Increased Expression of N2BA Titin Corresponds to More Compliant Myofibrils in Athlete's Heart
| Autor: | Tamás Radovits, Dalma Kellermayer, Attila Oláh, Bálint Kiss, Miklós S.Z. Kellermayer, Béla Merkely, Henk Granzier, Hedvig Tordai |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Sarcomere Myofibrils transverse stiffness Protein Isoforms Connectin Cardiomegaly Exercise-Induced Biology (General) Spectroscopy biology Cardiac muscle Heart General Medicine musculoskeletal system Adaptation Physiological Computer Science Applications Cardiac myofibril Chemistry medicine.anatomical_structure Cardiology cardiovascular system cardiac myofibril Titin AFM Gene isoform Sarcomeres medicine.medical_specialty animal structures QH301-705.5 Athlete's heart macromolecular substances Catalysis Article Inorganic Chemistry Internal medicine Elastic Modulus Physical Conditioning Animal medicine Animals titin Physical and Theoretical Chemistry Rats Wistar QD1-999 Molecular Biology business.industry Myocardium Organic Chemistry Myocardial Contraction Rats Disease Models Animal Ventricle biology.protein Myofibril business athlete’s heart |
| Zdroj: | International Journal of Molecular Sciences Volume 22 Issue 20 International Journal of Molecular Sciences, Vol 22, Iss 11110, p 11110 (2021) |
| ISSN: | 1422-0067 |
| Popis: | Long-term exercise induces physiological cardiac adaptation, a condition referred to as athlete’s heart. Exercise tolerance is known to be associated with decreased cardiac passive stiffness. Passive stiffness of the heart muscle is determined by the giant elastic protein titin. The adult cardiac muscle contains two titin isoforms: the more compliant N2BA and the stiffer N2B. Titin-based passive stiffness may be controlled by altering the expression of the different isoforms or via post-translational modifications such as phosphorylation. Currently, there is very limited knowledge about titin’s role in cardiac adaptation during long-term exercise. Our aim was to determine the N2BA/N2B ratio and post-translational phosphorylation of titin in the left ventricle and to correlate the changes with the structure and transverse stiffness of cardiac sarcomeres in a rat model of an athlete’s heart. The athlete’s heart was induced by a 12-week-long swim-based training. In the exercised myocardium the N2BA/N2B ratio was significantly increased, Ser11878 of the PEVK domain was hypophosphorlyated, and the sarcomeric transverse elastic modulus was reduced. Thus, the reduced passive stiffness in the athlete’s heart is likely caused by a shift towards the expression of the longer cardiac titin isoform and a phosphorylation-induced softening of the PEVK domain which is manifested in a mechanical rearrangement locally, within the cardiac sarcomere. |
| Databáze: | OpenAIRE |
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