Quantification of VEGFRs, NRP1, and PDGFRs on Endothelial Cells and Fibroblasts Reveals Serum, Intra-Family Ligand, and Cross-Family Ligand Regulation

摘要

Computational modeling of angiogenesis is limited by a lack of experimental data on angiogenic receptor levels. Recent receptor profiling quantified vascular endothelial growth factor receptors (VEGFRs); however data on other angiogenic receptors, such as platelet derived growth factor receptors (PDGFRs), are also necessary for the development of an accurate angiogenesis model. Here, we establish conditions for membrane PDGFR quantification. Additionally, we determine how several environmental conditions control membrane PDGFR levels on human dermal fibroblasts. We demonstrate that membrane PDGFR beta concentrations are negatively correlated with bothmedia serumconcentration and cell growth rate, in vitro. We also show VEGF-A(165)-mediated downregulation of membrane PDGFR alpha (similar to 25%) and PDGFR beta (similar to 30%), following a 24-h treatment. This supports the idea that VEGF-A(165) acts independently of VEGFRs to signal through PDGFRa and PDGFRb. We observe that PDGF-AA and PDGF-AB down-regulate membrane PDGFR alpha by up to 55 and 75%, respectively, while having little to no effect on PDGFR beta or NRP1. We observe that PDGF-BB effects both PDGFRs and NRP1: membrane PDGFRa and PDGFRb were downregulated by up to 70 and 90%, respectively, whereas membrane NRP1 was upregulated by up to 40%. These data provide the necessary insight to accurately represent PDGFRs in angiogenesis models, while offering new insight into the regulation of membrane PDGFRs.