Effects of protein and gene transfer of the angiopoietin-1 fibrinogen-like receptor-binding domain on endothelial and vessel organization

Cornelia C. Weber, Hao Cai, Martin Ehrbar, Hisashi Kubota, Georg Martiny-Baron, Wilfried Weber, Valentin Djonov, Ernst Weber, Ajit S. Mallik, Martin Fussenegger, Karl Frei, Jeffrey A. Hubbell, Andreas H. Zisch

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The vessel-stabilizing effect of angiopoietin-1 (Ang1)/ Tie2 receptor signaling is a potential target for pro-angiogenic therapies as well as anti-angiogenic inhibition of tumor growth. We explored the endothelial and vascular specific activities of the Ang1 monomer, i.e. dissociated from its state as an oligomer. A truncated monomeric Ang1 variant (i.e. ΔAng1) containing the isolated fibrinogen-like receptor-binding domain of Ang1 was created and recombinantly produced in insect cells. ΔAng1 ligated the Tie2 receptor without triggering its phosphorylation. Moreover, monomeric ΔAng1 was observed to bind α5β1 integrin with similar affinity compared with Tie2. Unexpectedly, in vitro treatment of endothelial cells with ΔAng1 showed some of the known effects of full-length Ang1, including inhibition of basal endothelial cell permeability and stimulation of cell adhesion as well as activation of MAPKs. Local treatment of the microvasculature of the developing chicken chorioallantoic membrane with the ΔAng1 protein led to profound reduction of the mean vascular length density, thinning of vessels, and reduction of the number of vessel branching points. Similar effects were observed in side-by-side experiments with the recombinant full-length Ang1 protein. These effects of simplification of the vessel branching pattern were confirmed through local gene transfer with lentiviral particles encoding ΔAng1 or full-length Ang1. Together, our findings suggest a potential use for exogenous Ang1 in reducing rather than increasing vascular density. Furthermore, we show that the isolated receptor-binding domain of Ang1 is capable of mediating some effects of full-length Ang1 independently of Tie2 phosphorylation, possibly through integrin ligation.

Original languageEnglish (US)
Pages (from-to)22445-22453
Number of pages9
JournalJournal of Biological Chemistry
Issue number23
StatePublished - Jun 10 2005
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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