NYMC Faculty Publications
Phosphorylation of Cardiac Sodium Channel at Ser571 Anticipates Manifestations of the Aging Myopathy
Author Type(s)
Faculty
DOI
10.1152/ajpheart.00325.2023
Journal Title
American Journal of Physiology. Heart and Circulatory Physiology
First Page
H1424
Last Page
H1445
Document Type
Article
Publication Date
6-1-2024
Department
Physiology
Second Department
Medicine
Third Department
Pathology, Microbiology and Immunology
Abstract
Diastolic dysfunction and delayed ventricular repolarization are typically observed in the elderly, but whether these defects are intimately associated with the progressive manifestation of the aging myopathy remains to be determined. In this regard, aging in experimental animals is coupled with increased late Na current () in cardiomyocytes, raising the possibility that conditions the modality of electrical recovery and myocardial relaxation of the aged heart. For this purpose, aging male and female wild-type (WT) C57Bl/6 mice were studied together with genetically engineered mice with phosphomimetic (gain of function, GoF) or ablated (loss of function, LoF) mutations of the sodium channel Nav1.5 at Ser571 associated with, respectively, increased and stabilized . At ∼18 mo of age, WT mice developed prolonged duration of the QT interval of the electrocardiogram and impaired diastolic left ventricular (LV) filling, defects that were reversed by inhibition. Prolonged repolarization and impaired LV filling occurred prematurely in adult (∼5 mo) GoF mutant mice, whereas these alterations were largely attenuated in aging LoF mutant animals. Ca transient decay and kinetics of myocyte shortening/relengthening were delayed in aged (∼24 mo) WT myocytes, with respect to adult cells. In contrast, delayed Ca transients and contractile dynamics occurred at adult stage in GoF myocytes and further deteriorated in old age. Conversely, myocyte mechanics were minimally affected in aging LoF cells. Collectively, these results document that Nav1.5 phosphorylation at Ser571 and the late Na current modulate the modality of myocyte relaxation, constituting the mechanism linking delayed ventricular repolarization and diastolic dysfunction. We have investigated the impact of the late Na current () on cardiac and myocyte function with aging by using genetically engineered animals with enhanced or stabilized , due to phosphomimetic or phosphoablated mutations of Nav1.5. Our findings support the notion that phosphorylation of Nav1.5 at Ser571 prolongs myocardial repolarization and impairs diastolic function, contributing to the manifestations of the aging myopathy.
Recommended Citation
Pizzo, E., Cervantes, D. O., Ketkar, H., Ripa, V., Nassal, D. M., Buck, B., Parambath, S. P., Di Stefano, V., Singh, K., Thompson, C. I., Mohler, P. J., Hund, T. J., Jacobson, J. T., Jain, S., & Rota, M. (2024). Phosphorylation of Cardiac Sodium Channel at Ser571 Anticipates Manifestations of the Aging Myopathy. American Journal of Physiology. Heart and Circulatory Physiology, 326 (6), H1424-H1445. https://doi.org/10.1152/ajpheart.00325.2023