Question:

Although the influence of several miRNAs on endothelial cell (EC) function has been reported, the diversity of miRNA expression between in vivo and in vitro conditions is unclear.

Methodology and Results:

The miRNA profiling revealed that miR-223 is highly expressed in freshly isolated EC but dramatically decreased in cultured HUVEC (P1), mouse lung EC and pig aorta EC. Overexpression of pre-miR-223 inhibited HUVEC migration in a scratch wound assay and transwell migration assay in response to VEGF or bFGF. Inhibitory effect of miR-223 on HUVEC proliferative responses to VEGF and bFGF was discovered with impaired AKT phosphorylation. miR-223 overexpression inhibited HUVEC tube formation on Matrigel and prevented the formation of HUVEC sprouts in a modified spheroid assay. Moreover, in miR-223 knockout mice we detected an increased neovascularisation in Matrigel plugs containing VEGF and bFGF and accelerated recovery of perfusion after hind limb ischemia. Beta 1 integrin (ITGB1) was identified as a target gene of miR-223 by proteomic approach and confirmed by western blot, qPCR and 3’ UTR reporter gene assay. Exogenous expressed ITGB1 not only rescued decreased ITGB1 in HUVEC cell surface, but also partially rescue miR-223 impaired endothelial tube formation. High level of ITGB1 in endothelial cells from aorta, lung and hind limb of miR-223 knockout mice proved the in vivo regulatory links between miR-223 and ITGB1.

Conclusion:

Taken together, these results suggest that miR-223 is an anti-angiogenic miRNA via targeting ITGB1, and indicate a therapeutic direction for angiogenic diseases through modulating miR-223.