Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Normal human skin fibroblast primary cell lines secrete over 50 proteins into culture medium. These have been mapped previously using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and this technique has now been used to investigate extracellular protein secretion by human osteoblasts in vitro. We report the mapping of a number of consistent markers specific to the osteoblast. In particular, one protein chain with posttranslational modifications was found to be unique to the osteoblast extracellular protein map. The absence of the N- and O-glycoforms of collagenase from the osteoblast profile in this study concurs with findings reported using the immunoprecipitation functional assay and Northern blot analysis. The use of 2-D PAGE in phenotypic assessment provides a more complete analysis than the standard range of single-parameter tests for osteoblasts. Mapping of extracellular and cellular proteins in addition to bone matrix protein analysis will allow a comprehensive analysis of normal osteoblast function. This technique may also be applied to the study of osteoblasts in relation to bone disease and in assessing the phenotypic shift within a normal osteoblast culture.
...
PMID:Two-dimensional polyacrylamide gel electrophoresis reveals differences between osteoblast and fibroblast extracellular proteins. 139 27

The lectin concanavalin A (ConA) causes fibroblasts to acquire an arborized morphology and to express elevated levels of collagenase. The temporal and mechanistic aspects of ConA regulation of matrix metalloproteinases (MMPs) and the tissue inhibitor of matrix metalloproteinases (TIMP) were characterized in early passage human fibroblasts. Collagenase (MMP-1), measured by functional assays in the absence of TIMP and also as immunoprecipitated [35S]methionine-labeled protein, was increased 10-20-fold following ConA (20 micrograms/ml, 2 x 10(-7) M) treatment for 24-72 h, with active collagenase comprising approximately 20% of the total collagenase activity. By comparison, MMP-2 (72-kDa gelatinase; molecular mass, 72 kDa, +dithiothreitol; 66 kDa, -dithiothreitol), analyzed by enzymography and following affinity purification, was increased less than 2-fold by ConA and was present entirely as an activated, 61-kDa (+dithiothreitol; 59 kDa, -dithiothreitol) form. Northern hybridization analyses revealed that ConA elevated the steady-state mRNA levels for MMPs; collagenase mRNA increased approximately 16-fold, MMP-2 increased 2-fold, and Pump-1, a recently described MMP gene, was induced. Concomitantly, a 10-fold reduction in TIMP protein and mRNA levels by ConA occurred. In comparison, 12-O-tetradecanoylphorbol-13-acetate (50 ng/ml, 8 x 10(-8) M), which also stimulates collagenase expression strongly (greater than 30-fold), elevated TIMP protein and mRNA levels (2- and 3-fold, respectively) and did not affect MMP-2 expression. The changes in MMP and TIMP mRNA levels induced by ConA were blocked by the protein synthesis inhibitor cycloheximide, and the half-lives of collagenase and MMP-2 mRNAs (53 and 46 h, respectively) were unaffected, indicating that ConA exerts its effects transcriptionally, through pathways requiring de novo protein synthesis. Increased transcription of the mmp genes was confirmed by nuclear run-on analyses; mmp-1 transcription was increased by greater than 25-fold, mmp-2 by approximately 3-fold, and Pump-1 by approximately 7-fold. In contrast, Timp gene transcription was reduced by approximately 80%, revealing reciprocal regulation of MMPs and TIMP during the induction of a resorptive cell phenotype. Decreased amounts of collagen and fibronectin, but not of SPARC (secreted protein, acidic and rich in cysteine) in the conditioned medium was the result of MMP activity since steady-state mRNA levels and transcription of the respective matrix protein genes were unaffected by ConA.
...
PMID:Concanavalin A produces a matrix-degradative phenotype in human fibroblasts. Induction and endogenous activation of collagenase, 72-kDa gelatinase, and Pump-1 is accompanied by the suppression of the tissue inhibitor of matrix metalloproteinases. 217 35

