| Abstract: | ![]()
Age‐related macular degeneration (AMD) is a major reason of blindness in the elderly. MicroRNAs are implicated in various pathological processes, including inflammation and apoptosis. In this study, we aim to investigate the biological functions of miR‐21‐3p in inflammation and apoptosis caused by lipopolysaccharide (LPS) in human retinal pigment epithelial (ARPE‐19) cells. The miR‐21‐3p inhibitor and mimic were transfected into ARPE‐19 cells for 48 hours, followed by exposed to LPS (10 μg/mL) for 24 hours. The mRNA and protein expression of IL‐6 and MCP‐1 were measured using real‐time PCR (RT‐PCR) and enzyme‐linked immunosorbent assays. Cell viability, apoptosis, caspase 3 activity, cleaved caspase‐3 and cleaved‐PARP protein levels were detected to evaluate the effects of miR‐21‐3p on apoptosis. Additionally, the target relationship between miR‐21‐3p and regulator of G‐protein signalling 4 (RGS4) was verified by dual luciferase reporter assay. RT‐PCR analysis demonstrated that LPS induced miR‐21‐3p expression. Inhibition of miR‐21‐3p reduced the mRNA and protein levels of IL‐6 and MCP‐1. Apoptosis, caspase‐3 activity, and cleaved‐caspase 3 and cleaved PARP protein levels were repressed by the miR‐21‐3p inhibitor. However, overexpression of miR‐21‐3p showed the opposite results. Furthermore, we identified that miR‐21‐3p directly targeted the 3′ untranslated region of RGS4. MiR‐21‐3p negatively regulated the expression of RGS4 both in mRNA and protein levels. Silencing RGS4 reduced the anti‐inflammatory and anti‐apoptotic effects of miR‐21‐3p inhibitor. Our results revealed that miR‐21‐3p inhibition targeted RGS4 to attenuate inflammatory responses and apoptosis caused by LPS in ARPE‐19 cells. |
