MicroRNA-411 plays a protective role in diabetic retinopathy through targeted regulating Robo4

K. Hu, J.-L. Li, X.-W. Yuan

Department of Ophthalmology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing University, Nanjing, China. hukai70@163.com

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• Ophthalmology

OBJECTIVE: The aim of this study was to explore the role of microRNA-411 in diabetic retinopathy (DR) and to further understand its mechanism of action.

MATERIALS AND METHODS: A rat model of diabetes (20 in the DM group) and a normal control group (20 in the control group) was established. The changes in blood glucose and body weight were compared between the two groups. At the same time, the expression changes in microRNA-411 and Roundabout 4 (ROBO4) in the two groups of rats were detected. The biological prediction of the potential binding sites of ROBO4 and microRNA-411 was verified by the Dual-Luciferase reporter gene assay, and the regulatory relationship of microRNA-411 to ROBO4 was verified in human retinal pigment epithelial cells (ARPE-19). Meanwhile, we investigated the effects of high glucose and hypoxia on the viability of ARPE-19 cells and explored whether microRNA-411 has a regulatory role in the effects. Finally, a cell reverse experiment was designed to verify whether microRNA-411 functions through ROBO4.

RESULTS: Compared with the NC group, the blood glucose of the DM group was significantly increased while the body weight was reduced. In addition, the expression level of microRNA-411 was markedly decreased in diabetic rats, and the mRNA and protein levels of ROBO4 were notably increased, which were all dependent on time. Biological prediction revealed that ROBO4 might be a potential target gene of microRNA-411, and the results of the Dual-Luciferase reporter gene assay confirmed that there is a binding relationship between them; meanwhile, microRNA-411 was proved to be able to inhibit the expression level of ROBO4 in vivo and in vitro. Both high glucose and hypoxia could inhibit the proliferation of ARPE-19 cells and increase the monolayer permeability. Additionally, up-regulation of microRNA-411 or down-regulation of ROBO4 could partially reverse this phenomenon. Cell reverse experiment showed that overexpression of ROBO4 partially reversed the protective effect of microRNA-411 on DR.

CONCLUSIONS: MicroRNA-411 was down-regulated in the rat model of diabetic retinopathy and played a protective role in this disease, which might be achieved by negatively regulating the expression level of ROBO4.

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