Abstract
Purpose :
Proliferative vitreoretinopathy (PVR) may lead to irreversible vision loss. Epithelial-to-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) is a critical event in the pathogenesis of PVR. Downregulation of Pigment Epithelium-Derived Factor (PEDF) is demonstrated to be associated with increased EMT in some cancers. The aim of the current study was to investigate the effects of PEDF on EMT induced by TGF-β in RPE cells.
Methods :
Sub-confluent human RPE cells were cultured in DMEM and pretreated with PEDF (10, 50,100, 200ng/ml) for 24hs and then stimulated with recombinant TGF-β2 (10ng/ml) for additional 24, 48 and 72 hrs with or without PEDF. The expressions of α-smooth muscle actin (α-SMA, an EMT marker) and fibronectin (FN) were examined using immunofluorescent staining, qRT-PCR and Western blotting respectively. The sub-confluent human RPE cells were cultured in DMEM and pretreated with PEDF (10, 50,100ng/ml) for 24hs and then stimulated with 20ng/ml PDGF-BB. RPE cell proliferation and migration were examined using MTT assay and Boyden chamber migration assay.
Results :
PEDF pretreatment caused a significant inhibition of RPE cell migration induced by PDGF-BB in a dose-dependent manner compared with controls (p<0.05). The maximal reduction of migration was seen with pretreatment of 100ng/ml of PEDF for 24 hours (p<0.01). However, PDGF-BB didn’t significantly stimulate the proliferation of the RPE cells. Furthermore, TGF-β2 increased expression of SMA and FN at both mRNA and protein levels compared with controls (p<0.05), but pre-treatment with PEDF did not significantly alter this effect. The result of immunofluorescent staining showed that the increased α-SMA and FN induced by TGF-β2 were not inhibited by treatment with PEDF.
Conclusions :
PEDF inhibits RPE cell migration induced by PDGF-BB. PEDF does not inhibit TGF-β2 induced EMT in RPE cells. Further experiment will be performed to analyze the mechanism of PEDF’s inhibitory effect on PDGF-BB induced RPE cell migration.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.