Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Laminin self-assembles in vitro into a polymer by a reversible, entropy-driven and calcium-facilitated process dependent upon the participation of the short arm globular domains. We now find that this polymer is required for the structural integrity of the collagen-free basement membrane of cultured embryonal carcinoma cells (ECC) and for the supramolecular organization and anchorage of laminin in the collagen-rich basement membrane of the Engelbreth-Holm-Swarm tumor (EHS). First, low temperature and EDTA induced the dissolution of ECC basement membranes and released approximately 80% of total laminin from the EHS basement membrane. Second, laminin elastase fragments (E4 and E1') possessing the short arm globules of the B1, B2, and A chains selectively acted as competitive ligands that dissolved ECC basement membranes and displaced laminin from the EHS basement membrane into solution. The fraction of laminin released increased as a function of ligand concentration, approaching the level of the EDTA-reversible pool. The smaller (approximately 20%) residual pool of EHS laminin, in contrast, could only be effectively displaced by E1' and E4 if the collagenous network was first degraded with bacterial collagenase. The supramolecular architecture of freeze-etched and platinum/carbon replicated reconstituted laminin gel polymer, ECC, and collagenase-treated EHS basement membranes were compared and found to be similar, further supporting the biochemical data. We conclude that laminin forms a network independent of that of type IV collagen in basement membranes. Furthermore, in the EHS basement membrane four-fifths of laminin is anchored strictly through noncovalent bonds between laminin monomers while one-fifth is anchored through a combination of these bonds and laminin-collagen bridges.
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PMID:Laminin forms an independent network in basement membranes. 157 69

Laminin is a large multidomain glycoprotein with diverse biological activities which include stimulation of neurite outgrowth, enhancement of tumor metastasis, and promotion of cell growth, adhesion, and differentiation. A 19 amino acid synthetic peptide derived from the E8 fragment of the laminin A chain (Cys-Ser-Arg-Ala-Arg-Lys-Gln-Ala-Ala-Ser-Ile-Lys-Val-Ala-Val-Ser-Ala-Asp -Arg- NH2) was identified which promotes metastasis and stimulates collagenase IV activity in the culture medium of B16 melanoma cells (Kanemoto et al., 1990). We report that this peptide, here designated LamA2091-2108, is also a potent stimulator of tissue plasminogen activator (t-PA)-catalyzed plasminogen activation, resulting in a 22-fold increase in the kcat/Km of the activation reaction. The activity of purified type I and type IV collagenase was inhibited by LamA2091-2108 with IC50 values of 3 and 43 microM, respectively. These data support an alternative mechanism for the appearance of collagenase activity in the culture media of melanoma cells, namely, that the peptide stimulates plasminogen activation, subsequently generating collagenase activity.
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PMID:Modulation of plasminogen activation and type IV collagenase activity by a synthetic peptide derived from the laminin A chain. 184 24

This paper reports the characterization of two immunologically related proteins that may be involved in cell adhesion during Drosophila development. These proteins, laminin chain A and a 240K component, share the epitope recognized by monoclonal antibody RD3 (Mab RD3). The two antigens show different developmental expression profiles. Laminin is detected only from 6 to 8 h of development onwards; its concentration increases during embryogenesis to reach steady-state value in larvae, pupae and adult flies. By contrast, the 240K antigen, not found in oocytes, is present before blastoderm stages; its concentration increases during gastrulation, decreases at the end of organogenesis and the antigen is no longer detected in third instar larvae. Light and electron microscope immunolocalization in imaginal discs indicates that laminin is distributed apically in the lumen and basally in the basal membrane that surrounds the nonevaginated disc. During morphogenesis laminin is detected at the basal side of the evaginating part of the disc epithelium. Immunolocalization on paraffin sections of early embryos suggests that the 240K antigen is related to (1) cell formation and polarization in association with cytoskeleton components, (2) establishment of cell-extracellular substratum interactions during the blastoderm cell sheet organization and (3) basement membrane deposition during embryonic germ cell layer segregation. This 240K protein is poorly or not glycosylated, is resistant to chondroitinase ABC and collagenase and appears therefore as a new extracellular component that might be specifically involved in early processes of morphogenesis.
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PMID:Expression of laminin and of a laminin-related antigen during early development of Drosophila melanogaster. 248 69

