MicroRNAs-223 Antagonises Angiogenesis by Targeting β1 Integrin and Preventing Growth Factor Signaling in Endothelial Cells
Rationale: Endothelial cells in situ are largely quiescent and their isolation and culture is associated with the switch to a proliferative phenotype.
Objective: To identify anti-angiogenic microRNAs (miRNAs) expressed by native endothelial cells that are altered after isolation and culture, as well as the protein targets that regulate responses to growth factors.
Methods and Results: Profiling studies revealed that miR-223 was highly expressed in freshly isolated human, murine and porcine endothelial cells but that levels decreased in culture. In primary cultures of endothelial cells, vascular endothelial cell growth factor (VEGF) and basic fibroblast growth factor (bFGF) further decreased miR-223 expression. The overexpression of pre-miR-223 did not affect basal endothelial cell proliferation but abrogated VEGF- and bFGF-induced proliferation as well as migration and sprouting. Inhibition of miR-223 in vivo using specific antagomirs potentiated postnatal retinal angiogenesis in wild-type mice while recovery of perfusion after hindlimb ligation and endothelial sprouting from aortic rings from adult miR-223-/y animals were enhanced. MiR-223 overexpression had no effect on the growth factor-induced activation of ERK1/2 but inhibited the VEGF- and bFGF-induced phosphorylation of their receptors and activation of Akt. β1 integrin was identified as a target of miR-223 and its downregulation reproduced the defects in growth factor receptor phosphorylation and Akt signaling seen after miR-223 overexpression. Reintroduction of β1 integrin into miR-223 ovexpressing cells was sufficient to rescue growth factor signaling and angiogenesis.
Conclusions: These results indicate that miR-223 is an anti-angiogenic miRNA that prevents endothelial cell proliferation at least partly by targeting β1 integrin.
- Growth factor receptor phosphorylation
- beta1 integrin
- aortic ring assay
- growth factors and cytokines
- vascular endothelial growth factor receptor
- vascular remodeling
- Received May 17, 2013.
- Revision received September 13, 2013.
- Accepted September 16, 2013.