Am J Physiol Heart Circ Physiol 2018; 315:H1453-H1462. [PMID: 30141984 PMCID: PMC6297809 DOI: 10.1152/ajpheart.00658.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 08/21/2018] [Accepted: 08/21/2018] [Indexed: 11/22/2022]
Abstract
Action potential duration (APD) alternans (APD-ALT), defined as beat-to-beat oscillations in APD, has been proposed as an important clinical marker for chronic atrial fibrillation (cAF) risk when it occurs at pacing rates of 120-200 beats/min. Although the ionic mechanisms for occurrence of APD-ALT in human cAF at these clinically relevant rates have been investigated, little is known about the effects of myofilament protein kinetics on APD-ALT. Therefore, we used computer simulations of single cell function to explore whether remodeling in myofilament protein kinetics in human cAF alters the occurrence of APD-ALT and to uncover how these mechanisms are affected by sarcomere length and the degree of cAF-induced myofilament remodeling. Mechanistically based, bidirectionally coupled electromechanical models of human right and left atrial myocytes were constructed, incorporating both ionic and myofilament remodeling associated with cAF. By comparing results from our electromechanical model with those from the uncoupled ionic model, we found that intracellular Ca2+ concentration buffering of troponin C has a dampening effect on the magnitude of APD-ALT (APD-ANM) at slower rates (150 beats/min) due to the cooperativity between strongly bound cross-bridges and Ca2+-troponin C binding affinity. We also discovered that cAF-induced enhanced thin filament activation enhanced APD-ANM at these clinically relevant heart rates (150 beats/min). In addition, longer sarcomere lengths increased APD-ANM, suggesting that atrial stretch is an important modulator of APD-ALT. Together, these findings demonstrate that myofilament kinetics mechanisms play an important role in altering APD-ALT in human cAF. NEW & NOTEWORTHY Using a single cell simulation approach, we explored how myofilament protein kinetics alter the formation of alternans in action potential duration (APD) in human myocytes with chronic atrial fibrillation remodeling. We discovered that enhanced thin filament activation and longer sarcomere lengths increased the magnitude of APD alternans at clinically important pacing rates of 120-200 beats/min. Furthermore, we found that altered intracellular Ca2+ concentration buffering of troponin C has a dampening effect on the magnitude of APD alternans.
Collapse
Affiliation(s)
- Melanie A Zile
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University , Baltimore, Maryland
| | - Natalia A Trayanova
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University , Baltimore, Maryland
| |
Collapse
|
16
|
Converse role of class I and class IIa HDACs in the progression of atrial fibrillation. J Mol Cell Cardiol 2018; 125:39-49. [PMID: 30321539 DOI: 10.1016/j.yjmcc.2018.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/25/2022]
Abstract
Atrial fibrillation (AF), the most common persistent clinical tachyarrhythmia, is associated with altered gene transcription which underlies cardiomyocyte dysfunction, AF susceptibility and progression. Recent research showed class I and class IIa histone deacetylases (HDACs) to regulate pathological and fetal gene expression, and thereby induce hypertrophy and cardiac contractile dysfunction. Whether class I and class IIa HDACs are involved in AF promotion is unknown. We aim to elucidate the role of class I and class IIa HDACs in tachypacing-induced contractile dysfunction in experimental model systems for AF and clinical AF. METHODS AND RESULTS: Class I and IIa HDACs were overexpressed in HL-1 cardiomyocytes followed by calcium transient (CaT) measurements. Overexpression of class I HDACs, HDAC1 or HDAC3, significantly reduced CaT amplitude in control normal-paced (1 Hz) cardiomyocytes, which was further reduced by tachypacing (5 Hz) in HDAC3 overexpressing cardiomyocytes. HDAC3 inhibition by shRNA or by the specific inhibitor, RGFP966, prevented contractile dysfunction in both tachypaced HL-1 cardiomyocytes and Drosophila prepupae. Conversely, overexpression of class IIa HDACs (HDAC4, HDAC5, HDAC7 or HDAC9) did not affect CaT in controls, with HDAC5 and HDAC7 overexpression even protecting against tachypacing-induced CaT loss. Notably, the protective effect of HDAC5 and HDAC7 was abolished in cardiomyocytes overexpressing a dominant negative HDAC5 or HDAC7 mutant, bearing a mutation in the binding domain for myosin enhancer factor 2 (MEF2). Furthermore, tachypacing induced phosphorylation of HDAC5 and promoted its translocation from the nucleus to cytoplasm, leading to up-regulation of MEF2-related fetal gene expression (β-MHC, BNP). In accord, boosting nuclear localization of HDAC5 by MC1568 or Go6983 attenuated CaT loss in tachypaced HL-1 cardiomyocytes and preserved contractile function in Drosophila prepupae. Findings were expanded to clinical AF. Here, patients with AF showed a significant increase in expression levels and activity of HDAC3, phosphorylated HDAC5 and fetal genes (β-MHC, BNP) in atrial tissue compared to controls in sinus rhythm. CONCLUSION: Class I and class IIa HDACs display converse roles in AF progression. Whereas overexpression of Class I HDAC3 induces cardiomyocyte dysfunction, class IIa HDAC5 overexpression reveals protective properties. Accordingly, HDAC3 inhibitors and HDAC5 nuclear boosters show protection from tachypacing-induced changes and therefore may represent interesting therapeutic options in clinical AF.
