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C L Mainardi

Publications and source records attributed to C L Mainardi.

At least 37 records · Page 2Linked to original sources
PubMed1985

Biochemical and immunological characterization of the secreted forms of human neutrophil gelatinase.

Human neutrophils contain a neutral metalloproteinase which degrades denatured collagens and potentiates the action of interstitial collagenase. This gelatinase is rapidly secreted from neutrophils stimulated with phorbol myristate acetate. The secreted enzyme has been purified by a combination of chromatography on DEAE-cellulose and gelatin-Sepharose. The purified enzyme was latent and had a specific activity of 24,000 units. Estimated molecular weight obtained by gel filtration was 150,000-180,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed three bands with relative molecular weights of 225,000, 130,000, and 92,000. Electrophoresis in the presence of a reducing agent revealed a single band of Mr = 92,000. All the proteins seen on the unreduced gel were found to contain proteolytic activity against gelatin and native type V collagen. Polyclonal antibodies were prepared against the Mr = 130,000 and 92,000 proteins. When analyzed by immunoblotting, both antibodies recognized all three proteins. Furthermore, the identical three proteins were identified by the antibodies when crude culture medium was immunoblotted. The purified enzyme was inhibited by EDTA and 1,10-phenanthroline but not by serine or thiol proteinase inhibitors, suggesting that the enzyme is a metalloendoproteinase. The enzyme had little or no activity against common protein substrates such as bovine serum albumin or casein. Native type I collagen was not cleaved under conditions where native type V collagen was extensively degraded.

Cells, Cultured↗
PubMed1984

Effect of dexamethasone, indomethacin, and lipopolysaccharide on the secretion of interstitial collagenase and type V collagenase by cultured macrophages.

The rabbit alveolar macrophage secretes at least two collagenolytic metalloproteinases in vitro including an interstitial collagenase and a type V collagenase. Using assays previously shown to discriminate between these two activities, the secretion of these two enzyme activities was investigated. Both enzyme activities accumulated in culture over 11 days and the release of both were similarly inhibited by cycloheximide. Collagenolytic activity was negligible in cell lysates. The interstitial collagenase was found in a latent form but the type V collagenase activity was active in the culture medium. When cultured in the presence of dexamethasone, the secretion of both the enzymes were identically inhibited in a dose-dependent manner. Indomethacin was an effective inhibitor of secretion of both collagenases at a concentration of 10(-5) M but not at lower concentrations. Finally, bacterial lipopolysaccharide stimulated the secretion of both type V and interstitial collagenase by these cells. These studies indicate that, like the interstitial collagenase, the type V collagenase is released from the cell as synthesized and is not stored intracellularly. Protein synthesis is necessary for the release of both these collagenases. Furthermore, the release of type V collagenase responded to dexamethasone, indomethacin, and lipopolysaccharide in a manner identical to the secretion of the interstitial collagenase suggesting that synthesis and secretion of these two enzymes are regulated in a similar manner.

Animals↗
PubMed1984

Heterogeneity among human collagenases demonstrated by monoclonal antibody that selectively recognizes and inhibits human neutrophil collagenase.

The heterogeneity of human collagenases has been examined using a monoclonal antibody to neutrophil collagenase. This antibody inhibited collagenase activity and, when covalently coupled to Sepharose, bound both latent and active enzyme. Although human neutrophil collagenase was inhibited by the antibody, the activity of human skin and rheumatoid synovial collagenase was not significantly diminished in the presence of the antibody. Competitive inhibition studies also differentiated between these collagenases. Only human neutrophil collagenase effectively blocked the antibody in a competitive enzyme-linked immunosorbent assay while skin and rheumatoid synovial collagenase again failed to interact with the antibody. The unequivocal recognition of neutrophil collagenase as an immunologically distinct entity from other collagenases supports the hypothesis that neutrophil collagenase is a separate gene product from fibroblast or synovial collagenase.

Animals↗
PubMed1984

Secretion of collagenolytic enzymes by human polymorphonuclear leukocytes.

