Astragaloside IV inhibits epithelial-mesenchymal transition and pulmonary fibrosis via lncRNA-ATB/miR-200c/ZEB1 signaling pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease involving multiple factors and genes. Astragaloside IV (ASV) is one of the main bioactive ingredients extracted from the root of Astragalus membranaceus, which plays an important role in anti-inflammatory, antioxidant and improve cardiopulmonary function. Epithelial-mesenchymal transition (EMT) is a key driver of the process of pulmonary fibrosis, and Zinc finger E-box-binding homeobox 1 (ZEB1) can promote pulmonary fibrosis in an EMT-dependent manner. Here, we found that ASV effectively inhibited the ZEB1 and EMT in both bleomycin (BLM)-induced rat pulmonary fibrosis and TGF-β1-treated A549 cells. To further elucidate the molecular mechanisms underlying effects of ASV in IPF, we explored the truth using bioinformatics, plasmid construction, immunofluorescence staining, western blotting and other experiments. Dual luciferase reporter assay and bioinformatics proved that miR-200c not only acts as an upstream regulatory miRNA of ZEB1 but also has binding sites for the lncRNA-ATB. In A549 cell-based EMT models, ASV reduced the expression of lncRNA-ATB and upregulated miR-200c. Furthermore, overexpression of lncRNA-ATB and silencing of miR-200c reversed the down-regulation of ZEB1 and the inhibition of EMT processes by ASV. In addition, the intervention of ASV prevented lncRNA-ATB as a ceRNA from regulating the expression of ZEB1 through sponging miR-200c. Taken together, the results showed that ASV inhibited the EMT process through the lncRNA-ATB/miR-200c/ZEB1 signaling pathway, which provides a novel approach to the treatment of IPF.