Collapse
|
17
|
Ferrantini C, Coppini R, Pioner JM, Gentile F, Tosi B, Mazzoni L, Scellini B, Piroddi N, Laurino A, Santini L, Spinelli V, Sacconi L, De Tombe P, Moore R, Tardiff J, Mugelli A, Olivotto I, Cerbai E, Tesi C, Poggesi C. Pathogenesis of Hypertrophic Cardiomyopathy is Mutation Rather Than Disease Specific: A Comparison of the Cardiac Troponin T E163R and R92Q Mouse Models. J Am Heart Assoc 2017; 6:JAHA.116.005407. [PMID: 28735292 PMCID: PMC5586279 DOI: 10.1161/jaha.116.005407] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background In cardiomyocytes from patients with hypertrophic cardiomyopathy, mechanical dysfunction and arrhythmogenicity are caused by mutation‐driven changes in myofilament function combined with excitation‐contraction (E‐C) coupling abnormalities related to adverse remodeling. Whether myofilament or E‐C coupling alterations are more relevant in disease development is unknown. Here, we aim to investigate whether the relative roles of myofilament dysfunction and E‐C coupling remodeling in determining the hypertrophic cardiomyopathy phenotype are mutation specific. Methods and Results Two hypertrophic cardiomyopathy mouse models carrying the R92Q and the E163R TNNT2 mutations were investigated. Echocardiography showed left ventricular hypertrophy, enhanced contractility, and diastolic dysfunction in both models; however, these phenotypes were more pronounced in the R92Q mice. Both E163R and R92Q trabeculae showed prolonged twitch relaxation and increased occurrence of premature beats. In E163R ventricular myofibrils or skinned trabeculae, relaxation following Ca2+ removal was prolonged; resting tension and resting ATPase were higher; and isometric ATPase at maximal Ca2+ activation, the energy cost of tension generation, and myofilament Ca2+ sensitivity were increased compared with that in wild‐type mice. No sarcomeric changes were observed in R92Q versus wild‐type mice, except for a large increase in myofilament Ca2+ sensitivity. In R92Q myocardium, we found a blunted response to inotropic interventions, slower decay of Ca2+ transients, reduced SERCA function, and increased Ca2+/calmodulin kinase II activity. Contrarily, secondary alterations of E‐C coupling and signaling were minimal in E163R myocardium. Conclusions In E163R models, mutation‐driven myofilament abnormalities directly cause myocardial dysfunction. In R92Q, diastolic dysfunction and arrhythmogenicity are mediated by profound cardiomyocyte signaling and E‐C coupling changes. Similar hypertrophic cardiomyopathy phenotypes can be generated through different pathways, implying different strategies for a precision medicine approach to treatment.
Collapse
MESH Headings
- Animals
- Calcium Signaling
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cardiomyopathy, Hypertrophic/diagnostic imaging
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/physiopathology
- Disease Models, Animal
- Excitation Contraction Coupling
- Fibrosis
- Genetic Markers
- Genetic Predisposition to Disease
- Hypertrophy, Left Ventricular/diagnostic imaging
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Myofibrils/metabolism
- Myofibrils/pathology
- Phenotype
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Troponin T/genetics
- Ventricular Dysfunction, Left/diagnostic imaging
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Remodeling
Collapse
Affiliation(s)
- Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Francesca Gentile
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Benedetta Tosi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Luca Mazzoni
- Department of NeuroFarBa, University of Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | | | - Leonardo Sacconi
- LENS, University of Florence & National Institute of Optics (INO-CNR), Florence, Italy
| | - Pieter De Tombe
- Loyola University Medical Center Department of Physiology, Chicago, IL
| | | | | | - Alessandro Mugelli
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| |
Collapse
|
18
|
Heijman J, Ghezelbash S, Wehrens XHT, Dobrev D. Serine/Threonine Phosphatases in Atrial Fibrillation. J Mol Cell Cardiol 2017; 103:110-120. [PMID: 28077320 DOI: 10.1016/j.yjmcc.2016.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 12/19/2022]
Abstract
Serine/threonine protein phosphatases control dephosphorylation of numerous cardiac proteins, including a variety of ion channels and calcium-handling proteins, thereby providing precise post-translational regulation of cardiac electrophysiology and function. Accordingly, dysfunction of this regulation can contribute to the initiation, maintenance and progression of cardiac arrhythmias. Atrial fibrillation (AF) is the most common heart rhythm disorder and is characterized by electrical, autonomic, calcium-handling, contractile, and structural remodeling, which include, among other things, changes in the phosphorylation status of a wide range of proteins. Here, we review AF-associated alterations in the phosphorylation of atrial ion channels, calcium-handling and contractile proteins, and their role in AF-pathophysiology. We highlight the mechanisms controlling the phosphorylation of these proteins and focus on the role of altered dephosphorylation via local type-1, type-2A and type-2B phosphatases (PP1, PP2A, and PP2B, also known as calcineurin, respectively). Finally, we discuss the challenges for phosphatase research, potential therapeutic significance of altered phosphatase-mediated protein dephosphorylation in AF, as well as future directions.
Collapse
Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Shokoufeh Ghezelbash
- 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 and Biophysics, Department of Medicine (Cardiology), Pediatrics, Baylor College of Medicine, Houston, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany.
| |
Collapse
|
19
|
Cañón S, Caballero R, Herraiz-Martínez A, Pérez-Hernández M, López B, Atienza F, Jalife J, Hove-Madsen L, Delpón E, Bernad A. miR-208b upregulation interferes with calcium handling in HL-1 atrial myocytes: Implications in human chronic atrial fibrillation. J Mol Cell Cardiol 2016; 99:162-173. [PMID: 27545043 DOI: 10.1016/j.yjmcc.2016.08.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 07/29/2016] [Accepted: 08/17/2016] [Indexed: 01/14/2023]
Abstract
MicroRNAs (miR) have considerable potential as therapeutic tools in cardiac diseases. Alterations in atrial miR are involved in the development of atrial fibrillation (AF), but the molecular mechanism underlying their contribution to atrial remodeling in chronic atrial fibrillation (CAF) is only partially understood. Here we used miR array to analyze the miR profile of atrial biopsies from sinus rhythm (SR) and CAF patients. qRT-PCR identified a distinctive CAF-miR signature and described conserved miR-208b upregulation in human and ovine AF atrial tissue. We used bioinformatics analysis to predict genes and signaling pathways as putative miR-208b targets, which highlighted genes from the cardiac muscle gene program and from canonical WNT, gap-junction and Ca2+ signaling networks. Results from analysis of miR-208b-overexpressing HL-1 atrial myocytes and from myocytes isolated from CAF patients showed that aberrant miR-208b levels reduced the expression and function of L-type Ca2+ channel subunits (CACNA1C and CACNB2) as well as the sarcoplasmic reticulum-Ca2+ pump SERCA2. These findings clearly pointed to CAF-specific upregulated miR-208b as an important mediator in Ca2+ handling impairment during atrial remodeling.
