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)

Corneal epithelial cells from 15-day chick embryos produce a fibronectin-rich extracellular matrix when cultured on glass, plastic and fibronectin-coated substrata. Cell culture in the presence of Streptomyces hyaluronidase or chondroitinase ABC resulted in considerable reduction of the matrix; collagenase had a lesser effect but nevertheless also reduced the matrix. In all enzyme treatments the cells attached and spread to form characteristic epithelial cell islands, but the marginal cells of these islands showed a marked reduction in the number of lamellipodia and focal contacts. Also, the immunofluorescent staining pattern for fibronectin was considerably reduced. Control cells cultured on a fibronectin-coated surface were able to reorganize the fibronectin into fibrils, whereas cells cultured in enzymes showed little or no ability to do so. The cellular reorganization of fibronectin could also be inhibited by the addition of L-azetidine-2-carboxylic acid (LACA), an inhibitor of collagen secretion. Cells plated out in the presence of LACA spread much better on collagen substrata than on plastic, glass or fibronectin. However, in all cases very little fibronectin matrix was detectable in the epithelial islands. The results suggest that components of the extracellular matrix (ECM) such as collagen, hyaluronic acid and chondroitin sulphates are not essential for the initial attachment and spreading of corneal epithelial cells in culture, but are important in the development of the ECM, and in maintaining a flattened morphology and spreading behaviour. It is suggested that fibronectin plays an important role in these interactions and that the ability of cells to organize fibronectin into fibrils is dependent on the presence of other ECM components such as glycosaminoglycans and collagen.
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PMID:Role of glycosaminoglycans and collagen in the development of a fibronectin-rich extracellular matrix in cultured embryonic corneal epithelial cells. 674 72

Fibronectin has been localized to basement membranes and cell surfaces with the light microscope by fluorescent staining of thick sections, and with the TEM by immunoperoxidase reaction. However, these methods are limited because it is difficult to appreciate the patterned distribution of fibronectin from sectioned material. We have developed a probe for fibronectin that facilitates its identification with the SEM. Our probe consists of two parts; the first component is a derivatized methacrylate microsphere 90 nm in diameter, linked to purified sheep anti-rabbit IgG. The second component is anti-fibronectin IgG raised in rabbits. Stage-3 to -12 chick embryos were fixed and the ectoderm covering the cranial mesoderm was removed. Embryos were treated with testicular hyaluronidase, exposed to rabbit anti-fibronectin IgG and finally to sheep anti-rabbit IgG conjugated microspheres. As expected, the basal lamina of surface and neural ectoderm as well as the remaining fibrous ECM were heavily decorated with microspheres, whereas control embryos treated with preimmune serum were beadless. Fibronectin was localized on the cell soma and processes of primary mesenchyme as early as stage 3. In addition, it was possible to decorate to various extents, populations of prosencephalic, mesencephalic, and rhombencephalic cranial neural crest cells. Our studies suggest that fibronectin is present in the cranium of chick embryos at earlier times than heretofore realized, and that fibronectin accumulates in a cranial to caudal gradient that reflects the sequential differentiation of the embryonic axis.
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PMID:SEM localization of cell-surface-associated fibronectin in the cranium of chick embryos utilizing immunolatex microspheres. 674 25

Indirect immunofluorescence has been used to study the distribution of fibronectin during the course of embryonic chick limb morphogenesis and differentiation. At all stages of development from 19 through 25, fibronectin is distributed throughout the non-differentiating mesenchymal tissue directly subjacent to the apical ectodermal ridge (AER), i.e. the mesenchyme extending 0.15 mm or so from the AER. Fibronectin is also distributed throughout the proximal condensing central core of the limb during the early stages of cartilage differentiation. In fact, fibronectin persists as a major component of the intercellular matrix in the central core of the limb following overt chondrogenic differentiation, since it is present as late as stage 27 throughout the well-differentiated cartilage rudiments of the radius, ulna, and humerus. The detection of fibronectin in differentiated cartilage is facilitated by pre-treatment of the sections with testicular hyaluronidase prior to immunofluorescent staining. In contrast to the chondrogenic central core of the limb, in the peripheral dorsal and ventral (myogenic) regions in which muscle differentiation is progressing, there is a progressive and striking diminution in fibronectin staining. By stage 27, little, if any, is present in the well-differentiated muscle primordia. Finally, at all stages of development, there is an accumulation of fibronectin at the ectodermal-mesenchymal interface, suggesting it is a component of embryonic limb basement membranes. On the basis of these observations, the possible role of fibronectin in limb cartilage and muscle differentiation and in other aspects of limb morphogenesis is discussed.
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PMID:Temporal and spatial distribution of fibronectin during development of the embryonic chick limb bud. 674 2