The polymorphonuclear leukocyte contains three proteinases capable of degrading the collagenous components of the connective tissue matrix. These proteinases, gelatinase, interstitial collagenase and elastase, were found to be rapidly secreted by the neutrophil in response to soluble stimuli with maximal accumulation of the gelatinase and interstitial collagenase occurring during a 20 minute incubation. When neutrophils were stimulated with the chemotactic peptide, formyl-met-leu-phe, gelatinase was the predominant collagenolytic enzyme detected. Stimulation of neutrophils with increasing doses of the Ca++ ionophore A23187 lead to a sequential release of collagenolytic proteinases. Gelatinase release was detected at Ca++ ionophore concentrations of .05-.1 microM, while significant release of interstitial collagenase required 0.5-1 microM A23187. Elastolytic activity was detected only at high concentrations of A23187 (5-10 microM). No release of lactic acid dehydrogenase was detected indicating that the enzyme release was not due to cell death. These studies suggest that the neutrophil may modulate its collagenolytic potential by selective release of collagenolytic proteinases.

Collagen↗
PubMed1984

Purification of a type V collagen degrading metalloproteinase from rabbit alveolar macrophages.

A proteinase capable of degrading the helical region of native human type V collagen was identified in serum-free culture medium from "in vivo-activated" rabbit alveolar macrophages. This enzyme was purified to homogeneity using a combination of gel-filtration, ion-exchange and affinity chromatography. Analysis of the purified material by gel electrophoresis revealed a single broad band with relative molecular mass of 82,000 daltons Enzyme activity was eluted from the gel in a region corresponding to the stained band. The protein band was also found to stain positively using the periodic acid-Schiff technique indicating that it was glycosylated. Amino acid analysis revealed a composition rich in acidic residues. The enzyme cleaved type V collagen into three large molecular weight doublets consistent with two cleavage sites within the helix but was inactive against native type I collagen. However, when type I or type V collagen was heat-denatured, the enzyme degraded the alpha chains to small molecular weight peptides.

Amino Acids↗
PubMed1984

Antibody to rabbit macrophage type V collagenase/gelatinase and its use to further characterize the enzyme.

A highly specific antiserum was raised against purified rabbit alveolar macrophage type V collagenase/gelatinase. The reactivity of the antiserum was tested in ELISA and was detected at a high titer. Competitive inhibition ELISA demonstrated a linear inhibition of reactivity by pure antigen if either pure antigen or crude culture medium was used as the solid phase antigen. In the latter case, greater than 90% inhibition was achieved indicating a high degree of specificity of the antibody. Immobilized antibody was successful in absorbing the type V collagenolytic activity. Immunoblot analysis of crude culture medium revealed a single immunoreactive band which correlated with both the stained gel of the purified antigen as well as the only zone of gelatinolysis in a gelatin/acrylamide gel. This monospecific antibody will be a useful tool in the further characterization of this enzyme as well as the delineation of its relative role in chronic inflammation.

Animals↗
PubMed1984

Lymphocyte modulation of fibroblast function in vitro: stimulation and inhibition of collagen production by different effector molecules.

Increased collagen deposition is a common feature of granulomatous and nongranulomatous inflammation associated with certain types of cell-mediated immune reactions in vivo. In the present study, we found that normal human peripheral blood mononuclear leukocytes cultured in vitro and stimulated by antigens or T cell mitogens release a 100 to 170 K m.w., heat-labile, trypsin-sensitive protein that stimulates dermal fibroblasts to produce increased quantities of type I and III collagens. Our data suggest that this collagen production protein is of T lymphocyte origin and that it preferentially stimulates production of collagen. We also observed that human mononuclear leukocytes release a different effector molecule with an m.w. of 55 K that inhibits fibroblast collagen production. Mononuclear leukocytes in culture are capable of releasing both the stimulator and the inhibitor of collagen production. The relative amounts of each of these factors elaborated by mononuclear leukocytes in culture appear to be influenced by several variables, such as cell density, type of stimulant used, and the duration of the culture period. These observations suggest that collagen production by fibroblasts in close proximity to sites in vivo where cell-mediated immune reactions are occurring might be regulated by both of these effector molecules.