In previous studies, we described a layer of tissue that formed around methylmethacrylate cement that had been implanted into the posterior cervical spine of dogs. We are now reporting on a rat model in which we induced, in the interface between the bone of the posterior elements of the dorsal spine and methylmethacrylate, the formation of a layer of tissue that was morphologically similar to the tissue that had been produced in the dogs. As in the dogs, we noted macrophages and giant cells and we demonstrated that the interface tissue synthesized several basement-membrane components (type-IV collagen, laminin, and fibronectin). In addition, we demonstrated the synthesis of an additional extracellular-matrix protein--type-VI collagen. We also showed that extracts of organ cultures of tissue from the rat model degraded type-I collagen into three-quarter and one-quarter-length fragments. Such enzymatic activity is characterized of mammalian collagenase, an enzyme that is known to play a critical role in the resorption of bone.
...
PMID:Characterization of tissue from the bone-polymethylmethacrylate interface in a rat experimental model. Demonstration of collagen-degrading activity and bone-resorbing potential. 254 19

Previous studies have suggested that vitamin D metabolites directly influence the differentiation and maturation of chondrocytes in calcifying cartilage. Recently, this laboratory has shown that the response of chondrocyte plasma membrane and matrix vesicle enzymes to 1,25-(OH)2D3 and 24,25-(OH)2D3 is both cell and membrane specific. The current study demonstrates that cell replication and matrix protein synthesis are also modulated by vitamin D. Confluent, third-passage growth zone (GC) and resting zone (RC) costochondral chondrocytes were incubated in medium containing 10(-13)-10(-7) M 1,25-(OH)2D3 or 10(-12)-10(-6) M 24,25-(OH)2D3. The amount of collagenase-digestible protein (CDP) secreted into the media was inversely proportional to the concentration of fetal bovine serum (FBS). At 10% FBS, greater than 80% of the CDP was incorporated into the matrix. 1,25-(OH)2D3 stimulated CDP and percentage collagen synthesis by GC cells but had no effect on the synthesis of noncollagenous protein (NCP). 1,25-(OH)2D3 inhibited CDP and percentage collagen synthesis by RC cells but did not alter NCP synthesis. [3H]thymidine incorporation was inhibited in both cell types, whether confluent or subconfluent cultures were examined. At 10(-6) and 10(-7) M 24,25-(OH)2D3, there was a significant decrease in CDP production and percentage collagen synthesis by RC cells but no effect on NCP. However, at 10(-9) and 10(-10) M hormone there was an increase in NCP production but no effect on CDP, resulting in a decrease in percentage collagen synthesis. CDP and NCP production were unaffected by 24,25-(OH)2D3 in GC cells. High concentrations of hormone inhibited [3H]thymidine incorporation in both cell types.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effects of vitamin D metabolites on collagen production and cell proliferation of growth zone and resting zone cartilage cells in vitro. 278 22

Recent studies of murine tumor models and certain human tumor cell lines have provided evidence for intratumor heterogeneity in expression of extracellular matrix receptors and in the elaboration of matrix-degrading enzymes. However, little is known about possible intratumoral heterogeneity in the production of matrix macromolecules. We have, therefore, examined the biosynthesis and secretion of matrix proteins by cells derived from a polyclonal human cell line (JH-17) established from a large cell undifferentiated carcinoma of the lung. For the present studies, we focused on the production of collagens and structural glycoproteins by two phenotypically different aneuploid clones, designated C13 and C22. These clones were distinctive in their inability to grow in soft agar or to form tumors in nude mice and had identical DNA contents. Tumor cells were labeled with [3H]proline and the newly synthesized proteins accumulating in the culture medium were identified using biochemical and immunologic techniques. Clone C13 secreted at least three genetically distinct collagens, including type V procollagen (PC), type IV procollagen, and a type VIII-like collagen. By contrast, the clone C22 synthesized fibronectin, and a single bacterial collagenase-sensitive and pepsin-resistant component consistent with type I trimer. These studies emphasize the potential diversity of matrix proteins synthesized by neoplastic cells and suggest that there is intratumoral heterogeneity in matrix protein biosynthesis in vivo. These studies further suggest that tumor-derived matrix may be altered during tumor progression or cell selection in vivo.
...
PMID:Heterogeneity in the production of collagens and fibronectin by morphologically distinct clones of a human tumor cell line: evidence for intratumoral diversity in matrix protein biosynthesis. 282 40

