Inhibitor of human collagenase from cultures of human tendon

Construction of wound repair model and function of recombinant TIMP from Hyriopsis cumingii

Metalloproteinase tissue inhibitors (TIMPs) have the activity of inhibiting matrix metalloproteinases (MMPs), which can promote cell growth, bind to the matrix, inhibit angiogenesis, and play a key role in extracellular matrix (ECM) metabolism regulation. In this study, TIMP-1, 2 from Hyriopsis cumingii (designated as HcTIMP-1, 2) were cloned and identified. Full-length cDNA of HcTIMP-1, 2 was 1160 bp and 729 bp, encoding 235 and 150 amino acid residues, respectively. The predicted molecular weight of HcTIMP-1 and 2 protein was 27.26 and 16.58 kDa, with isoelectric points of 8.89 and 8.72, respectively. HcTIMP-2 contained only one netrin (NTR) domain at the N-terminal but lacked a C-terminal domain. The mRNA of HcTIMP-1, 2 was expressed in hepatopancreas, gills, muscles, hemocytes, and mantles, which had the highest expression in hemocytes and muscles. The expression of HcTIMP-1, 2 had increased remarkably in hemocytes after bacterial challenge. After trauma, HcTIMP-1, 2 genes had the highest expression level in the first day. This indicated that HcTIMP-1 and 2 were involved in the immune response of H. cumingii. The soluble recombinant proteins HcTIMP-1, 2 were expressed efficiently in Escherichia coli BL21 (DE3) by constructing pET32a-TIMP1, 2 recombinant plasmids. The concentration of the recombinant was 0.14 and 0.31 mg/mL, respectively. The recombinant HcTIMP-1, 2 proteins were shown to inhibit human MMP2 activity and promoted the growth of NBL-7 and HUVE cells.

The tissue inhibitors of metalloproteinases (TIMPs): an ancient family with structural and functional diversity

Tissue inhibitors of metalloproteinases (TIMPs) are widely distributed in the animal kingdom and the human genome contains four paralogous genes encoding TIMPs 1 to 4. TIMPs were originally characterized as inhibitors of matrix metalloproteinases (MMPs), but their range of activities has now been found to be broader as it includes the inhibition of several of the disintegrin-metalloproteinases, ADAMs and ADAMTSs. TIMPs are therefore key regulators of the metalloproteinases that degrade the extracellular matrix and shed cell surface molecules. Structural studies of TIMP-MMP complexes have elucidated the inhibition mechanism of TIMPs and the multiple sites through which they interact with target enzymes, allowing the generation of TIMP variants that selectively inhibit different groups of metalloproteinases. Engineering such variants is complicated by the fact that TIMPs can undergo changes in molecular dynamics induced by their interactions with proteases. TIMPs also have biological activities that are independent of metalloproteinases; these include effects on cell growth and differentiation, cell migration, anti-angiogenesis, anti- and pro-apoptosis, and synaptic plasticity. Receptors responsible for some of these activities have been identified and their signaling pathways have been investigated. A series of studies using mice with specific TIMP gene deletions has illuminated the importance of these molecules in biology and pathology.

Biomimetic approaches to tendon repair

The linear organization of collagen fibers in tendons results in optimal stiffness and strength at low strains under tensile load. However, this organization makes repairing ruptured or lacerated tendons extremely difficult. Current suturing techniques to join split ends of tendons, while providing sufficient mechanical strength to prevent gapping, are inadequate to carry normal loads. Immobilization protocols necessary to restore tendon congruity result in scar formation at the repair site and peripheral adhesions that limit excursion. These problems are reviewed to emphasize the need for novel approaches to tendon repair, one of which is the development of biomimetic tendons. The objective of the empirical work described here was to produce biologically-based, biocompatible tendon replacements with appropriate mechanical properties to enable immediate mobilization following surgical repair. Nor-dihydroguaiaretic acid (NDGA), a di-catechol from creosote bush, caused a dose dependent increase in the material properties of reconstituted collagen fibers, achieving a 100-fold increase in strength and stiffness over untreated fibers. The maximum tensile strength of the optimized NDGA treated fibers averaged 90 MPa; the elastic modulus of these fibers averaged 580 MPa. These properties were independent of strain rates ranging from 0.60 to 600 mm/min. Fatigue tests established that neither strength nor stiffness were affected after 80 k cycles at 5% strain. Treated fibers were not cytotoxic to tendon fibroblasts. Fibroblasts attached and proliferated on NDGA treated collagen normally. NDGA-fibers did not elicit a foreign body response nor did they stimulate an immune reaction during six weeks in vivo. The fibers survived 6 weeks with little evidence of fragmentation or degradation. The polymerization scheme described here produces a fiber-reinforced NDGA-polymer with mechanical properties approaching an elastic solid. The strength, stiffness and fatigue properties of the NDGA-treated fibers are comparable to those of tendon. These fibers are biocompatible with tendon fibroblasts and elicit little rejection or antigenic response in vivo. These results indicate that NDGA polymerization may provide a viable approach for producing collagenous materials that can be used to bridge gaps in ruptured or lacerated tendons. The tendon-like properties of the NDGA-fiber would allow early mobilization after surgical repair. We predict that timely loading of parted tendons joined by this novel biomaterial will enhance mechanically driven production of neo-tendon by the colonizing fibroblasts and result in superior repair and rapid return to normal properties.

