Isolated lymphatic endothelial cells transduce growth, survival and migratory signals via the VEGF-C/D receptor VEGFR-3

Vascular endothelial growth factor receptor-3 (VEGFR-3/Flt4) binds two know n members of the VEGF ligand family, VEGF-C and VEGF-D, and has a critical function in the remodelling of the primary capillary vasculature of midgest ation embryos. Later during development, VEGFR-3 regulates the growth and m aintenance of the lymphatic vessels. In the present study, we have isolated and cultured stable lineages of blood vascular and lymphatic endothelial c ells from human primary microvascular endothelium by using antibodies again st the extracellular domain of VEGFR-3. We show that VEGFR-3 stimulation al one protects the lymphatic endothelial cells from serum deprivation-induced apoptosis and induces their growth and migration. At least some of these s ignals are transduced via a protein kinase C-dependent activation of the p4 2/p44 MAPK signalling cascade and via a wortmannin-sensitive induction of A kt phosphorylation. These results define the critical role of VEGF-C/VEGFR- 3 signalling in the growth and survival of lymphatic endothelial cells. The culture of isolated lymphatic endothelial cells should now allow further s tudies of the molecular properties of these cells.