Platelet release of trimolecular complex components MT1-MMP/TIMP2/MMP2: involvement in MMP2 activation and platelet aggregation

Abstract

Matrix metalloproteinase 2 (MMP2) has been reported to be secreted by collagen-stimulated platelets, and active MMP2 has been shown to play a role in platelet aggregation. It has been demonstrated that MMP2 activation is dependent on the complex (membrane type 1 [MT1]-MMP/tissue inhibitor of MMP2 [TIMP2]) receptor and MMP2. We have investigated human platelets as a possible source of MT1-MMP, and we have studied its role in MMP2 activation and in platelet aggregation. Gelatin zymograms showed the existence of MMP2 at proforms (68 kd) and activated-enzyme forms (62-59 kd) in supernatants of resting and activated platelets, respectively. No gelatinolytic activity was associated with the platelet pellet after aggregation, suggesting a total release of MMP2 during cell activation. By Western blot analysis in nonreduced conditions, MT1-MMP was found on resting platelet membranes in 2 forms–the inactive 45-kd form and an apparent 89-kd form, which totally disappeared under reduced conditions. After platelet degranulation, only the 45-kd form was detected. Reverse transcription–polymerase chain reaction experiments showed the expression in platelets of messenger RNA encoding for MMP2, MT1-MMP, and TIMP2. Flow cytometry analysis showed that MT1-MMP, MMP2, and TIMP2 expressions were enhanced at the activated platelet surface. MMP inhibitors, recombinant TIMP2, and synthetic BB94 inhibited collagen-induced platelet aggregation in a concentration-dependent manner, indicating the role of activated MT1-MMP in the modulation of platelet function. In conclusion, our results demonstrate the expression of the trimolecular complex components (MT1-MMP/TIMP2/MMP2) by blood platelets as well as the ability of MMP inhibitors to modulate the aggregating response.

Metformin blocks migration and invasion of tumour cells by inhibition of matrix metalloproteinase‐9 activation through a calcium and protein kinase Cα‐dependent pathway: phorbol‐12‐myristate‐13‐acetate‐induced/extracellular signal‐regulated kinase/activator protein‐1

“…Metformin also inhibited MMP‐2 expression in a dose‐dependent manner (Figure 2D). Because MMP‐9 activity is tightly regulated by endogenous inhibitors, that is, tissue inhibitors of metalloproteinase (TIMPs) (Kazes et al ., 2000), we further examined the expression level of TIMP‐1 and ‐2 by semi‐quantitative RT–PCR, but their expression remained essentially unchanged by treatment with metformin (Figure 2E). These results indicate that the lack of effect of metformin on RNA levels for TIMP‐1 and ‐2 may also contribute to suppression of cell invasion.…”

Membrane type‐1 matrix metalloproteinase stimulates tumour cell‐induced platelet aggregation: role of receptor glycoproteins

“…The mechanism by which MMP‐2 is activated at the surface of cancer cells is fully dependent on the activity of MT1‐MMP ( Sato et al , 1994 ; Strongin et al , 1995 ). Recently, Kazes et al (2000) showed that resting platelets express the latent form of MT1‐MMP on their surface and this is activated during collagen‐induced platelet aggregation. The authors hypothesized that MT1‐MMP may contribute to collagen‐induced platelet aggregation.…”

“…Recent evidence has shown that in addition to embryonic development, morphogenesis, physiological and pathological remodelling, MMPs also act as signalling molecules regulating processes such as vascular reactivity, leukocyte activation and platelet function (Sternlicht & Werb, 2001; Jurasz et al , 2002 ). Indeed, we and others have previously described novel pathways of platelet aggregation that are mediated via the release of matrix metalloproteinase‐1 (MMP‐1) and MMP‐2 from platelets ( Sawicki et al , 1997 ; Sawicki et al , 1998 ; Kazes et al , 2000 ; Martinez et al , 2001 ; Radomski et al , 2001 ; Chung et al , 2002 ; Galt et al , 2002 ; Jurasz et al , 2002 ). Interestingly, MMP‐2 release from platelets and cancer cells stimulates TCIPA ( Jurasz et al , 2001a ).…”

“…In addition to its role as an activator of MMP‐2, membrane‐tethered membrane type‐1 matrix metalloproteinase (MT1‐MMP) (MMP‐14, GenBank™ U41078) is a key enzyme in tumour cell migration and invasion ( Hotary et al , 2000 ; Koshikawa et al , 2000 ; Belkin et al , 2001 ; Itoh et al , 2001 ). MT1‐MMP is also present on the surface of collagen‐aggregated platelets ( Kazes et al , 2000 ).…”

Matrix metalloproteinase‐13 unlucky for the forming thrombus

“…Platelets also express MMP‐14, which has a transmembrane domain and is often found in complex with pro‐MMP‐2 and an associated inhibitor, tissue inhibitor of metalloproteinase (TIMP)‐2 . Whether MMP‐9 is produced by platelets or originates from external sources and simply binds to platelets remains a matter of some conjecture, and the anti‐aggregatory effects of MMP‐9 on platelets remain to be elucidated.…”