Human shoulder tendon biopsy samples in organ culture produce procollagenase and tissue inhibitor of metalloproteinases

OBJECTIVE

To investigate the production of the matrix metalloproteinase (MMP), collagenase (MMP-1), and its natural inhibitor, the tissue inhibitor of metalloproteinases (TIMP) by diseased human tendon samples in organ culture.

METHODS

Portions of tendons were excised from the shoulders of patients undergoing shoulder surgery, classified as either proximal to the lesion (abnormal) or distal to the lesion (normal) according to their macroscopic appearance at surgery, and placed in organ culture for periods of up to 28 days. The release of collagenase and TIMP activity in the conditioned culture medium was measured.

RESULTS

Procollagenase and TIMP were both produced by all the tendon samples for an extended period of time. The levels of enzyme and inhibitor varied between patients, but in most of them TIMP levels were greater than collagenase levels. In one sample of calcified tendon, procollagenase levels were greater than those of TIMP. The mean level of collagenase produced by tendon proximal to the lesion and tendon distal to the lesion were not significantly different (95.2 (SD 106.8) U/g and 34.0 (45.3) U/g, respectively), while the corresponding figures for TIMP were 109.7 (62.3) U/g and 53.0 (27.9) U/g (p = < 0.05), although there was considerable variation in some samples. Western blotting and collagen fragment analysis confirmed that the collagenolytic activity detected was attributable to the metalloproteinase fibroblast collagenase (MMP-1).

CONCLUSIONS

Tendon tissue can actively secrete procollagenase, an enzyme that, once activated, is capable of remodelling collagen, the major connective tissue component of tendon. Collagenase is produced even in unstimulated cultures, although the concentrations of TIMP are usually greater than that of collagenase in most samples. Some activation of collagenase appeared to have occurred. These results indicate that tendon tissue cells are capable of producing a remodelling response, even in end stage tendon disease.

Purification and sequence analysis of two rat tissue inhibitors of metalloproteinases

Two protein inhibitors of metalloproteinases (TIMP) were isolated from medium conditioned by the clonal rat osteosarcoma line UMR 106-01. Initial purification of both a 30-kDa inhibitor and a 20-kDa inhibitor was accomplished using heparin-Sepharose chromatography with dextran sulfate elution followed by DEAE-Sepharose and CM-Sepharose chromatography. Purification of the 20-kDa inhibitor to homogeneity was completed with reverse-phase high-performance liquid chromatography. The 20-kDa inhibitor was identified as rat TIMP-2. The 30-kDa inhibitor, although not purified to homogeneity, was identified as rat TIMP-1. Amino terminal amino acid sequence analysis of the 30-kDa inhibitor demonstrated 86% identity to human TIMP-1 for the first 22 amino acids while the sequence of the 20-kDa inhibitor was identical to that of human TIMP-2 for the first 22 residues. Treatment with peptide:N-glycosidase F indicated that the 30-kDa rat inhibitor is glycosylated while the 20-kDa inhibitor is apparently unglycosylated. Inhibition of both rat and human interstitial collagenase by rat TIMP-2 was stoichiometric, with a 1:1 molar ratio required for complete inhibition. Exposure of UMR 106-01 cells to 10(-7) M parathyroid hormone resulted in approximately a 40% increase in total inhibitor production over basal levels.