Cell Division↗
PubMed1983

Interleukin 1 stimulation of collagenase production by cultured fibroblasts.

Interleukin 1 is a monokine that exerts biological effects on a variety of target cells in vitro. In this report, interleukin 1 has been found to be capable of stimulating collagenase production by cultured dermal fibroblasts. The concentrations of interleukin 1 that stimulate fibroblast collagenase production are similar to those that stimulate mouse thymocyte proliferation. Analyses by high performance liquid chromatography indicate that interleukin 1, rather than a contaminating monokine, is responsible for this effect on fibroblasts. Interleukin 1, released in vivo by macrophages infiltrating sites of tissue damage or inflammation, may function to stimulate the release of collagenase by connective tissue fibroblasts.

Chromatography, High Pressure Liquid↗
PubMed1983

Alterations in collagen production in mixed mononuclear leukocyte-fibroblast cultures.

The cell-cell interactions between fibroblasts and mononuclear leukocytes (MNL) which promote alterations in collagen accumulation were examined using a system of co-culture of human fibroblasts and peripheral blood MNL. The stimulation of collagen production was optimal after 48 h of co-culture and the increase in collagen correlated directly with the number of MNL added. The enhancement of collagen production was seen in both autologous and allogeneic co-cultures. Stimulation of non-collagenous protein was also noted. Co-culture supernatants contained soluble substances that were capable of stimulating collagen production, although they stimulated collagen production to a lesser degree than direct co-culture. Fractionation of these supernatants on Sephadex G-200 revealed a predominant area of stimulatory activity at 160,000 mol wt. Lesser areas of activity were noted at molecular weights of 80,000 and 25,000. Determination of the types of collagen produced by fibroblasts during co-culture with MNL showed that the ratio of type I:III collagen was decreased. These alterations in both the quantitative and qualitative accumulation of collagen mimic the changes often seen in wound healing and early inflammation suggesting that cellular interactions between fibroblasts and MNL may be important in the modulation of collagen production in normal and pathologic states.

Cells, Cultured↗
PubMed1983

7S domain constitutes the amino-terminal end of type IV collagen: an immunochemical study.

The collagenous material from bovine kidney cortex was prepared by pepsin digestion of cortex homogenates. The 7S collagen was isolated after bacterial collagenase digestion of collagenous basement membrane material and was further purified by molecular sieve and ion exchange chromatography. The antibodies were raised in rabbits against a purified 7S collagen preparation. The pepsin-derived collagenous fragments alpha 1(IV)130K, 95K and alpha 2(IV)120K prepared from bovine cortex were tested for their cross-reactivity with the antiserum. The fragment alpha 1(IV)130K was found to be significantly cross-reactive. The results show the presence of common structural antigenic determinants between 7S collagen and alpha 1(IV)130K fragment, thus indicating that 7S collagen is located at the amino-terminal end of type IV collagen.

Amino Acids↗
PubMed1983

Interstitial collagenase secretion and giant cell formation from rabbit alveolar macrophages. Effects of dexamethasone.

Rabbit alveolar macrophages (AM) induced by complete Freund's adjuvant have been used as a model for activated AM. We studied the effects of in vivo and in vitro corticosteroid on collagenase release and spontaneous formation of multinucleated giant cells (MGC) in culture with this system. Dexamethasone 10- through 10(-7) molar concentration in vitro inhibited both collagenase release and spontaneous AM fusion. Daily in vivo administration of dexamethasone to as much as 0.128 mg/kg similarly suppressed these AM functions in culture. These studies show that in vitro and in vivo corticosteroids inhibit collagenase release and MGC formation of rabbit AM in culture in doses comparable to those used therapeutically in humans. This model may be useful in examining the mechanisms of cell fusion and functions of MGC in granulomatous lung disease.

