Global microRNA expression profiling: curcumin (diferuloylmethane) alters oxidative stress-responsive microRNAs in human ARPE-19 cells.

Purpose: In recent years, microRNAs (miRNAs) have been reported to play important roles in a broad range of biologic processes, including oxidative stress-mediated ocular diseases. In addition, the polyphenolic compound curcumin has been shown to possess anti-inflammatory, antioxidant, anticancer, antiproliferative, and proapoptotic activities. The aim of this study was to investigate the impact of curcumin on the expression profiles of miRNAs in ARPE-19 cells exposed to oxidative stress. Methods: MiRNA expression profiles were measured in ARPE-19 cells treated with 20 μM curcumin and 200 μM H 2 O 2 . PCR array analysis was performed using web-based software from SABiosciences. The cytotoxicity of ARPE-19 cells was determined with the CellTiter-Blue cell viability assay. The effects of curcumin on potential miRNA targets were analyzed with quantitative real-time PCR and western blotting. Results: Curcumin treatment alone for 6 h had no effect on ARPE-19 cell viability. Incubation with H 2 O 2 (200 µM) alone for 18 h decreased cell viability by 12.5%. Curcumin alone downregulated 20 miRNAs and upregulated nine miRNAs compared with controls. H 2 O 2 downregulated 18 miRNAs and upregulated 29 miRNAs. Furthermore, curcumin pretreat- ment in cells exposed to H 2 O 2 significantly reduced the H 2 O 2 -induced expression of 17 miRNAs. As determined with quantitative real-time PCR and western blotting, curcumin increased the expression of antioxidant genes and reduced angiotensin II type 1 receptor, nuclear factor-kappa B, and vascular endothelial growth factor expression at the mes- senger RNA and protein levels. Conclusions: The results demonstrated that curcumin alters the expression of H 2 O 2 -modulated miRNAs that are puta- tive regulators of antioxidant defense and renin-angiotensin systems, which have been reported to be linked to ocular diseases.