miRNA-24 Down-Regulates Endothelial Nitric Oxide Synthase Expression and Inhibits Endothelial Cell Tube Formation

Abstract

Background: This study is to investigate the effects of miR-24 on expression of eNOS and Sp1, the proliferation, migration, and tube formation abilities of human umbilical vein endothelial cells (HUVECs). Results: After transfection with miR-24 overexpression plasmid or anti-miR-24, miR-24 was successfully over-expressed or inhibited. Compared with the control group, the HUVEC proliferation and cell number in the miR-24 high expression group was significantly decreased. Moreover, for the miR-24 high expression group, the cell motility was slower, and the migrating cells were significantly decreased by 61.20%, with very few capillaries in the Matrigel assay. Furthermore, the mRNA and protein expression levels of eNOS were decreased by 44.44% and 47.00 %, respectively. Meanwhile, the mRNA and protein levels of Sp1 were significantly decreased by 34.88% and 68.00%, respectively. In the miR-24 interference group, the above indexes were decreased compared with control group, while significantly increased compared with the miR-24 high expression group, especially concerning the number of branches and the tube length. Moreover, the Sp-1 and eNOS mRNAs were found to be the direct targets of miR-24 by a luciferase reporter system.Conclusion: Over-expression of miR-24 significantly suppresses cell proliferation, migration, and tube formation ability of HUVECs, via regulating eNOS expression. The transcription factor Sp1, a target of miR-24, might contribute to the eNOS expression regulation and the inhibiting effects on HUVECs.