One of the phenotypic hallmarks of migrating endothelial cells, both in vivo and in vitro, is expression of the urokinase-type plasminogen activator (u-PA), a key mediator of extracellular proteolysis. In the study reported here, we have used an in vitro model of endothelial cell migration to explore the mechanism of this phenomenon. We have found that wounding of an endothelial cell monolayer triggers a marked, rapid and sustained increase in expression of a specific high-affinity receptor for u-PA (u-PAr) on the surface of migrating cells. Migrating cells displayed an increase in the levels of u-PA and u-PAr mRNAs, and this increase was mediated by endogenous basic fibroblast growth factor (bFGF). We also show that the increase in u-PA activity on migrating cells can be accounted for by an increase in receptor-bound u-PA, and that the increase in activity is also dependent on endogenous bFGF. These results demonstrate that the expression of plasmin-mediated proteolytic activity by migrating endothelial cells is a consequence of increased production of both u-PA and its receptor, and that this in turn is mediated by endogenous bFGF. This suggests that u-PA, produced at increased levels by migrating cells, binds to u-PAr whose expression is upregulated on the same cells. These observations are in accord with the postulated role of u-PAr in mediating efficient and spatially restricted extracellular proteolysis, particularly in the context of cell migration.
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August 01 1993
Upregulation of urokinase receptor expression on migrating endothelial cells
MS Pepper,
MS Pepper
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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AP Sappino,
AP Sappino
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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R Stöcklin,
R Stöcklin
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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R Montesano,
R Montesano
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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L Orci,
L Orci
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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JD Vassalli
JD Vassalli
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
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MS Pepper
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
AP Sappino
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
R Stöcklin
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
R Montesano
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
L Orci
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
JD Vassalli
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1993) 122 (3): 673–684.
Citation
MS Pepper, AP Sappino, R Stöcklin, R Montesano, L Orci, JD Vassalli; Upregulation of urokinase receptor expression on migrating endothelial cells. J Cell Biol 1 August 1993; 122 (3): 673–684. doi: https://doi.org/10.1083/jcb.122.3.673
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