Vasculotropin/Vascular endothelial growth factor is an autocrine growth factor for human retinal pigment epithelial cells cultued in vitro

Abstract

Vasculotropin (VAS), also called vascular endothelial growth factor (VEGF) or vascular permeability factor, is a secreted growth factor whose target cell specificity has been reported as restricted to vascular endothelium. Its effects are mediated by at least two distinct membrane-spanning tyrosine kinase receptors, KDR and flt-1; the expression of which also seems restricted to vascular endothelium. We describe here that cultured human retinal pigment epithelial (HRPE) cells express both KDR and flt-1 receptors, bind VAS/VEGF on two high affinity sites (apparent Kd of 9 and 210 pM corresponding to 940 and 18,800 sites per cell) and proliferate or migrate upon recombinant VAS/VEGF addition. HRPE cells also express the mRNA corresponding to the 121 and 165 amino acid forms of VAS/VEGF. HRPE cells release in their own culture medium and store in their extracellular matrix self-mitogenic and chemoattractant factors indistinguishable from 121 and 165 VAS/VEGF isoforms. The autocrine role of VAS/VEGF was confirmed by the inhibition of these bioactivities by neutralizing specific anti-VAS/VEGF antibodies.

Overexpression of vascular endothelial growth factor induces cell transformation in cooperation with fibroblast growth factor 2

“…In human retinal pigment epithelial (RPE) cells, we also evidenced high a nity binding sites for VEGF, associated with mitogenic and chemotactic e ects. These cells express the mRNA coding for the two VEGF receptors, KDR and¯t-1 (Guerrin et al, 1995). In agreement with Adamis et al (1993), we found that cultured RPE cells express the 121 and 165 amino acid forms of VEGF.…”

“…Our previous studies have evidenced that VEGF acts as an autocrine growth factor for human RPE cells (Guerrin et al, 1995). To determine whether the eightfold increase of bioactive VEGF modi®ed the growth characteristics of rat RPE cells, proliferation assays were performed in monolayers and in soft agar.…”

“…Cells were grown to subcon¯uence and incubated or not with 100 mg/ml of anti-FGF2 (PloueÈ t et al, 1989) or anti-VEGF (Guerrin et al, 1995) IgG for 24 h at 378C. The cultures were then washed twice in ice-cold binding medium (DMEM-20 mM HEPES, pH 7.3-gelatin 1 mg/ml) and incubated in the same medium with 10 ng/ml [ 125 I]FGF-2.…”

“…The activation of KDR receptor induces mitogenicity in endothelial cells (Waltenberger et al, 1994). Although VEGF activity is mainly restricted to endothelial cells, we recently reported a VEGF autocrine loop in human retinal pigment epithelial (RPE) cells (Guerrin et al, 1995).…”

Inhibitory efficacy of hypoxia-inducible factor 1α short hairpin RNA plasmid DNA-loaded poly (D, L-lactide-co-glycolide) nanoparticles on choroidal neovascularization in a laser-induced rat model

“…28,53 Earlier studies have indicated that disruption of the binding between HIF-1 and proangiogenic promoters may selectively diminish the activation of the HIF-1-driven target genes. 54 Therefore, inhibition of HIF-1a could directly or indirectly regulate the expression of these angiogenic factors, especially VEGF, thus leading to the suppression of CNV. The technology of RNAi is an intriguing and powerful method of gene downregulation, which has been widely used to study gene function and target discovery.…”