Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.17 (MMP-3)
 3,419 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibronectin fragments have both catabolic and anabolic activities toward articular cartilage explants in vitro. Whereas a 1 nM concentration of an N-terminal 29 kDa fibronectin fragment (Fn-f) increases the proteoglycan (PG) content of cartilage without induction of matrix metalloproteinases (MMPs), 0.1-1 microM Fn-f temporarily suppresses PG synthesis and enhances MMP release. The higher concentrations cause an initially rapid PG depletion during the first week of culture, followed by much slower PG loss and gradually increasing rates of PG synthesis. To test for the involvement of mediators, human articular cartilage was cultured with Fn-f, and conditioned media were assayed for selected cytokines and factors. With 1 nM Fn-f, the release of the anabolic factors, insulin growth factor-I and transforming growth factor beta1, from cultured cartilage was enhanced by 50-100% during the entire 28-day culture period and this was associated with both supernormal rates of PG synthesis and PG content. However, the higher concentrations of Fn-f additionally enhanced release, by at least 10-fold, of the cytokines, tumour necrosis factor alpha, interleukin-1alpha, interleukin-1beta and interleukin-6 while causing depletion of cartilage PG. Release of tumour necrosis factor alpha, interleukin 1beta and interleukin 1alpha peaked at days 2, 3 and 9 during or slightly after the period of maximal PG depletion and decreased to control levels by days 7, 7 and 21 respectively, whereas release of interleukin 6 was enhanced throughout the culture period. Neutralizing antibodies to the catabolic cytokines reduced Fn-f-mediated MMP-3 release and suppression of PG synthesis. The temporal aspects of this interplay between catabolic and anabolic factors are consistent with the kinetics of Fn-f-mediated cartilage damage and attempted repair and may be relevant to cartilage damage and repair in vivo.
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PMID:Fibronectin-fragment-induced cartilage chondrolysis is associated with release of catabolic cytokines. 903 63

The binding properties of the COOH-terminal hemopexin-like domain (C domain) of human gelatinase A (matrix metalloproteinase-2, 72-kDa gelatinase) were investigated to determine whether the C domain has binding affinity for extracellular matrix and basement membrane components. Recombinant C domain (rC domain) (Gly417-Cys631) was expressed in Escherichia coli, and the purified protein, identified using two antipeptide antibodies, was determined by electrospray mass spectrometry to have a mass of 25,925 Da, within 0.1 Da of that predicted. As assessed by microwell substrate binding assays and by column affinity chromatography, the matrix proteins laminin, denatured type I collagen, elastin, SPARC (secreted protein that is acidic and rich in cysteine), tenascin, and MatrigelTM were not bound by the rC domain. Unlike the hemopexin-like domains of collagenase and stromelysin, the rC domain also did not bind native type I collagen. Nor were native or denatured types II, IV, V, and X collagen, or the NC1 domain of type VII collagen bound. However, binding to heparin and fibronectin (Kd, 1.1 x 10(-6) M) could be disrupted by 0.58-0.76 and 0.3 M NaCl, respectively. Using nonoverlapping chymotrypsin-generated fragments of fibronectin, binding sites for the rC domain were found on both the 40-kDa heparin binding and the 120-kDa cell binding fibronectin domains (Kd values, approximately 4-6 x 10(-7) M). The Ca2+ ion, but not the potential structural Zn2+ ion, were found to be essential for maintaining the binding properties of the protein. The apo-form of the rC domain did not bind heparin, and both ethylenediaminetetraacetic acid and the specific Ca2+ ion chelator 1, 2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid, but not the Zn2+ ion chelator 1,10-phenanthroline, eluted the holo form of the rC domain from both heparin-Sepharose and fibronectin. Inductive coupled plasma mass spectrometry also did not detect a Zn2+ ion in the rC domain. In contrast, reduction with 65 mM dithiothreitol did not interfere with heparin binding, further emphasizing the crucial structural role played by the Ca2+ ion. Together, these data demonstrate for the first time that the hemopexin-like domain of gelatinase A has a binding site for fibronectin and heparin, and that Ca2+ ions are important in maintaining the structure and function of the domain.
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PMID:The hemopexin-like domain (C domain) of human gelatinase A (matrix metalloproteinase-2) requires Ca2+ for fibronectin and heparin binding. Binding properties of recombinant gelatinase A C domain to extracellular matrix and basement membrane components. 905 49

