Proteolysis of the urokinase-type plasminogen activator receptor by metalloproteinase-12: implication for angiogenesis in fibrin matrices.
Pericellular proteolysis plays an important role in cell migration and the formation of new capillary structures. The plasminogen activator/plasmin and matrix degrading metalloproteinase (MMP) cascades act together in the remodeling of matrix and cell-matrix contacts. Previously we have shown that the formation of capillary structures by human foreskin microvascular endothelial cells (hMVECs) in a 3-dimensional fibrin matrix requires a functional urokinase-type plasminogen activator receptor (u-PAR). Here we report on the unexpected finding that inhibition of hMVEC-derived MMP activity by BB94 (batimastat) increased the outgrowth of capillary structures in a fibrin matrix. BB94 prevented the release of the u-PA binding domain D1 of u-PAR and thereby increased the number of functional u-PARs on hMVECs without affecting the u-PAR messenger RNA levels. Comparison of various types of protease inhibitors pointed to the prime involvement of MMP activity. Using recombinant MMPs it was shown that MMP-12 activity was able to release the D1 domain of cellularly expressed u-PAR. In addition, the expression of MMP-12 in control and basic fibroblast growth factor/tumor necrosis factor-alpha-stimulated hMVECs was shown by reverse transcriptase-polymerase chain reaction, suggesting that endothelial cell-derived MMP-12 may be involved in angiogenesis-related u-PAR shedding. This new mechanism of u-PAR cleavage provides new insights into the mutual interactions between the MMP and u-PA/plasmin systems. Moreover, it may be helpful in the interpretation of recent data on the use of specific MMP inhibitors in the treatment of several types of cancer.
Koolwijk
P
P
Department of Vascular and Connective Tissue Research, Gaubius Laboratory TNO-PG, Leiden, The Netherlands. p.koolwijk@pg.tno.nl
Sidenius
N
N
Peters
E
E
Sier
C F
CF
Hanemaaijer
R
R
Blasi
F
F
van Hinsbergh
V W
VW
D001665:Binding Sites; D015153:Blotting, Western; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology; D005337:Fibrin; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015870:Gene Expression; D006801:Humans; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008833:Microcirculation; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013876:Thiophenes / Q000494:pharmacology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
C524898:PLAUR protein, human; D011480:Protease Inhibitors; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D013876:Thiophenes; D014409:Tumor Necrosis Factor-alpha; D016222:Fibroblast Growth Factor 2; D010649:Phenylalanine; D005337:Fibrin; C080985:batimastat; D014568:Urokinase-Type Plasminogen Activator; D008666:Metalloendopeptidases