Amphiregulin promotes cardiac fibrosis post myocardial infarction by inducing the endothelial-mesenchymal transition via the EGFR pathway in endothelial cells

The endothelial-mesenchymal transition (EndMT) plays a key role in the development of cardiac fibrosis (CF) after acute myocardial infarction (AMI). The results of our previous study showed that amphiregulin (AR) ex- pression was enhanced after MI. However, the role of AR on EndMT post MI remains unknown. This study aimed to elucidate the impact of AR on EndMT post MI and the associated molecular mechanisms. AR expression was markedly enhanced in infarct border area post MI, and endothelial cells were one of the primary cell sources of AR secretion. Stimulation with AR promoted endothelial cell proliferation, invasion, migration, collagen synthesis and EndMT. In addition, EGFR and downstream gene expression was significantly enhanced. In vivo, EndMT was significantly inhibited after lentivirus-AR-shRNA was delivered to the myocardium post MI. In addition, silencing AR ameliorated cardiac function by decreasing the extent of CF. Furthermore, the levels of EGFR pathway components in endothelial cells extracted from infarct border myocardium were all significantly decreased in lentivirus-AR-shRNA-treated MI mice. Our results demonstrate that AR induces CF post MI by enhancing EndMT in endothelial cells. Thus, targeting the regulation of AR may provide a potentially novel therapeutic option for CF after MI.