MiR-10b alleviates high glucose-induced human retinal endothelial cell injury by regulating TIAM1 signaling

Purpose: To investigate the effects of microRNA (miR)-10b on high glucose (HG)-induced human retinal endothelial cell (HREC) injury and the mechanisms involved.Methods: Levels of miR-10b were measured in HRECs using quantitative reverse transcriptasepolymerase chain reaction (qRT-PCR) after the addition of glucose (5.5 and 30 mM). Cell viability was measured using Cell Counting Kit-8 assay, while levels of reactive oxygen species (ROS) weredetermined using fluorimetry. An enzyme-linked immunosorbent assay (ELISA) was used to measure cellular apoptosis. Luciferase reporter assay was used to validate the miR-10b-binding sites of target genes. The levels of T-cell lymphoma invasion and metastasis (TIAM1) and NADPH oxidase-2 (NOX2) were determined using qRT-PCR. Ras-related C3 botulinum toxin substrate 1 (Rac1) activation was evaluated using a pull-down assay. The protein levels of TIAM1 and Rac1 were assayed by western blotting.Results: After HG stimulation, miR-10b expression was downregulated. Viability of HRECs decreased, whereas ROS production increased. However, the overexpression of miR-10b inhibited apoptosis and ROS production in HG-treated HRECs (p < 0.05), while luciferase reporter analysis revealed a possible binding site for miR-10b to target the 3'-untranslated region (UTR) of TIAM1. In addition, the overexpression of miR-10b distinctly reduced the expression levels of TIAM1 and NOX2, but decreased the activation of Rac1 in HG-treated HRECs (p < 0.05); these inhibitory effects of miR-10b were significantly reversed after TIAM1 application.Conclusion: MiR-10b alleviates HG-induced HREC injury by regulating TIAM1 signaling. MiR-10b therapy is a potential therapeutic strategy for patients suffering from diabetic retinopathy. Keywords: MicroRNA-10b, Human retinal endothelial cells, High glucose, TIAM1-Rac1 axis