Tgf-β Induces Epithelial Mesenchymal Transition With Snai1 and Snai2 Up-Regulation in Human Corneal Epithelial Cells

Abstract

Introduction: : Epithelial-mesenchymal transition (EMT) is estimated to play an important role in various ocular disease such as wound healing and tissue fibrosis. However, it remains unclear the underlying mechanism of EMT-induction in human corneal epithelial cells (HCECs). We investigated the effect of TGF-β on cellular response and EMT-related gene expression in HCECs.

Methods: : TGF-β mediated cellular proliferation and activation of TGF-β signaling pathway of HCECs were evaluated by MTT assay, flowcytometry and immunoblotting, respsectively. Quantitative real-time RT-PCR (qRT-PCR) was performed to measure the mRNA levels of several EMT markers such as VIM, FN1, SNAI1, SNAI2 and TWIST1. EMT-related morphological changes were detected immunofluorescence microscopy.

Results: : TGF-β-stimulation inhibited the cellular proliferation and induced cell cycle arrest significantly. Immunoblotting analysis demonstrated TGF-β increased the expression of phospho-smad2 in time and dose dependent manners. TGF-β elicited cell scattering and elongation of cell-shape. The mRNA expression levels of VIM, FN1, SNAI1, SNAI2 were significantly induced by TGF-β (p<0.05), whereas TWIST1 expression was unchanged in detecting qRT-OCR. In addition, we detected a sustained inductions of SNAI1 and SNAI2 expression by TGF-β stimuli in HCECs.

Conclusions: : TGF-β regulates the cell proliferation and expression levels of EMT makers in HCECs. This study may provide a novel insight into TGF-β₁-mediated EMT.

Keywords: cornea: basic science • EMT (epithelial mesenchymal transition) • growth factors/growth factor receptors