Purification and characterization of a new tissue inhibitor of metalloproteinases (TIMP-2) from mouse colon 26 tumor cells

Mouse colon 26 tumor cells were shown to produce collagenase inhibitor in culture. The inhibitor was purified more than 2,000-fold from the culture medium by passage through DE-52 cellulose, CM-52 cellulose, Ultrogel AcA 54, Con A-Sepharose, and Sephadex G-50 Superfine columns. The inhibitor did not bind to Con A-Sepharose as do most other collagenase inhibitors. The inhibitor showed a single band (Mr = 20.5 k) on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and inhibitory activity against interstitial collagenases and gelatinases, except for bacterial collagenase. Double-immunodiffusion analysis using monospecific anti-serum against tissue inhibitor of metalloproteinases (TIMP) from bovine dental pulp showed that colon 26 inhibitor did not cross-react immunologically with the pulp inhibitor. NH2-Terminal protein sequence data were obtained for the first 36 residues of the colon 26 inhibitor, and the first 20 of them exhibited a sequence almost identical with that of a new TIMP recently designated as TIMP-2.

Neutral metalloprotease from tendons

Tendon repair following trauma, rupture, or surgery involves both synthesis and degradation of collagen in order to reweave new collagen bundles in with the old. Using an in situ assay on polyacrylamide gels containing gelatin, we have identified protease activity from tendon tissue and from tendon cells in culture. A population of synovial cells from the epitenon surrounding the tendon as well as the tendon fibroblasts themselves were examined. The cells and the conditioned medium from both cell populations exhibited a major band of gelatin-degrading activity at 70 kdaltons and a minor band of activity at 60 kdaltons. When preparations were reacted with p-aminophenylmercuric acetate (APMA) before electrophoresis, a third band appeared at 63 kdaltons. The main band at 70 kdaltons comigrated with a [35S]methionine-radiolabeled protein band. Inhibitor and pH studies identified the enzymes as neutral metalloproteases requiring disulfide bonds for activity. No proteolytic activity was detected on casein-containing gels, ruling out the presence of stromelysin. Since electrophoresis in the presence of SDS would separate the metalloprotease from the smaller molecular weight inhibitor (TIMP), these in situ assays provide a sensitive screening system for gelatin-degrading enzymes present in tendon without prior removal of TIMP.

Separation and partial characterization of three forms of collagenase inhibitor from bovine gingiva

Three forms of collagenase inhibitor were isolated; one bound to Con A-Sepharose and the other two did not. The Con A-bound (Mr 38,000) and the two unbound (Mr 50,000 and 22,000) inhibitors contained about 20, 15 and 65% of the total inhibitory activity, respectively. The bound and one of the unbound (Mr 22,000) inhibitors were fairly specific for mammalian collagenase; the other unbound inhibitor was rather non-specific and also inhibited trypsin and thermolysin, but not bacterial collagenase. All the inhibitors were heat stable (90 degrees C, 30 min) and unaffected by 4-aminophenylmercuric acetate, but were inactivated by reduction and alkylation.

Streptozotocin-induced diabetes and the rat periodontium: decreased relative collagen production

This is the first study concerning the extent to which relative collagen production (RCP) in rat periodontal tissues is affected by diabetes. Determination of RCP, rather than individual production rates for collagen or for non-collagen protein, was deemed necessary because saturation of all proline pools in tissues of diabetics (and non-diabetic controls) was not achieved. Such non-saturation occurred despite the injection of a pool-expanding dose of proline (400-1150 mg/rat), non-saturation indicated by the lesser specific radioactivity (S.R.) of free-[3H]proline in tissues than that of the injected solution. RCP was decreased in five periodontal tissues (incisor and molar gingiva, incisor and molar periodontal ligament, antemolar palatal mucosa) and in skin. Diabetes-decreased RCP seems to result from decreased collagen synthesis and increased intracellular degradation, although some evidence is presented for increased extracellular degradation of recently secreted collagen.

