AB239. Icariside II enhances endothelial nitric oxide synthase expression by suppressing miR-155 in diabetic-like human cavernous endothelial cells

Background To investigate the role of Icariside II (ICA II) on endothelial nitric oxide synthase (eNOS) expression regulated by miR-155, the human cavernous endothelial cells (HCECs) were exposed to a diabetic-like environment and treated with ICA II. Methods HCECs were treated with 200 µg/mL BSA as the Normal Control group (NC), with 200 µg/mL AGE-BSA plus 250 mg/dL glucose as the diabetes mellitus (DM) group, or with an addition of ICA II in DM group as the treatment group (DM+ICA II). Bioinformatics were first used to predict miRNAs targeting eNOS gene and then potential candidates including miR-155, miR-543, miR-31, miR-429, miR-200b were further verified by real-time PCR in a diabetic-like condition. Expressions levels of miRNAs, eNOS and the receptor for advanced glycation end products (RAGE) were performed by Real-time PCR; Protein expression levels of eNOS and RAGE were analyzed by western blot; nitric oxide (NO) content was detected by DAF-FM DA probe and NaNO2 standard curve methods. Results The expression of miR-155 in DM group is significantly higher than that that in the normal control (NC) group, whereas this phenomenon was effectively reversed by ICA II treatment. Furthermore, the miR-155 targeting gene eNOS and its consequent NO product were significantly reduced in DM group, while these changes were also recovered after ICA II treatment. Conclusions In this study, we demonstrated that ICA II could promotes eNOS mRNA and protein levels by suppressing miR-155 in HCECs exposed to a diabetic-like environment.