Collagenases (first of three parts)

Chemical and enzymatic characterization of the collagenase from the insect Hypoderma lineatum

The collagenase from the larvae Hypoderma lineatum, with a molecular weight of 24 000 and isoelectric point of 4.1, was obtained in homogeneous form by ion-exchange chromatography. It is stoichiometrically inhibited by diisopropylfluorophosphate. On the other hand it is unaffected by ethylenediaminetetraacetate, p-chloromercuribenzoate, dithiothreitol, N-tosyllysine chloromethyl ketone, N-tosylphenylalanine chloromethyl ketone and ovomucoid trypsin inhibitor. The enzyme which degrades native collagen in its helical parts, has a specific activity on thermally reconstituted collagen fibrils of 150 micrograms collagen degraded x min-1 x (mg enzyme)-1 at 37 degrees C. It hydrolyses casein but has no esterolytic activity characteristic of trypsin, chymotrypsin nor elastase. It has no action on the synthetic peptide 4-phenylazobenzyloxycarbonyl-L-prolyl-L-leucyl-L-glycyl-L-prolyl-D-arginine. The amino acid composition of Hypoderma collagenase indicates a distinct similarity with the serine proteinases of the trypsin family and with another athropode serine collagenase, that of the fiddler crab Uca pugilator. This suggests that eucaryotic collagenases with digestive rather than morphogenic function represent a new category of members of the trypsin family.

Collagenase in the lower respiratory tract of patients with idiopathic pulmonary fibrosis

To test the hypothesis that idiopathic pulmonary fibrosis (IPF) is mediated through collagenase present in the lower respiratory tract, we used the fiberoptic bronchoscope to obtain fluid from the lower respiratory tract of 24 patients with IPF, 18 controls and nine patients with sarcoidosis. The fluid was analyzed for a variety of enzymes, including collagenase. Fifteen of 21 patients with IPF showed collagenase activity, whereas normal controls and patients with sarcoidosis showed none (P greater than 0.001, for all comparisons). In two patients with IPF who were re-evaluated after eight to 24 months, the collagenase activity was persistent. Fluid from patients with IPF also contained elevated levels of a non-specific neutral protease (P greater than 0.01 compared with controls), but there was no elastase activity in fluid from patients with IPF or from controls. The collagenase found in lavage fluid in IPF cleaved lung collagen into collagenase-specific TCA and TCB fragments. We conclude that in IPF the collagen of the lung is subjected to sustained lysis, followed by disordered resynthesis, and that the presence of active collagenase in the lower respiratory tract is a specific feature of the alveolitis associated with this disease.

Collagenase production by synovial fibroblasts treated with phorbol myristate acetate

A series of intracellular events occurring after treatment of rabbit synovial fibroblasts with 0.01 micrograms/ml phorbol myristate acetate (PMA) were measured. Ten minutes after addition of PMA, there was a temporary increase in intracellular cyclic AMP levels, followed by a transient decrease in incorporation of 3H-thymidine into DNA. Approximately 500 ng/mg cell protein of PGE2 were found in culture medium from the 12- to 24-hour incubation period, but significant collagenase was not detectable until 24 to 36 hours. Treatment with aspirin or indomethacin abolished PGE2 production but did not affect collagenase levels. Production of enzyme was associated with a cessation of cell proliferation, measured by protein content/culture and cell number. No enzyme was detectable in untreated cultures. Synovial fibroblasts treated with phorbol myristate acetate may provide a good model for studies on the mechanism of induction of collagenase production.

