Angiogenesis in platelet endothelial cell adhesion molecule-1-null mice.
Platelet endothelial cell adhesion molecule (PECAM)-1 has been previously implicated in endothelial cell migration; additionally, anti-PECAM-1 antibodies have been shown to inhibit in vivo angiogenesis. Studies were therefore performed with PECAM-1-null mice to further define the involvement of PECAM-1 in blood vessel formation. Vascularization of subcutaneous Matrigel implants as well as tumor angiogenesis were both inhibited in PECAM-1-null mice. Reciprocal bone marrow transplants that involved both wild-type and PECAM-1-deficient mice revealed that the impaired angiogenic response resulted from a loss of endothelial, but not leukocyte, PECAM-1. In vitro wound migration and single-cell motility by PECAM-1-null endothelial cells were also compromised. In addition, filopodia formation, a feature of motile cells, was inhibited in PECAM-1-null endothelial cells as well as in human endothelial cells treated with either anti-PECAM-1 antibody or PECAM-1 siRNA. Furthermore, the expression of PECAM-1 promoted filopodia formation and increased the protein expression levels of Cdc42, a Rho GTPase that is known to promote the formation of filopodia. In the developing retinal vasculature, numerous, long filamentous filopodia, emanating from endothelial cells at the tips of angiogenic sprouts, were observed in wild-type animals, but to a lesser extent in the PECAM-1-null mice. Together, these data further establish the involvement of endothelial PECAM-1 in angiogenesis and suggest that, in vivo, PECAM-1 may stimulate endothelial cell motility by promoting the formation of filopodia.
Cao
Gaoyuan
G
Pulmonary, Allergy and Critical Care Division, SVM-Hill Pavilion, Room 410B, 380 South University Avenue, Philadelphia, PA 19104-3945, USA.
Fehrenbach
Melane L
ML
Williams
James T
JT
Finklestein
Jeffrey M
JM
Zhu
Jing-Xu
JX
Delisser
Horace M
HM
D000818:Animals; D002465:Cell Movement / Q000235:genetics; D002478:Cells, Cultured; D003094:Collagen; D004338:Drug Combinations; D006801:Humans; D007797:Laminin; D051379:Mice; D009369:Neoplasms / Q000098:blood supply / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D018919:Neovascularization, Physiologic / Q000235:genetics / Q000502:physiology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000502:physiology*; D011509:Proteoglycans; D011554:Pseudopodia / Q000502:physiology; D012160:Retina / Q000254:growth & development; D012171:Retinal Vessels; D020764:cdc42 GTP-Binding Protein / Q000096:biosynthesis
D004338:Drug Combinations; D007797:Laminin; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; D020764:cdc42 GTP-Binding Protein