The aims of the present study were to elucidate the regulatory effect of exogenous Tribbles homologue 3 (TRB3) expression on the Wnt/β‑catenin signaling pathway and epithelial‑mesenchymal transition (EMT) in transforming growth factor‑β1 (TGF‑β1)‑induced mouse alveolar epithelial cells (MLE‑12) and investigate the underlying regulatory mechanisms. TRB3 expression was upregulated and downregulated using gene overexpression and RNA interference techniques, respectively. TGF‑β1‑stimulated MLE‑12 cells were examined for EMT and activation condition of the Wnt/β‑catenin signaling pathway using Cell Counting Kit‑8, flow cytometry, western blotting, reverse transcription‑quantitative PCR, ELISA and immunofluorescence techniques. During TGF‑β1‑induced EMT, TRB3 expression was found to be significantly upregulated (P<0.05). In the TRB3 overexpression group, upregulated expression of β‑catenin and EMT‑related genes and proteins was observed (P<0.05), and an increase in fibrosis‑related factors in the cell culture supernatant was detected (P<0.05); however, the results were the opposite in the TRB3 downregulated group (P<0.05). TRB3 may be involved in the regulation of EMT in TGF‑β1‑induced MLE‑12 cells through the Wnt/β‑catenin signaling pathway.
Keywords: epithelial-mesenchymal transition; idiopathic pulmonary fibrosis; transforming growth factor-β1; Tribbles homologue 3; Wnt/β-catenin signaling pathway.