Changes in expression of epithelial and mesenchymal proteins in primary human small airway epithelial cells (SAEC) and large airway epithelial cells (LAEC) stimulated with TGFβ1 in vitro.

Both SAEC and LAEC cell cultures were stimulated with TGFβ1 (50 ng/ml) for 96 h and cellular protein was collected and analyzed by Western blots. (A) Initial immunoblots suggested a marked increase in mesenchymal markers and corresponding decrease in epithelial markers after 96 h of stimulation. Quantification of immunoblots showed that there was significantly (*p<0.05) increased expression of the mesenchymal markers (B) Vimentin (Vim) and (C) EDA-Fibronectin (EDA-Fn) as well as significantly decreased expression of epithelial markers (D) Zona Occludens -1 (ZO-1) and (E) Cytokeratin-19 (Ck-19) (all normalized to β-actin). SAEC was also found to be more susceptible to EMT as the increase in mesenchymal markers and decrease in epithelial markers was significantly greater for SAEC compared to LAEC after 96 hours of TGFβ1 stimulation (p<0.05, n = 23). Data presented as median ± IQR.