Extracellular matrix proteins synthesized and secreted by adherent human tumor cell lines were analyzed using metabolic labelling with glycine and proline in the presence of ascorbate, polypeptide analysis and polyacrylamide gel electrophoresis, affinity chromatography, collagenase digestion, and immunofluorescence staining. The results showed a characteristic pattern of matrix proteins for each tumor cell type. Tumor cell lines of mesenchymal origin produced mostly interstitial types (I and II) of collagen and fibronectin. Carcinoma cell lines secreted only basement membrane proteins, type IV collagen, laminin and fibronectin, but not interstitial collagen. A melanoma and a rhabdomyosarcoma cell line produced type V of procollagen that has not previously been described in cell culture. Neuroblastoma cells were shown to be phenotypically heterogeneous also with respect to matrix protein production. We propose that the analysis of extracellular matrix proteins may serve as an adjunct in the classification of human tumors.
...
PMID:Extracellular matrix proteins characterize human tumor cell lines. 627 24

Treatment of mouse MC3T3-E1 cells with ascorbic acid initiates the formation of a collagenous extracellular matrix and synthesis of several osteoblast-related proteins. We recently showed that ascorbic acid dramatically increases alkaline phosphatase and osteocalcin mRNAs and that this induction is blocked by inhibitors of collagen triple-helix formation (Franceschi and Iyer, J Bone Miner Res 7:235). In the present study, the relationship between collagen matrix formation and osteoblast-specific gene expression is explored in greater detail. Kinetic studies revealed that ascorbic acid increased proline hydroxylation in the intracellular procollagen pool within 1 h and stimulated the cleavage of type I collagen propeptides beginning at 2.5 h. Mature alpha 1(I) and alpha 2(I) collagen components were first detected at 10 h and continued to increase in both cell layer and culture medium for up to 72 h. Ascorbic acid also increased the rate of procollagen secretion from cell layers to culture medium. The secretion of another matrix protein, fibronectin, was only slightly affected. Alkaline phosphatase or its mRNA was first detected 2-3 days after ascorbic acid addition, but osteocalcin mRNA was not seen until day 6. Two inhibitors of collagen triple-helix formation, ethyl-3,4-dihydroxybenzoate and 3,4-dehydroproline, inhibited procollagen hydroxylation and alkaline phosphatase induction. 3,4-Dehydroproline also inhibited the induction of alkaline phosphatase and osteocalcin mRNAs. Surprisingly, induction was not blocked if cells were exposed to ascorbic acid before inhibitor addition. Alkaline phosphatase was also partially inhibited if cells were grown in the presence of purified bacterial collagenase. These results indicate that the induction of osteoblast markers by ascorbic acid does not require the continuous hydroxylation and processing of procollagens and suggest that a stable, possibly matrix-associated signal is generated at early times after ascorbic acid addition that allows subsequent induction of osteoblast-related genes.
...
PMID:Effects of ascorbic acid on collagen matrix formation and osteoblast differentiation in murine MC3T3-E1 cells. 807 60

Gallium is a Group IIIa transitional element with therapeutic efficacy in the treatment of metabolic bone disorders. Previously described antiresorptive effects of gallium on osteoclasts are not sufficient to account for the full range of effects of gallium on bone structure and metabolism. We have recently shown that gallium nitrate inhibits osteocalcin gene expression and the synthesis of osteocalcin protein, an osteoblast-specific bone matrix protein that is thought to serve as a signal to trigger osteoclastic resorption. Here we present evidence for an additional mechanism by which gallium may function to augment bone mass by altering matrix protein synthesis by osteoblastic and fibroblastic cells. Rat calvarial explants exposed to gallium nitrate for 48 h showed increased incorporation of 3H-proline into hydroxyproline and collagenase digestible protein. In addition, gallium treatment increased steady-state mRNA levels for fibronectin and type I procollagen chains in primary rat calvarial osteoblast-enriched cultures, the ROS 17/2.8 osteoblastic osteosarcoma line, and nontransformed human dermal fibroblasts. These findings suggest that the exposure of mesenchymally-derived cells to gallium results in an altered pattern of matrix protein synthesis that would favor increased bone formation.
...
PMID:Gallium nitrate increases type I collagen and fibronectin mRNA and collagen protein levels in bone and fibroblast cells. 822 74

