Activation of vascular endothelial growth factor receptor-1 sustains angiogenesis and Bcl-2 expression via the phosphatidylinositol 3-kinase pathway in endothelial cells

Cai, Jun, Ahmad, Shakil, Jiang, Wen G., Huang, Jianhua, Kontos, Christopher D., Boulton, Mike and Ahmed, Asif (2003). Activation of vascular endothelial growth factor receptor-1 sustains angiogenesis and Bcl-2 expression via the phosphatidylinositol 3-kinase pathway in endothelial cells. Diabetes, 52 (12), pp. 2959-2568.

Abstract

Vascular insufficiency and retinal ischemia precede many proliferative retinopathies and stimulate secretion of various vasoactive growth factors, including vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF). It is unclear, however, how PlGF, which is elevated in proliferative diabetic retinopathy and is a VEGF homolog that binds only to VEGF receptor (VEGFR)-1, promotes pathological angiogenesis. When primary microvascular endothelial cells were grown on collagen gels, PlGF-containing ligands upregulated Bcl-2 expression and stimulated the formation of capillary-like tube networks that were retained for up to 14 days in culture. The inhibition of VEGFR-1 results in a dramatic decrease in the number of capillary connections, indicating that VEGFR-1 ligands promote branching angiogenesis. In contrast, VEGF-induced tube formations and Bcl-2 expression were significantly decreased at the end of this period. Flow cytometry analysis of annexin-V/propidium iodide-stained cells revealed that PlGF and PlGF/VEGF heterodimer inhibited apoptosis in serum-deprived endothelial cells. These two growth factors stimulated a survival signaling pathway phosphatidylinositol 3-kinase (PI3K), as identified by increased Akt phosphorylation and because blocking PI3K signalling by adenovirus-mediated overexpression of wild-type phosphatase and tensin homolog on chromosome 10 (PTEN) disrupted angiogenesis and decreased Bcl-2 expression by PlGF and PlGF/VEGF heterodimer, whereas a dominant-negative PTEN mutant enhanced endothelial sprout formation and Bcl-2 expression. Together, these findings indicate that PlGF-containing ligands contribute to pathological angiogenesis by prolonging cell survival signals and maintaining vascular networks.

Publication DOI: https://doi.org/10.2337/diabetes.52.12.2959
Divisions: Life & Health Sciences > Biosciences
Life & Health Sciences
Aston Medical School
Uncontrolled Keywords: empty virus,VEGF receptor,VEGFR,vascular endothelial growth factor,VEGF,tumor necrosis factor-α,bovine retinal endothelial cell,phosphatase and tensin homolog on chromosome 10,microvascular endothelial cell basal medium,phosphatidylinositol 3-kinase,PI3K,placenta growth factor,platelet-derived growth factor,adenovirus of wild-type phosphatase and tensin homolog on chromosome 10,adenovirus of catalytic inactive mutant of phosphatase and tension homolog on chromosome 10
Full Text Link: http://diabetes.diabetesjournals.org/content/52/12/2959
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Published Date: 2003-12
Authors: Cai, Jun
Ahmad, Shakil ( 0000-0002-9294-0475)
Jiang, Wen G.
Huang, Jianhua
Kontos, Christopher D.
Boulton, Mike
Ahmed, Asif

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