[Experimental study on tissue and cell reactions after implantation of xenogeneic collagen sponges (author's transl)]

164 inbred Wistar rats received subcutaneous and intraperitoneal implants of xenogeneic collagen sponges and were examined by light- and electron microscopy as well as immunohistologically, to establish tissue and cell reactions and the time of collagen reabsorption. 4 to 5 weeks after implantation the xenogeneic collagen sponge was completely absorbed. All the inflammatory and reparative reactions were non-specific. Granulation tissue appeared soon (3 days after implantation) with new synthesis of fine collagen fibrils, mainly of type III, followed by type I collagen fibers. Myofibroblasts, with intracellular evidence of myosin and collagen (Type I and III) were sporadically present in the granulation tissue after day 5 and regularly after day 10. Small scar granulomas without xenogenic collagen were detectable even 4 to 6 months after collagen implantation. Reabsorption and regression of collagen granulomas occurred faster after xenogeneic collagen implantation than after using surgical cat sutures. From the morphological point of view, there is no indication of specific sensitization against xenogeneic collagen or of a specific immunologic process.

Collagen in normal and abnormal tissues

Despite being a very widespread protein, collagen is an unusual molecule possessing a great tensile strength conferred by a rope-like structure and intermolecular crosslinks. Our current knowledge of the biosynthesis of collagen is providing some insights into certain diseases of connective tissue and is also helping us to understand the healing processes of wounds and diseased tissues.

Binding of chemotactic collagen-derived peptides to fibroblasts. The relationship to fibroblast chemotaxis

We previously showed that collagen, alpha-chains, and collagen-derived peptide fragments induce chemotactic migration of human fibroblasts in vitro. We now describe biochemical and immunological evidence showing there are binding sites for collagen peptides on fibroblast membranes.By the use of (14)C-labeled alpha1(I) chain, binding to intact fibroblasts was demonstrated. The process was reversible, and time- and fibroblast concentration-dependent. Scatchard plot analyses of the data obtained for the binding of alpha1(I) suggested that there are congruent with 16 x 10(6) binding sites per fibroblast with an association constant of 1.1 x 10(7)/M for alpha1(I). Dissociation of the bound radioactivity and subsequent chromatographic analysis on agarose A-1.5 m revealed that the alpha1 was unaltered. The binding of (14)C-labeled alpha1 was inhibited by each of the CNBr peptides derived from alpha1 chain of chick skin collagen and CNBr peptide mixtures of various genetic types of collagen chains. Immunofluorescence studies with anti-alpha1 antibody showed that alpha1-treated fibroblasts exhibited strong immunofluorescence. The intensity of fluorescence was markedly diminished by prior absorption of the antibody with alpha1. The alpha1-treated cells stained with preimmune sera did not show significant fluorescence.Dose-response curves of fibroblast chemotaxis induced by alpha1 and the binding of alpha1 by fibroblasts correlate closely. Furthermore, the potency of alpha1-CNBr peptides as chemotactic agents correlates with their ability to inhibit the binding of labeled alpha1(I). These data suggest the hypothesis that collagenderived peptides cause fibroblast chemotactic migration by acting on fibroblast membranes.

Hereditary osteodysplasia with acro-osteolysis. (The Hajdu-Cheney syndrome)

A mother and son with acro-osteolysis (Hajdu-Cheney syndrome) are described. In addition to osteolysis of the distal phalanges, these patients have a generalized osseous dysplasia with osteoporosis, premature loss of teeth, short stature and a distinctive facial appearance. In one of the cases an enlarged sella turcica was associated with no abnormality of endocrine function. A biopsy specimen taken from an area of active osteolysis in a phalanx was studied by light and electron microscopy. There was active replacement of central medullary bone by a fibrous and angiomatous process characterized by the presence of small, thick-walled vessels and an unusual number of interspersed nerve fibers and mast cells. A neurovascular dysfunction with local release of osteolytic mediators may be involved in the pathogenesis of the disorder, but the nature of the osteolytic factor is unknown.

Characterisation of cathepsin B and collagenolytic cathepsin from human placenta

1. Human placental cathepsin B and collagenolytic cathepsin were separated by chromatography on columns of Amberlite CG-50. Collagenolytic cathepsin was partially purified by chromatography on DEAE-Sephadex (A-50) and Sephadex G-100. Cathepsin B was purified by chromatography on CM-cellulose and Sephadex G-100. 2. Both enzymes required activation by thiol compounds and were bound to organomercurial-Sepharose-4B. Sulphydryl-blocking reagents were inhibitory, which confirmed an essential thiol group to be present. 3. The enzymes degraded soluble calf skin collagen and insoluble bovine tendon collagen in the telopeptide region at pH 3.5 and 28 degrees C to yield mainly alpha-chain components. 4. In contrast to cathepsin B, collagenolytic cathepsin was found not to hydrolyse any of the low-molecular-weight synthetic substrates that were tested. 5. Leupeptin, a structural analogue of arginine-containing synthetic substrates, and antipain, an inhibitor of papain, were strongly inhibitory to both enzymes. 6. The isoelectric points of the enzymes were similar, being 5.4 for cathepsin B and 5.1 for collagenolytic cathepsin. 7. From chromatography on Sephadex G-100 the molecular weight of cathepsin B was calculated to be 24 500 and that of collagenolytic cathepsin to be 34 600.

Basement membrane changes under neoplastic oral mucous membrane. Ultrastructural observations, review of the literature, and a unifying concept

This study explores the morphologic nature of the basement membrane under neoplastic oral mucous membrane. Of particular interest is the progression of changes associated with dysplasia, carcinoma in situ, and invasive carcinoma. On the basis of a critical review of the literature and our own ultrastructural observations, we present a unifying concept for the development of these basement membrane changes. This concept proposes that neoplastic epithelial cells may produce a collagenolytic enzyme which is released into the epithelial intercellular spaces. This enzyme permeates to the basement membrane, causes breaks in the basement membrane, and focal loss of stromal area contiguous with intercellular spaces. The neoplastic basal cells develop pseudopodia that eventually extend through the breaks in the basement membrane. This concept suggests that the basement membrane changes herald the progression of carcinoma in situ to invasive carcinoma.

Ultrastructural alterations in collagen associated with microscopic foci of human emphysema

Postmortem and biopsy lung samples were examined with a dissecting microscope and classified into three categories: no overdistended air spaces visible, mild destruction and some fenestration of the septa with minimal confluence of air spaces, and more advanced breakdown of alveolar walls with at least a sixfold increase in air space to a 1300 mu diameter. Prominent ultrastructural tissue alterations were found within the focal regions where fenestration of the alveolar wall and some confluence of air spaces were identified. Edema and rearrangement of the supportive tissues were noted in the alveolar septa adjacent to foci having the greatest alveolar enlargement. Randomized electron dense collagen fibrils were found only in these areas, whereas the normal alveolar septa contained uniformly parallel collagen fibrils. Many of the randomized fibrils had sufficient swelling to display prominent internal spiraling. Other changes in structure and cell numbers were consistently found in association with the altered collagen. These included: separation of the type I epithelial cells from the basal lamina and some autolysis of the cytoplasmic organelles, numerous flattened type II epithelial cells, and aggregations of pulmonary macrophages.

Quantitation and immunocytochemical localization of human skin collagenase in basal cell carcinoma

Human skin collagenase was quantitated by radioimmunoassay in 21 basal cell carcinomas. Immunoreactive collagenase protein was found to be approximately 2-fold greater in extracts of these tumors than in extracts of normal skin, suggesting that this enzyme may be important in the pathogenesis of soft tissue destruction in vivo. To further define the role of collagenase in such destruction, immunofluorescent staining with specific antiserum to human skin collagenase was used to localize collagenase in the basal cell carcinomas. The enzyme was found only in the stromal elements surrounding the tumor islands. No staining of the epithelial components of the basal cell carcinomas was found. These findings suggest that the normal connective tissue elements may have been stimulated to produce an increased amount of collagenase and emphasize the importance of epithelial-stromal interaction in soft tissue invasiveness.

A new factor that may control collagen resorption

Specific collagenases responsible for the initial enzymic step leading to degradation of the collagen fibrils of connective tissues have been found in both latent and active forms. The most important factor controlling the local activity of collagenase extracellularly may be an inhibitor that is synthesised by connective tissues, and it is proposed that latent enzymes are all enzyme-inhibitor complexes.

The degradation of articular collagen by neutrophil proteinases

The action of the serine proteinase (EC 3.4.21--)of human neutrophil leucocytes, elastase and cathepsin G, on cartilage and tendon was investigated. With cartilage, both enzymes first degraded the proteoglycan, then solubilized collagen by an attack on the terminal peptides, destroying the inter- and intramolecular cross-links. There was little degradation of the helical region of the type II collagen. Elastase also solubilized type I collagen from tendon, though this was less susceptible than cartilage collagen, and attacked the terminal peptides and perhaps the helical region of type I skin collagen in solution. Cathepsin G had little or no effect on type I collagen of skin or tendon. Since massive infiltration of joint tissues by neutrophil leucocytes is a prominent feature of inflammatory joint disease, it may well be that elastase and cathepsin G make a significant contribution to the tissue damage that occurs.

PZ-peptidase activity in human uterine cervix in pregnancy at term

PZ-peptidase (EC 3.4.--) was detected in human uterine cervix distributed in the soluble fraction after 100 000 x g centrifugation. Optimum pH for PZ-peptidase was observed to be pH 7.2--7.4, except for two of the preparations examined. PZ-peptidase activity was found to significantly increase in pregnancy at term as compared with that in a control group.

Changes in the collagenolytic activity released by primary VX-2 carcinoma cultures as a function of tumor growth

Serum-free media of minced tissue cultures of VX-2 rabbit carcinoma contained a specific collagenolytic activity capable of releasing soluble radioactive peptides from [14C]-labeled collagen fibrils. It was also capable of reducing the viscosity of acid-soluble collagen solutions by cleaving the tropocollagen (TC) molecules primarily at one site to TCA (75%) and TCB (25%) fragments. Three chromatographic fractions were separated by gel filtration: F1, (MW 85-110,000) present in larger amounts in early cultures of younger tumor tissue; F2, (MW-35-40,000) the major component with maximum production in the day 3 media of younger and advanced tumor tissues; F3, (MW 18-22,000) the minor component. Early cultures of younger tumor tissue contained a latent collagenase and were subject to trypsin activation suggesting the presence of inactive enzyme precursors or an enzyme-inhibitor complex.

Tumor cell collagenase and its inhibition by a cartilage-derived protease inhibitor

Human osteosarcoma and mammary carcinoma cells were cultured separately in a medium supplemented with fetal calf serum, until they were confluent. The medium was then replaced by serum-free medium supplemented with heparin. Both cell cultures secreted collagenase, and this activity was inhibited by a cartilage-derived protein of low molecular weight. Since cartilage is rarely invaded by neoplasms, the presence of this inhibitor may play an important role in the regulation of tumor invasion.

Localization of collagenase in human middle ear cholesteatoma

The process of connective tissue breakdown in chronic otitis media is described in the context of recent advances in our understanding of collagen degradation and bone resorption. The significance of the initial step in collagen breakdown, brought about by the action of a specific collagen dissolving enzyme is emphasized in terms of recent studies in other chronic inflammatory diseases characterized by connective tissue breakdown. Bone resorption, a characteristic feature of chronic otitis media, requires the breakdown of collagen, which comprises over 90 percent of bone protein. Evidence in support of collagenase in bone resorption from adjacent tissue (in this case, inflammatory connective tissue) would require identification of the enzyme in cells involved in the inflammatory process adjacent to the resorbing bone. Collagenase was found localized in frozen sections of canal wall skin, middle ear granulation and in cholesteatoma by a specific binding of the enzyme with an antiserum produced against purified human skin collagenase. The antigen antibody complex was labelled with fluorescein. Collagenase appeared in the subepithelial connective tissue of cholesteatoma, granulation tissue from the middle ear and the dermis of canal skin; but was not seen in the keratin layer, epithelium or the epidermal appendages. The enzyme appeared within certain fibroblasts, macrophages and endothelial cells of capillary buds. Collagenase enhanced by chronic inflammation attacks the intact collagen molecule, making it susceptible to further digestion by other proteases that are also products of inflammation. This process brings about resorption of connective tissue and bone.

