Abstract
Purpose :
Mitochondrial dysfunction plays a pathogenic role in diabetic retinopathy. The purpose of this study was to explore the role of miRNA451a (miR-451a) in mitochondrial dysfunction induced by diabetes.
Methods :
Vitreous and epiretinal membrane samples were collected from 14 patients with proliferative diabetic retinopathy (PDR). The membranes were used for immunolabeling of ki-67 protein and RPE65 protein to identify retinal pigment epithelial cells. The vitreous samples were divided into two groups according to Ki-67 expression. Vitreous miRNA profiles were analyzed using miRNA-specific qPCR microarray. The expression of miR-451a was measured by RT-PCR in DB/DB mice. The expression of miR-451a, was quantified by q-PCR in ARPE-19 cells under diabetic conditions. The potential downstream targets of the miRNA were predicted and confirmed by dual luciferase assay, qRT-PCR and Western blotting. Mitochondrial function changes were measured by Seahorse after transfection of miR-451a mimics and inhibitor into ARPE19 cells.
Results :
In proliferative vitreoretinopathy membrane, RPE cells account for 2.57%±3.19%(1.61%-11.11%). Proliferative index (PI) = 2.57%±3.19%(1.61%-11.11%). Some RPE cells were Ki-67-positvie cells. MiRNA-specific qPCR microarray showed that the level of miR-451a was substantially higher from the eye with Ki-67-positive membrane than the eye with Ki-67-negative membrane. The expression of miR-451 in the retina was increased by 4-fold in 6-month-old DB/DB mice, compared to age-matched non-diabetic controls (P=0.03). In ARPE19 cells, high glucose up-regulated miR-451a expression. HNE down-regulated miR-451a expression. Bioinformatic analysis and luciferase assay identified activating transcription factor 2 (ATF2) as a potential target of miR-451a. RT-PCR and Western blotting revealed that overexpression of miR-451a down-regulated the expression of ATF2 (P<0.05). The mitochondrial function was enhanced by miR-451a mimics, while suppressed by inhibitor. The basal oxygen consumption rate (OCR) and maximal OCR in miR-451a overexpression group were significantly higher than control group (P=0.014, 0.015). Under high glucose condition, overexpression of miR-451a enhanced the mitochondrial function.
Conclusions :
MiR-451a/ATF2 plays a role in regulation of the mitochondrial function in the RPE, which open new perspectives for the development of effective therapies of PDR.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.