Collapse
Affiliation(s)
- Susana Cañón
- Cardiovascular Development and Repair Department, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain; Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Adela Herraiz-Martínez
- Cardiovascular Research Centre, CSIC-ICCC, Barcelona, Spain; Instituto de Investigación Biomédica Sant Pau, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Marta Pérez-Hernández
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Begoña López
- Program for Cardiovascular Diseases, Centre for Applied Medical Research, University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Felipe Atienza
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - José Jalife
- Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Area of Myocardial Pathophysiology, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain
| | - Leif Hove-Madsen
- Cardiovascular Research Centre, CSIC-ICCC, Barcelona, Spain; Instituto de Investigación Biomédica Sant Pau, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Eva Delpón
- Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain
| | - Antonio Bernad
- Cardiovascular Development and Repair Department, Spanish National Cardiovascular Research Center (CNIC), Madrid, Spain; Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
| |
Collapse
|
20
|
Pioner JM, Racca AW, Klaiman JM, Yang KC, Guan X, Pabon L, Muskheli V, Zaunbrecher R, Macadangdang J, Jeong MY, Mack DL, Childers MK, Kim DH, Tesi C, Poggesi C, Murry CE, Regnier M. Isolation and Mechanical Measurements of Myofibrils from Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Stem Cell Reports 2016; 6:885-896. [PMID: 27161364 PMCID: PMC4911495 DOI: 10.1016/j.stemcr.2016.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 01/25/2023] Open
Abstract
Tension production and contractile properties are poorly characterized aspects of excitation-contraction coupling of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Previous approaches have been limited due to the small size and structural immaturity of early-stage hiPSC-CMs. We developed a substrate nanopatterning approach to produce hiPSC-CMs in culture with adult-like dimensions, T-tubule-like structures, and aligned myofibrils. We then isolated myofibrils from hiPSC-CMs and measured the tension and kinetics of activation and relaxation using a custom-built apparatus with fast solution switching. The contractile properties and ultrastructure of myofibrils more closely resembled human fetal myofibrils of similar gestational age than adult preparations. We also demonstrated the ability to study the development of contractile dysfunction of myofibrils from a patient-derived hiPSC-CM cell line carrying the familial cardiomyopathy MYH7 mutation (E848G). These methods can bring new insights to understanding cardiomyocyte maturation and developmental mechanical dysfunction of hiPSC-CMs with cardiomyopathic mutations. The contractile properties of hiPSC-CM myofibrils have not been previously studied hiPSC-CMs cultured on nanopatterned surfaces develop elongated, aligned myofibrils hiPSC-CMs myofibrils have contractile properties similar to human fetal myofibrils hiPSC-CMs can be used to study development of genetically based cardiac diseases
Collapse
Affiliation(s)
- Josè Manuel Pioner
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 63, 50134 Florence, Italy.
| | - Alice W Racca
- Bioengineering, University of Washington, Seattle, WA 98109, USA
| | - Jordan M Klaiman
- Bioengineering, University of Washington, Seattle, WA 98109, USA
| | - Kai-Chun Yang
- Medicine, Division of Cardiology, University of Washington, Seattle, WA 98195, USA
| | - Xuan Guan
- Rehabilitation Medicine, University of Washington, Seattle, WA 98109, USA
| | - Lil Pabon
- Pathology, University of Washington, Seattle, WA 98109, USA
| | | | | | | | - Mark Y Jeong
- Medicine, Division of Cardiology, University of Colorado, Denver, CO 80262, USA
| | - David L Mack
- Rehabilitation Medicine, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Martin K Childers
- Rehabilitation Medicine, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Deok-Ho Kim
- Bioengineering, University of Washington, Seattle, WA 98109, USA
| | - Chiara Tesi
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 63, 50134 Florence, Italy
| | - Corrado Poggesi
- Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 63, 50134 Florence, Italy
| | - Charles E Murry
- Bioengineering, University of Washington, Seattle, WA 98109, USA; Medicine, Division of Cardiology, University of Washington, Seattle, WA 98195, USA; Pathology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA
| | - Michael Regnier
- Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA
| |
Collapse
|
21
|
Nitta T, Ishii Y, Fujii M, Miyagi Y, Sakamoto SI, Hiromoto A, Imura H. Restoration of sinus rhythm and atrial transport function after the maze procedure: U lesion set versus box lesion set. J Thorac Cardiovasc Surg 2016; 151:1062-9. [DOI: 10.1016/j.jtcvs.2015.10.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 10/21/2015] [Accepted: 10/29/2015] [Indexed: 11/16/2022]
|
22
|
Impact of Genotype on the Occurrence of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy. Am J Cardiol 2016; 117:1151-9. [PMID: 26869393 DOI: 10.1016/j.amjcard.2015.12.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/26/2015] [Accepted: 12/26/2015] [Indexed: 12/19/2022]
Abstract
Genes associated with hypertrophic cardiomyopathy (HC) are not uniformly expressed in the atrial myocardium. Whether this may impact susceptibility to atrial fibrillation (AF) is unresolved. To analyze the prevalence and clinical correlates of AF in relation to genotype in a large HC cohort, prevalence and clinical profile of AF were assessed in 237 patients with HC, followed for 14 ± 10 years. Patients were divided into 3 genetic subgroups: (1) MYBPC3 (58%), (2) MYH7 (28%), and (3) "other genotypes" (14%; comprising TNNT2, TNNI3, TPM1, MYL2, complex genotypes, Z-line, and E-C coupling genes). Left atrial size was similar in the 3 subsets. AF occurred in 74 patients with HC (31%), with no difference among groups (31% in MYBPC3, 37% in MYH7 and 18% in other genotypes, p = 0.15), paroxysmal/persistent AF (12%, 18%, and 12%, respectively; p = 0.53), paroxysmal/persistent evolved to permanent (12%, 12%, and 3%, p = 0.36) or permanent AF (7%, 7%, and 3%, p = 0.82). Age at AF onset was younger in the group with other genotypes (37 ± 10 years) compared to the first 2 groups (53 ± 14 and 51 ± 17, respectively; p = 0.05) because of early onset associated with complex genotypes and a specific JPH2 mutation associated with abnormal intracellular calcium handling. At multivariate analysis, independent predictors of AF were atrial diameter (p ≤0.05) and age at diagnosis (p = 0.09), but not genetic subtype (p = 0.35). In conclusion, in patients with HC, genetic testing cannot be used in clinical decision making with regard to management strategies for AF. Genotype is not predictive of onset or severity of AF, which appears rather driven by hemodynamic determinants of atrial dilatation. Exceptions are represented by rare genes suggesting specific molecular pathways for AF in genetic cardiomyopathies.
Collapse
|
23
|
Vikhorev PG, Ferenczi MA, Marston SB. Instrumentation to study myofibril mechanics from static to artificial simulations of cardiac cycle. MethodsX 2016; 3:156-70. [PMID: 27047763 PMCID: PMC4796715 DOI: 10.1016/j.mex.2016.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/28/2016] [Indexed: 01/26/2023] Open
Abstract
Many causes of heart muscle diseases and skeletal muscle diseases are inherited and caused by mutations in genes of sarcomere proteins which play either a structural or contractile role in the muscle cell. Tissue samples from human hearts with mutations can be obtained but often samples are only a few milligrams and it is necessary to freeze them for storage and transportation. Myofibrils are the fundamental contractile components of the muscle cell and retain all structural elements and contractile proteins performing in contractile event; moreover viable myofibrils can be obtained from frozen tissue.We are describing a versatile technique for measuring the contractility and its Ca2+ regulation in single myofibrils. The control of myofibril length, incubation medium and data acquisition is carried out using a digital acquisition board via computer software. Using computer control it is possible not only to measure contractile and mechanical parameters but also simulate complex protocols such as a cardiac cycle to vary length and medium independently. This single myofibril force assay is well suited for physiological measurements. The system can be adapted to measure tension amplitude, rates of contraction and relaxation, Ca2+ dependence of these parameters in dose-response measurements, length-dependent activation, stretch response, myofibril elasticity and response to simulated cardiac cycle length changes. Our approach provides an all-round quantitative way to measure myofibrils performance and to observe the effect of mutations or posttranslational modifications. The technique has been demonstrated by the study of contraction in heart with hypertrophic or dilated cardiomyopathy mutations in sarcomere proteins.
