Introduction:
Dysregulated angiogenesis is a critical characteristic for endothelial dysfunction disorders. This study aimed to determine functions of microRNA-126 in formation of tube and investigated the potential mechanisms.

Material and methods:
The synthesized microRNA-126 control and microRNA-126 inhibitor plasmids were transfected into human umbilical-vein endothelial cells (HUVECs) using lipofectamine 2000 reagent. Cell counting kit-8 (CCK-8) was employed to measure proliferative capability of HUVECs. Transwell analysis was used to evaluate HUVECs invasive ability. Real time PCR (RT-PCR) was utilized to access epidermal growth factor-like domain 7 (EGFL7) and microRNA-126 mRNA transcription. Tube-forming capability in HUVECs was determined. Dual-luciferase assay and linear-regression analysis were conducted to measure interaction between EGFL7 and microRNA-126 molecule. Phosphoinositide-3-kinase/protein kinase-B (PI3K/AKT) signaling pathway associated molecules were evaluated using western blot assay.

Results:
Silencing of microRNA-126 significantly enhanced proliferative capability and invasive ability of HUVECs compared to those of microRNA-126 control group (p<0.05). microRNA-126 silencing remarkably promoted tube formation and significantly up-regulated EGFL7 compared to those of microRNA-126 control group (p<0.05). microRNA-126 could interact with EGFL7 molecule. microRNA-126 was also negatively correlated with EGFL7 molecule in HUVECs (p<0.05). Silencing of microRNA-126 significantly enhanced p-PI3K/PI3K ratio compared to that of microRNA-126 control group (p<0.05). microRNA-126 silencing also remarkably increased p-AKT/AKT ratio compared to that of microRNA-126 control group (p<0.05).

Conclusions:
microRNA-126 modulated angiogenesis and tube formation through increasing EGFL7 expression and phosphorylating PI3K/AKT signaling pathway.