|
Effect of neutrophil-generated
angiostatin on CAM neovascularization
|
 |
 |
|
Chicken
embryo CAMs were implanted with gelatin sponges treated with 500
ng of FGF2 or vehicle at day 8 of development. When indicated,
1.2 mg of purified neutrophil-generated
angiostatin (PMN-A K1-3) were added daily to the sponges until
day 10. Note the absence of newly formed blood vessels converging
towards the sponge in PMN-A K1-3 treated implants (bottom) when
compared to implants treated with FGF2 alone (top).
|
Back to: Presta's lab
ABSTRACT
The contribution of polymorphonuclear neutrophils (PMN) to host defense and natural immunity extends well beyond their traditional role as professonial phagocytes.
In this study, we demonstrate that, upon stimulation with proinflammatory stimuli, human PMN release enzymatic activities that, in vitro, generate bioactive angiostatin fragments from purified plasminogen. We also provide evidence that these angiostatin-like fragments, comprising kringle domain 1 to kringle domain 3 (kringle 1-3) of plasminogen, are generated as a byproduct of the selective proteolytic activity of neutrophil-secreted elastase (NE).
Remarkably, affinity purified angiostatin kringle 1-3 fragments generated by neutrophils inhibited basic fibroblast growth factor (FGF2)-induced endothelial cell proliferation in vitro, and both vascular endothelial growth factor (VEGF)-induced angiogenesis in the matrigel plug assay and FGF2 plus VEGF-induced angiogenesis in the chick embryo chorioallantoic membrane assay, in vivo.
These results
represent the first demonstration that biologically active angiostatin-like
fragments can be generated by inflammatory human neutrophils. Since angiostatin
is a potent inhibitor of angiogenesis, tumor growth and metastasis, the
data suggest that activated PMN not only act as potent effectors of inflammation,
but might also play a critical role in the inhibition of angiogenesis
in inflammatory diseases and tumors, by generation of a potent anti-angiogenic
molecule.
J. Immunol., in press.