Collapse
Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Michael A Ferenczi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Steven B Marston
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| |
Collapse
|
24
|
Opacic D, van Bragt KA, Nasrallah HM, Schotten U, Verheule S. Atrial metabolism and tissue perfusion as determinants of electrical and structural remodelling in atrial fibrillation. Cardiovasc Res 2016; 109:527-41. [DOI: 10.1093/cvr/cvw007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/12/2016] [Indexed: 12/14/2022] Open
|
25
|
Pellman J, Sheikh F. Atrial fibrillation: mechanisms, therapeutics, and future directions. Compr Physiol 2016; 5:649-65. [PMID: 25880508 DOI: 10.1002/cphy.c140047] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, affecting 1% to 2% of the general population. It is characterized by rapid and disorganized atrial activation leading to impaired atrial function, which can be diagnosed on an EKG by lack of a P-wave and irregular QRS complexes. AF is associated with increased morbidity and mortality and is a risk factor for embolic stroke and worsening heart failure. Current research on AF support and explore the hypothesis that initiation and maintenance of AF require pathophysiological remodeling of the atria, either specifically as in lone AF or secondary to other heart disease as in heart failure-associated AF. Remodeling in AF can be grouped into three categories that include: (i) electrical remodeling, which includes modulation of L-type Ca(2+) current, various K(+) currents and gap junction function; (ii) structural remodeling, which includes changes in tissues properties, size, and ultrastructure; and (iii) autonomic remodeling, including altered sympathovagal activity and hyperinnervation. Electrical, structural, and autonomic remodeling all contribute to creating an AF-prone substrate which is able to produce AF-associated electrical phenomena including a rapidly firing focus, complex multiple reentrant circuit or rotors. Although various remodeling events occur in AF, current AF therapies focus on ventricular rate and rhythm control strategies using pharmacotherapy and surgical interventions. Recent progress in the field has started to focus on the underlying substrate that drives and maintains AF (termed upstream therapies); however, much work is needed in this area. Here, we review current knowledge of AF mechanisms, therapies, and new areas of investigation.
Collapse
Affiliation(s)
- Jason Pellman
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | | |
Collapse
|
26
|
Zhang D, Hu X, Henning RH, Brundel BJJM. Keeping up the balance: role of HDACs in cardiac proteostasis and therapeutic implications for atrial fibrillation. Cardiovasc Res 2015; 109:519-26. [PMID: 26645980 DOI: 10.1093/cvr/cvv265] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/29/2015] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are long-lived post-mitotic cells with limited regenerative capacity. Proper cardiomyocyte function depends critically on the maintenance of a healthy homeostasis of protein expression, folding, assembly, trafficking, function, and degradation, together commonly referred to as proteostasis. Impairment of proteostasis has a prominent role in the pathophysiology of ageing-related neurodegenerative diseases including Huntington's, Parkinson's, and Alzheimer's disease. Emerging evidence reveals also a role for impaired proteostasis in the pathophysiology of common human cardiac diseases such as cardiac hypertrophy, dilated and ischaemic cardiomyopathies, and atrial fibrillation (AF). Histone deacetylases (HDACs) have recently been recognized as key modulators which control cardiac proteostasis by deacetylating various proteins. By deacetylating chromatin proteins, including histones, HDACs modulate epigenetic regulation of pathological gene expression. Also, HDACs exert a broad range of functions outside the nucleus by deacetylating structural and contractile proteins. The cytosolic actions of HDACs result in changed protein function through post-translational modifications and/or modulation of their degradation. This review describes the mechanisms underlying the derailment of proteostasis in AF and subsequently focuses on the role of HDACs herein. In addition, the therapeutic potential of HDAC inhibition to maintain a healthy proteostasis resulting in a delay in AF onset and progression is discussed.
Collapse
Affiliation(s)
- Deli Zhang
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Xu Hu
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Bianca J J M Brundel
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
27
|
Brandenburg S, Arakel EC, Schwappach B, Lehnart SE. The molecular and functional identities of atrial cardiomyocytes in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1882-93. [PMID: 26620800 DOI: 10.1016/j.bbamcr.2015.11.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 12/28/2022]
Abstract
Atrial cardiomyocytes are essential for fluid homeostasis, ventricular filling, and survival, yet their cell biology and physiology are incompletely understood. It has become clear that the cell fate of atrial cardiomyocytes depends significantly on transcription programs that might control thousands of differentially expressed genes. Atrial muscle membranes propagate action potentials and activate myofilament force generation, producing overall faster contractions than ventricular muscles. While atria-specific excitation and contractility depend critically on intracellular Ca(2+) signalling, voltage-dependent L-type Ca(2+) channels and ryanodine receptor Ca(2+) release channels are each expressed at high levels similar to ventricles. However, intracellular Ca(2+) transients in atrial cardiomyocytes are markedly heterogeneous and fundamentally different from ventricular cardiomyocytes. In addition, differential atria-specific K(+) channel expression and trafficking confer unique electrophysiological and metabolic properties. Because diseased atria have the propensity to perpetuate fast arrhythmias, we discuss our understanding about the cell-specific mechanisms that lead to metabolic and/or mitochondrial dysfunction in atrial fibrillation. Interestingly, recent work identified potential atria-specific mechanisms that lead to early contractile dysfunction and metabolic remodelling, suggesting highly interdependent metabolic, electrical, and contractile pathomechanisms. Hence, the objective of this review is to provide an integrated model of atrial cardiomyocytes, from tissue-specific cell properties, intracellular metabolism, and excitation-contraction (EC) coupling to early pathological changes, in particular metabolic dysfunction and tissue remodelling due to atrial fibrillation and aging. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
Collapse
Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Eric C Arakel
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Molecular Biology, University Medical Center Göttingen, 37073 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany; Department of Cardiology & Pulmonology, University Medical Center Göttingen, 37075 Göttingen, Germany; German Centre for Cardiovascular Research (DZHK) site Göttingen, 37075 Göttingen, Germany.
| |
Collapse
|
28
|
Abstract
Optimal cardiac function depends on proper timing of excitation and contraction in various regions of the heart, as well as on appropriate heart rate. This is accomplished via specialized electrical properties of various components of the system, including the sinoatrial node, atria, atrioventricular node, His-Purkinje system, and ventricles. Here we review the major regionally determined electrical properties of these cardiac regions and present the available data regarding the molecular and ionic bases of regional cardiac function and dysfunction. Understanding these differences is of fundamental importance for the investigation of arrhythmia mechanisms and pharmacotherapy.