Human corneal endothelial cells (HCEC) were isolated by means of enzymatic treatment of excised corneas. The corneas were incubated for 1.5 hr together with a high concentration of collagenase (0.5%), followed by a long-term incubation (up to 16 hr) using a low concentration of the enzyme (0.04%). Endothelial cells were enriched against contaminating fibroblasts by using a selective L-valine-free medium which inhibited fibroblast growth during the first passages. Subcultures of HCEC were passaged for more than 20 generations without showing signs of senescence. Laminin and chondroitin sulfate functioned as a substrate for HCEC, promoting proliferation and allowing the cells to grow in monolayer formation. The inclusion of fibroblast growth factor (FGF) as well as chondroitin sulfate in the medium led to an additional increase in the rate of proliferation.
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PMID:Isolation and long-term cultivation of human corneal endothelial cells. 318 1

Fibroblast (F) and epithelial (E) cells were obtained as primary outgrowths from explants of fetal porcine maxillary molars and subcultured up to four passages in monolayers enriched with either cell type. Histology of a tooth bud after 1 day in culture showed intact odontogenic E cell layers which were the probable source of the E cell outgrowths. After 2 months in culture, the fourth passage E cells demonstrated morphological differentiation by an alteration in cell packing and the formation of domes and nodules, when E and F cells were cocultured. Occasionally the nodules grew to considerable size, indicating the potential of these cells to aggregate and reorganize into odontogenic tissues even on culture dishes. The cells were characterized in monolayer culture by immunocytochemical staining. Laminin and type IV collagen staining was distributed diffusely throughout the culture, whereas type I collagen and osteonectin staining was predominantly localized in the F cells. Radiolabelled proteins from both E and F cell media produced similar collagen patterns (95% type I, 4% type V, 1% other), except that the F cells appeared to produce active collagenase. In addition, the E cells produced two radiolabelled proteins (relative masses of 50,000 and 53,000) that reacted with an affinity-purified antibody directed against porcine amelogenin. These experiments show that cells subcultured from tooth buds and grown in monolayer cultures can be used to study tooth organogenesis in vitro, as well as enamel protein biosynthesis.
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PMID:Enamel protein and collagen production by cells subcultured from porcine tooth bud explants. 343 66

Sera from patients with poststreptococcal glomerulonephritis (PSGN) known to have antibodies to proteoglycans were studied for the presence of antibodies against other basement membrane (BM) components. BM collagen (type IV) was isolated in the native state by extracting bovine anterior lens capsule (ALC) with 0.5 M acetic acid. The 7-S (collagenous) domain and the NC-1 (noncollagenous) domain of type IV collagen were obtained after bacterial collagenase digestion of ALC followed by gel filtration. Laminin was isolated from the mouse EHS tumor and fibronectin from human plasma. Immunologic studies, using an ELISA and electroimmunoblot, revealed the presence of antibodies that reacted with intact, native type IV collagen and the 7-S collagenous domain of this molecule. Reaction with the NC-1 (noncollagenous) domain was minimal, and not higher than that obtained with control sera. Laminin reaction strongly with the patients' sera, but fibronectin did not. Unlike sera from patients with Goodpasture syndrome, which contain antibodies primarily against the NC-1 (noncollagenous) domain of type IV collagen, sera from patients with acute PSGN contain antibodies against all the major macromolecular components of BM. This difference in immunologic reactivity may account for the observed differences in the pathologic picture at the glomerular level.
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PMID:Antibodies to basement membrane collagen and to laminin are present in sera from patients with poststreptococcal glomerulonephritis. 395 May 43

