Xin-Fu-Kang oral liquid mitigates chronic heart failure through NR4A1-Dependent regulation of endoplasmic reticulum-mitochondrial crosstalk in Cardiomyocytes.

Background: Chronic heart failure (CHF) is the terminus of a variety of cardiovascular diseases. Xin-Fu-Kang oral liquid (XFK), a natural herbal compound, has been used in CHF treatment for decades. However, further investigation is required to elucidate the fundamental mechanisms.

Study Design And Methods: Transverse aortic constriction (TAC) was performed in mouse models. The pharmacological efficacy of XFK was confirmed by assessing cardiac function and the observation of pathological alterations in myocardial tissue. Following this, single-cell sequencing (scRNA-seq) was implemented. With the identification of XFK metabolites in rat serum via UPLC-QE MS, molecular docking was utilized to conduct preliminary validation of putative therapeutic targets. Subsequently, the phenylephrine-induced model of cardiac pressure overload was established for conducting additional verification and rescue experiments by silencing NR4A1 in vitro.

Results: XFK intervention significantly ameliorated cardiac function in the TAC-induced CHF model. Based on scRNA-seq, cardiomyocytes exhibited the most notable alterations following XFK intervention, with NR4A1 identified as a significantly differentially expressed gene after both TAC induction and XFK intervention. In vitro experiments demonstrated that XFK enhanced mitochondrial function, mitigated oxidative stress, and restored mitophagy in a NR4A1-dependent manner, consequently decreasing apoptosis in PE-induced H9C2. Furthermore, the upstream mechanism was associated with capacity of XFK to mitigate endoplasmic reticulum stress and regulate crosstalk between the two organelles.

Conclusion: XFK counteracts cardiac chronic pressure overload through regulating NR4A1-mediated functional interaction between endoplasmic reticulum and mitochondria in cardiomyocytes, further preserves mitochondria function and prevents apoptosis. This finding indicates a novel pharmacological therapy for CHF.