Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diabetes is accompanied by impaired platelet function and accelerated vascular disease. To find out whether a correlation exists between these two complications, and if modifications occurring in diabetic platelets influence their relationship with endothelium, we have studied the interaction between platelets isolated from plasma of diabetic patients and bovine valvular endothelial cells (VEC), in culture. For quantitative analysis, normal and diabetic [3H]-adenine-labeled platelets were incubated with confluent VEC grown in Dulbecco's modified Eagle medium, containing 4.5 g/l glucose, for 30 min at 37 degrees C. After extensive washing and solubilization of the monolayer, the calculated adhesion index showed a two-fold increased adherence of diabetic platelets to VEC as compared to normal platelets. Statistical analysis (by Pitman randomization test) indicated that the adhesion was significantly higher (p = 0.0003) than that of normal platelets to VEC. To partially identify the membrane components implicated in the adhesion process, either platelets or VEC were treated with neuraminidase, trypsin or heparinase prior to the adhesion assay. Trypsin or neuraminidase treatment of platelets significantly diminished their adherence to VEC, suggesting a role of platelets sialylated glycoproteins in the adhesion process. Neuraminidase or heparinase treatment of VEC increased the adhesion of both normal and diabetic platelets, indicating that the cell membrane sialyl residues and heparan sulfate participate in the normal thromboresistant properties of VEC. Transmission and scanning electron microscopy revealed a close apposition between platelets and VEC with the formation of an adhesion plaque, characterized by fine fibrillar bridges between the plasma membranes of the two cells.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Increased adhesion of human diabetic platelets to cultured valvular endothelial cells. 145 40

We have previously reported that exposing cultured Madin Darby canine kidney (MDCK) cells to the polycation protamine (PRO) results in increased short-circuit current and decreased barrier integrity as measured by mannitol permeability and transepithelial electrical resistance. To further investigate the interaction of PRO with the surface of epithelial cells, we labeled PRO with [14C] with use of reductive alkylation. [14C]PRO bound to the cells in a biphasic pattern. Approximately 10% of the [14C]PRO was bound to the cells in the first 5 min, followed by an additional 10% that was bound over the next 25 min. No additional [14C]PRO bound to the cells after the initial 30 min. Binding of [14C]PRO was inhibited by "cold" PRO, which suggested specificity. Binding was also inhibited by polyanions, serum, and albumin, agents previously found to protect MDCK cells from PRO-induced injury. The binding of PRO to MDCK cells was not inhibited by incubation of the MDCK cells with neuraminidase, to remove surface sialic acid residues, or with heparinase, to remove surface heparan sulfate, even though metabolic labeling experiments demonstrated that neuraminidase decreased cell sialic acid and heparinase decreased cell heparan sulfate. Neuraminidase and heparinase offered no protection from PRO injury and had no effect themselves on mannitol permeability. Incubation of the cells with trypsin, however, blunted both the binding of PRO to the cells and the increase in mannitol permeability after exposure of the cells to PRO.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Protamine interaction with the epithelial cell surface. 153 21

The effect of specific glycosaminoglycan-hydrolyzing enzymes on the ruthenium red staining of pig spermatozoa was studied. Washed spermatozoa were incubated at 35 degrees C in buffer or with neuraminidase 0.5 units/ml, heparinase 0.2 mg/ml, or chondroitinase ABC 2.0 units/ml. After incubation sperm cells were washed, stained with ruthenium red and studied under the electron microscope. Anionic sites in the surface of untreated spermatozoa follow regularly the plasma membrane, but present are numerous processes constituting what has been defined as the glycocalyx. Neuraminidase did not affect the distribution of ruthenium red on the surface of the spermatozoa, but eliminated almost completely the processes of the glycocalyx. Heparinase caused loss of the ruthenium red-stained sites on the membrane surface of pig spermatozoa with less influence on the dense processes of the glycocalyx. A similar loss of ruthenium red-stained sites was observed with nitrous acid treatment. A striking effect of treatment with chondroitinase ABC was the production of a typical acrosome reaction.
 ...
PMID:Glycosaminoglycan-sulfate as plasma membrane component of pig spermatozoa. 169 1

To gain insight into the cellular and molecular mechanisms underlying cell interactions in the early postnatal mouse cerebellum, Ca2+-dependent and -independent aggregation mechanisms were characterized using single cell suspensions under conditions that allow discrimination between the two mechanisms. When cerebellar cells were derived from newborn to 10-day-old mouse cerebellum, both mechanisms were active and showed no major change in activity during this time period. Mg2+ could not replace Ca2+ in the Ca2+-dependent mechanism. In contrast to the Ca2+-independent mechanisms, the Ca2+-dependent mechanism was inactive at low temperatures, suggesting a necessity for molecular rearrangement within the surface membrane during aggregation. Neuraminidase, chondroitinase, heparinase or hyaluronidase treatment of cells did not influence the aggregation of cells under Ca2+-dependent and -independent conditions. Chondroitin sulfate inhibited and hyaluronic acid stimulated the Ca2+-dependent mechanism, whereas chondroitin sulfate only slightly and hyaluronic acid strongly inhibited the Ca2+-independent one. Dextran sulfate slightly inhibited both mechanisms, whereas heparin and fucoidan, a complex sulfated carbohydrate, did not influence cell aggregation, while they strongly inhibited attachment of cells to laminin. The polycation poly-L-lysine slightly stimulated the Ca2+-independent mechanism, but inhibited the Ca2+-dependent one. Interestingly, chondroitin sulfate and hyaluronic acid strongly stimulated cell aggregation under conditions where both mechanisms were almost destroyed or inactive. Dextran sulfate showed only a small effect under these conditions. These observations indicate that different molecular mechanisms are active in cell-cell versus cell-extracellular matrix interactions and suggest a hitherto unknown complexity in molecular mechanisms during early postnatal cerebellar development.
 ...
PMID:Characterization of Ca2+-dependent and -independent aggregation mechanisms among mouse cerebellar cells. 246 13

The luminal surfaces of the endothelium lining the two surfaces of the aortic arterial (AAR) and ventricular (AVT), and mitral ventricular (MVT) and atrial (MAT), valve cusps were studied with cationic ferritin (CF) and ferritin (Fer)-conjugated lectins (WGA, RCA, SBA). The arterial (AAR) and ventricular (MVT) surfaces of the aortic and mitral cusps, which are exposed to more turbulent fluid mechanical forces and lower wall shear stresses, had the greatest density of CF labeling. The endothelia of the four surfaces displayed a gradient of decreasing density from the nuclear region to the periphery. Neuraminidase, chondroitinase ABC and AC, heparinase, heparitinase, hyaluronidase (testicular), and pronase E digestions suggested that a significant number of the anionic sites labeled by CF are associated with sialoglycoproteins and glycosaminoglycans such as chondroitin 4/6 sulfates, dermatan sulfates, and heparan sulfates. The localization of WGA receptors on the endothelium of AAR and MVT demonstrated a greater density of sialyl moieties than on the AVT and MAT. There was no binding of Fer-RCA with specificity for D-galactopyranosides or Fer-SBA with affinity for N-acetylglucosamine and D-galactose to the endothelium unless it was first treated with neuraminidase. Hence, sialic acids are shown to be among the more superficial components of this glycocalyx and to be largely responsible for the greater densities over the endothelium of AAR and MVT.
 ...
PMID:Anionic surface properties of aortic and mitral valve endothelium from New Zealand white rabbits. 384 Jun 42

The ultrastructural organization of ruthenium red (RR) stainable material within small blood vessels located in the limbus of the rabbit eye was studied. Proteoglycans were identified in this material by digesting tissues with Streptomyces hyaluronidase, testicular hyaluronidase, chondroitinase ABC, or heparinase before ruthenium red staining. Neuraminidase digestion enabled separate identification of sialoglycoprotein. The luminal surface of endothelial cells demonstrates an RR-stained glycocalyx containing both sialoglycoprotein and proteoglycans, which are removed by testicular hyaluronidase and crude heparinase. The basal coat of endothelial cells and small granules (10-20 nm in diameter) located within the basal lamina stain with RR and are removed only by crude heparinase. The surface coat of smooth muscle cells and small granules (10-20 nm) within their basal laminas are also digested by crude heparinase. Large proteoglycan granules (20-50 nm), which are completely removed by testicular hyaluronidase and partially digested by Streptomyces hyaluronidase, are deposited between the connective tissue fibers of the media and adventitia. Other large granules that are attached to collagen fibers contain enzyme-resistant anionic materials. The surface coat of adventitial fibroblasts is removed only by crude heparinase. Thin filaments (3-5 nm in diameter) interconnect the cell coat material, basal lamina granules, and large connective tissue granules, to form a network of proteoglycans that traverses the intima, media, and adventitia. The highly ordered arrangement of proteoglycans in the microvascular wall suggests that these macromolecules play several roles in microvascular function.
 ...
PMID:Proteoglycans in the microvasculature. I. Histochemical localization in microvessels of the rabbit eye. 616 46

To investigate the chemical nature of the cationic ferritin (CF)-binding sites of the differentiated microdomains of the capillary endothelium, the vasculature of the mouse pancreas and intestinal mucosa was perfused in situ with neuraminidase, hyaluronidase, chondroitinase ABC, heparinase, and three proteases: trypsin, papain, and pronase. Proteases of broad specificity removed all anionic sites, suggesting that the latter are contributed by acid glycoproteins or proteoglycans. Neuraminidase, hyaluronidase, and chondroitinase ABC reduced the density of CF-binding sites on the plasmalemma proper, but had no effect on either coated pits or fenestral diaphragms. Heparinase removed CF-binding sites from fenestral diaphragms and had no effect on coated pits. Taken together, these results indicate that the anionic sites of the fenestral diaphragms are contributed primarily by heparan sulfate and/or heparin, whereas those of the plasmalemma proper are of mixed chemical nature. The membranes and diaphragms of plasmalemmal vesicles and transendothelial channels do not bind CF in control specimens; this condition is not affected by the enzymic treatments mentioned above.
 ...
PMID:Differentiated microdomains on the luminal surface of the capillary endothelium. II. Partial characterization of their anionic sites. 645 53