Apigenin inhibits endothelial-to-mesenchymal transition of coronary artery endothelial cells and myocardial fibrosis by regulating ribosome biogenesis through GTPBP4 modulation.

Myocardial fibrosis is a complex pathological process that often leads to myocardial dysfunction, heart failure, and ultimately, death. A critical contributor to the development of cardiac fibrosis is the endothelial-to-mesenchymal transition (EndMT). Apigenin, a natural compound derived from Matricaria chamomilla, has shown potential anti-fibrotic effects, although its precise mechanism of action is not fully understood. This study investigated the effects of apigenin (API) on EndMT and myocardial fibrosis using an in vitro human coronary artery endothelial cell EndMT model and an in vivo animal model of fibrosis. At appropriate concentrations, apigenin significantly inhibited TGF-β1-induced EndMT and myocardial fibrosis without affecting cell viability. Mechanistically, we found that apigenin suppressed ribosome biogenesis in coronary endothelial cells. Through differential gene screening, GTP-binding protein 4 (GTPBP4) was identified as a key target gene regulating ribosome biogenesis during the progression of myocardial fibrosis. Our results indicate that GTPBP4 plays a pivotal role in the apigenin-mediated inhibition of both ribosome biogenesis and EndMT in these cells. By downregulating GTPBP4 expression, apigenin suppressed EndMT, alleviated myocardial fibrosis, improved cardiac function, and reduced biomarkers of myocardial injury. These findings demonstrate for the first time that apigenin mitigates myocardial fibrosis and EndMT by inhibiting GTPBP4 expression, positioning apigenin as a promising therapeutic candidate for the prevention and treatment of myocardial fibrosis.