Fresh frozen tissue sections of human articular cartilage was treated without and with human testicular hyaluronidase (2 x 10(6) units/l) for 60 min at 37 degrees C and stained by the indirect immunoperoxidase technique with rabbit antihuman fibronectin. The rabbit antihuman fibronectin was purified by affinity chromatography on human fibronectin-Sepharose. Fibronectin was only found on the acellular surface of the articular cartilage in tissue sections not treated with hyaluronidase. In this surface layer, probably identical to "lamina splendens", the arrangement of fibronectin was as a membrane. No collagen was seen in this area by van Gieson staining. No staining for fibronectin was found in the cartilage matrix or in the chondrocytes. Treatment of the cartilage tissue with hyaluronidase resulted in visualization of high amount of fibronectin in the cartilage matrix, with the highest intensity around the chondrocytes. The staining of the acellular surface layer of the articular cartilage was identical with the results obtained without hyaluronidase treatment. These results indicate that articular cartilage is rich in fibronectin probably in complex with hyaluronic acid, and that the chondrocytes produce fibronectin in situ. It also demonstrates the steric hindrance of hyaluronic acid aggregates in diffusion of the antibody and the value of hyaluronidase treatment of tissue before demonstration of fibronectin.
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PMID:Demonstration of fibronectin in human articular cartilage by an indirect immunoperoxidase technique. 675 2

The biosynthesis of fibronectin during the in vivo development of matrix-induced endochondral bone was investigated by using [35S]methionine in rats. The dmineralized bone matrix that was implanted subcutaneously to induce local bone formation bound circulating fibronectin. This may be an important initial requirement for cell attachment to the matrix. Fibronectin was present throughout the development of bone but accounted for the largest percentage of total protein synthesized during mesenchymal cell proliferation and hematopoiesis. Fibronectin was identified in tissue extracts by its (i) comigration on electrophoretic NaDodSO4/polyacrylamide gels with human and rat plasma fibronectin, (ii) affinity for denatured collagen, (iii) crossreactivity with purified antibody of rat plasma fibronectin, and (iv) insensitivity to collagenase digestion. Fibronectin was localized by immunofluorescence in the extracellular matrix during the period of mesenchymal cell proliferation. During chondrogenesis, fibronectin was demonstrated in the differentiating chondrocytes. Fibronectin was detectable in the cartilage matrix only after hyaluronidase treatment. During vascular invasion, prior to osteogenesis, fibronectin was localized in association with endothelial cells. These observations demonstrate a possible role of fibronectin in collagenous matrix-mesenchymal cell interaction in vivo.
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PMID:Synthesis and localization of fibronectin during collagenous matrix-mesenchymal cell interaction and differentiation of cartilage and bone in vivo. 699 Apr 20

It has been suggested that an extracellular matrix - and cell surface - associated glycoprotein, fibronectin, plays a role in the positioning of cells in morphogenesis and in the maintenance of orderly tissue organization. In the present study the appearance and distribution of fibronectin during in ovo chick limb development has been investigated by indirect immunofluorescence techniques in H.H. stages 20-30. Fibronectin is not detectable until just prior to the transition from the morphogenetic to the cytodifferentiation phase of development. Beginning at H.H. stage 25, successive nonrandom patterns of fibronectin detection and distribution, which resemble the subsequent cartilaginous elements, precede overt chondrogenesis as detected by Alcian blue staining. This corresponds to the onset of the cytodifferentiation phase of limb development. As the accumulation of acidic proteoglycan increases in the cartilage matrix and the mesenchymal cells become more round in appearance, the presence of detectable fibronectin decreases and is ultimately seen only in the perichondria and basement membrane. However, predigestion of developed cartilage tissue with testicular hyaluronidase, prior to fibronectin staining, indicated that fibronectin remains a major constituent of cartilage matrix and is apparently masked by cartilage-specific proteoglycans. This study of chick limb development is consistent with the hypothesis that fibronectin may be a molecule that facilitates the spatial organization of cartilaginous primordia cytodifferentiation.
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PMID:Spatiotemporal patterns of fibronectin distribution during embryonic development. I. Chick limbs. 703 Nov 64

It has recently been demonstrated with the chick limb in ovo that successive nonrandom patterns of fluorescent staining with specific antibodies to fibronectin indicate the cartilagenous primordia prior to overt chondrogenesis. Given the apparent nonequivalence of embryonic cartilages, the purpose of this study was to determine whether this phenomenon was unique to developing chick limbs or is a more general characteristic of chondrogenesis. The appearance and distribution of fibronectin during chick first and second branchial arch development in ovo was investigated by indirect immunofluorescence techniques in H.H. stages 15-26. Fibronectin can be detected in early stages in areas presumed to be composed mainly of ectomesenchyme. During later stages of development, successive nonrandom patterns of fibronectin distribution appear to precede overt chondrogenesis as demonstrated by alcian blue staining. Pretreatment of cartilage with testicular hyaluronidase, prior to fibronectin staining, revealed that fibronectin was still present, suggesting that it was masked by proteoglycans. Fibronectin was also detected in the developing membrane bones of the mandible. The nonrandom patterning of fibronectin distribution in ovo in chick branchial arches and limb buds, respectively derived from neural crest and somatic mesoderm, were similar. It appears that specific patterns of fibronectin distribution were characteristic of chondrogenesis, regardless of the embryonic origin of the cartilage. This phenomenon may prove to be an extremely useful probe for early developmental skeletal abnormalities.
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PMID:Spatiotemporal patterns of fibronectin distribution during embryonic development. II. Chick branchial arches. 704 Apr 41

