Anemoside B4 ameliorates septic cardiomyopathy by activating SRC-mediated PI3K/AKT/mTOR pathway to alleviate mitochondrial dysfunction and cardiomyocyte senescence.

Abstract

OBJECTIVE: This study explored the protective effects of Anemoside B4 (AB4) against septic cardiomyopathy (SCM) and investigated the underlying mechanisms involving mitochondrial dysfunction and cellular senescence. METHODS: LPS-induced and cecal ligation and puncture (CLP)-induced SCM models were established in C57BL/6 mice, with LPS-stimulated H9c2 cardiomyocytes used for in vitro validation. AB4 was administered in graded doses, and the SRC-specific inhibitor PP2 was used in rescue experiments. AB4's effects were assessed using echocardiography, histopathology, Western blotting, RT-qPCR, and molecular docking to evaluate AB4-SRC binding. RESULTS: AB4 exhibited dose-dependent protection in both LPS- and CLP-induced SCM models, enhancing cardiac function and mitigating myocardial damage. High-dose AB4 (AB4-H) demonstrated the most pronounced enhancements, reinstating myocardial integrity and diminishing inflammation, as indicated by echocardiogram and HE staining. AB4 directly interacted with SRC in both in vivo and in vitro settings, activating the PI3K/AKT/mTOR pathway, which reinstated mitochondrial function by diminishing mitochondrial reactive oxygen species (ROS) levels, augmenting ATP generation, and increasing mitochondrial morphology. AB4 also suppressed cardiomyocyte senescence, as indicated by diminished senescence markers and factors associated with the senescence-associated secretory phenotype (SASP). Significantly, PP2, a selective SRC inhibitor, nullified AB4's protective effects, thereby indicating that AB4 operates through the SRC-mediated PI3K/AKT/mTOR pathway. CONCLUSIONS: AB4 was a promising therapeutic candidate for SCM, with its protective effects mediated through the SRC-mediated PI3K/AKT/mTOR pathway, which in turn enhanced mitochondrial function and inhibited cardiomyocyte senescence. These findings highlighted the potential of targeting this pathway in treating sepsis-induced cardiac injury.