MicroRNA-223 Antagonizes Angiogenesis by Targeting β1 Integrin and Preventing Growth Factor Signaling in Endothelial Cells

Abstract

Rationale: Endothelial cells in situ are largely quiescent, and their isolation and culture are associated with the switch to a proliferative phenotype. Objective: To identify antiangiogenic microRNAs 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 those levels decreased in culture. In primary cultures of endothelial cells, vascular endothelial cell growth factor and basic fibroblast growth factor further decreased miR-223 expression. The overexpression of precursor-miR-223 did not affect basal endothelial cell proliferation but abrogated vascular endothelial cell growth factor–induced and basic fibroblast growth factor–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, whereas recovery of perfusion after femoral artery 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 vascular endothelial cell growth factor–induced and basic fibroblast growth factor–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 antiangiogenic microRNA that prevents endothelial cell proliferation at least partly by targeting β1 integrin.

MicroRNA-223 Made Its Way Into Vascular Research

“…In conclusion, Shi et al 4 made an important observation that should be taken into account in future research; caution is needed when extrapolating miRNA expression findings ex vivo/in vitro into an in vivo scenario. In addition, the authors identified a novel finding with potential clinical importance of miR-223 to be of great diagnostic and therapeutic use in the combat of cardiovascular diseases.…”

“…In this issue of Circulation Research, Shi et al 4 identified the reason why only recently miR-223 made its way into vascular research. The authors identified that freshly isolated endothelial cells display high levels of miR-223 that was lost quickly under culture conditions.…”

Recent Developments in Cardiovascular Genetics and Genomics

“…12,84,[92][93][94][95][96][97] Similarly, a large number of microRNAs are implicated in vascular phenotypes ranging from pulmonary hypertension to aortic aneurysm. 77,79,[98][99][100][101][102][103][104][105][106][107] For example, microRNA-145 was recently shown to be upregulated in the lung tissue of patients with pulmonary hypertension and might be a contributing factor to the pathogenesis of pulmonary hypertension. 108 MicroRNA-10, microRNA-15a, microRNA-16, microRNA-26a, microR-NA-223, and microRNA-663 are involved in angiogenesis and regulate vascular smooth muscle and endothelial cell phenotypes.…”

“…108 MicroRNA-10, microRNA-15a, microRNA-16, microRNA-26a, microR-NA-223, and microRNA-663 are involved in angiogenesis and regulate vascular smooth muscle and endothelial cell phenotypes. 76,98,[105][106][107] MicroRNA-29b, microRNA-22, and microRNA-30c are involved in myocardial interstitial fibrosis and heart failure. 97,109,110 An intriguing function of microRNAs is in cell-fate determination, differentiation, and cardiac regeneration.…”

Circulation Research “In This Issue” Anthology

“…Beta1 Integrin, a Direct Target of miR-223 (p 1320) 68 MicroRNA-223 prevents proliferation of endothelial cells and is antiangiogenic, say Shi et al…”