title: VEGF-C alters barrier function of cultured lymphatic endothelial cells through a VEGFR-3-dependent mechanism.
abstract: BACKGROUND
  The lymphatic endothelium is an important semi-permeable barrier separating lymph from the interstitial space. However, there is currently a limited understanding of the lymphatic endothelial barrier and the mechanisms of lymph formation. The objectives of this study were to investigate the potential active role of lymphatic endothelial cells in barrier regulation, and to test whether the endothelial cell agonists VEGF-A and VEGF-C can alter lymphatic endothelial barrier function.
  
  
  RESULTS
  Cultured adult human dermal microlymphatic endothelial cells (HMLEC-d) and human umbilical vein endothelial cells (HUVEC) were respectively used as models of lymphatic and vascular endothelium. Transendothelial electrical resistance (TER) of endothelial monolayers served as an index of barrier function. Cells were treated with VEGF-A, VEGF-C, or the VEGFR-3 selective mutant VEGF-C156S. MAZ51 was used to inhibit VEGFR-3 signaling. The results show that while VEGF-A causes a time-dependent decrease in TER in HUVEC, there is no response in HMLEC-d. In contrast, VEGF-C and VEGF-C156S cause a similar decrease in TER in HMLEC-d that is not observed in HUVEC. These results corresponded to the protein expression of VEGFR-2 and VEGFR-3 in these cell types, determined by Western blotting. In addition, the VEGF-C- and VEGF-C156S-induced TER changes were inhibited by MAZ51.
  
  
  CONCLUSIONS
  The results indicate differential responses of the lymphatic and vascular endothelial barriers to VEGF-A and VEGF-C. Furthermore, our data suggest that VEGF-C alters lymphatic endothelial function through a mechanism involving VEGFR-3.
authors.affiliation: Department of Surgery, Division of Research, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA. jwbreslin@ucdavis.edu
authors.forename: Jerome W
authors.initials: JW
authors.lastname: Breslin
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Yuan
authors.forename: Mack H
authors.initials: MH
authors.lastname: Wu
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D018925:Chemokines / Q000302:isolation & purification / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D004729:Endothelium, Lymphatic / Q000166:cytology* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D014471:Umbilical Veins / Q000166:cytology; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism*; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D018925:Chemokines; D042582:Vascular Endothelial Growth Factor C; D040321:Vascular Endothelial Growth Factor Receptor-3