Selective inhibition by kringle 5 of human plasminogen on endothelial cell migration, an important process in angiogenesis.
Biochem Biophys Res Commun 1998;
247:414-9. [PMID:
9642142 DOI:
10.1006/bbrc.1998.8825]
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Abstract
Angiogenesis is a multi-step process that includes endothelial cell proliferation, migration, basement membrane degradation, and new lumen organization. Angiostatin, an internal fragment of plasminogen comprising the first four triple disulfide-linked kringle structures, is one of the most potent endogenous angiogenesis inhibitors described to date. The kringle 5 domain of plasminogen, which shares high sequence homology with the four kringles of angiostatin, was previously shown to antagonize endothelial cell growth. We now describe that the recombinant kringle 5 of human plasminogen inhibits endothelial cell migration with an IC50 (concentration for half maximal inhibition) of approximately 500 nM. We demonstrate that the lysine-binding sites of kringle 5 may not be involved in its anti-migratory activities. The anti-migratory activity of kringle 5 is similar to that of angiostatin. Kringle 5 also shows selective inhibition on endothelial cells as opposed to other cell types. Relative to its native form, reduced kringle 5 displays a significant increase in anti-migratory activity, implying that the kringle conformation may shield kringle 5 from effectively interacting with endothelial cells. This report thus constitutes the first demonstration that kringle 5 of plasminogen is a selective inhibitor for endothelial cell migration.
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