Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of formation of the maxillary sinuses is not elucidated as yet, although their morphology during embryogenesis is well described. In the prenatal period, the pneumatization hypothesis is not valid. As the molecular approach to this problem is difficult to apply to human samples, we decided to apply immunohistochemical reactions to analyse the synthesis of selected molecules involved in the rebuilding of tissues. Hematoxylin-eosin staining and immunohistochemical reactions for the detection of MMPs (matrix metalloproteinases), one of their inhibitor TIMP 1 (tissue inhibitor of MMPs), BMP 6 (bone morphogenetic protein 6) and TGF-beta (transforming growth factor beta) were performed in the epithelium the mucosa of the maxillary sinuses of several human foetuses from the collection of the Anatomical Institute. The age of the foetuses was 8, 11, 15, 16, 17, 18 and 22 weeks. An intense positive reaction for MMPs 1, 2 and 3 was found in the mucosal epithehum of developing sinuses in the whole series of foetuses was found. The reaction was more intense in advanced stages of foetal development. Tissue derived inhibitor TIMP was hardly detectable, regardless of the age of samples. However, the intensity of the reaction for TGFbeta was strong in both young and more mature sinus epithelium. The presence of BMP 6, a member of the superfamily of TGFbeta, was detected although the intensity of this reaction in the epithelium was rather weak. Both TGFbeta and BMP 6 are well known as regulators of differentiation in the course of organogenesis. Results of the histochemical analysis suggest the possible involvement of the epithelium in the growth and formation of the maxillary sinuses. The main argument for this is intense reaction for MMP proteases which, as in bone, regulate the turnover and rebuilding processes of the extracellular matrix (ECM).
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PMID:Human mucosal epithelium involvement in prenatal growth of maxillary sinuses. 1261 77

Bone is distinguished from other tissues by its mechanical properties, in particular stiffness. However, we know little of how osteoblasts react to the stiffness of their microenvironment; in this study we describe their response to a dense (>10 wt.%) collagenous 3D environment. Primary pre-osteoblasts were seeded within a novel form of native collagen, dense collagen, and cultured for up to 14 days in the presence and absence of osteogenic supplements: analysis was via Q-PCR, histology, fluorescent in situ zymography, MMP loss-of-function and tensile testing. Differentiation as measured through the up-regulation of Bsp (247-fold), Alp (14.2-fold), Col1A1 (4.5-fold), Mmp-13 (8.0-fold) and Runx2 (1.2-fold) transcripts was greatly accelerated compared to 2D plastic at 7 and 14 days in the same medium. The scale of this enhancement was confirmed through the use of growth factor stimulation on 2D via the addition of BMP-6 and the Hedgehog agonist purmorphamine. In concert, these molecules were capable of the same level of osteo-induction (measured by Bsp and Alp expression) as the dense collagen alone. Mineralisation was initially localised to remodelled pericellular regions, but by 14 days embedded cells were discernible within regions of apatite (confirmed by MicroRaman). Tensile testing of the matrices showed that this had resulted in a significant increase in Young's modulus at low strain values, consistent with a stiffening of the matrix. To determine the need for matrix remodelling in the mineralisation event the broad spectrum MMP Inhibitor Ilomastat was used. It was found that in its presence mineralisation could still occur (though serum-specific) and the apoptosis associated with MMP inhibition in hydrated collagen gels was abrogated. Analysis of gene expression indicated that this was due to the up-regulation of Mmp-13 in the presence of Ilomastat in dense collagen (400-fold), demonstrating a powerful feedback loop and a potential mechanism for the rescue from apoptosis. Osteoid-like matrix (dense collagen) is therefore a potent stimulant of osteoblast differentiation in vitro and provides an environment that enables survival and differentiation in the presence of MMP inhibition.
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PMID:Dense collagen matrix accelerates osteogenic differentiation and rescues the apoptotic response to MMP inhibition. 1850 16