Vaspin contributes to autophagy and endothelial-to-mesenchymal transition via PI3K-/AKT-mTOR pathway

Visceral adipose tissue-derived serine protease inhibitor (Vaspin) was found to have anti-inflammatory, anti-apoptosis, and pro-autophagy activities. Our investigation is aimed to ascertain the effect of Vaspin on hypoxia-evoked endothelial-mesenchymal transition (EndMT) in human cardiac microvascular endothelial cells (HCMECs).In vitro assays including CCK8, TUNEL, western blots, RT-qPCR to assess the effect of Vaspin on hypoxia-induced cell injuries, endothelial-mesenchymal transition (EndMT) and the inflammatory state in HCMECs. Transmission electron microscopy (TEM) was used to monitor autophagosome formation in HCMECs. The autophagy related proteins coupled with the critical effectors of PI3K/AKT-mTOR signaling pathway were also detected by western blots. In vivo assays including HE and ELISA to assess the effects of Vaspin on myocardial fibrosis pathology and type I and type III collagen in rats.Vaspin pretreatment dramatically dose-dependently restored the proliferative impairment and the induced EndMT in HCMECs by hypoxia. The Vaspin-pretreated HCMECs also presented with attenuated expression of increased IL-1β, TNF-α and IL-6 by hypoxia a dose-dependent manner. Vaspin alleviated rat MF. The impact of Vaspin is also related to the increased autophagy and activated PI3K/AKT-mTOR signaling pathway. The protective and pro-autophagy activity of Vaspin was antagonized by the PI3K/AKT-mTOR inhibitor LY294002.Vaspin ameliorated the hypoxia-stimulated cell injuries and EndMT by activating autophagy via PI3K/AKT-mTOR signaling pathway.