Long noncoding RNA BDNF-AS inversely regulated BDNF and modulated high-glucose induced apoptosis in human retinal pigment epithelial cells

In this study, we characterized the functional role of long noncoding RNA (lncRNA), brain derived neurotrophic factor anti-sense (BDNF-AS) in regulating D-glucose-induced (DGI) apoptosis in human retinal pigment epithelial (RPE) cells. Human RPE cell line, ARPE-19 cells were cultured in vitro and treated with various concentrations of D-glucose for 24h. A TUNEL assay was applied with immunohistochemical and quantitative approaches to assess the apoptotic effect of D-glucose. Under the condition of 50mM D-glucose, qPCR was used to assess gene expression of BDNF and BDNF-AS in ARPE-19 cells. Using siRNA transfection, BDNF-AS was endogenously knocked down in ARPE-19 cells. The effects of BDNF-AS downregulation on DGI apoptosis and BDNF expression were assessed by TUNEL assay, qPCR, and Western blot, respectively. Furthermore, in BDNF-AS-downregulated ARPE-19 cells, secondary siRNA transfection was conducted to knock down endogenous BDNF expression. Its effect on BDNF-AS-associated apoptotic regulation was further evaluated. High concentrations of D-glucose induced significant apoptosis in ARPE-19 cells in vitro. With treatment of 50mM D-glucose, BDNF was markedly downregulated whereas BDNF-AS upregulated in ARPE-19 cells. SiRNA-mediated BDNF-AS downregulation ameliorated DGI apoptosis and upregulated BDNF in ARPE-19 cells. In addition, inhibiting BDNF reversed the protective effect of BDNF-AS downregulation on DGI apoptosis. Our results suggest that BDNF-AS, through inverse regulation of BDNF, might play a critical role in the process of DGI apoptosis in diabetic retinopathy.