LPS‑induced downregulation of microRNA‑204/211 upregulates and stabilizes Angiopoietin‑1 mRNA in EA.hy926 endothelial cells.

Angiopoietin‑1 (ANG‑1), a ligand of the endothelial cell‑specific TIE2 surface receptor, acts in a complementary and coordinated manner with vascular endothelial growth factor during the process of angiogenesis. ANG‑1 can be used as a clinically informative biomarker of disease severity and outcome in severe sepsis. The epithelium‑specific Ets transcription factor 1 can activate ANG‑1 transcription in the setting of inflammation; however, relatively little is known about the regulation of ANG‑1 by microRNAs (miRs). It was observed that lipopolysaccharide (LPS) significantly increased ANG‑1 mRNA and protein expression in EA.hy926 cells. ANG‑1 was identified as a potential target gene of miR‑204 and miR‑211. Overexpression of miR‑204/211 partially reversed the LPS‑induced ANG‑1 expression in EA.hy926 cells. Furthermore, overexpression of miR‑204/211 significantly reduced the activity of a luciferase reporter gene containing the wild‑type ANG‑1 3'‑untranslated region (UTR), but did not influence the activity of a luciferase reporter gene containing the ANG‑1 3'‑UTR with a mutated miR‑204/211 binding site, confirming that miR‑204/211 can bind to the ANG‑1 3'‑UTR and post‑transcriptionally regulate ANG‑1. Additionally, LPS enhanced the stability of ANG‑1 mRNA by reducing the abundance of miR‑204/211. Overexpression of miR‑204/211 reduced the migration of EA.hy926 cells in vitro. The present study demonstrated that ANG‑1 is a novel direct target gene of miR‑204 and miR‑211; in addition, LPS was able to inhibit this effect by reducing the expression of miR‑204 and miR‑211.