Intracellular collagen fibers at the pannus-cartilage junction in rheumatoid arthritis

Sections of the pannus-articular cartilage junction from a patient with rheumatoid arthritis (RA) were prepared for electron microscopy. Cells at this interface contained membrane-bound collagen fibrils, apparently in various stages of digestion. Previous studies have demonstrated intracellular collagen fibrils at sites of very active and rapid collagen resorption. It is suggested that at certain times in certain patients with RA, phagocytosis of cartilage collagen fragments and subsequent intracellular digestion may serve as a supplemental pathway to extracellular collagen degradation.

Collagenase production by rheumatoid synovial cells: stimulation by a human lymphocyte factor

Human peripheral blood lymphocytes incubated in culture for 1 to 3 days at 37 degree C, but not at 4 degree C, release a soluble factor which can stimulate, up to 400-fold, collagenase production by isolated, adherent, rheumatoid synovial cells. Production of lymphocyte factor is enhanced by phytohemagglutinin or concanavalin A. By gel filtration the factor has an apparent molecular weight of about 12,000.

Collagenase and its natural inhibitors in relation to the rheumatoid joint

This report attempts to summarize our present knowledge of rheumatoid synovial collagenase and its natural serum inhibitors, beta1-anticollagenase and alpha2-macroglobulin, in relation to cartilage collagen resorption in the rheumatoid joint. Immunolocalization of collagenase across the cartilage/pannus junction is described, and in the light of the finding of the specific, small molecular weight beta1-anticollagenase we propose a model of cartilage erosion based on the interaction between collagenase and its natural inhibitors.

Biochemical characteristics and biological significance of the genetically-distinct collagens

In recent years it has become evident that genetic polymorphism is dramatically expressed in the structural protein, collagen. Current information on the biochemical properties, biosynthesis, and tissue distribution of Type I, II, and III collagens is summarized with special reference to possible unique functional roles fulfilled by each of these collagens.

Some characteristics of collagenase activity in gingival crevicular fluid and its relationship to gingival diseases in humans

Collagenase activity in human gingival fluid was measured using a radioactive collagen fibril assay. The activity was positively correlated with the severity of gingival disease. The fluid collagenase seemed to be controlled by alpha 2-macroglobulin, based on its activation by NaSCN, and to be present solely in the extracellular fraction. Examination of the collagen breakdown products by acrylamide gel electrophoresis indicated that the fluid collagenase was of tissue rather than bacterial origin.

Regulation of calcium metabolism

This paper reviews the regulation of calcium metabolism in man. The body's calcium economy is determined by the relationship between the intestinal absorption of calcium, the renal handling of calcium, and by the movements of calcium in and out of the skeleton. These processes are influenced by many factors, the most important of which are parathyroid hormone and the hormones derived from the renal metabolism of vitamin D, notably 1,24-dihydroxyvitamin D3. The role of endogenous calcitonin in man is still controversial, but there are several other hormones which have some influence on calcium metabolism, including thyroid hormone, growth hormone, and the adrenal and gonadal steroids. Clinical disorders of calcium metabolism and their treatment are discussed in terms of the disturbances in normal physiology they represent.

Production of collagenase by mouse peritoneal macrophages in vitro. Characterization of sites of cleavage of tropocollagen

Macrophages from mineral oil-stimulated mice produce collagenase at a constant rate over several days in culture. Phagocytosis of latex does not increase production of enzyme. Gel electrophoretic and electron microscopic analyses indicate that the specificity of the macrophage enzyme is similar to that of other previously characterized mammalian collagenases.

Substrate specificity of vetebrate collagenase

Substrate specificity of purified tadpole collagenase (EC 3.4.24.3) has been studied using eleven synthetic peptides. A pentapeptide, t-butyloxycarbonylprolylalanylglycylisoleucylalanine amide, was susceptible to the action of the enzyme and an octapeptide, acetylprolylglutaminylglycylisoleucylalanylglycylglutaminylarginine ethyl ester, was proposed to be the best substrate for vertebrate collagenase among the peptides tested.

