title: The Epstein-Barr virus causes epithelial-mesenchymal transition in human corneal epithelial cells via Syk/src and Akt/Erk signaling pathways.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  The cellular response to EBV was assessed by real-time PCR, Western blot, migration assay, invasion assay, inhibitor assay, and ELISA assay.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan, Republic of Korea.
authors.forename: Ga Bin
authors.initials: GB
authors.lastname: Park
authors.forename: Daejin
authors.initials: D
authors.lastname: Kim
authors.forename: Yeong Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Seonghan
authors.initials: S
authors.lastname: Kim
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Lee
authors.forename: Jae Wook
authors.initials: JW
authors.lastname: Yang
authors.forename: Dae Young
authors.initials: DY
authors.lastname: Hur
mesh_terms: D002465:Cell Movement; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D058750:Epithelial-Mesenchymal Transition; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D020031:Epstein-Barr Virus Infections / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D000072377:Syk Kinase
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Akt; Epstein-Barr virus; Erk; Src; Syk; TGF-β1; epithelial–mesenchymal transition; human corneal epithelial cell