Down-Regulation Of Kruppel-Like Factor-4 By MicroRNA-92A Is Critical For Regulation Of Endothelial Function By Sonic Hedgehog Signaling

Background Sonic hedgehog (Shh) signaling was implicated in arteriosclerosis. MicroRNA-92a (miRNA-92a) was demonstrated that associated with maintaining endothelial function. MiRNA -92 is also overexpressed specifically in human medulloblastoma with a Shh signaling. Whether Shh signaling regulated the endothelial function in endothelial cells has yet to be elucidated. Here, our study aimed to access the mechanism of Shh signaling for regulation of endothelial function.Methods and Results Overexpression of Shh signaling increased the level of miRNA-92a and decreased the level of kruppel-like factor-4 (KLF4) mRNA and protein, and down-regulation of Shh signaling will decrease miRNA -92a and increased KLF4 in human umbilical vein endothelial cells (HUVECs), suggesting that KLF4 is regulated by Shh signaling. In silico analyses predicted highly conserved binding sites in the 3’-untranslated region (3’UTR) of KLF4 for miR-92a. There are two evolutionarily conserved miR-92a sites in KLF4 3’UTR. Luciferase reporter assays demonstrated functional interactions of miR-92a with 3’UTR sequences of KLF4 and with the specific binding site. Knockdown of miR-92a increased the expression of KLF4 and endothelial nitric oxide synthase (eNOS) and thrombomodulin at mRNA and protein levels. Furthermore, we co-transfected Shh and anti-miR-92a into HUVECs,and the level of Shh-induced KLF4 was ascended. Our study revealed that overexpression of Shh up-regulated the level of miR-92a to inhibit KLF4.Conclusion Our study demonstrates that Shh signaling increased the level of miR-92a, which can inhibit KLF4 expression to damage endothelial function.