REGULATION OF THE UPAR UPA SYSTEM EXPRESSED ON MONOCYTES BY THE DEACTIVATING CYTOKINES, IL-4, IL-10 AND IL-13 - CONSEQUENCES ON CELL-ADHESION TO VITRONECTIN AND FIBRINOGEN/
J. Paysant et al., REGULATION OF THE UPAR UPA SYSTEM EXPRESSED ON MONOCYTES BY THE DEACTIVATING CYTOKINES, IL-4, IL-10 AND IL-13 - CONSEQUENCES ON CELL-ADHESION TO VITRONECTIN AND FIBRINOGEN/, British Journal of Haematology, 100(1), 1998, pp. 45-51
Urokinase (uPA) and its receptor (uPAR) have been proposed to be invol
ved in monocyte migration by inducing degradation of matrix proteins,
In addition, uPAR is also implicated in cell adhesion to the vascular
wall, The adhesive function of uPAR depends on a direct interaction wi
th vitronectin which is increased by uPA and by modification of cell s
urface integrin (such as CD11b-CD18) when associated to uPAR. In this
study we analysed the role of three deactivating cytokines, IL-4, IL-1
0 and IL-13, on the surface expression of uPA, uPAR and CD11b by monoc
ytes and their consequences on monocyte adhesion to immobilized fibrin
ogen and vitronectin. IL-10 induced a decrease in uPA and CD11b after
18 h incubation and a delayed decrease in uPAR which was only signific
ant after 48 h incubation. These results may explain the decrease in m
onocyte adhesion, which was observed after an 18 h incubation with IL-
10, on immobilized vitronectin and fibrinogen. In contrast, IL-4 and I
L-13 induced a decrease in uPAR after 18 h and a significant increase
in uPA both in the cell lysates and at the cell surface, as well as an
increase in cell surface associated CD11b. These cytokines did not mo
dify cell adhesiveness to vitronectin or fibrinogen despite the increa
se in CD11b-CD18. This could be due to the decrease in uPAR because CD
11b-CD18/uPAR forms a cell-adhesion complex. In addition, the increase
in uPA induced by IL-4 could counterbalance the direct interaction of
uPAR with vitronectin. The increase in uPA suggests that IL-4 and IL-
13 could induce plaque fissuring by monocytes, whereas IL-10 may induc
e protection against matrix protein degradation by decreasing uPA.