title: VEGF induces TGF-β1 expression and myofibroblast transformation after glaucoma surgery.
abstract: Subconjunctival fibrosis at the surgical site determines the outcome of glaucoma surgery. Myofibroblast transformation has a significant role in fibrosis, and vascular endothelial growth factor (VEGF) is reported to trigger myofibroblast transformation by inducing transforming growth factor (TGF)-β1. In the present study, we used IHC, Western blot analysis, enzyme-linked immunosorbent assay, and electron microscopy to determine the contribution of VEGF to myofibroblast transformation in subconjunctival fibrosis after glaucoma surgery. A rabbit trabeculectomy model was generated, and VEGF stimulation or VEGF inhibition was performed during surgery. VEGF stimulation induced TGF-β1 expression in a dose-dependent manner. Down-regulation of epithelial markers (E-cadherin and β-catenin) and up-regulation of mesenchymal marker (α-smooth muscle actin) were observed in the subconjunctival layers after trabeculectomy with VEGF stimulation. Up-regulations of Smad and Snail, which play a central role in myofibroblast transformation, were observed in the conjunctival and subconjunctival layers at the site of trabeculectomy. Electron microscopy revealed changes of the conjunctival epithelial cells, especially the presence of myofilaments and increased rough endoplasmic reticulum in the cytoplasm. Myofibroblast transformation was activated by VEGF stimulation and decreased by VEGF inhibition. These findings suggest that VEGF potentially affected the TGF-β1/Smad/Snail pathway, thereby triggering myofibroblast transformation. Therapeutic approaches modulating VEGF may control myofibroblast transformation and reduce subconjunctival fibrosis after glaucoma surgery.
authors.affiliation: Department of Ophthalmology and Visual Science, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hae-Young L
authors.initials: HY
authors.lastname: Park
authors.forename: Jie Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Chan Kee
authors.initials: CK
authors.lastname: Park
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D000068258:Bevacizumab; D003228:Conjunctiva / Q000378:metabolism / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000648:ultrastructure; D005355:Fibrosis; D008297:Male; D008854:Microscopy, Electron; D058628:Myofibroblasts / Q000187:drug effects* / Q000378:metabolism; D011184:Postoperative Period; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051785:Smad Proteins / Q000096:biosynthesis; D000071250:Snail Family Transcription Factors; D014130:Trabeculectomy / Q000009:adverse effects*; D014157:Transcription Factors / Q000096:biosynthesis; D053773:Transforming Growth Factor beta1 / Q000096:biosynthesis*; D015854:Up-Regulation / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000502:physiology
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D051785:Smad Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab