Binding of latent rheumatoid synovial collagenase to collagen fibrils

Heparan sulfate proteoglycans as extracellular docking molecules for matrilysin (matrix metalloproteinase 7)

Many matrix metalloproteinases (MMPs) are tightly bound to tissues; matrilysin (MMP-7), although the smallest of the MMPs, is one of the most tightly bound. The most likely docking molecules for MMP-7 are heparan sulfate proteoglycans on or around epithelial cells and in the underlying basement membrane. This is established by extraction experiments and confocal microscopy. The enzyme is extracted from homogenates of postpartum rat uterus by heparin/heparan sulfate and by heparinase III treatment. The enzyme is colocalized with heparan sulfate in the apical region of uterine glandular epithelial cells and can be released by heparinase digestion. Heparan sulfate and MMP-7 are expressed at similar stages of the rat estrous cycle. The strength of heparin binding by recombinant rat proMMP-7 was examined by affinity chromatography, affinity coelectrophoresis, and homogeneous enzyme-based binding assay; the K(D) is 5-10 nM. Zymographic measurement of MMP-7 activity is greatly enhanced by heparin. Two putative heparin-binding peptides have been identified near the C- and N-terminal regions of proMMP-7; however, molecular modeling suggests a more extensive binding track or cradle crossing multiple peptide strands. Evidence is also found for the binding of MMP-2, -9, and -13. Binding of MMP-7 and other MMPs to heparan sulfate in the extracellular space could prevent loss of secreted enzyme, provide a reservoir of latent enzyme, and facilitate cellular sensing and regulation of enzyme levels. Binding to the cell surface could position the enzyme for directed proteolytic attack, for activation of or by other MMPs and for regulation of other cell surface proteins. Dislodging MMPs by treatment with compounds such as heparin might be beneficial in attenuating excessive tissue breakdown such as occurs in cancer metastasis, arthritis, and angiogenesis.

Cytokine-induced endogenous procollagenase stored in the extracellular matrix of soft connective tissue results in a burst of collagen breakdown following its activation

Numerous data strongly suggest the involvement of cytokines and the matrix metalloproteinase collagenase (MMP-1) in the pathogenesis of periodontitis. Recently, we have demonstrated that, upon culturing under the influence of IL-1 alpha + EGF, a large amount of inactive procollagenase (MMP-1) is stored in the extracellular matrix of periosteal tissue. We now show that this endogenous reservoir of proenzyme can be operative after activation with plasmin and is able to induce a rapid and almost complete breakdown of the collagenous extracellular matrix. The level of collagen degradation following activation showed a strong correlation with the amount of proenzyme that was incorporated in the tissue. The highest level of degradation (70% of the total amount of collagenous proteins) was found with the IL-1 alpha + EGF-treated explants, followed by those treated with IL-1 alpha alone (35%). Explants cultured with EGF or in the absence of cytokines, containing only small amounts of procollagenase, showed little collagen breakdown following plasmin activation (7%). Inhibition of metalloproteinases by EDTA, or blockage of plasmin by PMSF, prevented the degradation in all explants irrespective of the amount of proenzyme present in the tissue. Our findings demonstrate that endogenous proenzyme stored in a native connective tissue matrix can be activated at a later time interval which results in a massive breakdown of the tissue. This study shows a possible pathway of collagenase-induced breakdown without recent de novo synthesis of the enzyme. Such a sequence may be operative in chronic inflammatory diseases, such as periodontitis, where production of procollagenase under the influence of cytokines spans a longer time period, whereas breakdown is often characterized by a cyclic behaviour.

The distribution of matrix metalloproteinases and tissue inhibitor of metalloproteinases in colorectal cancer

Studies suggest that the interplay between matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), is an important mediator of tumour invasion and metastasis. Using immunohistochemistry, 40 specimens of colorectal cancer were examined for the presence of TIMP-1 and the MMPs, stromelysin, gelatinases A and B and interstitial collagenase. Neither enzyme nor TIMP-1 was detected in histologically normal mucosa. Within malignant tissue, stromelysin and gelatinase A were conspicuously absent in tumour cells but were immunolocalized to the extracellular matrix and for gelatinase A also to peritumoural fibroblast-like cells. Gelatinase B was confined to polymorphonuclear leucocytes. Interstitial collagenase was not identified. TIMP-1 was present in only three of the 40 tumours within the malignant stroma. These observations suggest that the mesenchymal elements of colorectal carcinomas, by acting as a source of MMPs and TIMPs, may modulate tumour invasion.

The distribution of matrix metalloproteinases and tissue inhibitor of metalloproteinases in colorectal cancer

Studies suggest that the interplay between matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs) is an important mediator of tumour invasion and metastasis. Using immunohistochemistry, 40 specimens of colorectal cancer were examined for the presence of TIMP-1 and the MMPs, stromelysin, gelatinases A and B and interstitial collagenase. Neither enzyme nor TIMP-1 was detected in histologically normal mucosa. Within malignant tissue, stromelysin and gelatinase A were conspicuously absent in tumor cells but were immunolocalized to the extracellular matrix and for gelatinase A also to peritumoural fibroblast-like cells. Gelatinase B was confined to polymorphonuclear leucocytes. Interstitial collagenase was not identified. TIMP-1 was present in only three of the 40 tumours within the malignant stroma. These observations suggest that the mesenchymal elements of colorectal carcinomas, by acting as a source of MMPs and TIMPs, may modulate tumour invasion.

Serum collagenase activity in chronic liver diseases

To examine whether serum collagenase activity reflects the amount of hepatic collagenase in the fibrotic liver, we measured serum collagenase activity in 67 patients with chronic liver disease and in 26 healthy controls. Collagenase activity in serum was measured after reactivation by denaturing and dissociating the inhibitors with 3 M KSCN and 1 mM aminophenylmercuric acetate. Serum collagenase activity was 35% lower than control in chronic persistent hepatitis, 48% lower in chronic active hepatitis, 56% lower in liver cirrhosis and 68% lower in hepatocellular carcinoma. To interpret this finding of low serum collagenase activity, we measured serum concentration of TIMP (Tissue Inhibitor of Metallo-Proteinases). Serum TIMP concentration was increased as liver disease developed, and it was inversely correlated with serum collagenase activity. These results suggest that in this assay condition serum collagenase activity is influenced by TIMP, and thus may not reflect the amount of hepatic collagenase in patients with chronic liver disease.

Serum collagenase activity in patients with chronic liver disease

To examine the clinical significance of serum collagenase activity in chronic liver disease, serum collagenase activity was determined in 50 patients with chronic liver disease and in 24 healthy controls. Collagenase activity was measured after reactivation by denaturing and dissociating the inhibitors with potassium thiocyanate and aminophenylmercuric acetate. In patients with chronic persistent hepatitis, serum collagenase activity was 37% lower than controls, 50% lower in those with chronic active hepatitis, 66% lower in those with cirrhosis and 68% lower in those with hepatocellular carcinoma. Serum collagenase activity was significantly and inversely correlated with serum levels of the aminoterminal propeptide of type III procollagen and type IV collagen 7S domain, indicating that serum collagenase activity decreased as liver active fibrogenesis and/or fibrosis occurred. In contrast, serum levels of the metalloproteinase inhibitor was 30% higher than controls in patients with chronic active hepatitis, 50% higher in those with cirrhosis and 80% higher in those with hepatocellular carcinoma and was inversely correlated with serum collagenase activity. These results suggest that in this assay condition serum collagenase activity is influenced by the metallo-proteinase tissue inhibitor and thus does not reflect the amount of collagenase in the fibrotic liver.

