Modulation of miRNAs by vitamin C in [H.sub.2][O.sub.2]-exposed human umbilical vein endothelial cells

Vitamin C plays a protective role in oxidative damage by blocking the effects of free radicals. The present study investigated the mechanisms through which vitamin C partly mediates anti-apoptotic and antioxidant functions via the regulation of microRNAs (miRNAs or miRs). For this purpose, a global miRNA expression analysis on human umbilical vein endothelial cells (HUVECs) treated with vitamin C was conducted using microarrays containing human precursor and mature miRNA probes. The results revealed that there were 42 identical miRNAs among the differentially expressed miRNAs in the HUVEC group and [H.sub.2][O.sub.2] + vitamin C-treated HUVEC group compared to the [H.sub.2][O.sub.2]-exposed HUVEC group, including 41 upregulated miRNAs and 1 down-regulated miRNA. Using bioinformatics analysis, differentially expressed miRNAs were investigated to identify novel target mRNAs and signaling pathways. Pathway enrichment analyses revealed that apoptosis, the mitogen-activated protein kinase (MAPK) signaling pathway, phosphoinositide 3-kinase (PI3K)/Akt signaling pathway and oxidative phosphorylation were significantly enriched. The results from western blot analysis demonstrated that the interleukin (IL)10, matrix metalloproteinase (MMP)2, cAMP-response element binding protein (CREB) and p-CREB protein expression levels in HUVECs transfected with hsa-miR-3928-5p and induced by [H.sub.2][O.sub.2] were significantly downregulated; the MAPK9, caspase-3 (CASP3) and p-CASP3 protein expression levels in HUVECs transfected with hsa-miR-323a-5p and induced by [H.sub.2][O.sub.2] were significantly downregulated. The present study therefore demonstrates that vitamin C partly exerts protective effects on HUVECs through the regulation of miRNA/mRNA axis expression.