title: Reduced adult endothelial cell EphB4 function promotes venous remodeling.
abstract: Reduced EphB4 expression is observed during vein graft adaptation and is associated with increased venous wall thickening. These findings suggest that EphB4 may mediate normal adult venous endothelial cell (EC) function and vein graft adaptation. We therefore tested the functional significance of EphB4 using EC with genetically reduced EphB4 signaling. EC were isolated from EphB4(+/+) and EphB4(+/-) mice. In vitro function was assessed through EC proliferation, migration, nitric oxide (NO) synthesis, and chemokine production. A mouse vein graft model was used to correlate in vitro findings with in vivo vein grafts. Smooth muscle cells (SMC) were subjected to proliferation and migration assays using EphB4(+/+) and EphB4(+/-) EC-conditioned medium. EphB4(+/-) EC exhibited diminished proliferation (P < 0.0001, n = 6), migration (P < 0.0001, n = 3), and NO production (P = 0.0012, n = 3). EphB4(+/-) EC had increased VEGF-A mRNA (P = 0.0006, n = 6) and protein (P = 0.0106, n = 3) as well as increased secretion of VEGF-A (P = 0.0010, n = 5), PDGF-BB (P < 0.0001, n = 6), and TGF-β1 (P < 0.0001, n = 6). EphB4(+/-)-conditioned medium promoted SMC proliferation (P < 0.0001, n = 7) and migration (P = 0.0358, n = 3). Vein grafts and EphB4(+/-) EC showed similarity with regard to VEGF-A and eNOS mRNA and protein expression. In conclusion, reduced venous EC EphB4 function is associated with a proangiogenic and mitogenic phenotype. EphB4(+/-) EC have increased secretion of SMC mitogens and reduced NO production that correlate with the thickened neointima formed during vein graft adaptation. These findings suggest that EphB4 remains active in adult venous EC and that loss of EphB4 plays a role in vein graft adaptation.
authors.affiliation: The Interdepartmental Program in Vascular Biology and Therapeutics and the Department of Surgery, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: Caroline C
authors.initials: CC
authors.lastname: Jadlowiec
authors.forename: Amanda
authors.initials: A
authors.lastname: Feigel
authors.forename: Chenzi
authors.initials: C
authors.lastname: Yang
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Feinstein
authors.forename: Susun T
authors.initials: ST
authors.lastname: Kim
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Collins
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kondo
authors.forename: Akihito
authors.initials: A
authors.lastname: Muto
authors.forename: Alan
authors.initials: A
authors.lastname: Dardik
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D002465:Cell Movement; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D008168:Lung / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D009154:Mutation; D010766:Phosphorylation; D036224:Receptor, EphB4 / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D014682:Vena Cava, Inferior / Q000637:transplantation
chemical_list: D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C086681:Ephb4 protein, mouse; D036224:Receptor, EphB4