Objective To observe the effect of epithelial-mesenchymal transdifferentiation (EMT) of human retinal pigment epithelial (RPE) cells induced by vitreous humor in vitro. Methods The third to fifth passage cultured RPE cells were divided into two groups of treatment by 10% serum containing Dulbecco minimum essential medium (DMEM)/F12 medium (group A), or the same medium supplemented with 25% human vitreous (group B). The morphological changes were observed with a phase contrast microscrope. Cell migration, invasion and contractility were tested using a scratch wound assay, Transwell invasion assay and collagen gel contraction analysis. The expression levels of alpha;-smooth muscle actin (SMA) and Snail1 were detected by reverse transcriptase polymerase chain reaction (RT-PCR). Results The RPE cells in group A were flat and gathered together. The RPE cells in group B grew as a fan-shaped projection at one edge and cone-shaped tail at the opposite edge, or spindle-shaped, and appeared to separate. In group A, filamentous actin distributed mainly at the margin of the cells with the distribution an oval shape. In group B, filamentous actin reorganized and formed fan-like flat pseudopodia at one edge of the cells. Compared to group A, the migration and invasion of the cells increased significantly (t=14.190, 22.630; P＜0.05), but contractility decreased remarkably (t=6.221, P＜0.05) in group B. Compared to group A, the expression level of Snail1 mRNA increased significantly (t=3.218, P=0.032), but the expression level of alpha;-SMA mRNA decreased (t=3.990, P=0.016). Conclusions Vitreous humor can induce the EMT of RPE cells. Increasing cell migration, cell invasion, and expression of Snail1 mRNA as well as up-regulated cellsprime; contractility and expression of alpha;-SMA mRNA may be the mechanism.
Objective To investigate the activation and role of signal transduction pathway of epidermal growth factor (EGF)-epidermal growth factor receptor (EGFR)-mitogen activated protein kinase (MAPK) in proliferation of human retinal pigment epithelial (RPE) cells. Methods Human RPE cells were stimulated with 0.1%，10% foetal calfserum (FCS) and EGF(0.1, 1, 10, 50 and 100 ng/ml)in 0.1% FCS Dulbeco′s modified Eagle′s medium (DMEM) and in 10% FCS DMEM for 3 days, respectively. Immunohistochemical staining and in situ hybridization were used to observe the expressions of EGFR protein and EGFR mRNA，respectively. Activation of MAPK was detected by immunohistochemical method with specific anti-phosphorylated ERK 1/2 antibody. Results The optimal concentrations of EGF were 10 ng/ml in 0.1% FCS DMEM and 1 ng/ml in 10% FCS DMEM. After 3 days of stimulation with EGF, phosphorylated ERK 1/2 staining was detectable in nucleus of RPE cells, whereas cells presented immunostaining for phosphorylated ERK 1/2 in the cytoplasm before stimulation. Conclusions EGF may improve the expression of EGFR protein and EGFR mRNA of RPE cells, and induced MAPK nuclear translocation in a concentration-dependent manner. EGF-EGFR-MAPK signal transduction pathway may play a key role in RPE cells proliferation, and serum exerts an important acceclerating function in the process. (Chin J Ocul Fundus Dis，2004，20：67-132)
Purpose:To evaluate the function of gap junction-mediated intercellular communication in cultured cells of retinal pigment epithelial(RPE) cells from porcine eyes. Methods:The cultured RPE cells were previously stained by a fluorescent probe 5, 6-carboxy fluorescein diacetate (CFDA) ,and then photobleach the fluorescent molecule in chosed cells. Using laser scanning confocal microscope (LSCM)to observe fluorescence recovery rate of the RPE cells which located in different condition. The function of gap junction communication was evaluated according to the fluorescence recovery rate. Results:The fluorescence recovered after photobleached and the fluorescent density of cells which touching to them descend. The recovery rate per minnte of the cells which the cell number it adjacent to was 1,2 and 3 respectively was 1. 997plusmn;0. 665, 4. 378plusmn;0. 811 and 8. 736plusmn;2. 084. Conclusion:The cultured porcine RPE cells have the function of gap junction communication,and its function proportion is associate to its adjoining cells number. （Chin J Ocul Fundus Dis,1996,12: 41-42）
ObjectiveTo investigate the effects of migration and expression from chemokine receptor 4 (chemokine receptor-4, CXCR4) of rat bone marrow mesenchymal stem cells (BMSCs) which were pretreated by atorvastatin (ATV) in vitro.MethodsIsolated, cultivated, identified the BMSCs, pretreated P4-P6 of BMSCs with different concentrations of ATV for 12 hours. The experimental group was divided into control group, 0.1 nM/L (group 0.1 nM), 1 nM/L (1 nM group), 10 nM/L (10 nM group), 100 nM/L (100 nM group), 1 000 nM/L (1 000 nM group). The mRNA and protein of CXCR4 were determined by real time-polymerase chain reaction and Western blot. Immunofluoreseence assay were used to detect the expression levels of CXCR4. The migration ability of BMSCs were measured by transwell chamber.ResultsImmunofluoreseence assay showed the protein level of CXCR4 of group 1 nM and 10 nM were significantly higher than the other group. RT-PCR and Western blot showed the protein and mRNA level of CXCR4 in 10 nM was higher than that in group 1 nM. The migration ability of group 10 nM was higher than 1 nM and control group.ConclusionsATV can be dose-dependent promote expression levels of CXCR4 of BMSCs cultivated in vitro.