Role of CTGF in TGF β_2-induced Epithelial Mesenchymal Transition in Human Lens Epithelial Cells
Objective:Posterior capsular opacification(PCO) is the main complication of modern cataract surgery and cause of poor vision post-operation.Residual lens epithelial cells (LECs) undergo epithelial mesenchymal transition(EMT) in the progress of PCO. Previous work has revealed that transforming growth factor beta(TGF-β)play an important role in PCO.Though it is extensively studied,the mechanism of TGF-βon lens is complex and not completely understood yet.Connective tissue growth factor (CTGF) is a matricellular protein that has been found to participate in EMT.So it is critical to understand the mechanism of CTGF,a potent growth factor in ocular media, in process of EMT in LECs.On the basis of previous studies,we established a research model for PCO in vitro.We also took the siRNA technique to selectively silence the expression of CTGF in LECs to investigate the role of CTGF in TGF-β_2 induced EMT in human lens epithelial cells.Methods:HLE B-3 cells were treated with different concentrations of TGF-β_2 to investigate effect of TGF-β_2 on expression of CTGF,connexin43 and a-SMA with western blot and RT-PCR.siRNA technique was operated to selectively silence the expression of CTGF gene.Then we analyzed the effect of siRNA interfere on TGF-β_2 induced EMT and adhesion of LECs with western blot and immunofluorescence.Results:HLE B-3 cells underwent morphological alteration and EMT under TGF-β_2 stimulation concomitant with dramatic up-regulation of CTGF mRNA and protein levels.The expression of Connexin43 was decreased after treatment of TGF-β_2,while the expression of a-SMA was increased.CTGF silencing by CTGF siRNA approaches showed that TGF-β_2-induced EMT and adhesion were CTGF dependent.Conclusion:CTGF is an essential downstream mediator of TGF-β_2-induced EMT in lens epithelial ceils.Selectively silence the expression of CTGF could be a potent therapeutic target of PCO.