Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study characterizes the core proteins of chondroitin sulfate-type glycosaminoglycans located in the interphotoreceptor matrix and establishes the tissue distribution of chondroitin immunoreactivity in human, bovine, mouse and rat retinas. Monoclonal antibodies specific to unsulfated (DeltaDiOS), 4-sulfated (DeltaDi4S) and 6-sulfated (DeltaDi6S) chondroitin were employed. Retinal sections and IPM samples were either (a) digested with chondroitinase ABC to expose antibody specific epitopes, (b) double digested with chondroitinase ABC and chondroitinase AC II to remove specific epitopes, or (c) left undigested to evaluate mimotope labeling. In tissue sections from each species studied, positive immunoreactivity to the DeltaDi6S antibody was present in the IPM surrounding both rods and cones. In human and bovine, DeltaDi6S labeling of the cone matrix compartments was more intense than labeling of the matrix surrounding rods. Intense DeltaDi6S immunoreactivity was present surrounding the foveal cones. In mouse and rat, no differences in labeling intensity of IPM surrounding rod and cone photoreceptors were evident, although labeling of the IPM near the apical surface of the retinal pigment epithelium and around the photoreceptor inner segments was more pronounced than that surrounding the outer segments. All DeltaDi6S antibody labeling was eliminated with chondroitinase AC II digestion. No IPM immunoreactivity in tissue sections was observed when the DeltaDi0S or DeltaDi4S antibodies were used. In Western blots of IPM extracts treated with chondroitinase ABC, prominent DeltaDi6S immunoreactive bands were present at approximately 230 kD and 150 kD in each species studied, with the exception of the human, where the 150 kD component is not a chondroitin proteoglycan. Each of the prominent DeltaDi6S immunoreactive bands showed minor immunoreactivity to the DeltaDi4S antibody. No DeltaDi0S immunoreactivity was noted in Western blots of IPM samples from any species. All immunoreactivity was lost following chondroitinase AC II digestion. These observations document similarities in the electrophoretic mobility of IPM proteoglycan core proteins released following chondroitinase ABC digestion in the four species studied, but reveal pronounced differences in the tissue distribution. Bovine and human IPM show greater concentrations of DeltaDi6S immunoreactivity surrounding cones than rods, whereas rodent tissues show higher concentrations near the retinal pigment epithelium and around the photoreceptor inner segments than around the outer segments. The pattern of distribution of these proteoglycan molecules is highly conserved in these species, suggesting a common role in IPM structure and function.
Exp Eye Res 1999 Sep
PMID:Chondroitin sulfate proteoglycan core proteins in the interphotoreceptor matrix: a comparative study using biochemical and immunohistochemical analysis. 1047 39

We describe a Czech patient with combined adenine phosphoribosyltransferase (APRT) deficiency (2,8-dihydroxyadenine urolithiasis) and N-acetylgalactosamine-6-sulfate sulfatase (GALNS) deficiency (mucopolysaccharidosis Type IVA, Morquio disease A). Adenine and its extremely insoluble derivative, 2,8-dihydroxyadenine, were identified in the urine, and APRT deficiency was confirmed in erythrocytes. There was excessive excretion of keratan sulfate in the urine, and GALNS deficiency was confirmed in leukocytes. GALNS and APRT are both located on chromosome 16q24.3, suggesting that the patient had a deletion involving both genes. PCR amplification of genomic DNA indicated that a novel junction was created by the fusion of sequences distal to GALNS exon 2 and proximal to APRT exon 3, and that the size of the deleted region was approximately 100 kb. The deletion breakpoints were localized within GALNS intron 2 and APRT intron 2. Several other genes, including the alpha subunit of cytochrome B (CYBA), which is deleted or mutated in the autosomal form of chronic granulomatous disease, are located in the 16q24.3 region, but PCR amplification showed that this gene was present in the proband. A patient with hemizygosity for GALNS deficiency and APRT deficiency has been reported from Japan recently. These findings indicate that: (i) APRT is located telomeric to GALNS; (ii) GALNS and APRT are transcribed in the same orientation (centromeric to telomeric); and (iii) combined APRT/GALNS deficiency may be more common than hitherto realized.
Mol Genet Metab 1999 Sep
PMID:Combined adenine phosphoribosyltransferase and N-acetylgalactosamine-6-sulfate sulfatase deficiency. 1047 85

