Detection of a latent soluble form of membrane type 1matrix metalloprotease bound with tissue inhibitor ofmatrix metalloproteinases-2 in periprosthetic tissues andfluids from loose arthroplasty endoprostheses

摘要

Membrane type 1 matrix metalloproteinase (MT1-MMP) is implicated inpericellular proteolysis, and, together with tissue inhibitor of matrix metalloproteinases-2 (TIMP-2), in the activation of pro-matrix metalloproteinase-2on the cell surface. It is expressed on the cell surface either activated or as aproenzyme. A soluble form of MT1-MMP (sMT1-MMP) has been previouslyidentified in periprosthetic tissues and fluid of patients with loosearthroplasty endoprostheses. The aim of this study was to examine periprosthetictissues and fluids from patients with loose arthroplasty endoprostheses,as well as tissues and fluids from patients with other disorders, for thepresence of sMT1-MMP, and to investigate its activation state and possiblerole. With antibody against MT1-MMP, a protein with molecular mass of~ 57 kDa was detected by western blotting in all samples tested, representinga soluble form of MT1-MMP, which cannot be ascribed to alternativesplicing, as northern blotting showed only one transcript. With various biochemicalmethods, it was shown that this species occurs in a latent formbearing the N-terminal prodomain, and, additionally, it is bound to TIMP-2, which appeared to be bound via its C-terminal domain to a site differentfrom the active site. Cell ELISA and immunohistochemical analysis revealedthat, besides fibroblasts, all other cells, such as inflammatory, epithelial,endothelial, giant and cancer cells, express MT1-MMP on their plasmamembrane as a proenzyme. Taking into account the proteolytic abilities ofMT1-MMP, the latent sMT1-MMP–TIMP-2 complex could be consideredas a new interstitial collagenase. However, the exact role, the productionmechanism and the cell origin of this complex remain to be elucidated.