Abstract
Purpose:
The role of miRNA in proliferative diabetic retinopathy (PDR) is still not well-known. We identified the changes of miRNA expression in the vitreous of patients with PDR, and investigated the potential role of miRNA-451 in PDR.
Methods:
Fourteen vitreous and epiretinal membrane samples were collected from PDR patients undergoing vitrectomy. The membranes were immediately fixed in paraformamaldehyde and immunolabeled with anti-Ki-67 protein, in combination with anti-RPE65 protein to indentify retinal pigment epithelial cell. The vitreous samples were divided into two groups according to Ki-67 expression of the membranes. One sample of each group was random selected for miRNA-specific qPCR microarray. In vitro cell proliferation and migration studies were done to support clinical data using ARPE-19 cells line. The potential downstream targets of miRNAs were predicted by bioinformatic analysis using web-based applications and confirmed by dual luciferase assay. The mRNA changes of identified downstream targets were examined by qRT-PCR.
Results:
In PVR membrane, some RPE cells were Ki-67-positive cells. MiRNA-specific qPCR microarray showed that the level of miR-451 was nearly 30 times higher in the vitreous that was random selected from the one eye with Ki-67-positive membrane than one eye with Ki-67-negative membrane. In vitro, high glucose up-regulated miR-451 expression of ARPE-19 cells in 24 hour and 48 hour. While overexpression of miR-451 inhibited RPE proliferation and migration within 48 hours after transfection with miRNA-451 mimics. Luciferase and bioinformatic analysis identified the novel activating transcription factor 2 (ATF-2) as a potential target of miR-451. RT-PCR results revealed that, in ARPE-19, overexpression of miR-451 down-regulated the expression of ATF-2 in 24 hours and 48 hours (P<0.05 ). Platelet-detived growth factor receptor α(PDGFRα), matrix metalloproteinase-2 (MMP-2), CyclinA1, CyclinD1, whose expression can be up-regulated by ATF-2 binding to their promoter, show the same change trend as ATF-2 (P<0.05).
Conclusions:
These findings support the role of miR-451/ATF-2/PDGFRα, MMP-2, CyclinA1, CyclinD1 as potential signaling pathways of cell proliferation and migration, which open new perspectives for the development of effective therapies of PDR.