Beta1 integrin expression on endothelial cells is required for angiogenesis but not for vasculogenesis.
Integrins are a family of cell adhesion receptors that are involved in cell-matrix and cell-cell communications. They facilitate cell proliferation, migration, and survival. Using the Cre-Lox system, we deleted beta1 integrin on Tie2-positive (Tie2-cre beta1 Int (fl/fl)) vascular endothelial cells. Deletion of beta1 integrin on vascular endothelial cells results in embryonic lethality. Blood vessel defects are encountered in the Tie2-Cre beta1 Int (fl/fl) embryos at embryonic age (E9.5), and embryos die before reaching E10.5. The embryos exhibit growth retardation and both histological evaluation and PECAM-1 staining of E9.5 embryos revealed defects in angiogenic sprouting and vascular branching morphogenesis. Large and medium-size vessel formation is not affected in these embryos. Angiogenic defects were observed in several regions of the embryo and yolk sacs. These results indicate that beta1 integrin expression on vascular endothelial cells is crucial for embryonic angiogenesis but dispensable for vasculogenesis.
Division of Matrix Biology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
Harikrishna
H
Tanjore
Elisabeth M
EM
Zeisberg
Behzad
B
Gerami-Naini
Raghu
R
Kalluri
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D018919:Neovascularization, Physiologic / Q000235:genetics*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D016133:Polymerase Chain Reaction; D042787:Receptor, TIE-2 / Q000235:genetics
D019012:Integrin beta1; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042787:Receptor, TIE-2