A biotinylated complex of aggrecan G1-domain and link protein was used to characterize the distribution of hyaluronan in paraffin-embedded sections of adult human and canine intervertebral disc and cartilage endplate. Limited chondroitinase ABC and trypsin digestions of the sections before staining was utilized to expose hyaluronan potentially masked by aggrecan. Hyaluronan concentration and hyaluronan to uronic acid ratio in different parts of the discs were measured as a background for the histological analysis. Hyaluronan staining was strong in the nucleus pulposus and inner parts of annulus fibrosus of both species, corroborated by biochemical assays of the same compartments. Particularly in human samples, hyaluronan in the interterritorial matrix of nucleus pulposus and annulus fibrosus was readily accessible to the probe without enzyme treatments. In contrast, the cell-associated hyaluronan signal was enhanced after trypsin or limited chondroitinase ABC-treatment of the sections, suggesting that pericellular hyaluronan was more masked by aggrecan than in the distant matrix. A puzzling feature of canine cartilage endplate cells was their intensive cell-associated hyaluronan signal, part of which appeared intracellular. Hyaluronan was abundant between the collagenous lamellae in annulus fibrosus, perhaps important in the plasticity of this tissue.
Histochem J 1999 Sep
PMID:Hyaluronan distribution in the human and canine intervertebral disc and cartilage endplate. 1057 27

Neurocan is one of the major chondroitin sulfate proteoglycans of perinatal rodent brain. HEK-293 cells producing neurocan recombinantly show changes in their behavior. The expression of full-length neurocan led to a detachment of the secreting cells and the formation of floating spheroids. This occurred in the continuous presence of 10% fetal bovine serum in the culture medium. Cells secreting fragments of neurocan-containing chondroitin sulfate chains and the C-terminal domain of the molecule showed a similar behavior, whereas cells expressing fragments of neurocan-containing chondroitin sulfate chains but lacking parts of the C-terminal domain did not show spheroid formation. Cells secreting the hyaluronan-binding N-terminal domain of neurocan showed an enhanced adhesiveness. When untransfected HEK-293 cells were plated on a surface conditioned by spheroid-forming cells, they also formed spheroids. This effect could be abolished by chondroitinase treatment of the conditioned surface. The observations indicate that the ability of the chondroitin sulfate proteoglycan neurocan to modulate the adhesive character of extracellular matrices is dependent on the structural integrity of the C-terminal domain of the core protein.
Exp Cell Res 2000 Sep 15
PMID:Modulation of extracellular matrix adhesiveness by neurocan and identification of its molecular basis. 1096 5

Antithrombin inhibits chemokine-induced migration of neutrophils by activating heparan sulfate proteoglycan-dependent signaling. Mechanisms of antithrombin's effects on neutrophils were, therefore, studied by testing function and expression of heparan sulfate proteoglycans in RT-PCR or flow cytometry and cell migration assays, respectively. In vitro effects of antithrombin on human neutrophil migration in modified Boyden chambers were abolished by pretreating cells with heparinase-1, chondroitinase, sodium chlorate, and anti-syndecan-4 antibodies. Expression of syndecan-4 mRNA and protein in neutrophils was demonstrated in RT-PCR and anti-syndecan-4 immunoreactivity assay, respectively. In the presence of pentasaccharide, antithrombin lost its activity on the cells. Data suggest that antithrombin regulates neutrophil migration via effects of its heparin-binding site on cell surface syndecan-4.
Biochem Biophys Res Commun 2001 Sep 14
PMID:Syndecan-4 as antithrombin receptor of human neutrophils. 1154 50

