FGF-2 binding to fibrin(ogen) is required for augmented angiogenesis.
We have shown previously that fibrin(ogen) binds fibroblast growth factor 2 (FGF-2) and potentiates stimulation of endothelial-cell (EC) proliferation. We have now used 2 FGF-2 mutants differing only in the 5 residues constituting the binding site to characterize the importance of this interaction in angiogenesis. The nonbinding (2212) and binding (221*2) mutants stimulated EC proliferation by 2.2 +/- 0.4-fold and 2.9 +/- 0.3-fold over control, respectively, and both were similar to wild-type (wt) FGF-2 (2.5 +/- 0.3-fold). Proliferation was augmented by fibrinogen to 5.3 +/- 1.2-fold and 4.8 +/- 0.8-fold with wtFGF-2 and 221*2, whereas no augmentation occurred with 2212 and fibrinogen. Using a placental explant model in a fibrin matrix, wtFGF-2 resulted in 2.6 +/- 0.9-fold more growth over control, and 221*2 increased growth 3.3 plus or minus 0.9-fold. Vessel outgrowth with 2212 was minimal and comparable to control. Similarly, fibrinogen potentiated wtFGF-2 or 221*2-mediated angiogenesis in the chicken chorioallantoic membrane model. In a mouse Matrigel implant model, fibrinogen significantly increased angiogenesis with either wtFGF-2 or 221*2, whereas there was no augmentation with 2212. These results demonstrate that binding of FGF-2 to fibrin(ogen) mediated by the 5-residue FGF-2-fibrin(ogen) interactive site is required for augmented angiogenesis.
Sahni
Abha
A
Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA. abha_sahni@urmc.rochester.edu
Khorana
Alok A
AA
Baggs
Raymond B
RB
Peng
Hu
H
Francis
Charles W
CW
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D049109:Cell Proliferation; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D005340:Fibrinogen / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D009154:Mutation; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010920:Placenta / Q000098:blood supply; D011485:Protein Binding / Q000235:genetics / Q000502:physiology
D016222:Fibroblast Growth Factor 2; D005340:Fibrinogen