Collagenase production by rabbit ligaments and tendon

Three periarticular connective tissues from normal rabbits were examined for collagenolytic activity. Enzyme activity was secreted by cultures of anterior cruciate ligament (ACL), medial collateral ligament (MCL) and patellar tendon (PT). A lag period of six days or more was often observed prior to the detection of active collagenase. We attributed this to the presence of an excess of inhibitor in the early days of culture. We quantitated the amount of enzyme and inhibitor produced in 13 days. The levels of collagenase in the ACL and MCL were comparable. The PT, however, consistently secreted more enzyme than the two periarticular (ACL and MCL) ligaments. The reaction products were analyzed for all three collagenases and compared to those generated by the rabbit skin enzyme. We observed the characteristic TCA and TCB collagen fragments for MCL and PT enzymes. Collagen cleavage by the ACL cultures resulted in a product with a molecular weight intermediate between the alpha 2 chain and the TCA piece. These data suggest that quantitative and qualitative differences exist in the ability of these similar connective tissues to degrade collagen.

Eriochrome black T inhibition of human skin collagenase, but not gelatinase, using both protein and synthetic substrates

The intracellular degradation of interstitial collagen is accomplished by two neutral metalloproteases, collagenase and gelatinase. Both enzymes are inhibited by metal chelating agents, by certain sulfhydryl reagents, and by similar protein inhibitors. Here, we demonstrate that the dye eriochrome black T (EBT) appears to be unique in its capacity to inhibit collagenase but not gelatinase. Using native reconstituted helical collagen in gel form at 37 degrees C, half-maximal inhibition of collagenase activity by EBT occurs at approximately 45 microM. EBT more effectively inhibits the breakdown of native collagen in solution, with a KI of approximately 8 microM. Using a newly-developed spectrophotometric substrate, AcProLeuGly-S-LeuLeuGly-OC2H5, a KI of 1.4 microM was calculated for EBT on collagenase. Although this same thiopeptolide serves as a substrate for gelatinase with kinetics similar to those of collagenase, no inhibition by EBT was observed. EBT also did not inhibit the gelatinase-mediated breakdown of the natural substrate, gelatin. The data suggest that EBT may have significant potential for allowing the differentiation in biological fluids of two metalloproteases with similar cleavage site specificities.

Intestinal bacteria and rheumatic disease

The striking clinical and pathological similarities between certain naturally occurring infectious diseases in animal species and those of some human rheumatic diseases, such as rheumatoid arthritis (RA), have stimulated the search for a microbial etiology of the latter syndrome. A long series of microbial species, including aerobic and anaerobic intestinal bacteria, mycoplasma and several viruses have been put into focus. Most often, however, an initially positive report has been followed by several reports denying an etiological role of the microbial species in focus. However, the concept of a microbial trigger in the etiology and symptomatology of RA is still a subject of intense debate. Recent results have indicated a reversed effect of gram-positive vs. gram-negative intestinal bacteria on adjuvant-induced arthritis in germfree rats and microbial peptidoglycans have been shown to play a major role in this experimental model. It has been shown that the intestinal flora may include bacteria containing antigenic determinant(s) cross-reacting with some markers within the HLA-system. The intestinal flora may also influence upon several digestive and absorptive functions and thereby acting upon parameters of importance in the development of rheumatic disease.

Antenatal diagnosis of recessive dystrophic epidermolysis bullosa: collagenase expression in cultured fibroblasts as a biochemical marker

We performed fetoscopy and skin biopsy on a 19-week fetus at risk for recessive dystrophic epidermolysis bullosa (RDEB). Ultrastructural analysis of the tissue revealed dermolytic blister formation in the skin characteristic of the disease. To develop a biochemical test for use in antenatal diagnosis of RDEB, we established skin fibroblast cultures from the 20-week aborted fetus. The collagenase production by fetal RDEB fibroblast cultures was greater than seen in normal fetal fibroblast cultures. The concentration in culture medium from fetal RDEB cultures was 5.42 +/- 0.74 micrograms/ml (mean +/- SE) compared with 2.24 +/- 1.11 micrograms/ml in normal adult control cultures and 2.05 +/- 0.61 micrograms/ml in cultures from patients with other genetic forms of epidermolysis bullosa (p less than 0.025). In contrast, the concentration of collagenase in the fetal RDEB culture medium was not different from that seen in cell cultures from known patients with RDEB (5.34 +/- 1.12 micrograms/ml). Collagenase activity of the fetal RDEB medium was also increased approximately 3.5-fold. These data indicate that enhanced expression of collagenase by fetal RDEB skin fibroblasts can serve as a biochemical adjunct, and possibly an alternative, to morphologic examination of tissue for antenatal diagnosis.

Hormonal control of collagenase inhibitor production in rabbit uterine cervical fibroblast-like cells

Rabbit uterine cervical fibroblast-like cells maintained in fetal calf serum-free medium were found to biosynthesize and secrete a collagenase inhibitor into the culture medium. All the properties of this inhibitor were similar to those that have been described so far for the tissue inhibitor of metalloproteinases. Both progesterone and 17 beta-estradiol significantly increased the level of collagenase inhibitor without the proliferation of cells. These data suggest that both progesterone and estradiol regulate collagenolysis in the uterus bifunctionally by acceleration of the inhibitor production in addition to their known inhibitory actions towards collagenase biosynthesis.

Human skin fibroblast collagenase: interaction with substrate and inhibitor

Human skin fibroblasts secrete collagen, procollagenase and a collagenase inhibitor. This study addresses the nature of the interaction between these important fibroblast products. The binding of procollagenase and of active collagenase to native collagen in solution was examined by employing Sephadex G-150 gel-filtration chromatography to separate bound versus unbound enzyme. Active enzyme bound readily to collagen; the equilibrium constant of binding, Kd, was calculated to be 5.1 to 10(-7)M. Thus, collagenase binds with nearly equal affinity to both monomeric collagen and aggregated fibrils (Kd = 9 X 10(-7)M; [Welgus et al., 1980]). Furthermore, since Kd congruent to Km congruent to 10(-6)M, the ratio k2/k1 must be extremely small, directly implicating the catalytic step represented by the rate constant k2, and not the binding of enzyme to substrate, as the rate-limiting step of collagenase action. In contrast, procollagenase demonstrated no capacity to bind to collagen. The interaction of procollagenase and of active collagenase with inhibitor was examined utilizing both conventional and high-precision liquid gel-filtration chromatography. A higher molecular weight complex could be demonstrated consisting of active collagenase and inhibitor; no such interaction occurred between procollagenase and the inhibitory protein. Analysis of Lineweaver-Burk plots showed that inhibition was accompanied by a corresponding change in Vmax; Km remained unchanged. Such results are indicative of a noncompetitive mechanism of inhibition and are consistent with the formation of an enzyme-inhibitor complex. The Ki of enzyme-inhibitor binding was determined to be less than 10(-9)M. The data indicate that procollagenase can neither interact with its specific inhibitor nor bind to collagen. Extracellular activation of the collagenase zymogen is thus a critical event, which can be followed either by binding to substrate or interaction with inhibitor.

Increased collagenolytic activity in severed and sutured tendons following topical application of exogenous collagen in chickens

To verify the role of collagenase in reduction of peritendinous adhesion by topical application of exogenous collagen, the flexor tendons of 30 chickens were severed and sutured. Exogenous, native enriched collagen solution (ECS) was introduced in the tendon sheath via a polyethylene catheter. The effect of ECS on collagenolytic activity in the healing tendon was assessed 1, 2, and 3 weeks later both by determining the relative amounts of dialyzable protein and hydroxyproline and by using the collagen film collagenase assay. The results obtained indicated a significant increase in both dialyzable hydroxyproline level and collagenolytic activity in the ECS-treated tendons as compared with the untreated controls. It is suggested that the effect of the topically applied exogenous collagen on increasing the collagenolytic activity may be directly related to previously observed increased gliding capacity of the tendons in the same experimental model.

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.

Activation of human gingival collagenase

To study the regulation of collagen degradation in periodontium, human gingival homogenate was incubated at 36 degrees C and the release of hydroxyproline was assayed as a measure of collagenase activity. Phenylmethylsulfonyl fluoride, soybean trypsin inhibitor and serum albumin inhibited the in vitro collagenolysis while p-aminophenylmercuric acetate, a sulfhydryl reagent, increased the degradation. When latent collagenase obtained from gingival fibroblast culture was added to the incubation a marked increase in the collagen degradation was found. This increase was prevented by phenylmethylsulfonyl fluoride. The data suggests that collagenase may exist in gingiva partly in a latent form and its activation may be brought about by 2 mechanisms. A serine proteinase present in tissue may activate collagenase by producing a limited cleavage, or the activation may occur through a reaction that involves the sulfhydryl groups of the collagenase molecule.

Metalloproteinase inhibitors from bovine cartilage and body fluids

Inhibitors of the mammalian metalloproteinases, collagenase, proteoglycanase and gelatinase were isolated from bovine cartilage (extracts and culture medium) and bovine amniotic fluid and serum. These inhibitors either bind or do not bind to concanavalin-A--Sepharose, with Mr (gel filtration) of about 30 000 and 20 000, respectively. Cartilage and chondrocyte culture media contained only concanavalin-A-binding inhibitors whereas cartilage extracts contained only a non-binding inhibitor: serum and amniotic fluid contained both forms of inhibitory activities. In moist biochemical respects, particularly in their abilities to inhibit metalloproteinases, all of the inhibitors were found to be similar. It is concluded that the forms of the inhibitors that differ in Mr may be closely related to the tissue inhibitor of metalloproteinases (TIMP) previously purified from rabbit and human sources. These findings help to clarify other studies on collagenase inhibitors and support the concept that TIMP-like inhibitors may be important in the control of connective tissue degradation.

Mouse bone collagenase inhibitor: purification and partial characterization of the inhibitor from mouse calvaria cultures

The organ culture of neonatal mouse calvaria produced both collagenase and collagenase inhibitor. The inhibitor was purified by a series of column chromatographies: DEAE-cellulose and CM-cellulose ion-exchange chromatography, concanavalin A-Sepharose and heparin-Sepharose affinity chromatography, and finally by Sephacryl S-200 gel filtration. The purified inhibitor migrated as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had a molecular mass of 28,000. The inhibitor was purified 140-fold to a specific activity of 163 units/mg with a yield of 18% over the first step of the purification by DEAE-cellulose chromatography. The inhibitor stained positively for carbohydrate with periodic acid-Schiff's reagent indicating, in conjunction with its affinity to concanavalin A, that the inhibitor is a glycoprotein. In addition to mouse bone collagenase, this inhibitor also inhibited chick bone, rat bone, rabbit corneal, and human gingival collagenase, but did not inhibit bacterial collagenase.

Characterization of the metalloproteinase inhibitor produced by bovine articular chondrocyte cultures

Primary cultures of bovine articular chondrocytes release a latent metalloproteinase which is activated by incubation with organomercurials to degrade proteoglycans. All the enzyme present in the culture medium is latent and binds to columns of heparin-Sepharose. The yield of activity from the heparin-Sepharose columns (measured after organomercurial treatment) is approximately 300-1000% depending on the chondrocyte culture batch. Recombination of column fractions shows that the increase in activity is due to the separation of an inhibitor of the metalloproteinase by the chromatographic step. The metalloproteinase inhibitor has a molecular weight of approximately 35000 (determined by Bio-Gel P-60 chromatography) and binds reversibly to columns of concavalin A-Sepharose. It is relatively heat stable (30 min at 60 degrees C) and resistant to inactivation by trypsin (2 h, 37 degrees C, 10 microgram/ml trypsin). The inhibitor is active against rat uterine collagenase and gelatinase but does not affect bacterial metalloproteinases such as thermolysin and Clostridium histolyticum collagenase.

Effects of retinol and dexamethasone on cytokine-mediated control of metalloproteinases and their inhibitors by human articular chondrocytes and synovial cells in culture

Human articular chondrocytes in culture produced large amounts of specific mammalian collagenase, gelatinase and proteoglycanase when exposed to dialysed supernatant medium derived from cultured human blood mononuclear cells (mononuclear cell factor) or to conditioned medium, partially purified by fractionation with ammonium sulphate (60-90% fraction), from cultures of human synovial tissue (synovial factor). Human chondrocytes and synovial cells also released into culture medium an inhibitor of collagenase of apparent molecular weight about 30 000, which appeared to be similar to the tissue inhibitor of metalloproteinases synthesised by tissues in culture. The amounts of free collagenase inhibitor were reduced in culture media from chondrocytes or synovial cells exposed to mononuclear cell factor or synovial factor. While retinol inhibited the production of collagenase brought about by mononuclear cell factor or synovial factor, it restored the levels of inhibitor, which were reduced in the presence of mononuclear cell factor or synovial factor. Dexamethasone markedly reduced the production of collagenase by synovial cells, while only partially inhibiting factor-stimulated collagenase production by chondrocytes. Addition of puromycin as an inhibitor of protein synthesis reduced the amounts of both collagenase and inhibitor to control or undetectable levels.

Inhibition of collagenase from Clostridium histolyticum by phosphoric and phosphonic amides

Di- and tripeptides with sequences present in collagen that are known to occupy the S1' through S3' subsites at the active site of the collagenase from Clostridium histolyticum do not themselves inhibit this zinc protease. Thus glycylproline, glycylprolylalanine, and their C-terminal amides are not inhibitors. N alpha-Phosphorylglycylproline, N alpha-phosphorylglycyl-L-prolyl-L-alanine, and their C-terminal amides are weak inhibitors with IC50's (concentration causing half-maximal inhibition) of 4.6, 0.8, 3, and 1.5 mM, respectively. Extension of glycyl-L-prolyl-L-alanine to L-leucyl-glycyl-L-prolyl-L-alanine gives a tetrapeptide known to occupy the S1, S1', S2', and S3' subsites of collagenase when present in collagen but that still does not itself inhibit the enzyme. (Isoamylphosphonyl)glycyl-L-prolyl-L-alanine, a peptide containing a tetrahedral phosphorus atom at the position of the amide carbonyl carbon of the L-leucylglycyl amide bond of the parent tetrapeptide, inhibits collagenase with an IC50 of 16 microM, at least 1000-fold more potent than the parent peptide. Substitution of the two-carbon ethyl chain of alanine for the five-carbon isoamyl chain of leucine increases the IC50 to 46 microM. Substitution of the n-decyl chain for the isoamyl chain does not change the IC50. (Isoamylphosphonyl)glycyl-glycyl-L-proline contains a tripeptide that does not occupy the S1' through S3' subsites of collagenase when this peptide is present in collagen and thus has an IC50 of 4.4 mM. (Isoamylphosphonyl)glycyl-L-prolyl-L-alanine may be an analogue of the tetrahedral transition state for the hydrolysis of the natural collagen substrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of collagenase and inhibitor (TIMP) by intracranial tumors and dura in vitro

The production of collagenase and collagenase inhibitor (TIMP) by various intracranial tumors (25 meningiomas, eight gliomas, seven metastases, four pituitary adenomas, and five others) was studied in short-term organ culture. While meningiomas produced negligible amounts of collagenase, two metastatic carcinomas of bronchial and breast origin produced significant amounts of the enzyme. Cultures of dura from an invasive meningioma and of bone invaded by a meningioma also produced collagenase. In varying amounts, TIMP was detected in culture media from most of the tumors studied; invasive tumors tended to produce less TIMP than noninvasive tumors. The results are discussed in relation to current views on tissue degradation and mechanisms of tumor invasion.

Proteinase inhibitors of human articular cartilage

Extracts of human articular cartilage contain a variety of inhibitors to serine, cysteine and metallo-proteinases. By gel filtration chromatography, inhibitory activity towards serine proteinases was resolved into two components of apparent molecular weights 62,000 and 12,000 daltons; whereas inhibitory activity towards cysteine proteinases eluted with an apparent molecular weight of 13,000 daltons. In both cases the low molecular weight inhibitors were further resolved into two components by ion-exchange chromatography. Inhibitory activity towards metallo-proteinases resolved into two components of apparent molecular weights 35,000 and 25,000 daltons. No inhibitor of aspartic proteinases was detected. Although most of the inhibitory activities to serine and cysteine proteinases could be extracted from cartilage with 1 M NaCl, the complete removal of metalloproteinase inhibitory activities required extraction with 4 M guanidinium chloride. This suggests that they are more strongly associated with the cartilage.

Retinoic acid inhibition of collagenase and gelatinase expression in human skin fibroblast cultures. Evidence for a dual mechanism

Human skin fibroblast cultures have been employed to study the effects of a variety of vitamin A analogues (retinoids) on the expression of two enzymes involved in collagen degradation in the skin, collagenase and a gelatinolytic protease. In normal and recessive dystrophic epidermolysis bullosa fibroblast cultures, retinoic acid compounds were effective inhibitors of the accumulation of both enzymes in the culture medium with half-maximal inhibitions occurring at 0.25-1 microM for collagenase and at 3-6 microM for the gelatinolytic protease. Various retinoids exhibited differing degrees of inhibitory actions, so that at a 1 microM concentration, relative inhibitions were: 13-cis-retinoic acid greater than all-trans-retinoic acid greater than aromatic retinoid (Ro 10-9359) much greater than retinol. The retinoic acid-mediated decrease in collagenase activity was accompanied by a parallel decrease in immunoreactive collagenase protein, suggesting that the retinoic acids were acting to inhibit synthesis of the enzyme. However, an additional effect of these agents was encountered. Although the retinoids themselves had no direct collagenase inhibitory action, medium derived from cultures maintained in these retinoids showed direct inhibitory capacity which was dependent both on the concentration of retinoic acid and on the length of time in culture. The results suggest that the retinoic acids modulate collagenase in vitro by two mechanisms: by decreasing the synthesis of enzyme protein and by modulating the expression of an inhibitory molecule.

