Up-regulation of microRNA-17 aggravates vascular endothelial damages in patients with sepsis possibly by down-regulating the expression of ATG 16 L gene

Aims: The present study is to determine the expression of microRNA-17 (miR-17) in the peripheral blood of patients with sepsis, and to investigate its biological functions and mechanisms of action. Methods: Peripheral blood (5 ml) was collected from 35 patients with sepsis and 20 healthy subjects for RNA extraction. Expression of miR-17 was measured using quantitative real-time polymerase chain reaction. Lipopolysaccharide was used to stimulate human umbilical vein endothelial cells (HUVEC). Transfection of HUVEC cells were performed by using Lipofectamine 2000. Cell-Counting Kit 8 assay, transwell assay, flow cytometry, and laser confocal microscopy were carried out to determine HUVEC cell proliferation, migration, apoptosis, and autophagy, respectively. Western blotting was employed to determine protein expression. Interference of ATG16L was achieved by using small interfering RNA. Dual luciferase reporter assay was used to test whether ATG16L is a target gene of miR-17. Results: Elevated expression of miR-17 in peripheral blood was closely related with the occurrence and development of sepsis. Lipopolysaccharide stimulation enhanced the expression of miR-17 in HUVEC cells. Expression of miR-17 inhibited the proliferation of HUVEC cells. Elevated expression of miR-17 reduced the migration ability of HUVEC cells. Increased miR-17 expression promoted the apoptosis of HUVEC cells possibly by regulating the expression of its target genes. Mir-17 expression inhibited the activation of autophagy-related signaling pathways in HUVEC cells, and reduced the autophagy activity of HUVEC cells. Mir-17 exerted its biological effects by regulating its predicted target gene ATG16L1. Mir-17 was able to bind with 3’-UTR of the mRNA of its target gene ATG16L1. Conclusions: The present study demonstrates that up-regulation of miR-17 aggravates vascular endothelial damages by inhibiting cell proliferation, migration and autophagy, and facilitating apoptosis. The mechanism of action is possibly the down-regulation of the expression of miR-17 target gene ATG16L.