Animals↗
PubMed1983

Identification of a type V collagen-degrading enzyme from human sputum.

An enzyme capable of degrading type V collagen was found in the sputum of patients with chronic obstructive pulmonary disease (COPD). This enzyme was found in a latent form and was activated by 4-aminophenylmercuric acetate (APMA). Molecular sieve chromatography on Ultrogel AcA-34 and affinity chromatography on type V collagen-Sepharose were successful in separating type V from type I collagenolytic activity. The enzyme became active after affinity chromatography and no longer required activation with APMA to manifest activity. It was found to be a metalloproteinase by virtue of its inhibition by ethylene-diaminetetraacetic acid and phenanthroline but not by phenylmethanesulfonyl fluoride or N-ethylmaleimide. Because degradation of matrix proteins is felt to be important in the pathogenesis of COPD, it is possible that the selective degradation of type V collagen by this enzyme may play a role in the development of COPD.

Chromatography, Affinity↗
PubMed1982

Production and preliminary characterization of monoclonal antibodies to rat plasma fibronectin.

We have produced several monoclonal antibodies which appear to be directed against different antigenic determinants of rat plasma fibronectin. Fibronectin was purified from rat plasma by affinity chromatography on gelatin-Sepharose and arginine-Sepharose columns. Mice were immunized and hybridomas were prepared by fusing spleen cells with Sp2/0-Ag14 myeloma cells using poly(ethylene glycol). Three hybridomas (RFN1, RFN2 and RFN3) were selected for characterization. All are IgG molecules, one is IgG2a, one IgG2b and one IgG1. Titers of ascites fluids produced using these hybridomas range from 102 400 to greater than 409 600. The antibodies cross-reacted to different degrees with human fibronectin. Rat fibronectin was radioactively labeled and cleaved using human polymorphonuclear leukocyte elastase. Four major peptides, Mr approx. 160 000, 140 000, 60 000 and 30 000 were produced. Each of the hybridoma antibodies immunoprecipitated different elastase peptides. RFN1 precipitated the Mr 160 000 peptide, RFN2 precipitated the Mr 160 000 and the Mr 140 000 peptide and RFN3 precipitated the Mr 60 000 peptide as well as low molecular weight material migrating at the buffer front. These antibodies will be useful in studies of structure/function relationships of rat fibronectin.

Animals↗
PubMed1982

Type-specific collagen degradation by eosinophils.

Despite the association of eosinophils with wound-healing and fibrotic processes, their collagenolytic ability has been poorly defined. By using highly purified eosinophil preparations (greater than 95% eosinophils) obtained from guinea-pigs by peritoneal lavage, we have examined type-specific collagen degradation by eosinophils using sensitive detection methods. The results show that eosinophils contain a metalloprotein that degrades types I and III collagens. This activity was apparent only after the addition of 4-aminophenylmercuric acetate to the reaction mixture, a finding similar to that for latent collagenases described from other sources. No collagenolytic activity against types IV and V collagens could be detected. Thus eosinophils may play a role in the alterations in connective-tissue matrices seen in physiological and pathological states.

Animals↗
PubMed1980

Specific cleavage of human type III collagen by human polymorphonuclear leukocyte elastase.

Purified polymorphonuclear leukocyte elastase degraded native human liver type III collagen at 27 degrees C by making a cleavage through the triple helix. The enzyme had no effect on human type I collagen. The reaction was inhibited by phenylmethanesulfonyl fluoride (PhCH2SO2F) but not by EDTA. The collagen reaction products were identical with those generated by human rheumatoid synovial collagenase when analyzed by polyacrylamide gel electrophoresis and gel filtration. NH2-trminal sequence analysis indicated that the enzyme cleaved at an isoleucyl-threonyl bond located 4 residues on the carboxyl side of the established cleavage site for animal collagenases. Therefore, it is likely that in pathologic states, type III collagen can be selectively depleted from the matrix by this enzyme.

Amino Acid Sequence↗