Collapse
Affiliation(s)
- Daniel C Bartos
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California Davis, Davis, California, USA
| |
Collapse
|
29
|
Losartan treatment attenuates tumor-induced myocardial dysfunction. J Mol Cell Cardiol 2015; 85:37-47. [PMID: 25988231 DOI: 10.1016/j.yjmcc.2015.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/28/2015] [Accepted: 05/11/2015] [Indexed: 12/21/2022]
Abstract
UNLABELLED Fatigue and muscle wasting are common symptoms experienced by cancer patients. Data from animal models demonstrate that angiotensin is involved in tumor-induced muscle wasting, and that tumor growth can independently affect myocardial function, which could contribute to fatigue in cancer patients. In clinical studies, inhibitors of angiotensin converting enzyme (ACE) can prevent the development of chemotherapy-induced cardiovascular dysfunction, suggesting a mechanistic role for the renin-angiotensin-aldosterone system (RAAS). In the present study, we investigated whether an angiotensin (AT) 1-receptor antagonist could prevent the development of tumor-associated myocardial dysfunction. METHODS AND RESULTS Colon26 adenocarcinoma (c26) cells were implanted into female CD2F1 mice at 8weeks of age. Simultaneously, mice were administered Losartan (10mg/kg) daily via their drinking water. In vivo echocardiography, blood pressure, in vitro cardiomyocyte function, cell proliferation assays, and measures of systemic inflammation and myocardial protein degradation were performed 19days following tumor cell injection. Losartan treatment prevented tumor-induced loss of muscle mass and in vitro c26 cell proliferation, decreased tumor weight, and attenuated myocardial expression of interleukin-6. Furthermore, Losartan treatment mitigated tumor-associated alterations in calcium signaling in cardiomyocytes, which was associated with improved myocyte contraction velocity, systolic function, and blood pressures in the hearts of tumor-bearing mice. CONCLUSIONS These data suggest that Losartan may mitigate tumor-induced myocardial dysfunction and inflammation.
Collapse
|
30
|
Ait Mou Y, Bollensdorff C, Cazorla O, Magdi Y, de Tombe PP. Exploring cardiac biophysical properties. Glob Cardiol Sci Pract 2015; 2015:10. [PMID: 26779498 PMCID: PMC4448074 DOI: 10.5339/gcsp.2015.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/26/2015] [Indexed: 11/03/2022] Open
Abstract
The heart is subject to multiple sources of stress. To maintain its normal function, and successfully overcome these stresses, heart muscle is equipped with fine-tuned regulatory mechanisms. Some of these mechanisms are inherent within the myocardium itself and are known as intrinsic mechanisms. Over a century ago, Otto Frank and Ernest Starling described an intrinsic mechanism by which the heart, even ex vivo, regulates its function on a beat-to-beat basis. According to this phenomenon, the higher the ventricular filling is, the bigger the stroke volume. Thus, the Frank-Starling law establishes a direct relationship between the diastolic and systolic function of the heart. To observe this biophysical phenomenon and to investigate it, technologic development has been a pre-requisite to scientific knowledge. It allowed for example to observe, at the cellular level, a Frank-Starling like mechanism and has been termed: Length Dependent Activation (LDA). In this review, we summarize some experimental systems that have been developed and are currently still in use to investigate cardiac biophysical properties from the whole heart down to the single myofibril. As a scientific support, investigation of the Frank-Starling mechanism will be used as a case study.
Collapse
Affiliation(s)
- Younss Ait Mou
- Qatar Cardiovascular Research Center, Qatar Foundation, Doha, Qatar
| | | | - Olivier Cazorla
- U1046 INSERM - UMR9214 CNRS- Université de Montpellier, Montpellier, France
| | - Yacoub Magdi
- Qatar Cardiovascular Research Center, Qatar Foundation, Doha, Qatar
| | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Heath Science Division, Loyola University Chicago, Maywood, Illinois 60153
| |
Collapse
|
31
|
Impact of tropomyosin isoform composition on fast skeletal muscle thin filament regulation and force development. J Muscle Res Cell Motil 2014; 36:11-23. [PMID: 25380572 DOI: 10.1007/s10974-014-9394-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/17/2014] [Indexed: 01/05/2023]
Abstract
Tropomyosin (Tm) plays a central role in the regulation of muscle contraction and is present in three main isoforms in skeletal and cardiac muscles. In the present work we studied the functional role of α- and βTm on force development by modifying the isoform composition of rabbit psoas skeletal muscle myofibrils and of regulated thin filaments for in vitro motility measurements. Skeletal myofibril regulatory proteins were extracted (78%) and replaced (98%) with Tm isoforms as homogenous ααTm or ββTm dimers and the functional effects were measured. Maximal Ca(2+) activated force was the same in ααTm versus ββTm myofibrils, but ββTm myofibrils showed a marked slowing of relaxation and an impairment of regulation under resting conditions compared to ααTm and controls. ββTm myofibrils also showed a significantly shorter slack sarcomere length and a marked increase in resting tension. Both these mechanical features were almost completely abolished by 10 mM 2,3-butanedione 2-monoxime, suggesting the presence of a significant degree of Ca(2+)-independent cross-bridge formation in ββTm myofibrils. Finally, in motility assay experiments in the absence of Ca(2+) (pCa 9.0), complete regulation of thin filaments required greater ββTm versus ααTm concentrations, while at full activation (pCa 5.0) no effect was observed on maximal thin filament motility speed. We infer from these observations that high contents of ββTm in skeletal muscle result in partial Ca(2+)-independent activation of thin filaments at rest, and longer-lasting and less complete tension relaxation following Ca(2+) removal.