Fibronectin has been localized by indirect immunofluorescence during the various phases of endochondral bone formation in response to subcutaneously implanted demineralized bone matrix. Its histologic appearance has been correlated with results of biosynthetic experiments. (a) The implanted collagenous bone matrix was coated with fibronectin before and during mesenchymal cell proliferation. (b) During proliferation of mesenchymal precursor cells, the newly synthesized extracellular matrix exhibited a fibrillar network of fibronectin. (c) During cartilage differentiation, the fibronectin in the extracellular matrix was apparently masked by proteoglycans, as judged by hyaluronidase treatment. (d) Differentiating chondrocytes exhibited a uniform distribution of fibronectin. (e) Fibronectin was present in a cottony array around osteoblasts during osteogenesis. (f) The developing hematopoietic colonies revealed fibronectin associated with them. Therefore, it appears that fibronectin is ubiquitous throughout the development of endochondral bone and bone marrow.
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PMID:Appearance of fibronectin during the differentiation of cartilage, bone, and bone marrow. 721 7

Rabbit intestinal epithelial cells, obtained after a limited hyaluronidase digestion, were incubated in medium with or without calf serum, on bacteriological plastic dishes. The dishes, either plain or coated with an air-dried type I collagen film, were pretreated with medium alone or eith medium containing purified laminin or purified fibronectin. Cells did not attach in significant numbers to untreated bacteriological plastic, even in the presence of serum. Cells did attach to collagen-coated dishes, and were judged viable on the basis of their incorporation of radiolabeled leucine into cell protein. Cell adhesion to the collagen substrate increased in proportion to the concentration of serum in the medium, with maximal attachment of 5% serum or greater. Pretreatment of plain or collagen-coated dishes with increasing amounts of fibronectin enhanced cell adhesion in a concentration-dependent manner. Either serum, or fibronectin-free serum in the medium enhanced cell attachment to substrates pretreated with either fibronectin or laminin. Thus, intestinal epithelial cells appear to possess surface receptors for both laminin and fibronectin. The evidence further suggests that calf serum may contain factors, other than fibronectin, capable of enhancing intestinal epithelial cell attachment to collagen substrates.
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PMID:Effect of serum, fibronectin, and laminin on adhesion of rabbit intestinal epithelial cells in culture. 731 Sep 2

Vascular endothelial cell (EC) wound healing was characterized on an EC-synthesized extracellular matrix (ECM) previously treated with enzymes and antibodies specific for ECM components. Using a computer-assisted video-microscope recording system capable of automatic EC recognition, we learned whether components of the EC-synthesized matrix influenced post-injury migration and wound healing in vitro. Localization of actin and its encoded mRNA using isoform-specific antibodies and labeled cDNA probes allowed for a direct correlation of living-cell behavior with cytoskeletal form and distribution. Results of these studies indicate that the computer-assisted EC tracking system allows for an automatic and reproducible analysis of EC behavior following injury in vitro. EC migrate fastest immediately following injury and then achieve a new, slower migration rate that is maintained until EC from one edge of 200- to 300-microns-wide wound zone contact EC from the other wound face. Treatment of EC-synthesized matrices with antibodies against fibronectin and laminin has no effect on EC migration following injury (-0.25 microns/min) or on cytoskeletal array. Similarly, digestion of these matrices with heparinase and hyaluronidase has no effect on wound healing rates. Slowly spreading EC cytoplasm, which borders the intact and antibody-treated EC matrices, is rich in actin but lacks myosin II. Two different preparations of collagenase (bacterial and mammalian) each potentiate EC wound healing in vitro. Bacterial collagenase treatment of the EC-synthesized matrices potentiates EC migration fivefold (1 micron/min) while treatment of EC-matrices with mammalian cell collagenase stimulates EC migration following injury some twofold (0.4 micron/min) over control values. Whereas EC on control matrices migrate in unison as a tissue-like sheet, EC on the collagenase-treated EC matrices migrate as individuals. Concomitant with the increased rates of migration following injury on the collagenase-treated EC-matrices is a two- to fourfold increase in the steady-state levels of beta-actin mRNA. This increase in actin mRNA abundance is observable by its preferential localization (seen by in situ hybridization) in the lamellae bordering the wound edge in association with beta-actin, which is exclusively localized there. Because beta-actin and its encoded mRNA are positioned together in association with the plasma membrane in regions of moving cytoplasm, it seems likely that beta-actin filament assembly is required for motility following endothelial injury.
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PMID:Molecular mechanisms regulating the vascular endothelial cell motile response to injury. 752 70


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