Upregulation of miR-424 inhibit retinal endothelial cells proliferation under high glucose condition via cyclin D1.

Introduction: Diabetic retinopathy is characterised by retinal vascular impairment. A number of aberrant microRNAs (miRNAs) have a role in the pathophysiology of vascular dysfunction. However, the relevance of miR-424 in retinal vascular endothelial cell dysfunction during hyperglycemia stress remains unknown. The purpose of this study is to investigate this issue.

Materials and methods: Rhesus macaque choroid retinal endothelial cell line (RF/6A) cells were cultivated in normal glucose (NG) and high glucose (HG) conditions. The mRNA expression of miR-424 and Cyclin D1 (CCND1) was quantified using qPCR, and the protein quantity of CCND1 was detected using Western Blot. miR-424 mimics, miR-424 inhibitors, miR-424 inhibitor+ siRNA-CCND1 or vehicle molecules were transfected into RF/6A cells. MTT test was used to assess cell proliferation, and flow cytometric analysis was used to assess cell cycle. The interaction between miR-424 and CCND1 was predicted using bioinformatics and validated using dual luciferase reporter analysis.

Results: miR-424 was up-regulated, and cell viability was reduced in HG compared to NG. By reversing the expression of miR-424 in certain situations, the phenotypes can be changed. CCND1 has been identified as a miR-424 target gene, and it may be regulated at the transcriptional and translational levels. Manipulation of silencing CCND1 can counteract the effect of transfecting miR-424 inhibitor into RF/6A cells under HG such as proliferation stimulation.

Conclusions: Our findings indicate that miR-424 plays an important role in hyperglycemia induced ARPE-19 cells damage, and it could be a new therapeutic target for DR by preventing retinal vascular cells from HG-induced injury.