title: Cooperative and redundant roles of VEGFR-2 and VEGFR-3 signaling in adult lymphangiogenesis.
abstract: Activation of vascular endothelial growth factor (VEGF) receptor-3 (VEGFR-3) by VEGF-C initiates lymphangiogenesis by promoting lymphatic proliferation and migration. However, it is unclear whether VEGFR-3 signaling is required beyond these initial stages, namely during the organization of new lymphatic endothelial cells (LECs) into functional capillaries. Furthermore, the role of VEGFR-2, which is also expressed on LECs and binds VEGF-C, is unclear. We addressed these questions by selectively neutralizing VEGFR-3 and/or VEGFR-2 for various time periods in an adult model of lymphangiogenesis in regenerating skin. While blocking either VEGFR-2 or VEGFR-3 with specific antagonist mAbs (DC101 and mF4-31C1, respectively) prior to lymphatic migration prevented lymphangiogenesis, blocking VEGFR-3 subsequent to migration did not affect organization into functional capillaries, and VEGFR-2 blocking had only a small hindrance on organization. These findings were confirmed in vitro using human LECs and anti-human antagonist mAbs (IMC-1121a and hF4-3C5): both VEGFR-2 and -3 signaling were required for migration and proliferation, but tubulogenesis in 3D cultures was unaffected by VEGFR-3 blocking and partially hindered by VEGFR-2 blocking. Furthermore, both in vitro and in vivo, while VEGFR-3 blocking had no effect on LEC organization, coneutralization of VEGFR-2, and VEGFR-3 completely prevented lymphatic organization. Our findings demonstrate that cooperative signaling of VEGFR-2 and -3 is necessary for lymphatic migration and proliferation, but VEGFR-3 is redundant with VEGFR-2 for LEC organization into functional capillaries.
authors.affiliation: Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Goldman
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Rutkowski
authors.forename: Jacqueline D
authors.initials: JD
authors.lastname: Shields
authors.forename: Miriella C
authors.initials: MC
authors.lastname: Pasquier
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Cui
authors.forename: Hugo G
authors.initials: HG
authors.lastname: Schmökel
authors.forename: Stephen
authors.initials: S
authors.lastname: Willey
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hicklin
authors.forename: Bronislaw
authors.initials: B
authors.lastname: Pytowski
authors.forename: Melody A
authors.initials: MA
authors.lastname: Swartz
mesh_terms: D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008208:Lymphatic System; D051379:Mice; D008807:Mice, Inbred BALB C; D015398:Signal Transduction; D012867:Skin / Q000378:metabolism; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism / Q000502:physiology*; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism / Q000502:physiology*; D014945:Wound Healing
chemical_list: D042582:Vascular Endothelial Growth Factor C; D040301:Vascular Endothelial Growth Factor Receptor-2; D040321:Vascular Endothelial Growth Factor Receptor-3