3.6 | TGF-β1 promoted ZO-1 and Col-a1 expression, but inhibited the proliferation of epithelial cells, whereas MG53 yielded reversed trends
A series of experiments, including cell proliferation and apoptosis assays, as well as ELISA-based detection of the secretion of soluble Col-a1 in the culture supernatant and the epithelial injury marker LDH, were performed to further understand the effects of MG53 and TGF-β1 on the epithelial barrier. We found that MG53 significantly promoted epithelial cell proliferation, whereas TGF-β1 inhibited this activity (Fig. 6A). ELISA-based analysis of soluble Col-a1 in the supernatant of the culture maintained for 72 h showed that TGF-β1 promoted the secretion of soluble Col-a1, whereas TGF-β1 inhibitors and Ad-MG53 reduced the secretion of soluble Col-a1 (Fig. 6B). Results of the in vitro cell membrane injury test and ELISA showed that both TGF-β1 and Ad-MG53 reduced LDH release (Fig. 6C). Results of flow cytometry indicated that Ad-MG53 inhibited cell apoptosis compared with negative control-MG53 (NC-MG53 ), (Fig. 6D).