Western Diet-Induced Impairment of Left Atrium Cardiomyocyte Contractility in Female Wistar Rats Is Associated with Slowdown in the Cross-Bridge Cycle and Dephosphorylation of cMyBP-C

Western Diet-Induced Impairment of Left Atrium Cardiomyocyte Contractility in Female Wistar Rats Is Associated with Slowdown in the Cross-Bridge Cycle and Dephosphorylation of cMyBP-C Full article

Journal

International Journal of Molecular Sciences
ISSN: 1422-0067 , E-ISSN: 1661-6596

Output data

Year: 2026, Volume: 27, Number: 3, Article number : 1508, Pages count : DOI: 10.3390/ijms27031508

Tags

Western diet; obesity; left and right atria; echocardiography; single cardiomyocyte mechanics; calcium transient; actin–myosin interaction; contractile protein phosphorylation

Authors

Mukhlynina Elena ¹ , Butova Xenia ² , Myachina Tatiana ¹ , Simonova Raisa ¹ , Antonets Yulia ¹ , Leiberova Anna ¹ , Kochurova Anastasia ¹ , Gusarova Evgeniya ^1,3 , Chumarnaya Tatiana ¹ , Kopylova Galina ¹ , Shchepkin Daniil ¹

Affiliations

1	Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomayskaya Str. 106, 620078 Yekaterinburg, Russia
2	Institute of Biomedical Problems RAS, Khoroshevskoye sh., 76A, 123007 Moscow, Russia
3	Regional Perinatal Center, Vorovskogo Str. 70, 454052 Chelyabinsk, Russia

Obesity is a major risk factor for heart failure and atrial fibrillation. This study investigated the effects of diet-induced obesity on the molecular and cellular mechanisms of cardiomyocyte contractility in the left and right atria (LA and RA). FemaleWistar rats were fed a Western diet (WD) for 18 weeks. Sarcomere dynamics and calcium transients were measured in unloaded cardiomyocytes. Actin–myosin interactions and contractile protein phosphorylation were assessed via an in vitro motility assay and phosphoprotein-specific gel electrophoresis. WD-fed rats developed obesity, hypertension, and metabolic alterations in the absence of echocardiographic or histological evidence of cardiac remodeling or systolic dysfunction. In LA cardiomyocytes, contractile dysfunction was indicated by increased calcium transient amplitude coupled with reduced shortening amplitude and relengthening velocity. This functional impairment correlated with a slowed myosin crossbridge cycle and dephosphorylation of cMyBP-C. In contrast, RA cardiomyocytes displayed only molecular changes in response to obesity, including altered phosphorylation of most sarcomeric proteins and a decelerated cross-bridge cycle, but showed no evident contractile dysfunction. Thus, an 18-week WD reflects the early stages of contractile impairment, where functional deficits are specific to the LA, while RA alterations are confined to the molecular level.

Mukhlynina E. , Butova X. , Myachina T. , Simonova R. , Antonets Y. , Leiberova A. , Kochurova A. , Gusarova E. , Chumarnaya T. , Kopylova G. , Shchepkin D.
Western Diet-Induced Impairment of Left Atrium Cardiomyocyte Contractility in Female Wistar Rats Is Associated with Slowdown in the Cross-Bridge Cycle and Dephosphorylation of cMyBP-C
International Journal of Molecular Sciences. 2026. V.27. N3. 1508 . DOI: 10.3390/ijms27031508 Scopus РИНЦ OpenAlex

Submitted:	Dec 3, 2025
Accepted:	Jan 30, 2026
Published print:	Feb 3, 2026
Published online:	Feb 3, 2026

Scopus:	2-s2.0-105030023059
Elibrary:	89677554
OpenAlex:	W7127352297

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