Hofhuis, Julia and Bersch, Kristina and Wagner, Stefan and Molina, Cristina and Fakuade, Funsho E. and Iyer, Lavanya M. and Streckfuss-Boemeke, Katrin and Toischer, Karl and Zelarayan, Laura C. and Voigt, Niels and Nikolaev, Viacheslav O. and Maier, Lars S. and Klinge, Lars and Thoms, Sven (2020) Dysferlin links excitation-contraction coupling to structure and maintenance of the cardiac transverse-axial tubule system. EUROPACE, 22 (7). pp. 1119-1131. ISSN 1099-5129, 1532-2092
Full text not available from this repository. (Request a copy)Abstract
Aims The multi-C2 domain protein dysferlin localizes to the T-Tubule system of skeletal and heart muscles. In skeletal muscle, dysferlin is known to play a role in membrane repair and in T-tubule biogenesis and maintenance. Dysferlin deficiency manifests as muscular dystrophy of proximal and distal muscles. Cardiomyopathies have been also reported, and some dysferlinopathy mouse models develop cardiac dysfunction under stress. Generally, the role and functional relevance of dysferlin in the heart is not clear. The aim of this study was to analyse the effect of dysferlin deficiency on the transverse-axial tubule system (TATS) structure and on Ca2+ homeostasis in the heart. Methods and results We studied dysferlin localization in rat and mouse cardiomyocytes by immunofluorescence microscopy. In dysferlin-deficient ventricular mouse cardiomyocytes, we analysed the TATS by live staining and assessed Ca2+ handling by patch-clamp experiments and measurement of Ca2+ transients and Ca2+ sparks. We found increasing co-localization of dysferlin with the L-type Ca2+-channel during TATS development and show that dysferlin deficiency leads to pathological loss of transversal and increase in longitudinal elements (axialization). We detected reduced L-type Ca2+-current (I-Ca,I-L) in cardiomyocytes from dysferlin-deficient mice and increased frequency of spontaneous sarcoplasmic reticulum Ca2+ release events resulting in pro-arrhythmic contractions. Moreover, cardiomyocytes from dysferlin-deficient mice showed an impaired response to beta-adrenergic receptor stimulation. Conclusions Dysferlin is required for TATS biogenesis and maintenance in the heart by controlling the ratio of transversal and axial membrane elements. Absence of dysferlin leads to defects in Ca2+ homeostasis which may contribute to contractile heart dysfunction in dysferlinopathy patients.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MEMBRANE REPAIR; HEART; Dysferlin; Excitation-contraction coupling; Transverse-axial tubule system; Calcium transients; Muscular dystrophy |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Innere Medizin II |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 19 Mar 2021 07:34 |
| Last Modified: | 19 Mar 2021 07:34 |
| URI: | https://pred.uni-regensburg.de/id/eprint/44256 |
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