We used affinity chromatography to isolate a specific laminin-binding protein from murine fibrosarcoma cells. These cells bind exogenous laminin to their surface with high affinity (Kd = 2 X 10(-9)M for laminin) with approximately 5 X 10(4) sites per cell. Laminin affinity chromatography of [35S]methionine-labeled cell extracts produced two distinct proteins. One was identified as Type IV (basement membrane) collagen based on its migration pattern on SDS gels and bacterial collagenase sensitivity. The other protein, which migrates as a single band or closely spaced doublet on reduced SDS gels, has a reduced molecular weight of 69,000. Using a nitrocellulose filter disk assay, we found that the latter protein specifically bound 125I-laminin with the same high affinity (Kd = 2 X 10(-9)M for laminin) as did intact fibrosarcoma cells. By iodinating intact cells, we demonstrated that this laminin-binding protein is on the cell surface. We conclude that this protein with reduced molecular weight of 69,000 is a subunit or component of a larger cell surface receptor protein for laminin in this fibrosarcoma model. This laminin receptor may mediate the interaction of the cell with its extracellular matrix.
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PMID:Isolation of a cell surface receptor protein for laminin from murine fibrosarcoma cells. 630 2

Basement membrane formation of fetal mouse intestinal epithelial cells was investigated in organoid cultures. Intestinal cells were dissociated with a commercial collagenase/dispase preparation, and the cells were grown at high density on a membrane filter at the interface between the medium and air. This type of culture allows the histotypical reorganization of cells. After 2 days in culture, epithelial cells began to accumulate on the surface, in particular the periphery of the culture. These cells were usually cuboid, and small vesicles were formed in the center of the culture. Laminin-positive material was observed at peripheral sites. However, no basement membrane could be identified beneath the epithelial cells at the electron-microscopic level. After 3 days, epithelial cells that had gathered at the periphery became columnar in shape. Laminin-positive material extended across the surface of the culture. However, the vesicles formed in the center of the culture were not associated with laminin-positive material. Basement membrane was observed by electron microscopy at some sites beneath groups of epithelial cells, but did not extend continuously beneath these cells. Some epithelial cells made contact with the underlying mesenchymal cells through the discontinuous basement membrane via intercellular contacts. After 5-6 days, the surface of the culture was almost completely covered with epithelial cells and, at some sites, villus-like structures were visible. Laminin-positive material was clearly detectable under epithelial cells, as well as around epithelial vesicles located in the center of the culture. By electron microscopy, basement membrane was clearly visible between the epithelial and mesenchymal cells. After 9 days, villus-like structures were rarely observed. After 3 weeks, the cell mass had become smaller and villi had disappeared. Basement membrane was extensively folded and no basement membrane was visible at some sites. Formation of basement membrane by epithelial cells in monolayer culture occurs in an incomplete and irregular manner. It occurs rapidly in organoid cultures that include mesenchyme and epithelium. The organoid culture used here should be a useful tool for studies of the formation and degeneration of the basement membrane as well as interactions between the epithelium and mesenchyme.
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PMID:Basement membrane formation of fetal mouse intestinal epithelial cells in organoid cultures. 856 Sep 71

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

During endochondral ossification and bone remodeling, osteoprogenitors (OP) attach to the matrix and differentiate into osteoblasts. To identify matrix proteins binding specifically these precursors, fetal rat calvaria (RC) cells were plated for 5-20 min in serum-free medium, on wells coated with various proteins and saturated with bovine serum albumin (BSA) to block nonspecific binding sites. Adherent cells were either counted or grown to assess bone colony (nodule) formation. As each nodule originates from the clonal division of one OP, the ratio (nodules/100 cells attached) measures the proportion of OP among adherent cells. Of numerous purified matrix proteins tested, laminin-1 and tenascin inhibited cell attachment, whereas fibronectin, bone sialoprotein, and type I collagen increased cell attachment and others had no effect. Only laminin-1 and, to a lesser extent, tenascin, enriched the cell population in OP. Laminin-1 acted time- and dose-dependently. In experiments in which cell attachment to laminin-coated but unsaturated wells was ensured by plating for 24 h in 10% fetal calf serum, laminin-1 had no effect on cell attachment nor on OP differentiation. In contrast, repeated plating of RC cells on laminin-1-coated/saturated wells depleted the population in OP, confirming that OP selection was a cell-attachment effect. When RC cell populations isolated by successive collagenase extractions were compared, the highest rate of OP enrichment on laminin-1 was obtained with the earliest populations, which were the most responsive to dexamethasone, a marker of early OP stages. In conclusion, laminin-1 recruits in vitro, through a cell-attachment effect, OP present in early RC cell populations, of which laminins are abundant extracellular matrix components.
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PMID:Selective attachment of osteoprogenitors to laminin. 1022 45


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