title: Pleiotrophin, a multifunctional angiogenic factor: mechanisms and pathways in normal and pathological angiogenesis.
abstract: OBJECTIVE
  This study seeks to integrate recent studies that identify new critical mechanisms through which the 136 amino acid secreted heparin-binding cytokine pleiotrophin (PTN, Ptn) stimulates both normal and pathological angiogenesis.
  
  
  RESULTS
  Pleiotrophin is directly angiogenic; it initiates an angiogenic switch in different cancer models in vivo. It acts as an angiogenic factor through multiple mechanisms that include a unique signaling pathway that activates newly identified downstream tyrosine kinases through a unique mechanism, an interaction with endothelial cells to initiate proliferation, migration, and tube formation, the regulation of basic fibroblast growth factor and vascular endothelial growth factor signaling, the remodeling of the stromal microenvironment, and induction of transdifferentiation of monocytes into endothelial cells. Recently also, domains of PTN that stimulate angiogenesis and peptides that function to inhibit PTN signaling have been identified.
  
  
  CONCLUSIONS
  Recent studies have identified new mechanisms dependent on activation of the PTN signaling pathway that regulate angiogenesis and new targets to use PTN to both stimulate angiogenesis and block its activity to control pathological angiogenesis.
authors.affiliation: The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Pablo
authors.initials: P
authors.lastname: Perez-Pinera
authors.forename: James R
authors.initials: JR
authors.lastname: Berenson
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Deuel
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D016207:Cytokines / Q000502:physiology*; D042783:Endothelial Cells / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D009389:Neovascularization, Pathologic / Q000503:physiopathology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; C066845:pleiotrophin