The effects of IL-1 beta and TGF-beta on the biosynthesis of extracellular matrix structural components relative to the metalloproteinases and their inhibitor TIMP1 in human articular chondrocytes were investigated. It has been proposed that TGF-beta, acting as a positive regulator of matrix accretion, can counteract the increased loss of cartilage matrix induced by IL-1 beta. To allow a comparison of their effects on mRNA levels for these different components, quantitation by competitive RT/PCR was employed. This method was found to give reproducible estimates of mRNA levels and the observed effects of IL-1 beta and TGF-beta on individual components of this system agree with qualitative data obtained by northern blotting. IL-1 beta had a more pronounced effect on aggrecan mRNA levels than on those for type II collagen. Similar quantitative differences were observed between collagenase and stromelysin mRNA levels. TGF-beta generally counteracted the effects of IL-1 beta, and new steady state levels were attained within 24 h. However, the reversal of IL-1 beta induced suppression of matrix protein mRNA levels appeared more effective than its suppression of the increase in stromelysin and collagenase mRNA levels. Similarly TGF-beta did not reduce the extent of IL-1 beta induced secretion of stromelysin at the protein level. TIMP1 mRNA levels were only slightly reduced by IL-1 beta; however this cytokine effectively suppressed its induction by TGF-beta. The higher concentrations of TGF-beta and longer exposure times required to overcome the suppressive effects of IL-1 beta suggest that the interaction between IL-1 beta and TGF-beta in the regulation of TIMP1 expression follows a different mechanism to that operating for the metalloproteinases and matrix proteins. Thus the overall potential of TGF-beta to inhibit proteolysis is attenuated by its much slower effect on TIMP1 mRNA levels.
...
PMID:Modulation of the catabolic effects of interleukin-1 beta on human articular chondrocytes by transforming growth factor-beta. 859 95

The biological basis for failure of the human anterior cruciate ligament to heal after rupture is unknown. Since this failure could be influenced by abnormalities in matrix protein production or degradation, or both, several diverse matrix protein markers were utilized to survey the state of these extracellular proteins in intrinsic anterior cruciate ligament fibroblasts. Matrix gene expression was visualized by in situ hybridization 9 to 365 days after rupture using probes for type-I collagen, collagenase, 72kDa-gelatinase, and tissue inhibitor of metalloproteinase. Remnants of anterior cruciate ligament were biopsied arthroscopically from 20 patients at reconstruction, fixed in 4% paraformaldehyde, and processed with cDNA probes for the aforementioned mRNAs. mRNA expression of type-I collagen was detected in all specimens, was equally distributed throughout the remnants, and remained evident even at 1 year after injury. Neither of the matrix-degrading enzymes nor their inhibitor (tissue inhibitor of metalloproteinase) was expressed at substantial levels at any time point. Collagen expression within the anterior cruciate ligament confirmed the viability of the ligament remnants for as long as 1 year after rupture. The lack of significant expression of the two matrix-degrading metalloproteinases by the fibroblasts is not consistent with an autodegradation of the remaining ruptured ligament tissue, and whether the lack of matrix remodelling may account, at least in part, for the poor healing response of the anterior cruciate ligament remains to be determined. This initial investigation by in situ hybridization techniques provides a descriptive profile of matrix gene expression in the damaged human anterior cruciate ligament.
...
PMID:Expression of collagen and matrix metalloproteinases in ruptured human anterior cruciate ligament: an in situ hybridization study. 898 26


1 2 3 4 5 Next >>

---