Abstract
Activation of MMPs in tissues is an important component of tissue injury. Based on earlier reports that (latent) proMMP-2 is incapable of forming a complex with TIMP-1, we reasoned that the identification of MMP-2:TIMP-1 complexes in blood might serve as a surrogate marker ("smoking gun") of MMP-2 activation in tissues. Using specific antibodies, we developed a sensitive and specific assay to detect MMP-2:TIMP-1 complexes. We were perplexed to find that approximate 40% of plasma specimens from healthy individuals had detectable levels of the MMP-2:TIMP-1 complexes. Employing recombinant TIMP-1 bound Sepharose beads and Western blots, we demonstrated binding between recombinant proMMP-2 and TIMP-1 proteins. Recombinant MMP-2 lacking the catalytic domain also bound to TIMP-1 coated beads. These data are consistent with TIMP-1 binding to the hemopexin or hinge domain of proMMP-2. The explanation for the presence of plasma proMMP-2:TIMP-1 complexes in selected healthy individuals remains to be determined. In contrast to our immunoassay and bead-binding experiments, proMMP-2 failed to bind to immobilized TIMP-1 employing surface plasmon resonance technology. Additional studies are needed to clarify these contrasting results.
Original language | English (US) |
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Pages (from-to) | 223-231 |
Number of pages | 9 |
Journal | Connective Tissue Research |
Volume | 50 |
Issue number | 4 |
DOIs | |
State | Published - 2009 |
Keywords
- Complex Formation
- ELISAs
- MMP
- MMP:TIMP Complexes
- Plasma
- TIMP
ASJC Scopus subject areas
- Rheumatology
- Biochemistry
- Orthopedics and Sports Medicine
- Molecular Biology
- Cell Biology