Paradigmatic identification of MMP-2 and MT1-MMP activation systems in cardiac fibroblasts cultured as a monolayer.
Activations of MMP-2 and membrane type 1-matrix metalloproteinase (MT1-MMP) have been correlated with cell migration, a key cellular event in the wound healing and tissue remodeling. We have previously demonstrated furin-dependent MMP-2 and MT1-MMP activations induced by type I collagen in cardiac fibroblasts. To understand mechanistic aspects of the regulation of MMP-2 and MT1-MMP activations by potential non-matrix factor(s) in cardiac fibroblasts, in the present study, we examined the effects of various agents including concanavalin A (ConA), a proteolytic phenotype-producing agent. We showed that treatment of cells with ConA activated pro-MMP-2, and that this activation concurred with elevated levels of cellular MT1-MMP and TIMP-2. The presence of active MT1-MMP and 43 and 36 kDa processed forms of MT1-MMP in a fraction of intracellular proteins prepared from ConA-treated cells suggests the possible internalization of differential forms of MT1-MMP. The appearance of 36 kDa processed form of MT1-MMP in conditioned media prepared from ConA-treated cells indicates the possible extracellular release of the further processed MT1-MMP fragment. Inhibition of furin in ConA-treated cells attenuated pro-MT1-MMP processing and the cellular TIMP-2 level, plus it reduced cell-released active MMP-2 in a time-dependent manner. These results suggest the involvement of furin in the ConA-induced activations of MT1-MMP and MMP-2. Furthermore, the existence of furin inhibitor-insensitive pro- and active MMP-2 species associated with ConA-treated cells implies that a mechanism independent of furin may perhaps account for the binding of the MMP-2 species to the cells. Supplementary material for this article can be found at http://www.mrw.interscience.wiley.com/suppmat/0730-2312/suppmat/94/suppmat_guo.tif.
Guo
Chun
C
Leicester School of Pharmacy, De Montfort University, Leicester, LE1 9BH, UK. chun.guo@man.ac.uk
Jiang
Juwei
J
Elliott
J Martin
JM
Piacentini
Lucia
L
D000818:Animals; D002478:Cells, Cultured; D045683:Furin / Q000037:antagonists & inhibitors; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D051381:Rats; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D015854:Up-Regulation
D019716:Tissue Inhibitor of Metalloproteinase-2; D045683:Furin; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2