title: Rac1 modulates the vitreous-induced plasticity of mesenchymal movement in retinal pigment epithelial cells.
abstract: BACKGROUND
  The vitreous has been shown to induce epithelial-mesenchymal transdifferentiation because it induces fibroblast-like morphology, enhanced migration and invasion in retinal pigment epithelial cells in proliferative vitreoretinopathy. Rac1 is the principal mediator of cell migration. In the current study, the relationship between Rac1 and cell migration, and invasion in vitreous-transformed retinal pigment epithelial cells was investigated using NSC23766, a specific inhibitor of Rac guanosine-5'-triphosphatase activity, and the involvement of a Rac1 guanosine-5'-triphosphatase-dependent pathway was detected.
  
  
  METHODS
  One-way design with multiple levels and repeated measurement design.
  
  
  METHODS
  The vitreous humor was collected from 20 healthy donor eyes and the retinal pigment epithelial cells were obtained from 9 healthy donor eyes.
  
  
  METHODS
  Human low-passage retinal pigment epithelial cells were treated with normal medium or 25% vitreous medium. Rac1 activity was measured using a pull-down assay. The cytotoxicity of NSC23766 was measured using the trypan blue dye exclusion test. Cell migration was measured using a wound healing assay. Cell invasion was determined using a transwell invasion assay. Protein expression of Rac1 and phosphorylation of LIM kinase 1 and cofilin were detected by Western blot analysis.
  
  
  METHODS
  Cell migration, invasion, Rac1 activity and phosphorylation of LIM kinase 1 and cofilin.
  
  
  RESULTS
  Rac1guanosine-5'-triphosphatase was activated in vitreous-transformed retinal pigment epithelial cells. A Rac inhibitor suppressed vitreous-induced migration and invasion in retinal pigment epithelial cells. Cofilin phosphorylation was activated by vitreous treatment but blocked by NSC23766.
  
  
  CONCLUSIONS
  Rac1 mediates vitreous-transformed retinal pigment epithelial cells' plasticity of mesenchymal movement via Rac1 guanosine-5'-triphosphatase-dependent pathways that modulate LIM kinase 1 and cofilin activity. Rac inhibition may be considered a novel treatment for proliferative vitreoretinopathy.
authors: State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China; Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, China.
authors: Xiong-gao
authors: XG
authors: Huang
authors: You-zhen
authors: YZ
authors: Chen
authors: Zhao-tian
authors: ZT
authors: Zhang
authors: Yan-tao
authors: YT
authors: Wei
authors: Hai-zhi
authors: HZ
authors: Ma
authors: Ting
authors: T
authors: Zhang
authors: Shao-chong
authors: SC
authors: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000634:Aminoquinolines / Q000494:pharmacology; D015153:Blotting, Western; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000502:physiology*; D002470:Cell Survival; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D054461:Lim Kinases / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D008875:Middle Aged; D010766:Phosphorylation; D011743:Pyrimidines / Q000494:pharmacology; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000378:metabolism; D018630:Vitreoretinopathy, Proliferative / Q000473:pathology*; D014822:Vitreous Body / Q000502:physiology*; D055815:Young Adult; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D000634:Aminoquinolines; D004791:Enzyme Inhibitors; C487513:NSC 23766; D011743:Pyrimidines; C107953:RAC1 protein, human; C515892:LIMK1 protein, human; D054461:Lim Kinases; D020830:rac1 GTP-Binding Protein
keywords: Rac1 GTPase; plasticity; proliferative vitreoretinopathy; retinal pigment epithelial cells; vitreous