Collagenases and collagen degradation

Degradation of interstitial collagens probably takes place through different enzymatic mechanisms than degradation of basement membrane and pericellular collagens. Interstitial collagens are resorbed under pathological and physiological conditions by collagenases which function extracellularly and cleave polypeptide chains in the collagen triple helix at specific loci resulting in solubilization from the fibril. Production of collagenase in humans is ascribable to fibroblast-like cells which can be stimulated to synthesize new enzyme for release outside of the cell. In several inflammatory conditions, such as rheumatoid synovitis, modulation of collagenase production is mediated by interactions with surrounding inflammatory cells. Monocyte-macrophages produce a stimulatory factor, which has homologies with interleukin 1, which not only increases collagenase synthesis but also PGE2 synthesis. The PGE2 in turn has profound effects on cellular function. Production of the mononuclear cell factor is modulated by several interactions including T lymphocytes and T lymphocyte products, collagen of the extracellular matrix and the Fc portion of immunoglobulins. It is probable, from analogies with other stimulants such as phorbol myristate acetate, that the increase in collagen synthesis is controlled at the level of transcription. Further regulation of collagenase action outside of the cell is probably accomplished by proteolytic activation of a latent collagenase zymogen and interactions with inhibitory proteins also produced by cells in the local environment of the resorptive process.

Proliferative diseases

A unifying concept that excessive proliferation of cells and turnover of cellular matrix contribute significantly to the pathogenesis of several diseases, including cancer, atherosclerosis, rheumatoid arthritis, psoriasis, idiopathic pulmonary fibrosis, scleroderma and cirrhosis of the liver, is presented. As corollaries to this concept, the following topics are considered: (1) the role of polypeptide hormones and hormone-like mediators in the initiation, promotion and maintenance of proliferative responses; (2) alterations in collagen metabolism and collagenase activity; (3) the role of proteinases; (4) the potential use of inhibitors of proteinases for prevention of disease; and (5) the potential use of inhibitors of proliferative polypeptide hormones for prevention of disease. As specific proteolytic and proliferative biochemical mechanisms which contribute to the pathogenesis of disease become identified, there is a unique opportunity to develop new pharmacologic methods of prevention.

A stereologic analysis of collagen phagocytosis by fibroblasts in three soft connective tissues with differing rates of collagen turnover

The purpose of this study was to assess the importance of the phagocytic mechanism of collagen resorption in the normal turnover and remodelling of soft connective tissues. Collagen phagocytosis by fibroblasts in rat skin, attached gingiva, and periodontal ligament was quantitated using the methodology of electron microscopic stereology. Periodontal ligament contained five and 15 times as much phagocytosed collagen as attached gingiva and skin respectively. Also, for each tissue examined, a positive correlation was observed between the amount of collagen phagocytosed and the known rate of mature collagen turnover.

Synthesis of a collagenase inhibitor by gingival fibroblasts in culture

Human collagenase was inhibited by test solutions of human gingival fibroblast culture media. The fibroblast-derived collagenase inhibitor was only slightly affected by 10 micrograms trypsin but was inactivated with 100 micrograms trypsin. The chaotropic agent KSCN (3 M) completely inactivated the inhibitor, whereas the thiol-blocking reagent, p-aminophenylmercuric acetate, partially inactivated the inhibitor. Inhibitory activity was retained at 60 degrees C but was abolished at 100 degrees C. Following ammonium sulfate fractionation, the fibroblast inhibitor was recovered in the supernatant at concentrations of at least 70% saturation. It is suggested that collagenase latency in soft connective tissues may derive from a collagenase-inhibitor complex formed by interaction of collagenase and a fibroblast-derived inhibitor.