Collapse
|
32
|
Greiser M, Kerfant BG, Williams GS, Voigt N, Harks E, Dibb KM, Giese A, Meszaros J, Verheule S, Ravens U, Allessie MA, Gammie JS, van der Velden J, Lederer WJ, Dobrev D, Schotten U. Tachycardia-induced silencing of subcellular Ca2+ signaling in atrial myocytes. J Clin Invest 2014; 124:4759-72. [PMID: 25329692 PMCID: PMC4347234 DOI: 10.1172/jci70102] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 08/28/2014] [Indexed: 01/06/2023] Open
Abstract
Atrial fibrillation (AF) is characterized by sustained high atrial activation rates and arrhythmogenic cellular Ca2+ signaling instability; however, it is not clear how a high atrial rate and Ca2+ instability may be related. Here, we characterized subcellular Ca2+ signaling after 5 days of high atrial rates in a rabbit model. While some changes were similar to those in persistent AF, we identified a distinct pattern of stabilized subcellular Ca2+ signaling. Ca2+ sparks, arrhythmogenic Ca2+ waves, sarcoplasmic reticulum (SR) Ca2+ leak, and SR Ca2+ content were largely unaltered. Based on computational analysis, these findings were consistent with a higher Ca2+ leak due to PKA-dependent phosphorylation of SR Ca2+ channels (RyR2s), fewer RyR2s, and smaller RyR2 clusters in the SR. We determined that less Ca2+ release per [Ca2+]i transient, increased Ca2+ buffering strength, shortened action potentials, and reduced L-type Ca2+ current contribute to a stunning reduction of intracellular Na+ concentration following rapid atrial pacing. In both patients with AF and in our rabbit model, this silencing led to failed propagation of the [Ca2+]i signal to the myocyte center. We conclude that sustained high atrial rates alone silence Ca2+ signaling and do not produce Ca2+ signaling instability, consistent with an adaptive molecular and cellular response to atrial tachycardia.
Collapse
Affiliation(s)
- Maura Greiser
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Benoît-Gilles Kerfant
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - George S.B. Williams
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Niels Voigt
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Erik Harks
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Katharine M. Dibb
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Anne Giese
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Janos Meszaros
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Sander Verheule
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ursula Ravens
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Maurits A. Allessie
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - James S. Gammie
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - W. Jonathan Lederer
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Dobromir Dobrev
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ulrich Schotten
- Department of Physiology, Maastricht University, Maastricht, the Netherlands. Center for Biomedical Engineering and Technology, Laboratory of Molecular Cardiology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA. Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany. Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, Manchester, United Kingdom. Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany. Division of Cardiac Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Laboratory for Physiology, VU University Medical Center, Amsterdam, the Netherlands
| |
Collapse
|
33
|
Reiser PJ, Moravec CS. Sex differences in myosin heavy chain isoforms of human failing and nonfailing atria. Am J Physiol Heart Circ Physiol 2014; 307:H265-72. [DOI: 10.1152/ajpheart.00810.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mammalian hearts express two myosin heavy chain (MHC) isoforms, which drive contractions with different kinetics and power-generating ability. The expression of the isoform that is associated with more rapid contraction kinetics and greater power output, MHC-α, is downregulated, with a concurrent increase in the relative amount of the slower isoform, MHC-β, during the progression to experimentally induced or disease-related heart failure. This change in protein expression has been well studied in right and left ventricles in heart failure models and in humans with failure. Relatively little quantitative data exists regarding MHC isoform expression shifts in human failing atria. We previously reported significant increases in the relative amount of MHC-β in the human failing left atrium. The results of that study suggested that there might be a sex-related difference in the level of MHC-β in the left atrium, but the number of female subjects was insufficient for statistical analysis. The objective of this study was to test whether there is, in fact, a sex-related difference in the level of MHC-β in the right and left atria of humans with cardiomyopathy. The results indicate that significant differences exist in atrial MHC isoform expression between men and women who are in failure. The results also revealed an unexpected twofold greater amount of MHC-β in the nonfailing left atrium of women, compared with men. The observed sex-related differences in MHC isoform expression could impact ventricular diastolic filling during normal daily activities, as well as during physiologically stressful events.
Collapse
Affiliation(s)
- Peter J. Reiser
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, Ohio; and
| | | |
Collapse
|
34
|
Witjas-Paalberends ER, Ferrara C, Scellini B, Piroddi N, Montag J, Tesi C, Stienen GJM, Michels M, Ho CY, Kraft T, Poggesi C, van der Velden J. Faster cross-bridge detachment and increased tension cost in human hypertrophic cardiomyopathy with the R403Q MYH7 mutation. J Physiol 2014; 592:3257-72. [PMID: 24928957 DOI: 10.1113/jphysiol.2014.274571] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The first mutation associated with hypertrophic cardiomyopathy (HCM) is the R403Q mutation in the gene encoding β-myosin heavy chain (β-MyHC). R403Q locates in the globular head of myosin (S1), responsible for interaction with actin, and thus motor function of myosin. Increased cross-bridge relaxation kinetics caused by the R403Q mutation might underlie increased energetic cost of tension generation; however, direct evidence is absent. Here we studied to what extent cross-bridge kinetics and energetics are related in single cardiac myofibrils and multicellular cardiac muscle strips of three HCM patients with the R403Q mutation and nine sarcomere mutation-negative HCM patients (HCMsmn). Expression of R403Q was on average 41 ± 4% of total MYH7 mRNA. Cross-bridge slow relaxation kinetics in single R403Q myofibrils was significantly higher (P < 0.0001) than in HCMsmn myofibrils (0.47 ± 0.02 and 0.30 ± 0.02 s(-1), respectively). Moreover, compared to HCMsmn, tension cost was significantly higher in the muscle strips of the three R403Q patients (2.93 ± 0.25 and 1.78 ± 0.10 μmol l(-1) s(-1) kN(-1) m(-2), respectively) which showed a positive linear correlation with relaxation kinetics in the corresponding myofibril preparations. This correlation suggests that faster cross-bridge relaxation kinetics results in an increase in energetic cost of tension generation in human HCM with the R403Q mutation compared to HCMsmn. Therefore, increased tension cost might contribute to HCM disease in patients carrying the R403Q mutation.