Collagenolytic activity of crustacean midgut serine proteases: comparison with the bacterial and mammalian enzymes

1. We have investigated the collagenolytic activity of the following serine proteases: proteinase K, subtilisin Novo, Staphylococcal endoproteinase Glu-C, Streptomyces pronases, the trypsins and chymotrypsins from shrimp midgut and bovine pancreas. 2. By assays on both the insoluble 3H-collagen fibrils and the soluble type I collagen, it was demonstrated that the shrimp midgut serine proteases, and less efficiently, the pronases from Streptomyces griseus, could hydrolyze collagen while the other serine proteases tested could not. 3. Our data indicate that the trypsins and chymotrypsins of shrimp (Penaeus monodon) directly and indirectly digest native collagen, and that the indirect pathway probably involves activation of procollagenase in the native collagen by these serine proteases.

The effect of phenytoin on collagenase and gelatinase activities in UMR 106-01 rat osteoblastic osteosarcoma cells

Phenytoin (PHT), a widely used anticonvulsant, has been shown to inhibit bone resorption in rodent organ cultures. The drug also has complex effects on bone metabolism including chronic clinical symptoms of osteomalacia. However, the precise mechanism of PHT action in bone is still unclear. Neutral collagenases that specifically cleave native collagen have been implicated in the turnover of connective tissue. The effect of PHT was assessed on collagenase and gelatinase activities from UMR 106-01 rat osteoblastic osteosarcoma cells. Semiconfluent cells were treated with PHT (50 and 10 micrograms/ml) in the presence of bovine parathyroid hormone, b-PTH-(1-34), at 10(-7) M for 24, 48, 72 and 96 h. The media were assayed following concentration, APMA activation, and incubation with native or denatured [3H]-methyl collagen substrate (approximately 100,000 dpm) at 27 degrees C for 18 h and 35 degrees C for 2 h, respectively. Enzyme activities were presented as primary counts per minute for each time point and calculated as % activity of PTH at 10(-7) M. Parathyroid hormone (10(-7) M) stimulated collagenase activity (approximately 65-fold) and gelatinase activity (approximately 400-fold). PHT (50 micrograms/ml) reduced the PTH-stimulated collagenase activity by 18-53% and the gelatinase activity by 58-72%. SDS PAGE and fluorography following PHT treatment indicated a PHT-induced partial inhibition of PTH-stimulated degradation to alpha A chains of Type I collagen. Phenytoin may inhibit bone resorption through its action on the transcription, synthesis, and/or secretion of the collagenolytic enzymes, collagenase and gelatinase.

Purification and properties of bovine nasal hyaline cartilage collagenase

1. Collagenase from bovine nasal hyaline cartilage was extracted with 1 and 3 M NaCl in Tris-CaCl2 buffer. 2. Two peaks of collagenase activity were revealed on DE52 ion exchange column, collagenase 1 and collagenase 2. 3. The apparent mol. wt of collagenase 1 and 2 as determined by SDS-PAGE were 68 and 43 kDa, respectively. 4. Both enzymes degrade native collagen type II into two characteristic products, TCA(3/4) and TCB(1/4), at 25 degrees C and pH 7.6. 5. Trypsin and aminophenylmercuric acetate were capable of increasing the collagenase 1 activity. 6. The two enzymes can be characterized as metalloproteinases since they were inhibited by EGTA and 1,10-phenanthroline. The use of proteinase inhibitors (N-ethylmaleimide, iodoacetic acid, phenylmethylsulphonyl fluoride, soybean trypsin inhibitor, pepstatin, dithiothreitol) showed that the enzymes do not contain serine, cysteine or aspartic acid in their active sites.

Procollagenase associated with the noncalcified matrix of bone and its regulation by parathyroid hormone

Collagenolytic enzyme activity associated with the noncalcified pool of collagen was studied using calvarial matrices from which the periosteal cell envelope had been removed. Aminophenylmercuric acetate (APMA) stimulated degradation of about 5% of the noncalcified collagen in matrices prepared from freshly dissected bone. Significantly more activity was detected if intact calvaria were cultured 24 h before removal of the cells, in which case 20-30% of the noncalcified collagen was degraded following treatment with APMA. Trypsin elicited a similar response. The collagen being degraded was representative of the entire pool of noncalcified collagen and was not underhydroxylated. Treatment of intact calvaria with parathyroid hormone (PTH) before removal of the cells increased the level of both active collagenase and procollagenase activity associated with the matrix. Enhanced 3H release was noted for PTH treated intact bone in the prior 24 h. Inactivation of endogenous procollagenase by phenanthroline had no effect on the ability of isolated calvarial cells to resorb the bone upon treatment with resorptive agents. The data show that PTH-stimulated collagenolysis of noncalcified collagen involves increased deposition of procollagenase onto the noncalcified matrix in addition to activation of the enzyme.

