Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.36 (hyaluronidase)
4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytotactin is an extracellular matrix protein that is involved in neuron-glia adhesion and is found in both neural and nonneural sites. It is synthesized by glia but not by neurons. In this study, we have examined the binding of cytotactin to a variety of extracellular matrix components using uniform microscopic beads (Covaspheres) that could be labeled and then linked to purified molecules. Cytotactin-coated beads bound well to neurons, and this binding was strongly inhibited by anti-cytotactin antibodies but not by anti-neural cell adhesion molecule (anti-N-CAM) antibodies. In contrast, the binding of N-CAM-coated beads to neurons was inhibited by anti-N-CAM antibodies and not by anti-cytotactin antibodies. To identify a neuronal ligand for cytotactin, we tested several molecules for their ability to block the binding of cytotactin-coated beads to cells. A proteoglycan-containing fraction that copurified with cytotactin from brain extracts strongly inhibited binding, whereas neither a heparan sulfate proteoglycan from Engelbreth-Holm-Swarm tumor cells nor soluble cytotactin itself had a significant inhibitory effect. The neural proteoglycan also inhibited the binding of cytotactin-coated beads to fibroblasts. Digestion with chondroitinase, heparitinase, and hyaluronidase as well as immunological analyses suggested that the predominant species in the active fraction was a chondroitin sulfate proteoglycan with a Mr280,000 core protein bearing HNK-1 antigenic determinants and also indicated that hyaluronic acid was present in this fraction. In experiments on in vitro synthesis, it was found that the proteoglycan was synthesized in culture by embryonic chicken brain tissue but not by embryonic chicken glial cells. A series of binding experiments was performed on appropriately derivatized beads to confirm that the proteoglycan is a ligand for cytotactin and to check for the possibility that other extracellular matrix proteins might interact with one or the other member of this binding couple. Proteoglycan-coated beads and cytotactin-coated beads coaggregated readily. The aggregation was inhibitable by anti-cytotactin antibodies, soluble cytotactin, or soluble proteoglycan. Addition of laminin inhibited the binding of cytotactin-coated beads to proteoglycan-coated beads or to cells; this is consistent with data indicating that laminin interacts with a component of the proteoglycan-containing fraction. In contrast, fibronectin bound to cytotactin, but it did not bind to proteoglycan or interfere with the binding of cytotactin to proteoglycan. The results of this study are in accord with the idea that the functions of extracellular matrix components during neural and nonneural development may be modulated both by competition for shared cell surface receptors and by a network of molecular interactions among the matrix components themselves.
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PMID:A proteoglycan with HNK-1 antigenic determinants is a neuron-associated ligand for cytotactin. 243 34

In order to clarify the biological characteristics of rat mammary tumors induced by 7,12-dimethylbenz-[a]-anthracene (DMBA), histochemical and immunohistochemical studies were performed. Two types of luminal spaces were observed within the tumor. In one type, the lumen was surrounded by eosinophilic columnar cells which were strongly reactive for soybean agglutinin (SBA) but weakly stained with keratin antibodies. In the luminal spaces, substances positive for PAS, dialyzed iron ferrocyanide or alcian blue and resistant to mucopolysaccharidase were occasionally observed. Ultrastructurally, the luminal surface was characterized by the presence of microvilli and tight junctions. In the other type, the lumen was often found in highly cellular foci and surrounded by pale, polygonal or elongated cells which were weakly stained with keratin antibodies but not SBA. The luminal spaces presented a peculiar structure filled mainly with mucoid substances sensitive to hyaluronidase, chondroitinase ABC and heparitinase, and the inner surface of the spaces was surrounded by basement membrane components: laminin, fibronectin and type IV collagen. The results of the present study therefore showed that DMBA-induced mammary tumor consists, partly, of a structure resembling human adenoid cystic carcinoma.
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PMID:Immunohistochemical studies of DMBA-induced rat mammary tumors. 245 33

Complete antigen visualization in the context of well-preserved tissue architecture is the goal of all immunohistochemical techniques. Frozen tissue section techniques achieve optimal antigen visualization but preserve tissue architecture poorly. On the other hand, formalin-fixed tissue section techniques preserve tissue architecture very well but result in antigen masking. Enzymatic digestion or salt extraction of formalin-fixed sections has been used to reestablish antigen expression. Recently acid-alcohol-fixed tissue has been used as a successful compromise between tissue architecture preservation and the visualization of cytoskeletal antigens. In an attempt to find an improved immunohistochemical process for non-cytoskeletal antigens, we compared avidin-biotin immunofluorescence staining in frozen, formalin-fixed, and acid-alcohol-fixed tissues. The fixed tissues were either untreated or treated with enzyme digestion or salt extraction. For this study, we examined healing cutaneous wounds in Yorkshire pigs with antibodies to fibronectin, laminin, von Willebrand factor VIII, and keratin. Although tissue architecture was poor, frozen sections provided the best antigen visualization and were therefore used as the standard for complete antigen expression. Formalin-fixed tissues had excellent tissue architecture, but most antigens were completely masked. Pre-treatment technique only partially overcame the antigen masking caused by formalin. In contrast, acid-alcohol fixation preserved tissue architecture almost as well as formalin and sometimes allowed complete antigen visualization; however, laminin and fibronectin were partially masked. Total recovery of the expression of these antigens could be obtained by pre-treating the acid-alcohol-fixed tissue with either hyaluronidase or 1 M NaCl. Therefore, acid-alcohol-fixed tissue appears best for extracellular matrix (ECM) protein immunostaining as well as for cytoskeletal staining. However, certain ECM antigens require hyaluronidase or 1 M NaCl treatment for optimal visualization.
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PMID:Optimization of immunohistochemical techniques to detect extracellular matrix proteins in fixed skin specimens. 246 79

