title: MicroRNA-124 Controls Transforming Growth Factor β1-Induced Epithelial-Mesenchymal Transition in the Retinal Pigment Epithelium by Targeting RHOG.
abstract: OBJECTIVE
  MicroRNA-124 (miR-124) is thought to be involved in the epithelial-mesenchymal transition (EMT) of RPE. We investigated the regulation of TGF-β1-induced EMT by miR-124 in human RPE cells (ARPE-19).
  
  
  METHODS
  Expression of miR-124 was evaluated after TGF-β1 treatment by quantitative RT-PCR. Phenotypic alterations were analyzed by Western blot analysis and immunocytochemical staining. Target validation was performed by a luciferase reporter assay to identify the putative target of miR-124.
  
  
  RESULTS
  The expression level of miR-124 was downregulated during the progression of EMT. Overexpression of miR-124 upregulated the levels of zonular occludens 1 and occludin, and downregulated those of fibronectin, α-smooth muscle actin, and vimentin. Furthermore, inhibition of endogenous miR-124 increased and decreased the levels of mesenchymal and epithelial factors, respectively. TargetScan predicted two well-conserved and two vertebrate-only conserved miR-124 target sequences in the 3' untranslated region (UTR) of the Ras homology Growth-related (RHOG) mRNA. Direct targeting of this 3' UTR by miR-124 was demonstrated using a luciferase assay. Silencing of RHOG using a specific siRNA had identical effects on EMT regulation. Overexpression of miR-124 repressed TGF-β1-induced RPE cell-collagen gel lattice contraction by altering cell spreading/cell-to-cell adhesion.
  
  
  CONCLUSIONS
  This study describes the regulation of EMT in RPE cells by TGF-β1/miR-124/RHOG signaling and suggests that the supplement of miR-124 exogenously would be a valuable therapeutic approach for the prevention or treatment of proliferative vitreoretinopathy.
authors.affiliation: Department of Ophthalmology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, Korea.
authors.forename: Jong Hwa
authors.initials: JH
authors.lastname: Jun
authors.affiliation: Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea 3Catholic Institute for Visual Science, The Catholic University of Korea, College of Medicine, Seoul, Korea.
authors.forename: Choun-Ki
authors.initials: CK
authors.lastname: Joo
mesh_terms: D026481:Blotting, Far-Western; D015153:Blotting, Western; D002460:Cell Line; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000378:metabolism* / Q000473:pathology; D053773:Transforming Growth Factor beta1 / Q000627:therapeutic use*; D018630:Vitreoretinopathy, Proliferative / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*
chemical_list: C509207:MIRN124 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; C075397:RHOG protein, human; D020741:rho GTP-Binding Proteins