Interstitial collagen types I and III are the predominant collagens in the amniotic and chorionic connective tissues. However, this matrix also contains proteoglycans, fibronectin, laminin, and elastin, which together with the collagens may undergo partial degradation prior to fetal membrane rupture at term. In this study, stromelysin (MMP-3) and tissue inhibitor of metalloproteinases-1 (TIMP-1) were immunolocalized in fetal membranes obtained at term prior to labor. MMP-3 stained the cells of the amniotic epithelium, fibroblasts and macrophages of the amniotic and chorionic matrix, and those of the chorionic cytotrophoblast; there was no staining in the maternal decidua. TIMP-1 showed a similar staining pattern, except that the staining was darker in some amniotic epithelial cells and was present in the maternal decidua. The maternal decidua produces the two human relaxins H1 and H2; the latter, when incubated with explants of human fetal membranes, caused a dose-dependent and significant increase in expression of the MMP-3 gene and its secreted protein into the media. A significant effect of relaxin H2 on 92-kDa gelatinase (MMP-9) gene expression was also shown--an effect requiring poly(A)+ RNA rather than total RNA. Both relaxin H1 and H2 caused a significant increase in secretion of MMP-9 protein and its enzyme activity in the media. The magnitude of the effects of the two relaxins was similar, in contrast to findings from other biological studies in which relaxin H2 was shown to be more active. Neither of the relaxins had any effect on 72-kDa gelatinase (MMP-2) activity or on the TIMP-1 protein or its activity. This study suggests that local relaxins may be involved in the degradation of the complex fetal membrane extracellular matrix and may cause activation of an enzyme cascade resulting in fully activated MMP-9. Such effects could be important in the degradative pathways occurring in the amnion and chorion in the peripartal period.
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PMID:An autocrine/paracrine role of human decidual relaxin. II. Stromelysin-1 (MMP-3) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). 909 60

Glomerulosclerosis is the final outcome of a number of different causes of glomerular injury, during which the structures of the glomerulus are obliterated by extracellular matrix. Accumulating evidence suggests that infiltrating macrophages play a pivotal role in the progression to glomerulosclerosis. The present study defines the role played by macrophages at both cellular and molecular levels in the initiation of the sclerotic process in cultured rat mesangial cells. Macrophage-conditioned medium (MPCM) generated from thioglycollate-elicited, lipopolysaccharide-stimulated macrophages upregulated mesangial cell fibronectin production in a dose- and time-dependent manner, independently of cell proliferation. Immunoprecipitation of metabolically labeled 35S-fibronectin confirmed that the matrix protein was synthesized de novo. The genes for fibronectin and the matrix proteins laminin and collagen IV were also found to be upregulated 2.86 +/- 0.24-, 4.94 +/- 0.17-, and 3.03 +/- 0.31-fold over controls, respectively (P < 0.001). Macrophage modulation of matrix turnover was suggested by an upregulation of both transin and tissue inhibitor of metalloproteinase-1 gene transcription. Transforming growth factor (TGF) beta1, platelet-derived growth factor, tumor necrosis factor (TNF) alpha, or interleukin (IL)-1beta could not be detected in the MPCM per se; however, TGFbeta1 and platelet-derived growth factor AB were found to be secreted into mesangial cell culture supernatants. Secretion was augmented 1.69 +/- 0.16- and 2.28 +/- 0.28-fold, respectively (both P < 0.001), in response to MPCM. Northern blot analysis demonstrated that protein secretion had been preceded by upregulation of the genes for these cytokines (2.2 +/- 0.4-fold [P < 0.001] and 5.7 +/- 1.2-fold [P < 0.004], respectively). Incubation of MPCM with either neutralizing antibody or the growth factor receptor antagonist suramin demonstrated that TGFbeta1 played a significant, although minor, role in MPCM-stimulated fibronectin production. In conclusion, this study provides compelling evidence for a direct role of macrophages in the progression to glomerulosclerosis.
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PMID:Macrophages promote prosclerotic responses in cultured rat mesangial cells: a mechanism for the initiation of glomerulosclerosis. 933 80

Cytokines, growth factors, and alterations in the extracellular matrix composition may play a role in maintaining hepatic stellate cells (HSC) in the activated state that is responsible for hepatic fibrogenesis. However, the signal transduction pathways that are stimulated by these factors in HSC remain to be fully elucidated. Recent evidence indicates that the mitogen-activated protein kinase (MAPK) family, including c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), plays an important role in the cellular response to stress. The aims of this study were to investigate whether fibronectin (FN) or the inflammatory cytokines interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) activate JNK, ERK, and AP-1 activity in HSC and induce the gene expression of the matrix metalloproteinase transin. Treatment of HSC with FN resulted in an up to 4.5-fold increase in ERK activity and a 2.1-fold increase in JNK activity. IL-1alpha and TNF-alpha produced up to a fourfold increase in JNK activity and a twofold increase in ERK activity. We then compared the effects of FN, IL-1alpha, and TNF-alpha on AP-1 activity and metalloproteinase mRNA induction. All three compounds increased AP-1 binding and promoter activity, and transin mRNA levels were increased 1.8-fold by FN, 2.2-fold by IL-1alpha, and 2.8-fold by TNF-alpha. Therefore, FN and inflammatory cytokines increase MAPK activity, stimulate AP-1 activity, and increase transin gene expression in HSC. Signal transduction pathways involving the MAPK family may play an important role in the regulation of matrix metalloproteinase expression by cytokines and FN in HSC.
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PMID:Fibronectin and cytokines increase JNK, ERK, AP-1 activity, and transin gene expression in rat hepatic stellate cells. 935 21