Collapse
Affiliation(s)
| | - Claudia Ferrara
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Ger J M Stienen
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands
| | - Michelle Michels
- Thorax Centre, Cardiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, USA
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| |
Collapse
|
35
|
Stillitano F, Lonardo G, Giunti G, Del Lungo M, Coppini R, Spinelli V, Sartiani L, Poggesi C, Mugelli A, Cerbai E. Chronic atrial fibrillation alters the functional properties of If in the human atrium. J Cardiovasc Electrophysiol 2013; 24:1391-400. [PMID: 23869794 DOI: 10.1111/jce.12212] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 05/24/2013] [Accepted: 05/29/2013] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Despite the evidence that the hyperpolarization-activated current (If) is highly modulated in human cardiomyopathies, no definite data exist in chronic atrial fibrillation (cAF). We investigated the expression, function, and modulation of If in human cAF. METHODS AND RESULTS Right atrial samples were obtained from sinus rhythm (SR, n = 49) or cAF (duration >1 year, n = 31) patients undergoing corrective cardiac surgery. Among f-channel isoforms expressed in the human atrium (HCN1, 2 and 4), HCN4 mRNA levels measured by RT-PCR were significantly reduced. However, protein expression was preserved in cAF compared to SR (+85% for HCN4); concurrently, miR-1 expression was significantly reduced. In patch-clamped atrial myocytes, current-specific conductance (gf) was significantly increased in cAF at voltages around the threshold for If activation (-60 to -80 mV); accordingly, a 10-mV rightward shift of the activation curve occurred (P < 0.01). β-Adrenergic and 5-HT4 receptor stimulation exerted similar effects on If in cAF and SR cells, while the ANP-mediated effect was significantly reduced (P < 0.02), suggesting downregulation of natriuretic peptide signaling. CONCLUSIONS In human cAF modifications in transcriptional and posttranscriptional mechanisms of HCN channels occur, associated with a slight yet significant gain-of-function of If , which may contribute to enhanced atrial ectopy.
Collapse
Affiliation(s)
- Francesca Stillitano
- Center for Molecular Medicine (C.I.M.M.B.A.), Department NEUROFARBA, University of Firenze, Florence, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Greiser M, Schotten U. Dynamic remodeling of intracellular Ca2+ signaling during atrial fibrillation. J Mol Cell Cardiol 2013; 58:134-42. [DOI: 10.1016/j.yjmcc.2012.12.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/14/2012] [Accepted: 12/17/2012] [Indexed: 12/23/2022]
|
37
|
Roosimaa M, Põdramägi T, Kadaja L, Ruusalepp A, Paju K, Puhke R, Eimre M, Orlova E, Piirsoo A, Peet N, Gellerich FN, Seppet E. Dilation of human atria: increased diffusion restrictions for ADP, overexpression of hexokinase 2 and its coupling to oxidative phosphorylation in cardiomyocytes. Mitochondrion 2012; 13:399-409. [PMID: 23268198 DOI: 10.1016/j.mito.2012.12.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 12/13/2012] [Accepted: 12/17/2012] [Indexed: 12/14/2022]
Abstract
Cardiac energy metabolism with emphasis on mitochondria was addressed in atrial tissue from patients with overload-induced atrial dilation. Structural remodeling of dilated (D) atria manifested as intracellular accumulation of fibrillar aggregates, lipofuscin, signs of myolysis and autophagy. Despite impaired complex I dependent respiration and increased diffusion restriction for ADP, no changes regarding adenylate and creatine kinase occurred. We observed 7-fold overexpression of HK2 gene in D atria with concomitant 2-fold greater activation of mitochondrial oxygen consumption by glucose, which might represent an adaption to increased energy requirements and impaired mitochondrial function by effectively joining glycolysis and oxidative phosphorylation.
Collapse
Affiliation(s)
- Mart Roosimaa
- Institute of Biomedicine, Faculty of Medicine, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Circulation Research
Thematic Synopsis. Circ Res 2012. [DOI: 10.1161/circresaha.112.280024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
39
|
Grandi E, Workman AJ, Pandit SV. Altered Excitation-Contraction Coupling in Human Chronic Atrial Fibrillation. J Atr Fibrillation 2012; 4:495. [PMID: 28496736 DOI: 10.4022/jafib.495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 02/10/2012] [Accepted: 03/19/2012] [Indexed: 12/19/2022]
Abstract
This review focuses on the (mal)adaptive processes in atrial excitation-contraction coupling occurring in patients with chronic atrial fibrillation. Cellular remodeling includes shortening of the atrial action potential duration and effective refractory period, depressed intracellular Ca2+ transient, and reduced myocyte contractility. Here we summarize the current knowledge of the ionic bases underlying these changes. Understanding the molecular mechanisms of excitation-contraction-coupling remodeling in the fibrillating human atria is important to identify new potential targets for AF therapy.
Collapse
Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Antony J Workman
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Sandeep V Pandit
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
40
|
Voigt N, Li N, Wang Q, Wang W, Trafford AW, Abu-Taha I, Sun Q, Wieland T, Ravens U, Nattel S, Wehrens XHT, Dobrev D. Enhanced sarcoplasmic reticulum Ca2+ leak and increased Na+-Ca2+ exchanger function underlie delayed afterdepolarizations in patients with chronic atrial fibrillation. Circulation 2012; 125:2059-70. [PMID: 22456474 DOI: 10.1161/circulationaha.111.067306] [Citation(s) in RCA: 468] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Delayed afterdepolarizations (DADs) carried by Na(+)-Ca(2+)-exchange current (I(NCX)) in response to sarcoplasmic reticulum (SR) Ca(2+) leak can promote atrial fibrillation (AF). The mechanisms leading to delayed afterdepolarizations in AF patients have not been defined. METHODS AND RESULTS Protein levels (Western blot), membrane currents and action potentials (patch clamp), and [Ca(2+)](i) (Fluo-3) were measured in right atrial samples from 76 sinus rhythm (control) and 72 chronic AF (cAF) patients. Diastolic [Ca(2+)](i) and SR Ca(2+) content (integrated I(NCX) during caffeine-induced Ca(2+) transient) were unchanged, whereas diastolic SR Ca(2+) leak, estimated by blocking ryanodine receptors (RyR2) with tetracaine, was ≈50% higher in cAF versus control. Single-channel recordings from atrial RyR2 reconstituted into lipid bilayers revealed enhanced open probability in cAF samples, providing a molecular basis for increased SR Ca(2+) leak. Calmodulin expression (60%), Ca(2+)/calmodulin-dependent protein kinase-II (CaMKII) autophosphorylation at Thr287 (87%), and RyR2 phosphorylation at Ser2808 (protein kinase A/CaMKII site, 236%) and Ser2814 (CaMKII site, 77%) were increased in cAF. The selective CaMKII blocker KN-93 decreased SR Ca(2+) leak, the frequency of spontaneous Ca(2+) release events, and RyR2 open probability in cAF, whereas protein kinase A inhibition with H-89 was ineffective. Knock-in mice with constitutively phosphorylated RyR2 at Ser2814 showed a higher incidence of Ca(2+) sparks and increased susceptibility to pacing-induced AF compared with controls. The relationship between [Ca(2+)](i) and I(NCX) density revealed I(NCX) upregulation in cAF. Spontaneous Ca(2+) release events accompanied by inward I(NCX) currents and delayed afterdepolarizations/triggered activity occurred more often and the sensitivity of resting membrane voltage to elevated [Ca(2+)](i) (diastolic [Ca(2+)](i)-voltage coupling gain) was higher in cAF compared with control. CONCLUSIONS Enhanced SR Ca(2+) leak through CaMKII-hyperphosphorylated RyR2, in combination with larger I(NCX) for a given SR Ca(2+) release and increased diastolic [Ca(2+)](i)-voltage coupling gain, causes AF-promoting atrial delayed afterdepolarizations/triggered activity in cAF patients.
