Intrinsic versus microenvironmental regulation of lymphatic endothelial cell phenotype and function.
Vascular endothelial cells are characterized by a high degree of functional and phenotypic plasticity, which is controlled both by their pericellular microenvironment and their intracellular gene expression programs. To gain further insight into the mechanisms regulating the endothelial cell phenotype, we have compared the responses of lymphatic endothelial cells (LECs) and blood vascular endothelial cells (BECs) to vascular endothelial growth factors (VEGFs). VEGFR-3-specific signals are sufficient for LEC but not BEC proliferation, as shown by the ability of the specific ligand VEGF-C156S to stimulate cell cycle entry only in LECs. On the other hand, we found that VEGFR-3 stimulation did not induce LEC cell shape changes typical of VEGFR-2-stimulated LECs, indicating receptor-specific differences in the cytoskeletal responses. Genes induced via VEGFR-2 also differed between BECs and LECs: angiopoietin-2 (Ang-2) was induced via VEGFR-2 in BECs and LECs, but the smooth muscle cell (SMC) chemoattractant BMP-2 was induced only in BECs. Both BECs and LECs were able to promote SMC chemotaxis, but contact with SMCs led to down-regulation of VEGFR-3 expression in BECs in a 3-dimensional coculture system. This was consistent with the finding that VEGFR-3 is down-regulated in vivo at sites of endothelial cell-pericyte/smooth muscle cell contacts. Collectively, these data show intrinsic cell-specific differences of BEC and LEC responses to VEGFs and identify a pericellular regulatory mechanism for VEGFR-3 down-regulation in endothelial cells.
Molecular/Cancer Biology Laboratory and Ludwig Institute for Cancer Research, Biomedicum Helsinki, Haartman Institute and Helsinki University Central Hospital, 00014 University of Helsinki, Finland.
Tanja
T
Veikkola
Marja
M
Lohela
Kristian
K
Ikenberg
Taija
T
Mäkinen
Thomas
T
Korff
Anne
A
Saaristo
Tatania
T
Petrova
Michael
M
Jeltsch
Hellmut G
HG
Augustin
Kari
K
Alitalo
D042702:Angiopoietin-2 / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D002450:Cell Communication; D002455:Cell Division; D002465:Cell Movement; D002478:Cells, Cultured; D004727:Endothelium / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D008208:Lymphatic System / Q000166:cytology*; D009130:Muscle, Smooth / Q000502:physiology; D010641:Phenotype; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism
D042702:Angiopoietin-2; C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D040321:Vascular Endothelial Growth Factor Receptor-3