In this study, the distribution of tenascin immunoreactivity in 44 cases of vulvar lichen sclerosus (LS) was investigated. To assess the epithelial basement membrane structure, immunostaining with an antibody to type IV collagen was performed. Ten selected cases were also analyzed by in situ hybridization with a tenascin RNA probe to study the cellular distribution of tenascin mRNA synthesis in LS. Strong tenascin immunoreactivity could be found in LS, especially in areas with subepithelial edema and marked inflammation. By in situ hybridization, signals for tenascin mRNA could be found in basal keratinocytes, dermal fibroblasts, and endothelial cells. Staining for type IV collagen often revealed attenuation and discontinuity in the basement membrane. The abnormal accumulation of tenascin in LS suggests that it may participate in the pathogenesis of this disease. As shown by in situ hybridization, the cell types responsible for tenascin synthesis are basal keratinocytes, dermal fibroblasts, and endothelial cells. Because tenascin, together with fibronectin, is able to upregulate the expression of 92 kDa collagenase and stromelysin in fibroblasts, the matrix destruction and basement membrane damage in LS may partly be a consequence of an abnormal accumulation and synthesis of tenascin. The upregulation of tenascin synthesis in dermal fibroblasts, endothelial cells, and keratinocytes in LS could be mediated by an abnormal expression of growth factors, most notably TGF-beta, which are able to stimulate tenascin synthesis in many non-neoplastic and neoplastic cell lines.
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PMID:Tenascin expression in lichen sclerosus. 942 Oct 69

Lung epithelial and mesenchymal cells are separated by a basement membrane. At late fetal gestation, this basement membrane in fenestrated, allowing epithelial cytoplasmic extensions to reach in close proximity of the interstitial fibroblast. The enzymes responsible for this focal basement membrane remodelling, and their cellular origin, remains to be defined. Basement membrane remodelling generally involves a special class of matrix-degrading enzymes, called metalloproteinases. Herein, we report that fetal lung cells originating from both tissue layers, mesoderm and endoderm, express the metalloproteinase genes, MMP-1 or interstitial collagenase, and MMP-3 or stromelysin. The inhibitor of metalloproteinases, TIMP-1, is mainly expressed in fetal lung fibroblasts. During late fetal development, MMP-1 mRNA expression in both cell types increases close to term (day 21, term = 22 days), while that of stromelysin and TIMP-1 remain constant. Both fibroblasts and epithelial cells express fibronectin (FN) mRNA. The expression of the FN gene in epithelial cells decreases slightly at the canalicular stage of lung development (days 19-20), whereas FN expression in fibroblasts is not changed with advancing gestation. Procollagen alpha 1 (I) mRNA is predominantly detected in fibroblasts whereas message for laminin B1 chain is primarily found in epithelial cells. Expression of procollagen alpha 1 (I) mRNA decreases in fibroblasts during the canalicular stage of fetal lung development compared to the pseudoglandular stage (day 18) but increases thereafter at the saccular stage (day 21) of development. Laminin B1 expression in epithelial cells declines with advancing gestation. These data are consistent with a process of basement membrane thinning during the canalicular stage, followed by metalloproteinase-mediated penetration. Further, a progressive reduction in laminin expression is consistent with progressive epithelial differentiation.
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PMID:Ontogeny of extracellular matrix gene expression by rat lung cells at late fetal gestation. 948 4

