Autocrine activity of soluble Flt-1 controls endothelial cell function and angiogenesis

Main Article Content

Shakil Ahmad Peter W Hewett Bahjat Al-Ani Samir Sissaoui Takeshi Fujisawa Melissa J Cudmore Asif Ahmed

Abstract

Background

The negative feedback system is an important physiological regulatory mechanism controlling angiogenesis. Soluble vascular endothelial growth factor (VEGF) receptor-1 (sFlt-1), acts as a potent endogenous soluble inhibitor of VEGF- and placenta growth factor (PlGF)-mediated biological function and can also form dominant-negative complexes with competent full-length VEGF receptors.

Methods and results

Systemic overexpression of VEGF-A in mice resulted in significantly elevated circulating sFlt-1. In addition, stimulation of human umbilical vein endothelial cells (HUVEC) with VEGF-A, induced a five-fold increase in sFlt-1 mRNA, a time-dependent significant increase in the release of sFlt-1 into the culture medium and activation of the flt-1gene promoter. This response was dependent on VEGF receptor-2 (VEGFR-2) and phosphoinositide-3'-kinase signalling. siRNA-mediated knockdown of sFlt-1 in HUVEC stimulated the activation of endothelial nitric oxide synthase, increased basal and VEGF-induced cell migration and enhanced endothelial tube formation on growth factor reduced Matrigel. In contrast, adenoviral overexpression of sFlt-1 suppressed phosphorylation of VEGFR-2 at tyrosine 951 and ERK-1/-2 MAPK and reduced HUVEC proliferation. Preeclampsia is associated with elevated placental and systemic sFlt-1. Phosphorylation of VEGFR-2 tyrosine 951 was greatly reduced in placenta from preeclamptic patients compared to gestationally-matched normal placenta.

Conclusion

These results show that endothelial sFlt-1 expression is regulated by VEGF and acts as an autocrine regulator of endothelial cell function.

Article Details

How to Cite
AHMAD, Shakil et al. Autocrine activity of soluble Flt-1 controls endothelial cell function and angiogenesis. Vascular Cell, [S.l.], v. 3, n. 1, p. 15, july 2011. ISSN 2045-824X. Available at: <https://vascularcell.com/index.php/vc/article/view/10.1186-2045-824X-3-15>. Date accessed: 19 sep. 2018. doi: http://dx.doi.org/10.1186/2045-824X-3-15.
Section
Original Research