[LIMR is involved in the inhibitory effect of antiflammin-1 on epithelial-mesenchymal transition in A549 cells].

Epithelial-mesenchymal transition (EMT) occurring in alveolar epithelial cells plays an important role in the development and progression of pulmonary fibrosis. Previous studies showed that antiflammin-1 (the active fragment of uteroglobin) effectively inhibited bleomycin-induced pulmonary fibrosis. However, its mechanism is still far from being clarified. In this study, we investigated the effects of antiflammin-1 on EMT in A549 cells induced by transforming growth factor-ß1 (TGF-ß1) and the underlying mechanism by using morphological observation and Western blot. The results showed that the expression of α-smooth muscle actin (α-SMA) increased significantly while the expression of E-cadherin decreased significantly in A549 cells following treatment with TGF-ß1 concomitant with morphological change of A549 cells from pebble-like shape epithelial cells to spindle-like mesenchymal shape. This process of EMT in A549 cells induced by TGF-ß1 was significantly inhibited when A549 cells were co-incubated with TGF-ß1 and antiflammin-1. Furthermore, the anti-lipocalin interacting membrane receptor (LIMR) antibody and PD98059 (an ERK signaling pathway blocker) attenuated the inhibitory effect of antiflammin-1 on TGF-ß1-induced EMT, respectively. Our findings indicate that antiflammin-1 can inhibit EMT in A549 cells induced by TGF-ß1, which is related to LIMR and its downstream ERK signaling pathway.