The Vegf Receptor FLT-1 (Vegfr-1) Is a Positive Modulator of Vascular Sprout Formation and Branching Morphogenesis

VEGF and endothelial guidance in angiogenic sprouting

“…10 However, FLT1 may help to shape the extracellular VEGF gradient, as the soluble form of FLT1 (sFLT1) might act as a VEGF sink, keeping VEGF levels low close to the vessel stalk cells. 26 Although all VEGF isoforms appear to induce filopodia formation, the effects on filopodia morphology and vascular patterning are strictly isoform specific. For example, Ruhrberg and colleagues found that mouse hindbrains expressing solely VEGF188 contained many tip cells that extended numerous long filopodia, whereas tip cells were sparser and tip cell filopodia shorter in the presence of VEGF120 only.…”

“…Bautch and colleagues had earlier suggested that cell proliferation and VEGF gradient formation in the embryoid body system is regulated by FLT1, in particular the soluble form, which acts as an extracellular VEGF sink around established vessels. 26,29 They then showed that diffusible VEGF120 and loss of soluble FLT1 both led to randomization of the cell division axis, and thus resulted in abberant vessels with enlarged diameter. Based on the results described above, it is tempting to speculate that the vascular abnormalities in mice expressing VEGF120 as the only VEGF isoform are caused by a combination of loss of tip cell polarization and increased stalk cell proliferation, as well as the loss of polarization of stalk cell cytokinesis (Fig.…”

Tubular sprouting as a mode of vascular formation in a colonial ascidian (tunicata)

“…VEGF is a critical inducer of proliferation, migration, sprouting, and tube formation in tissues during angiogenesis (Tammela et al, 2005). Its binding sites VEGFR-1/Flt-1 and VEGFR-2/Flk-1 work in a competitive way to regulate the VEGF signal in response to variations in physiological conditions (Ferrara et al, 2003;Kearney et al, 2004;Roberts et al, 2004;Ferrara, 2005;Marti, 2005;Nanka et al, 2006).…”

Growth Potential of Orbital Cavernous Hemangioma Suggested by Vascular Endothelial Growth Factor and its Receptor Flk-1

“…Flt-1 negatively modulates vascular growth by controlling the rate of endothelial cell division by dampening signaling through flk-1. 12,15,16,22) VEGF signaling through flk-1 produces several cellular responses, including a strong mitogenic signal and a survival signal for endothelial cells and their precursors. 2,7) VEGF is thought to act through a paracrine pathway via receptors flt-1 and flk-1.…”