Investigating the Function of MicroRNAs in Human Retinal Microvascular Endothelial Cells of Diabetic Retinopathy

Diabetic retinopathy (DR) is the main complication of diabetes mellitus (DM). Recent studies have implicated microRNAs dysfunction in human retinal microvascular endothelial cell (HRMEC). In this study, we aim to investigate the apoptotic promotion of miR-29b-3p by blocking SIRT1 in HRMEC for DR situation. To identify the regulating relationship between miR-29b-3p and SIRT1, HRMECs were transfected with miR-29b-3p mimics/inhibitors or their negative controls. Cell viability was assessed with the cell counting kit-8 (CCK-8) assay, and apoptotic cells were stained by one-step TUNEL assay kit. Gene and protein expression were assayed by RT-qPCR and Western blotting separately. Dual-luciferase reporter assay using HEK293T cells was performed to show the direct interaction of miR-29b-3p and the 3'-UTR of SIRT1. HRMECs were identified as >95% positive for CD31 and vWF. Upregulated miR-29b-3p decreased the expression of SIRT1 and increased the ratio of Bax/Bcl-2, while downregulated miR-29b-3p increased the expression of SIRT1 protein and downregulated the ratio of Bax/Bcl-2. Dual-luciferase reporter assay showed the direct interaction of miR-29b-3p and SIRT1. The dysregulation of miR-29b-3p/SIRT1 is a potential mechanism of HRMEC apoptosis in DR. miR-29b-3p/SIRT1 may be a potential therapeutic target for DR.