Downregulation of microRNA-181a attenuates hydrogen peroxide-induced human lens epithelial cell apoptosis in vitro

Apoptosis of human lens epithelial (HLE) cells is a process closely associated with cataract formation. The aim of the present study was to explore the effects of microRNA (miR)-181a against hydrogen peroxide (H2O2)-induced apoptosis in HLE cells in vitro. The recombinant lentiviral plasmid pLKO. 1-puro-miR-181a was constructed and used to transfect human HLE-B3 cells with the short hairpin (sh)RNA to silence the expression of miR-181a. The apoptotic rate of both HLE-B3 cells in which miR-181a expression was stably silenced and in untransfected HLE-B3 cells was assessed in the presence of H2O2 using flow cytometry. The mRNA expression levels of the apoptosis-related genes caspase-3 (CASP3) and B-cell lymphoma-2-associated X protein (BAX), and of the potential target genes for miR-181a, c-MET, cyclooxygenase 2 (COX-2) and snail family transcriptional repressor 2 (SNAI2) were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) levels were assessed using ELISA. RT-qPCR analysis revealed that miR-181a expression was downregulated in HLE-B3 cells following transfection with miR-181a-shRNA. Treatment with H2O2 significantly reduced the viability of HLE-B3 cells, whereas miR-181a knockdown was revealed to attenuate the effects on cell viability following H2O2 treatment. In addition, the downregulation of miR-181a expression significantly decreased H2O2-induced cell apoptosis, which was accompanied by a downregulation in CASP3 and BAX and COX-2 expression. Furthermore, the levels of MDA were decreased, whereas the levels of SOD and CAT were increased following miR-181a silencing. The present findings suggested that miR-181a knockdown may protect HLE-B3 cells against H2O2-induced apoptosis in vitro. The molecular mechanisms involved in the protective effects of miR-181a silencing may involve the suppression of CASP3, BAX and COX-2 expression, and the inhibition of MDA generation.