MicroRNA-203a-3p regulates CoCl2-induced apoptosis in human retinal pigment epithelial cells by targeting suppressor of cytokine signaling 3

Abstract Purpose The apoptosis of human retinal pigment epithelial cells (RPEs) plays a critical role in the pathogenesis of diabetic retinopathy (DR), but the molecular mechanisms remain unclear. In this study, we explored the function of miR-203a-3p in CoCl2-induced RPEs apoptosis. Methods The cellular localization of miR-203a-3p was assessed by in situ hybridization. Luciferase reporter assays were performed to validate that suppressor of cytokine signaling 3(SOCS3) as a direct target of miR-203a-3p. Effects of miR-203a-3p manipulation on RPEs apoptosis were evaluated using TdT-mediated dUTP Nick-End Labeling (TUNEL) and Flow Cytometry. Expression levels of miR-203a-3p was analyzed by RT-PCR, the expression of target proteins was detected by western blot. Results miR-203a-3p was found to be located in the RPE layer of the retinas from normal and diabetic rats and SOCS3 was a direct target of miR-203a-3p. miR-203a-3p mimics resulted in improved CoCl2-induced apoptosis of RPEs, overexpression of SOCS3 or c-Jun N-terminal kinase (JNK) inhibitor SP600125 reversed the pro-apoptotic effect of miR-203a-3p, to a certain extent. Conclusions Our data implied a crucial role of miR-203a-3p as a novel regulator of CoCl2-induced RPEs apoptosis through SOCS3. Deregulation of miR-203a-3p / SOCS3/JNK/c-Jun cascade thus may serve as an important contributor to RPEs apoptosis in DR.