Fig. 6.

Endothelial cells derived from human umbilical vein endothelial cells (HUVEC) express low levels of classic Netrin receptors and both Netrin-1 (NTN-1) and Netrin-4 (NTN-4) ligands. a mRNA levels of classic (■) and non-classic (□) Netrin receptors were quantified by qPCR relative to GAPDH expression (dashed line). Values are mean ± S.E.M. (n = 7). b Absence of DCC expression in HUVEC was established by Western blot, while Neogenin-1 as well as UNC5b and UNC5c expression could be detected. Endogenous Netrins and vascular endothelial growth factor (VEGF) expression in HUVEC was determined by Western blot. β-actin was used as internal reference (n = 5–7). c The non-classical Netrin receptor integrin α3β1 was also detected by flow cytometry (n = 3). d Immunofluorescence for receptors and ligands in HUVEC (magnification × 63). eNOS (endothelial nitric oxide synthase) or CD-31 (PECAM) were used as endothelial cell markers and DAPI for nuclear counterstain