Collapse
Affiliation(s)
- Niels Voigt
- Division of Experimental Cardiology, Medical Faculty Mannheim, University of Heidelberg, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Schotten U, Verheule S, Kirchhof P, Goette A. Pathophysiological mechanisms of atrial fibrillation: a translational appraisal. Physiol Rev 2011; 91:265-325. [PMID: 21248168 DOI: 10.1152/physrev.00031.2009] [Citation(s) in RCA: 863] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that can occur as the result of numerous different pathophysiological processes in the atria. Some aspects of the morphological and electrophysiological alterations promoting AF have been studied extensively in animal models. Atrial tachycardia or AF itself shortens atrial refractoriness and causes loss of atrial contractility. Aging, neurohumoral activation, and chronic atrial stretch due to structural heart disease activate a variety of signaling pathways leading to histological changes in the atria including myocyte hypertrophy, fibroblast proliferation, and complex alterations of the extracellular matrix including tissue fibrosis. These changes in electrical, contractile, and structural properties of the atria have been called "atrial remodeling." The resulting electrophysiological substrate is characterized by shortening of atrial refractoriness and reentrant wavelength or by local conduction heterogeneities caused by disruption of electrical interconnections between muscle bundles. Under these conditions, ectopic activity originating from the pulmonary veins or other sites is more likely to occur and to trigger longer episodes of AF. Many of these alterations also occur in patients with or at risk for AF, although the direct demonstration of these mechanisms is sometimes challenging. The diversity of etiological factors and electrophysiological mechanisms promoting AF in humans hampers the development of more effective therapy of AF. This review aims to give a translational overview on the biological basis of atrial remodeling and the proarrhythmic mechanisms involved in the fibrillation process. We pay attention to translation of pathophysiological insights gained from in vitro experiments and animal models to patients. Also, suggestions for future research objectives and therapeutical implications are discussed.
Collapse
Affiliation(s)
- Ulrich Schotten
- Department of Physiology, University Maastricht, Maastricht, The Netherlands.
| | | | | | | |
Collapse
|
42
|
Miragoli M, Moshkov A, Novak P, Shevchuk A, Nikolaev VO, El-Hamamsy I, Potter CMF, Wright P, Kadir SHSA, Lyon AR, Mitchell JA, Chester AH, Klenerman D, Lab MJ, Korchev YE, Harding SE, Gorelik J. Scanning ion conductance microscopy: a convergent high-resolution technology for multi-parametric analysis of living cardiovascular cells. J R Soc Interface 2011; 8:913-25. [PMID: 21325316 PMCID: PMC3104336 DOI: 10.1098/rsif.2010.0597] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular diseases are complex pathologies that include alterations of various cell functions at the levels of intact tissue, single cells and subcellular signalling compartments. Conventional techniques to study these processes are extremely divergent and rely on a combination of individual methods, which usually provide spatially and temporally limited information on single parameters of interest. This review describes scanning ion conductance microscopy (SICM) as a novel versatile technique capable of simultaneously reporting various structural and functional parameters at nanometre resolution in living cardiovascular cells at the level of the whole tissue, single cells and at the subcellular level, to investigate the mechanisms of cardiovascular disease. SICM is a multimodal imaging technology that allows concurrent and dynamic analysis of membrane morphology and various functional parameters (cell volume, membrane potentials, cellular contraction, single ion-channel currents and some parameters of intracellular signalling) in intact living cardiovascular cells and tissues with nanometre resolution at different levels of organization (tissue, cellular and subcellular levels). Using this technique, we showed that at the tissue level, cell orientation in the inner and outer aortic arch distinguishes atheroprone and atheroprotected regions. At the cellular level, heart failure leads to a pronounced loss of T-tubules in cardiac myocytes accompanied by a reduction in Z-groove ratio. We also demonstrated the capability of SICM to measure the entire cell volume as an index of cellular hypertrophy. This method can be further combined with fluorescence to simultaneously measure cardiomyocyte contraction and intracellular calcium transients or to map subcellular localization of membrane receptors coupled to cyclic adenosine monophosphate production. The SICM pipette can be used for patch-clamp recordings of membrane potential and single channel currents. In conclusion, SICM provides a highly informative multimodal imaging platform for functional analysis of the mechanisms of cardiovascular diseases, which should facilitate identification of novel therapeutic strategies.
Collapse
Affiliation(s)
- Michele Miragoli
- Cardiovascular Science, National Heart and Lung Institute, Imperial College London, , Dovehouse Street, London SW36LY, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Greiser M, Lederer WJ, Schotten U. Alterations of atrial Ca(2+) handling as cause and consequence of atrial fibrillation. Cardiovasc Res 2010; 89:722-33. [PMID: 21159669 DOI: 10.1093/cvr/cvq389] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Atrial fibrillation (AF) is the most prevalent sustained arrhythmia. As the most important risk factor for embolic stroke, AF is associated with a high morbidity and mortality. Despite decades of research, successful (pharmacological and interventional) 'ablation' of the arrhythmia remains challenging. AF is characterized by a diverse aetiology, including heart failure, hypertension, and valvular disease. Based on this understanding, new treatment strategies that are specifically tailored to the underlying pathophysiology of a certain 'type' of AF are being developed. One important aspect of AF pathophysiology is altered intracellular Ca(2+) handling. Due to the increase in the atrial activation rate and the subsequent initial [Ca(2+)](i) overload, AF induces 'remodelling' of intracellular Ca(2+) handling. Current research focuses on unravelling the contribution of altered intracellular Ca(2+) handling to different types of AF. More specifically, changes in intracellular Ca(2+) homeostasis preceding the onset of AF, in conditions which predispose to AF (e.g. heart failure), appear to be different from changes in Ca(2+) handling developing after the onset of AF. Here we review and critique altered intracellular Ca(2+) handling and its contribution to three specific aspects of AF pathophysiology, (i) excitation-transcription coupling and Ca(2+)-dependent signalling pathways, (ii) atrial contractile dysfunction, and (iii) arrhythmogenicity.
Collapse
Affiliation(s)
- Maura Greiser
- Department of Physiology, Maastricht University, Maastricht, The Netherlands
| | | | | |
Collapse
|