Rac1 modulates the vitreous-induced plasticity of mesenchymal movement in retinal pigment epithelial cells.
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.


DESIGN
One-way design with multiple levels and repeated measurement design.


PARTICIPANTS AND SAMPLES
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.


MAIN OUTCOME MEASURES
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.
['Huang|Xiong-gao|XG|', 'Chen|You-zhen|YZ|', 'Zhang|Zhao-tian|ZT|', 'Wei|Yan-tao|YT|', 'Ma|Hai-zhi|HZ|', 'Zhang|Ting|T|', 'Zhang|Shao-chong|SC|']
D000293:Adolescent D000328:Adult D000368:Aged D000634:Aminoquinolines D015153:Blotting, Western D002461:Cell Line, Transformed D002465:Cell Movement D002470:Cell Survival D054338:Cell Transdifferentiation D002478:Cells, Cultured D004791:Enzyme Inhibitors D006801:Humans D054461:Lim Kinases D059630:Mesenchymal Stem Cells D008875:Middle Aged D010766:Phosphorylation D011743:Pyrimidines D055213:Retinal Pigment Epithelium D018630:Vitreoretinopathy, Proliferative D014822:Vitreous Body D055815:Young Adult D020830:rac1 GTP-Binding Protein
plasticity retinal pigment epithelial cells vitreous proliferative vitreoretinopathy Rac1 GTPase