Inhibition, by lanthanides, of neutral proteinases secreted by human, rheumatoid synovium

Fragments of human, rheumatoid synovium were maintained on organ culture for three days under serum-less conditions. Their conditioned media contained collagenolytic, gelatinolytic and caseinolytic activities, which were susceptible to inhibition by lanthanide ions. Of the four lanthanides tested, Sm3+ proved the best inhibitor of gelatinase and caseinase, while La3+ inhibited collagenase the most strongly. Inhibition of collagenase by La3+ was uncompetitive. A direct binding assay confirmed the greater association between collagen fibrils and collagenase in the presence of La3+. Ca2+ was not required for binding of the uninhibited enzyme to collagen, but acted to stabilize collagenase against thermoinactivation.

Studies in vivo and in vitro on the uptake and degradation of soluble collagen alpha 1(I) chains in rat liver endothelial and Kupffer cells

Intravenously administered 125I-labelled monomeric alpha 1 chains (125I-alpha 1) of collagen type I were rapidly cleared and degraded by the liver of rats. Isolation of the liver cells after injection of the label revealed that the uptake per liver endothelial cell equalled the uptake per Kupffer cell, whereas the amount taken up per hepatocyte was negligible. The uptake of 125I-alpha 1 in cultured cells was 10 times higher per liver endothelial cell than per Kupffer cell. The ligand was efficiently degraded by cultures of both cell types. However, spent medium from cultures of Kupffer cells, unlike that from cultures of other cells, contained gelatinolytic activity which degraded 125I-alpha 1. The presence of hyaluronic acid, chondroitin sulphate or mannose/N-acetylglucosamine-terminal glycoproteins, which are endocytosed by the liver endothelial cells via specific receptors, did not interfere with binding, uptake or degradation of 125I-alpha 1 by these cells. Unlabelled alpha 1 and heat-denatured collagen inhibited the binding to a much greater extent than did native collagen. The presence of fibronectin or F(ab')2 fragments of anti-fibronectin antibodies did not affect the interaction of the liver endothelial cells, or of other types of liver cells, with 125I-alpha 1. The accumulation of fluorescein-labelled heat-denatured collagen in vesicles of cultured liver endothelial cells is evidence that the protein is internalized. Moreover, chloroquine, 5-dimethylaminonaphthalene-1-sulphonylcadaverine (dansylcadaverine), monensin and cytochalasin B, which impede one or more steps of the endocytic process, inhibited the uptake of 125I-alpha 1 by the liver endothelial cells. Leupeptin, an inhibitor of cathepsin B and 'collagenolytic cathepsins', inhibited the intralysosomal degradation of 125I-alpha 1, but had no effect on the rate of uptake of the ligand. The current data are interpreted as follows. (1) The ability of the liver endothelial cells and the Kupffer cells to sequester circulating 125I-alpha 1 efficiently may indicate a physiological pathway for the breakdown of connective-tissue collagen. (2) The liver endothelial cells express receptors that specifically recognize and mediate the endocytosis of collagen alpha 1(I) monomers. (3) The receptors also recognize denatured collagen (gelatin). (4) Fibronectin is not involved in the binding of alpha 1 to the receptors. (5) Degradation occurs intralysosomally by leupeptin-inhibitable cathepsins.