Serum proline imino-peptidase activity in normal adult subjects and in patients with Paget's disease of bone

The activity of proline imino-peptidase (EC 3.4.1.4) may provide a measure of collagen degradation, and a method for its estimation in human serum is described. The mean value of this enzyme activity in 48 normal adults of 4.7 mU/l (S.D. 0.9) did not change with sex, age or dietary collagen. In 8 patients with liver disease associated with elevated levels of plasma alkaline phosphatase activity the mean value was normal (4.5 mU/l, S.D. 1.5). However, in 25 patients with untreated Paget's disease of bone, values were significantly increased (mean 7.4 mU/l; S.D. 2.8; p less than 0.001) and were positively correlated with plasma alkaline phosphatase activity (r = 0.75; p less than 0.001) and with urine total hydroxyproline excretion (r = 0.68; p less than 0.001). In patients given disodium ethane-1-hydroxy-1,1-diphosphonate for 3--6 months, serum proline imino-peptidase activity decreased to normal values.

Haemorrhagic and inflammatory properties of collagenase from C. histolyticum

Collagenase from Clostridium histolyticum induced haemorrhages when applied to the surface of dog lung; it exerted a similar effect on mouse lung when injected intrathoracically. Injected into rat paws, bacterial collagenase induced haemorrhage and oedema. Effects of collagenase were prevented by several procedures that inhibit collagenolytic activity (heating at various temperatures and incubation with metal-complexing agents such as EDTA, penicillamine and dithiothreitol). Protein protease inhibitors, dexamethasone and standard acidic anti-inflammatory drugs had only a slight or no effect on collagenase-induced haemorrhages; dexamethasone and acidic anti-inflammatory drugs blocked collagenase-induced oedema. Inhibition of endogenous kinin-releasing mechanisms by administration of hexadimethrine, a recognized inhibitor of the activation of clotting Factor XII, and depletion of kininogen by administration of carrageenin blocked collagenase-induced oedema. Collagenase did not increase permeability of rat skin vessels, nor did it release potential inflammatory mediators, such as bradykinin or prostaglandins, from plasma or platelets. Bacterial collagenase-induced haemorrhage presumably resulted from enzymatic destruction of membranous structures; at least a portion of the inflammatory response may be due to activation of a kinin-like system.

[Bursting pressure of colon in the rats and proteinase inhibition (author's transl)]

In the early postoperative period (third postoperative day) the colonic enterotomies show 45 per cent higher bursting pressure following administration of Aprotinin than the control group (p less than 0,02). On the fifth postoperative day no difference was noted between both groups. The interpretation of the results is difficult because specific parameters such as collagen content and collagenase activity were not determinated. The relationship between colonic anastomotic breakdown and collagenase and therefore the question of collagenase inhibition have to be discussed. It is suggested that activation of procollagenase is prevented because trypsin and kallikrein are inhibited by Aprotinin.

The dynamics of collagen deposition in liver damaged by CCl4

The rates of synthesis and catabolism of collagen are determined in the livers of normal rats and of rats treated with carbon tetrachloride. Several experimental conditions are applied with the intention of investigating the dynamic processes separately, in order to determine the relevant values. The deposition of collagen in liver after damage by CCl4 is a consequence of the reduction of turnover with a simultaneous increase in collagen-production. Together with the increase in synthesis, which seems to be a consequence of a numerical increase in cells, there is a reduction in catabolism of collagen: the more severe the damage, the more marked is the decrease of specific catabolism. Collagen-deposition in the liver is thus the result of accumulation. The results indicate the possibility that collagen-catabolism is effected by enzymes produced by adjacent parenchymal cells, so that their destruction enhances the accumulation of collagen material. The findings mentioned above are discussed in the context of the general criteria of scar-formation and the repair of damaged tissues.