Invest Ophthalmol Vis Sci. 2014 Mar 20;55(3):1770-9. doi: 10.1167/iovs.13-12988.
The Epstein-Barr virus causes epithelial-mesenchymal transition in human corneal epithelial cells via Syk/src and Akt/Erk signaling pathways.
Park GB1, Kim D, Kim YS, Kim S, Lee HK, Yang JW, Hur DY.
Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan, Republic of Korea.
Although Epstein-Barr virus (EBV)-associated keratitis is rare, it can cause acute corneal necrosis and neovascularization. We aimed to examine the signaling mechanism by which EBV causes epithelial-mesenchymal transition (EMT) in human corneal epithelial cells (HCECs) in vitro.
The cellular response to EBV was assessed by real-time PCR, Western blot, migration assay, invasion assay, inhibitor assay, and ELISA assay.
A model of EBV-induced EMT was established in HCECs. The EBV induced morphologic changes in the cells; the loss of epithelial markers E-cadherin, ZO-1, and β-catenin; and an increase in the mesenchymal markers N-cadherin, Vimentin, Snail, and TCF8/Zeb1. The EBV infection also led to the nuclear translocation of Snail and TCF8/Zeb1; enhanced the secretion of IL-6, IL-8, VEGF, TGF-β1, TNF-α, and MCP-1; and upregulated the expression of MMP2 and MMP9. The EBV-infected HCECs exhibited increased migration and invasiveness compared to uninfected HCECs. We measured the involvement of Syk, Src, PI3K/Akt, and Erk signaling, but not Smad, in EMT by EBV-induced TGF-β1. We demonstrated that treatment with TGF-β1, TGF-β receptors, Syk, or Src inhibitor blocked TGF-β1, Syk, or Src signaling activation, and EMT development by EBV. Moreover, these inhibitors prevented PI3K/Akt and Erk activation.
An EBV infection in HCECs can lead to a mesenchymal fibroblast-like morphology, and cause EMT through the activation of PI3K/Akt and Erk by TGF-β1-mediated Syk and Src signaling. This phenomenon may have implications for EBV-associated keratitis and molecular approaches to treatment.
Akt; Epstein-Barr virus; Erk; Src; Syk; TGF-β1; epithelial–mesenchymal transition; human corneal epithelial cell