Polypeptide proteinase inhibitor from human articular cartilage

A polypeptide proteinase inhibitor from human articular cartilage has been purified to homogeneity by stepwise Sephadex G-75, heparin-Sepharose and octyl-Sepharose affinity chromatography. The inhibitor is strongly cationic (pI greater than or equal to 10.5) and consists of two non-identical polypeptides associated by means of electrostatic and/or hydrophobic interactions. Amino acid analysis of the aggregate confirmed that the polypeptide was rich in basic, and hydrophobic amino acids and contained only one disulphide bridge. Sedimentation equilibrium studies showed that the aggregate had MW congruent to 7000 which could be dissociated into two polypeptides each of MW congruent to 3500. While the subunits were primarily serine proteinase inhibitors the aggregate form could also inhibit bacterial collagenase and pepsin but not thermolysin nor the cysteine proteinases, ficin or bromelain. Binding of 125I-labelled human cartilage inhibitor to heparin, keratan sulphate and proteoglycan subunit was demonstrated using gel exclusion chromatography but no interaction was detected with chondroitin 6-sulphate or hyaluronic acid. Binding of cartilage inhibitor subunits to link proteins was also shown by polyacrylamide electrophoresis. These data suggest that the human cartilage inhibitor may be localised at specific sites on the proteoglycan complex where it would be ideally placed to attenuate degradation by matrix proteinases or constitute part of an enzyme-inhibitor complex.

Role of collagenases in tumor cell invasion

Collagenases are a family of metalloproteinases which may play a role in facilitating tumor cell invasion of the extracellular matrix. Tumor cells traverse two types of extracellular matrix: basement membranes and interstitial stroma, at multiple stages of the metastatic process. The matrix is a dense meshwork of collagen, proteoglycans, elastin and glycoproteins. Normally the matrix does not contain open spaces large enough for cell movement. Therefore numerous investigators have postulated that collagenolytic proteases, secreted by tumor cells or associated host cells, breakdown the extracellular matrix during tumor cell invasion. A large number of animal and human tumors have been shown to contain collagenase at a higher level than corresponding benign tissues. Separate collagenolytic metalloproteinases have been identified which degrade specific types of collagen. A basement membrane collagenolytic protease was shown to be elevated in a series of metastatic murine tumor cells. Immunologic studies using antibodies specific for collagenase have demonstrated that in vivo, tumor cells can produce collagenase. Therefore identification of collagenase in cultured lines of tumor cells is not an artifact of in vitro cultivation. In some cases, tumor cells may induce host cells to produce collagenase. The best evidence to date that collagenases actually play a role in invasion is derived from experiments in which natural collagenase inhibitors block tumor cell invasion of extracellular matrix in vitro.

Enhanced neutral protease activity in proliferating rheumatoid synovial cells

Proteolytic enzymes associated with rheumatoid synovial cells (RSC) have been implicated in the degradation of articular cartilage. Proteases have been measured in proliferating rheumatoid synovial cells (P-RSC), proliferating nonrheumatoid synovial cells (P-NSC), and their nonproliferating counterparts (NP-RSC and NP-NSC). The P-RSC and P-NSC exhibit enhanced total surface-associated plus secreted neutral protease activity, as compared with NP-RSC and NP-NSC. The P-RSC exhibited significantly higher protease activity in this category compared to P-NSC. The RSC also secreted higher levels of secreted proteases alone compared to NSC. The secreted protease activity alone was not related to the proliferative state of the cells. Extractable protease activity was measured in early-passaged and serially-passaged P-RSC, NP-RSC, P-NSC, and NP-NSC. Extractable cellular protease activity measured at pH ranges from 5.0 through 8.0 was not significantly different between P-RSC and NP-RSC or between P-NSC and NP-NSC. The RSC contained elevated extractable cellular protease activity measured at pH ranges from 5.0 through 8.0 compared to extracts from later-passaged cells. The neutral protease activity in the early-passaged RSC was also higher than that measured at pH 6.0 or 8.0. In synovial cells cellular protease activity was related to the proliferative state and the origin of the cells. The P-RSC exhibited the highest levels of surface associated plus secreted neutral protease activity. The RSC also possessed the highest levels of extractable protease activity compared to NSC.

