title: Necl-5/poliovirus receptor interacts with VEGFR2 and regulates VEGF-induced angiogenesis.
abstract: BACKGROUND
  Vascular endothelial growth factor (VEGF), a major proangiogenic agent, exerts its proangiogenic action by binding to VEGF receptor 2 (VEGFR2), the activity of which is regulated by direct interactions with other cell surface proteins, including integrin α(V)β(3). However, how the interaction between VEGFR2 and integrin α(V)β(3) is regulated is not clear.
  
  
  OBJECTIVE
  To investigate whether Necl-5/poliovirus receptor, an immunoglobulin-like molecule that is known to bind integrin α(V)β(3), regulates the interaction between VEGFR2 and integrin α(V)β(3), and to clarify the role of Necl-5 in the VEGF-induced angiogenesis.
  
  
  RESULTS
  Necl-5-knockout mice displayed no obvious defect in vascular development; however, recovery of blood flow after hindlimb ischemia and the VEGF-induced neovascularization in implanted Matrigel plugs were impaired in Necl-5-knockout mice. To clarify the mechanism of the regulation of angiogenesis by Necl-5, we investigated the roles of Necl-5 in the VEGF-induced angiogenic responses in vitro. Knockdown of Necl-5 by siRNAs in human umbilical vein endothelial cells (HUVECs) inhibited the VEGF-induced capillary-like network formation on Matrigel, migration, and proliferation, and conversely, enhanced apoptosis. Coimmunoprecipitation assays showed the interaction of Necl-5 with VEGFR2, and knockdown of Necl-5 prevented the VEGF-induced interaction of integrin α(V)β(3) with VEGFR2. Knockdown of Necl-5 suppressed the VEGFR2-mediated activation of downstream proangiogenic and survival signals, including Rap1, Akt, and endothelial nitric oxide synthase.
  
  
  CONCLUSIONS
  These results demonstrate the critical role of Necl-5 in angiogenesis and suggest that Necl-5 may regulate the VEGF-induced angiogenesis by controlling the interaction of VEGFR2 with integrin α(v)β(3), and the VEGFR2-mediated Rap1-Akt signaling pathway.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kinugasa
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Amano
authors.forename: Seimi
authors.initials: S
authors.lastname: Satomi-Kobayashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakayama
authors.forename: Muneaki
authors.initials: M
authors.lastname: Miyata
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kubo
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nagamatsu
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kurogane
authors.forename: Fumie
authors.initials: F
authors.lastname: Kureha
authors.forename: Shota
authors.initials: S
authors.lastname: Yamana
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Hirata
authors.forename: Jun
authors.initials: J
authors.lastname: Miyoshi
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Rikitake
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000502:physiology*; D017209:Apoptosis / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D023421:Models, Animal; D009363:Neoplasm Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D011991:Receptors, Virus / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000502:physiology*; D020827:rap1 GTP-Binding Proteins / Q000502:physiology
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D039302:Integrin alphaVbeta3; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D011991:Receptors, Virus; C476587:Taa1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; C066100:poliovirus receptor; D040301:Vascular Endothelial Growth Factor Receptor-2; D051057:Proto-Oncogene Proteins c-akt; D020827:rap1 GTP-Binding Proteins