Benign and malignant fibrous histiocytomas are composed of an admixture of fibroblast-like and histiocyte-like cells and of a changing amount of fibre structures which tend to be arranged in a so-called storiform pattern. In order to study the organization of the extracellular matrix, the distribution of fibronectin was investigated immunohistochemically. Using the PAP technique and the indirect immunofluorescence method, paraffin sections of formaldehyde fixed tissue specimens of 25 tumours (12 benign fibrous histiocytomas, 12 malignant fibrous histiocytomas, and 1 atypical fibroxanthoma) were studied. A pretreatment with hyaluronidase and proteolytic enzymes (trypsin, pronase, pepsin) was performed to unmask the antigen. Best results were obtained with pronase E or, sometimes even better, by employing a combination of pronase E and hyaluronidase. Generally fibronectin could be demonstrated in the matrix substances of fibrohistiocytic tumours, but the immunohistochemical staining patterns of benign and malignant tumours differed. In benign fibrous histiocytomas, a regular distribution of fibronectin was found in cellular areas. Parallel to formation of collagen fibres, the reaction decreased and in dermatofibromas showing abundant hyalinized collagen the staining proved to be quite weak. In malignant fibrous histiocytomas, the immunostaining was very irregular. In cellular areas consisting of spindle cells, an intense reaction could be observed. Tumours with storiform or fascicular fields exhibit a delicate network of fibronectin encircling individual fibroblast-like cells. In the course of fibre formation, the matrix staining for fibronectin revealed a distribution similar but not identical with that obtained with the reticulin stain. Simultaneous to the occurrence of collagen fibre bundles, fibronectin decreased and in areas of hyalinization the staining was considerably diminished. In areas of undifferentiated small cells, in myxoid zones as well as foci of xanthoma cells, and in pleomorphic portions the immunostain was negative. The distribution in atypical fibroxanthoma is similar to that observed in storiform and pleomorphic variants of malignant fibrous histiocytomas. The results support the suggestion that fibronectin is the first sign of the typical basic pattern of fibrohistiocytic tumours preceding the formation of reticulin and collagen fibres. The expression of fibronectin on cell surfaces as well as in intercellular matrix may be closely related to the organization of the growth patterns of fibrohistiocytic tumours.
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PMID:Fibronectin in relation to growth patterns of fibrohistiocytic tumours--an immunohistochemical study of benign and malignant fibrous histiocytomas. 282 24

Human hemopoietic blast colony-forming cells (BI-CFCs) recognize and adhere to the extracellular matrix (ECM) produced by marrow-derived stromal cells in vitro. We have investigated the requirements for this interaction by testing the capacity of BI-CFCs to adhere to ECM components under a variety of conditions. Binding was prevented completely by prior treatment of stromal ECM with nitrous acid, in large part by treatment with heparitinase or hyaluronidase, and slightly by treatment with chondroitinases. Whereas heparan sulfate isolated from marrow stromal cultures effectively blocked binding, heparan sulfate from bovine kidney did not. Chondroitin sulfate and hyaluronic acid did not have any effect in this test. In contrast, collagen was not sufficient for the interaction because dishes coated with collagen type I or IV did not act as adhesive surfaces for BI-CFCs. Ligands for integrin receptors (e.g., fibronectin) did not participate in BI-CFC binding because the synthetic pentapeptide glycine-arginine-glycine-asparagine-serine did not compete with stroma in binding BI-CFCs. These findings indicate that heparan sulfate in the bone marrow microenvironment is necessary for BI-CFC binding to ECM and may contribute to localizing hemopoietic stem cells in hemopoietic tissue.
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PMID:Heparan sulfate is necessary for adhesive interactions between human early hemopoietic progenitor cells and the extracellular matrix of the marrow microenvironment. 297 4

Sodium deoxycholate extraction was used to isolate extracellular matrix from various cultured cells: human and murine embryonic fibroblasts, epithelial lines of mouse (MPTR), rat (IAR 2 and IAR 20), pig (SPEV) and cow (FBT). Protein composition of the matrix was studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunofluorescence. The matrix morphology was investigated by scanning electron microscopy. In cell lines FBT and MPTR the major component of the matrix was laminin, whereas in other lines and fibroblasts it was fibronectin. The matrix of the majority of lines had a fibrillar structure, and the fibrils usually formed networks. MPTR cells had a punctate matrix composed of laminin and collagen type IV, densely covering the substratum. The treatment of the matrix by hyaluronidase and/or DNAase I did not influence its protein composition. The isolated matrix of different structure and composition may serve a biological substratum in studies of normal tumor cell behavior in tissue culture.
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PMID:[Isolation and characteristics of the extracellular matrix of cultured cells]. 304 77