A commercial preparation of 800-kDa hyaluronic acid (HA), (ARTZ from Seikagaku, Inc.), has been used as a therapeutic intervention in the treatment of osteoarthritis (OA). We tested the effect of this HA form, HA/800, in an in vitro cartilage chondrolytic system in which a specific amino-terminal 29-kDa fragment of fibronectin (Fn-f) penetrates cartilage tissue to activate chondrocytes to amplify two major chondrolytic activities: suppression of proteoglycan (PG) synthesis and induction of matrix metalloproteinases. We report that HA/800 did not block damage by Fn-f in serum free cartilage cultures. However, HA/800 was effective in blocking the ability of 100 nM Fn-f to cause the degradation and release of half of the total cartilage PG from cartilage in 10% serum/DMEM cultures. While the Fn-f caused a half-time for PG release of 3 days, continuous exposure to 0.1 or 1 mg/ml HA/800 slowed the half-time to 12 days. Further, a single 1 day pre-incubation with 0.1 or 1 mg/ml HA/800 was sufficient to decrease the half-time of 100 nM Fn-f mediated PG depletion to 7 and 12 days, respectively. HA/800 completely blocked the effect of 10 nM Fn-f. Blocking of Fn-f-mediated cartilage PG depletion was associated with a decreased concentration of Fn-f on the superficial cartilage surface and decreased penetration into the cultured cartilage tissue. Further, the two major chondrolytic activities of the Fn-f, suppression of synthesis of PG and enhanced release of stromelysin-1, were suppressed by HA/800. HA/800 also partially restored PG in cartilage first damaged with the Fn-F. We conclude that HA/800 slows Fn-f-mediated cartilage chondrolysis in vitro and has some reparative potential. The damage blocking activity appears to be associated with the ability of HA/800 to block penetration of the Fn-f, rather than with direct effects on cartilage tissue.
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PMID:Hyaluronic acid suppresses fibronectin fragment mediated cartilage chondrolysis: I. In vitro. 949 38

The addition of fibronectin fragments to cultured cartilage causes an initial suppression of proteoglycan synthesis, induction of matrix metalloproteinases, and resultant decrease in proteoglycan content by about 50% during the first few days in culture. Because the proteoglycan loss appears to be limited, we investigated whether the fibronectin fragments induce anabolic responses that might counter the damage. The effects of various lengths of exposure of cultured cartilage to the fibronectin fragment on proteoglycan content, proteoglycan synthesis rates, stromelysin-1 release, and tumor necrosis factor-alpha, interleukin-1alpha, and interleukin-6 release were investigated. The results showed that about 7 days of exposure of cultured cartilage to the fibronectin fragment was required for maximal cytokine release, proteoglycan depletion, and stromelysin-1 release. However, nearly maximal suppression of proteoglycan synthesis occurred within 1 day of the addition of the fibronectin fragment and, after its removal, the rates increased to supernormal levels. Decreasing exposure to 3 days caused only a small decrease in cartilage proteoglycan content, although stromelysin-1 release still occurred. Decreasing exposure to 1 day caused an immediate increase in proteoglycan synthesis and an increase to supernormal proteoglycan contents. The effect of first treating cartilage with the fibronectin fragment for various periods and then allowing a recovery was to make the cartilage more resistant to secondary exposures. This study shows that cartilage damage can be caused by short exposures to the fibronectin fragment and that exposures either optimal or suboptimal for damage additionally amplify anabolic processes to make the cartilage resistant to further damage and, thus, condition it against pending amplification of damage.
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PMID:Exposure of cartilage to a fibronectin fragment amplifies catabolic processes while also enhancing anabolic processes to limit damage. 962 98

Stromelysin, a member of the matrix metalloproteinase family, demonstrates wide substrate specificity with the ability to degrade proteoglycan, fibronectin, laminin, casein, and the nonhelical region of collagen. The two forms of stromelysin (SL), types 1 (MMP-3) and 2 (MMP-10), share 82% sequence homology, but exhibit differences in cellular synthesis and inducibility by cytokines and growth factors in vitro. However, the distribution of the two isoforms in bone has not been reported. We investigated the presence of SL-1 and SL-2 in human osteophytic and neonatal rib bone using immunohistochemistry and, combined with a new method of in situ zymography, determined the activity of the immunolocalized stromelysins. Latent SL-1 was strongly expressed in the extracellular matrix in fibrous tissue surrounding areas of endochondral ossification in osteophytes, and adjacent to the periosteum of fetal rib bone. Active SL-1 expression was detected in osteocytes and the matrix surrounding osteocytic lacunae. SL-2 showed intense cell-associated staining at sites of resorption in areas of endochondral ossification and in resorptive cells at the chondro-osseous junction, which correlated with enzyme activity detected by zymography. Within the rib, active SL-2 expression was localized in chondrocytes of the growth plate, whereas only occasional SL-1 signal was evident. Vascular areas showed strong SL-2 staining with some proteolytic activity. SL-2, but not SL-1, was strongly expressed in osteoclasts and most mononuclear cells within the marrow. At sites of bone formation both isoforms were expressed by osteoblasts with SL-1 also present in osteoid. These results demonstrate, for the first time, the differential expression of SL-1 and SL-2 in developing human bone, indicating specific roles for the two isoforms. In situ zymography demonstrates that SL-2 is produced in an active form with associated degradation, whereas SL-1, in a matrix-bound proenzyme form, may act as a reservoir for later activation.
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PMID:Stromelysin-1 (MMP-3) and stromelysin-2 (MMP-10) expression in developing human bone: potential roles in skeletal development. 966 24


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