Resibufogenin promotes angiogenesis via the VAV3-mediated ITGA5-VEGF signaling axis in macrophages to alleviate myocardial infarction.

Abstract

Myocardial infarction (MI) continues to be a leading cause of global mortality. Resibufogenin (RBG), a principal bioactive constituent derived from Venenum Bufonis, is well recognized for its potent cardiotonic properties. Nevertheless, the therapeutic potential of RBG in the context of MI remains to be fully elucidated. This study revealed that RBG exerted significant cardioprotective effects in a murine model of MI by preserving cardiac function, attenuating myocardial injury, and increasing vascular density. Proteomic analysis revealed that angiogenesis was the predominant biological process associated with RBG-responsive proteins. Integrated proteomic analysis and mechanistic validation demonstrated that RBG activated the ITGA5-VEGF signaling axis, a pathway essential for its therapeutic efficacy, in a macrophage-dependent manner. Notably, both pharmacological inhibition of ITGA5 and depletion of macrophages completely abrogated RBG-mediated cardioprotection in the MI model. Furthermore, RBG significantly increased endothelial cell proliferation, migration, and tube formation in a macrophage-endothelial cell coculture system. More importantly, RBG upregulated ITGA5 expression in macrophages through activation of the VAV3/CDC42 signaling pathway. Collectively, these findings demonstrate that RBG is a promising therapeutic agent for myocardial infarction and acts via the macrophage-specific VAV3/CDC42-mediated ITGA5/VEGF signaling pathway to promote reparative angiogenesis. This study elucidates the cardioprotective effects and underlying mechanisms of RBG and establishes a scientific basis for the discovery of novel therapeutic agents from natural products.