The role of miR-328 in high glucose-induced endothelial-to-mesenchymal transition in human umbilical vein endothelial cells.

Aims: Endothelial-to-mesenchymal transition (EndMT) contribute to diabetic cardiac fibrosis, the underlying mechanisms are poorly understood. In the study, we aimed to investigate the role of miR-328 in EndMT mediated by high glucose (HG) and the signaling pathways implicated in human umbilical vein endothelial cells (HUVECs).

Materials And Methods: EndMT of HUVECs was determined by immunofluorescent staining and western blot of the markers CD31 and α-SMA. Real-time polymerase chain reaction was used to detect mRNA expression of miR-328 and transforming growth factor β (TGF-β). SB431542 was used to study the relation of miR-328 and TGF-β during EndMT induced by HG. Over-expression and inhibition of miR-328 were achieved by transduction of miR-328 and antagomiR-328. The effects of miR-328 on expression of type I and III collagen, p-MEK1/2, p-ERK1/2 were examined by Western blot.

Key Findings: The level of miR-328 was significantly up-regulated in HG-induced EndMT. MiR-328 showed the independent capability of inducing EndMT, which was not related to TGF-β, and this effect was abrogated by antagomiR-328. MiR-328 affected type I collagen in a time- and dose-dependent manner and enhanced protein expression of type I and III collagens. Further investigation displayed that a significantly higher expression of p-MEK1/2 and p-ERK1/2 in HUVECs transduced with miR-328, and a lower expression of p-MEK1/2 and p-ERK1/2 in cells transduced with antagomiR-328.

Significance: These results suggest a novel role for miR-328 in HG-induced EndMT, MEK1/2-ERK1/2 pathway is likely to be involved in the associated effects. Our findings may suggest antagomiR-328 as an alternative agent in prevention of HG-induced EndMT.