Protein synthesis in rheumatoid synovial tissue

1. Function of synoviocytes and other cells in the synovium A. Histologic Considerations 1. Electron microscopic studies 2. In vivo and in vitro phagocytosis studies 3. Fluorescent antibody staining B. Culture techniques 1. Problems posed by study of isolated cells 2. Long-term explant cultures 3. Advantages of short-term incubations of synovial fragments 4. Isolation of immunoglobulins C. Non-Immunoglobulin Products of the Synovium 1. Products of normal synovium 2. Alterations induced by rheumatoid arthritis II. The Local Immune response in Rheumatoid Synovitis A. Evidence for Active Immune Stimulation 1. Meditators of cellular immunity in synovial fluid 2. Effect of synovectomy 3. Type and amount of immunoglobulin produced B. Local Commitment of Antibody Response 1. Effect of exogenous immunization 2. Rheumatoid factors. 3. Pepsin agglutinators C. 1. Relative enrichment for IgG-3 subclass 2. Increase in lambda-light chain composition III. Pathogenetic Considerations in Rheumatoid Arthritis A. Comparison of Rheumatoid versus Experimental Immune Synovitis 1. Chronic synovitis as a local immune response. 2. Role of cartilage complexes in substaining chronic synovitis B. Significance of the Restriction in the Immunoglobulin Response in Rheumatoid Arthritis 1. Analogy with other disease states in man 2. Common antigen in RA?

Neutral proteinases from articular chondrocytes in culture. I. A latent collagenase that degrades human cartilage type II collagen

Culture media collected from secondary monolayer and spinner cultures of rabbit articular chondrocytes showed evidence of collagenolytic activity by the following criteria: (1) Amicon PM-10 concentrates of culture medium released [14C] glycine from reconstituted rabbit skin collagen fibrils at 37 degrees C; (2) medium concentrated by lyophilization decreased the relative viscosity of human cartilage collagen in solution. The loss in viscosity was partially inhibited if medium was preincubated with o-phenanthroline, and (3) degradation of human cartilage collagen after 60 h incubation at 24 degrees C was characterized primarily by the appearance of 75 000 dalton (TCA) and 25 000 dalton ((TCB) products. The majority of the collagenase (EC 3.4.24.3) from cultured chondrocytes was secreted in latent form, since preincubation with either trypsin or p-aminophenylmercuric acetate significantly increased activity against human cartilage collagen. Chondrocyte collagenase may be important in mediating the normal slow turnover of cartilage collagen and may be particularly active in collagen destruction associated with early stages of synovial joint arthritides, before attack by non-cartilage cells or extra-articular soft tissues.

What controls collagen resorption in vivo?

The local control of collagen degradation in mammals in vivo is currently considered to depend primarily on variations on the level of activity of specific collagenases. Such variations are believed to depend on three factors: a) the rate of active collagenase synthesis and/or of activation of inactive enzyme precursors; b) the action of serum and/or tissue collagenase inhibitors; and c) different combinations of both mechanisms. We suggest that another element contributing to the regulation of collagen degradation in vivo is the susceptibility of the substrate. Support for this suggestion is derived from two sources: 1) experimental data, indicating that the rate of collagen degradation depends on the genetic type of substrate, on its state of aggregation (including degree of cross-linking), and on the nature and amount of other macromolecules associated with collagen in vivo. Other experimental findings supporting our hypothesis are the universal presence of collagen-bound collagenase, the apparent greater affinity of the enzyme for the more recently synthetized substrate molecules, and the increased amounts of intact collagen that may be solubilized from some tissues undergoing massive collagen degradation, 2) analogy with currently accepted views on intracellular protein catabolism, which cannot be rejected a priori as irrelevant to the problem.

Collagenase immunolocalization in cultures of rheumatoid synovial cells

Cultures of rheumatoid synovial cells that have been enzymatically dissociated and are adherent to a culture vessel are morphologically heterogeneous. When these cells are cultured on a collagenous substrate for 2 to 6 days at 37 degrees C in serum-free medium, they produce collagenase. A monospecific antibody to human collagenase has localized the enzyme extracellularly around cytoplasmic extensions of dendritic cells and intracellularly within a few macrophage-like and fibroblast-like cells.