miR‑133b regulates proliferation and apoptosis in high‑glucose‑induced human retinal endothelial cells by targeting ras homolog family member A.

The aim of the present study was to investigate the role of microRNA (miR)‑133b in high‑glucose‑induced human retinal endothelial cells (hRECs), particularly regarding its potential targeting of ras homolog family member A (RhoA). To establish the high‑glucose‑induced diabetic retinopathy (DR) model, hRECs were cultured in high‑glucose medium for 1, 2 and 3 days. An Annexin allophycocyanin (APC)/7‑aminoactinomycin D (7‑AAD) staining assay was performed to measure the apoptosis of hRECs. Next, the cells were transfected with miR‑133b inhibitors or mimics, and the cell proliferation and apoptosis were measured by MTT and Annexin‑APC/7‑AAD staining assays, respectively. In addition, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), western blotting and immunocytochemistry were used to detect the expression levels of RhoA, Rho‑associated protein kinase 1 (ROCK1), LIM domain kinase 1 (LIMK), myosin light chain (MLC) and phosphorylated (p)‑MLC. It was observed that high‑glucose or miR‑133b inhibitor treatment attenuated the apoptosis of hRECs, and upregulated the mRNA and protein expression levels of RhoA, ROCK1 and LIMK, as well as the p‑MLC protein level, in the hRECs. However, miR‑133b overexpression inhibited the cell proliferation, promoted apoptosis, and downregulated the mRNA and protein levels of RhoA, ROCK1 and LIMK, as well as p‑MLC protein, in high‑glucose‑induced hRECs. In conclusion, overexpression of miR‑133b inhibited the proliferation and promoted apoptosis in a DR cell model by downregulating RhoA expression.