The uppermost superficial surface layer of articular cartilage, the 'lamina splendens' which provides a very low friction lubrication surface in articular joints, was investigated using atomic force microscopy (AFM). Complementary specimens were also observed under SEM at -10 degrees C without dehydration or sputter ion coating. Fresh adult pig osteochondral specimens were prepared from the patellas of pig knee joints and digested with the enzymes, hyaluronidase, chondroitinase ABC and alkaline protease. Friction coefficients between a pyrex glass plate and the osteochondral specimens digested by enzymes as well as natural (undigested) specimens were measured, using a thrust collar apparatus. Normal saline, hyaluronic acid (HA) and a mixture of albumin, globulin, HA (AGH) were used as lubrication media. The surface irregularities usually observed in SEM studies were not apparent under AFM. The articular cartilage surface was resistant to hyaluronidase and also to chondroitinase ABC, but a fibrous structure was exhibited in alkaline protease enzymes-digested specimens. AFM analysis revealed that the thickness of the uppermost superficial surface layer of articular cartilage was between 800 nm and 2 microm in adult pig articular cartilage. The coefficient of friction (c.f.) was significantly higher in chondroitinase ABC and alkaline protease enzymes digested specimens. Generally, in normal saline lubrication medium, c.f. was higher in comparison to HA and AGH lubrication media. The role of the uppermost, superficial surface layer of articular cartilage in the lubrication mechanism of joints is discussed.
J Anat 2001 Sep
PMID:Role of uppermost superficial surface layer of articular cartilage in the lubrication mechanism of joints. 1155 3

Glycosaminoglycans (GAGs) are linear carbohydrate polymers containing repetitive sequences of differently sulfated uronic acid and glycosamine residues that are recognized by antibodies raised against proteoglycans. We have developed a method to demonstrate such repetitive sequence motifs in isolated GAG chains immobilized on hydrophobic membranes derivatized with cationic detergents. Six monoclonal antibodies directed against Cs (2B6, 3B3, Cs56, and 1B5), Hs (HepSS), and Ks (5D4) were used to detect native and chondroitinase-generated epitopes in the immobilized GAGs. All antibodies, except 1B5, were able to detect epitopes in both proteoglycans and isolated GAGs. Type of detergent and buffer composition affected the accessibility and the retention of immobilized GAGs. The epitope density, i.e., the number of repetitive epitopes per GAG mass, was estimated as the ratio between antibody (epitope) and Alcian blue (mass) staining measured simultaneously. The epitope profiles, using six antibodies, were different for each sample (CsA, CsC, Ds, Hs, intact cartilage, and human serum). The epitope profile may be used as a structural characteristic of a GAG population. Electrophoretic separation of GAGs based on their glucuronic/ioduronic acid content and O-sulfate/N-sulfate ratio was performed using a diethylene glycol-diaminobutanol agarose gel. The electrophoretic populations were characterized by immunoblotting to detergent-treated membranes.
Anal Biochem 2002 Sep 15
PMID:Quantitation of repetitive epitopes in glycosaminoglycans immobilized on hydrophobic membranes treated with cationic detergents. 1241 32

PTP zeta is a receptor-type protein-tyrosine phosphatase that is synthesized as a chondroitin sulfate proteoglycan and uses pleiotrophin as a ligand. The chondroitin sulfate portion of this receptor is essential for high affinity binding to pleiotrophin. Here, we purified phosphacan, which corresponds to the extracellular domain of PTP zeta, from postnatal day 7 (P7) and P12 rat cerebral cortex (PG-P7 and PG-P12, respectively) and from P20 rat whole brain (PG-P20). The chondroitin sulfate of these preparations displayed immunologically and compositionally different structures. In particular, only PG-P20 reacted with the monoclonal antibody MO-225, which recognizes chondroitin sulfate containing the GlcA(2S)beta 1-3GalNAc(6S) disaccharide unit (D unit). Analysis of the chondroitinase digestion products revealed that GlcA beta 1-3GalNAc(4S) disaccharide unit (A unit) was the major component in these preparations and that PG-P20 contained 1.3% D unit, which was not detected in PG-P7 and PG-P12. Interaction analysis using a surface plasmon resonance biosensor indicated that PG-P20 had approximately 5-fold stronger affinity for pleiotrophin (dissociation constant (KD) = 0.14 nM) than PG-P7 and PG-P12, although all these preparations showed similar low affinity binding to pleiotrophin after chondroitinase ABC digestion (KD = 1.4 approximately 1.6 nM). We also found that shark cartilage chondroitin sulfate D containing approximately 20% D unit bound to pleiotrophin with moderate affinity (KD = 2.7 nM), whereas whale cartilage chondroitin sulfate A showed no binding to this growth factor. These results suggest that variation of chondroitin sulfate plays important roles in the regulation of signal transduction in the brain.
J Biol Chem 2003 Sep 12
PMID:Heterogeneity of the chondroitin sulfate portion of phosphacan/6B4 proteoglycan regulates its binding affinity for pleiotrophin/heparin binding growth-associated molecule. 1284 14