We compared the distribution of fibronectin and chondronectin within the matrix of canine articular cartilage. Fibronectin was found throughout the matrix as well as pericellularly. In contrast, chondronectin was observed predominantly associated with the cell or pericellular matrix. Interactions of these molecules with matrix components in the pericellular matrix probably differs, however, since concentrations of hyaluronidase which prevented detection of pericellular fibronectin allowed detection of chondronectin. Chondronectin and fibronectin were detected in osteoarthritic cartilage as well as in disease-free cartilage. Penetration of biotinylated fibronectin into cartilage from the external medium occurred only in osteoarthritic cartilage and proceeded only from the articular surface. Disease-free cartilage appeared to maintain a barrier to fibronectin penetration from the articular surface which was sustained even after the proteoglycan content was markedly depleted by incubation of cartilage with catabolin or lipopolysaccharide. In cartilage that was proteoglycan-depleted, the only detectable penetration of external fibronectin was from the cut surface.
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PMID:Immunohistochemical localization of fibronectin and chondronectin in canine articular cartilage. 328 48

We have examined the adhesion of primary Sertoli cells to a seminiferous tubule basement membrane (STBM) preparation in vitro. The STBM isolation procedure (Watanabe, T.K., L.J. Hansen, N.K. Reddy, Y.S. Kanwar, and J.K. Reddy, 1984, Cancer Res., 44:5361-5368) yields segments of STBM that retain their histotypic form in both three-dimensional tubular geometry and ultrastructural appearance. The STBM sleeves contain two laminae: a thick, inner basal lamina that was formed in vivo between Sertoli cells and peritubular myoid cells; and a thinner, outer basal lamina that was formed between myoid cells and sinusoidal endothelial cells. Characterization by immunofluorescence and SDS PAGE revealed that the isolated STBM retained fibronectin, laminin, and putative type IV collagen among its many components. When the STBM sleeves were gently shaken with an enriched fraction of primary Sertoli cells, the Sertoli cells bound preferentially to the lumenal basal lamina at the ends of the STBM sleeves. Few Sertoli cells bound to either the outer basal lamina of the STBM sleeves or to vascular extracellular matrix material which contaminated the STBM preparation. 3T3 cells, in contrast, bound to all surfaces of the STBM sleeves. Pretreatment of the STBM sleeves with proteases, 0.1 M Na metaperiodate, 4 M guanidine HCl, or heating to 80 degrees-90 degrees C inhibited lumenal Sertoli cell binding, but binding was not inhibited by chondroitinase ABC, heparinase, hyaluronidase, or 4 M NaCl. The lumenal Sertoli cell binding occurred in the presence or absence of added soluble laminin, but not fibronectin. The addition of soluble laminin, but not fibronectin, restored random binding of Sertoli cells to trypsinized STBM sleeves. Our in vitro model system indicates that Sertoli cells recognize differences in two basal laminae produced in vivo on either side of myoid cells.
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PMID:Sertoli cell binding to isolated testicular basement membrane. 352 69

The presence and localization of fibronectin in normal and acutely inflamed appendices in man was studied using indirect immunoperoxidase technique on sections of formaldehyde fixed and paraffin embedded tissue, following pretreatment with pepsin and testicular hyaluronidase. In the normal appendix fibronectin was demonstrated in the region of the basement membrane of the surface epithelium, in the loose connective tissue, in the perimysium around the individual smooth muscle cells and in the vessel walls. In the acutely inflamed appendices, fibronectin was found in the luminal necrotic area, both intercellularly and in the cytoplasma of some inflammatory cells. In relation to the surface inflammation and in the tissue matrix corresponding to the acute inflammatory reaction fibronection was, compared to the normal appendix, found in increased amount. Furthermore, a comparison between the use of a primary antibody to fibronectin, produced in our collaborating laboratory and two different commercial primary antibodies showed that the staining results concerning the localization of fibronectin were equal for all three antibodies, whereas the commercial antibodies showed a weaker staining intensity and some unspecific staining compared to the antibody produced in our collaborating laboratory.
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PMID:Demonstration of fibronectin in normal and acutely inflamed appendix. 355 6

Heterogeneity of synovial fluid fibronectin was studied by means of Laurell cross-immunoelectrophoresis in patients with rheumatoid arthritis, posttraumatic synovitis and other arthropathies. Prior to hyaluronidase treatment all the synovial fluid samples exhibited the fibronectin heterogeneity, which disappeared after the action of hyaluronidase. The data obtained suggest that complexes of fibronectin and hyaluronic acid are responsible for physico-chemical heterogeneity of fibronectin in synovial fluid.
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PMID:[Complex-formation with hyaluronic acid as a cause of fibronectin heterogeneity in the synovial fluid]. 366 Jul 29


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