title: Autocrine VEGF and IL-8 Promote Migration via Src/Vav2/Rac1/PAK1 Signaling in Human Umbilical Vein Endothelial Cells.
abstract: OBJECTIVE
  Pro-angiogenic factors VEGF and IL-8 play a major role in modulating the migratory potential of endothelial cells. The goal of this study was to investigate the effect of autocrine VEGF and IL-8 in the form of self-conditioned medium (CM) on human umbilical vein endothelial cells (HUVECs).
  
  
  METHODS
  Enzyme-linked immunosorbent assay (ELISA) examined the automatic secretion of VEGF and IL-8 protein by HUVECs. Western blot, small interfering RNA (siRNA), pulldown and Transwell assays were used to explore the role and the mechanism of autocrine VEGF and IL-8 in migration of HUVECs.
  
  
  RESULTS
  Neutralizing VEGF and IL-8 in CM significantly abrogated CM-induced migration of HUVECs. Autocrine VEGF and IL-8 increased Src phosphorylation, Rac1 activity and PAK1 phosphorylation in a time dependent manner. Additionally, blocking Rac1 activity with Rac1 siRNA largely abolished autocrine VEGF and IL-8-induced cell migration. Vav2 siRNA suppressed autocrine VEGF and IL-8-induced Rac1 activation and cell migration. Furthermore, blocking Src signaling with PP2, a specific inhibitor for Src, markedly prevented autocrine VEGF and IL-8-induced Vav2 and Rac1 activation as well as consequently cell migration. PAK1 siRNA also significantly abolished autocrine VEGF and IL-8-induced cell migration.
  
  
  CONCLUSIONS
  We demonstrated for the first time that autocrine VEGF and IL-8 promoted endothelial cell migration via the Src/Vav2/Rac1/PAK1 signaling pathway. This finding reveals the molecular mechanism in the increase of endothelial cell migration induced by autocrine growth factors and cytokines, which is expected to provide a novel therapeutic target in vascular diseases.
authors.affiliation: Children's Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ju
authors.affiliation: Children's Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Children's Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.affiliation: Children's Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lou
authors.affiliation: Department of Pediatrics, Nanjing Maternity and Child Health Care Hospital of Nanjing Medical University, Nanjing, China.|Institute of Pediatrics, Nanjing Medical University, Nanjing, China.
authors.forename: Xirong
authors.initials: X
authors.lastname: Guo
mesh_terms: D019898:Autocrine Communication / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D051567:Proto-Oncogene Proteins c-vav; C107953:RAC1 protein, human; C093651:VAV2 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D019061:src-Family Kinases; C515903:PAK1 protein, human; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein
keywords: Endothelial cells; IL-8; PAK1; Rac1; Src; VEGF