Degradation of collagen network and proteoglycan (PG) macromolecules are signs of articular cartilage degeneration. These changes impair cartilage mechanical function. Effects of collagen degradation and PG depletion on the time-dependent mechanical behavior of cartilage are different. In this study, numerical analyses, which take the compression-tension nonlinearity of the tissue into account, were carried out using a fibril reinforced poroelastic finite element model. The study aimed at improving our understanding of the stress-relaxation behavior of normal and degenerated cartilage in unconfined compression. PG and collagen degradations were simulated by decreasing the Young's modulus of the drained porous (nonfibrillar) matrix and the fibril network, respectively. Numerical analyses were compared to results from experimental tests with chondroitinase ABC (PG depletion) or collagenase (collagen degradation) digested samples. Fibril reinforced poroelastic model predicted the experimental behavior of cartilage after chondroitinase ABC digestion by a major decrease of the drained porous matrix modulus (-64+/-28%) and a minor decrease of the fibril network modulus (-11+/-9%). After collagenase digestion, in contrast, the numerical analyses predicted the experimental behavior of cartilage by a major decrease of the fibril network modulus (-69+/-5%) and a decrease of the drained porous matrix modulus (-44+/-18%). The reduction of the drained porous matrix modulus after collagenase digestion was consistent with the microscopically observed secondary PG loss from the tissue. The present results indicate that the fibril reinforced poroelastic model is able to predict specifically characteristic alterations in the stress-relaxation behavior of cartilage after enzymatic modifications of the tissue. We conclude that the compression-tension nonlinearity of the tissue is needed to capture realistically the mechanical behavior of normal and degenerated articular cartilage.
J Biomech 2003 Sep
PMID:Fibril reinforced poroelastic model predicts specifically mechanical behavior of normal, proteoglycan depleted and collagen degraded articular cartilage. 1289 46

Fracture toughness of cartilage and cartilage replacement tissues is important in injury and disease. For example, cartilage is thought to weaken before it fibrillates in the disease osteoarthritis. Since both loading rate and proteoglycan content affect viscoelastic properties, they may both affect fracture toughness of cartilage and cartilage analogs. In this study, fracture toughness of tissue grown in chondrocyte culture was measured as a function of loading rate and proteoglycan digestion. Control tissue and tissue digested with chondroitinase ABC (cABC) to remove proteoglycans were tested at displacement rates of 0.1 and 0.5 mm/sec. Displacement rate had no effect on fracture toughness for either control or digested tissue. Proteoglycan digestion reduced tissue thickness by 30% and when evaluated on a material basis increased fracture toughness. There was no interaction between digestion and loading rate. When the fracture toughness was normalized to collagen content, which removed the effect of tissue shrinkage, there was no effect of proteoglycan digestion on fracture toughness. These data suggest that proteoglycans do not contribute to tissue toughness, other than by reducing thickness and increasing collagen density.
J Mater Sci Mater Med 2002 Sep
PMID:The effects of displacement rate and proteoglycan digestion on the fracture resistance of tissue grown from chondrocyte culture. 1534 45


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