BACKGROUND: Cardiac remodeling, a pathological process induced by hypertension and related cardiovascular diseases, is characterized by cardiomyocyte apoptosis and hypertrophy. However, current treatments targeting hemodynamic load fail to reverse established remodeling. While Qihuang Zhuyu Formula (QHZYF) has demonstrated cardiovascular benefits, its direct role in counteracting these cellular features of remodeling remains unclear. The ubiquitin-mediated degradation of p53 is a promising therapeutic target, given its pivotal role in regulating apoptosis and hypertrophy. Notably, Bmal1 is a key upstream regulator of p53 ubiquitination. Therefore, targeting the Bmal1-p53 degradation axis offers a novel therapeutic approach to alleviate cardiomyocyte apoptosis and hypertrophy.
AIM OF THE STUDY: This study aims to validate whether QHZYF mitigates cardiomyocyte apoptosis and hypertrophy by modulating Bmal1-mediated p53 ubiquitination, thereby paving the way for integrating traditional Chinese medicine with Western therapies.
METHODS: The chemical composition of QHZYF was analyzed using UPLC-Q/TOF-MS. Network pharmacology identified TP53 as the primary target in cardiac remodeling. In vivo, abdominal aortic constriction-induced cardiac remodeling rats were treated with QHZYF. Cardiac structure, fibrosis, cardiomyocyte apoptosis), and hypertrophy were quantitatively assessed. In vitro, angiotensin II-stimulated cardiomyocytes were treated with QHZYF to assess oxidative stress markers, apoptosis, hypertrophy, and the expression of related proteins and mRNAs. Co-immunoprecipitation confirmed direct Bmal1-p53 binding, and ubiquitination assays clarified the role of QHZYF in modulating Bmal1-mediated p53 ubiquitination.
RESULTS: Network pharmacology identified TP53 as the central target of QHZYF in cardiac remodeling. In vivo, QHZYF significantly reduced cardiomyocyte apoptosis and hypertrophy, with a concomitant reduction in fibrosis. In vitro, QHZYF inhibited angiotensin II-induced apoptosis and hypertrophy by modulating the Bmal1-p53 pathway. Co-immunoprecipitation confirmed direct interaction between Bmal1 and p53, and ubiquitination assays showed that QHZYF counteracted angiotensin II-mediated suppression of p53 ubiquitination. This effect was abrogated by Bmal1 knockdown and rescued by Mdm2 overexpression, conclusively demonstrating that QHZYF regulates Bmal1-mediated p53 ubiquitination to mitigate pathological remodeling.
CONCLUSION: QHZYF mitigates cardiomyocyte apoptosis and hypertrophy by regulating Bmal1-mediated p53 ubiquitination and degradation, providing a mechanistic basis for its role in attenuating cardiac remodeling.
