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:3.1.6.4 (chondroitinase)
2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lymphocyte-high endothelial venule (HEV) cell interaction is an essential element of the immune system, as it controls lymphocyte recirculation between blood and lymphoid organs in the body. This interaction involves an 85-95-kD class of lymphocyte surface glycoprotein(s), CD44. A subset of lymphocyte CD44 molecules is modified by covalent linkage to chondroitin sulfate (Jalkanen, S., M. Jalkanen, R. Bargatze, M. Tammi, and E. C. Butcher. 1988. J. Immunol. 141:1615-1623). In this work, we show that removal of chondroitin sulfate by chondroitinase treatment of lymphocytes or incubation of HEV with chondroitin sulfate does not significantly inhibit lymphocyte binding to HEV, suggesting that chondroitin sulfate is not involved in endothelial cell recognition of lymphocytes. Affinity-purified CD44 antigen was, on the other hand, observed to bind native Type I collagen fibrils, laminin, and fibronectin, but not gelatin. Binding to fibronectin was studied more closely, and it was found to be mediated through the chondroitin sulfate-containing form of the molecule. The binding site on fibronectin was the COOH-terminal heparin binding domain, because (a) the COOH-terminal heparin-binding fragment of fibronectin-bound isolated CD44 antigen; (b) chondroitin sulfate inhibited this binding; and (c) finally, the ectodomain of another cell surface proteoglycan, syndecan, which is known to bind the COOH-terminal heparin binding domain of fibronectin (Saunders, S., and M. Bernfield. 1988. J. Cell Biol. 106: 423-430), inhibited binding of CD44 both to intact fibronectin and to its heparin binding domain. Moreover, inhibition studies showed that binding of a lymphoblastoid cell line, KCA, to heparin binding peptides from COOH-terminal heparin binding fragment of fibronectin was mediated via CD44. These findings suggest that recirculating lymphocytes use the CD44 class of molecules not only for binding to HEV at the site of lymphocyte entry to lymphoid organs as reported earlier but also within the lymphatic tissue where CD44, especially the subset modified by chondroitin sulfate, is used for interaction with extracellular matrix molecules such as fibronectin.
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PMID:Lymphocyte CD44 binds the COOH-terminal heparin-binding domain of fibronectin. 173 Jul 78

We have demonstrated previously that the neural cell adhesion molecule (NCAM) interacts with a neuronal heparan sulfate proteoglycan. The binding of this proteoglycan(s) by NCAM appears to be required for NCAM-mediated cell adhesion, although the mechanism is unclear. In the present study we show that a heparan sulfate proteoglycan copurifies with NCAM, and provide an initial biochemical characterization of the proteoglycan. The copurification of a heparan sulfate proteoglycan with NCAM was demonstrated following immunopurification of NCAM from a detergent extract of cell membranes derived from Na2(35)SO4-labeled neural retinal cells. A large-molecular-weight, 35SO4-labeled molecule copurified with NCAM isolated from these neural cell cultures, and was resistant to chondroitinase ABC treatment, but degraded completely by nitrous acid treatment. These results indicate that the molecule is a heparan sulfate proteoglycan. Although this proteoglycan copurifies with NCAM, it is not detected when the neuron-glia cell adhesion molecule (NgCAM) is immunopurified using the 8D9 monoclonal antibody. The heparan sulfate proteoglycan may also be a membrane-associated proteoglycan since it interacts with phenyl-Sepharose. Molecular weight characterization of the proteoglycan by gel filtration chromatography indicates a molecular weight of 400-520 kDa. The heparan sulfate glycosaminoglycan chains were shown to have an average molecular weight of approximately 40 kDa, and the polypeptide backbone was estimated to be 120 kDa by polyacrylamide gel electrophoresis. These data therefore demonstrate that a neuronal heparan sulfate proteoglycan copurifies with NCAM.
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PMID:Characterization of a heparan sulfate proteoglycan that copurifies with the neural cell adhesion molecule. 252 15

Ng-CAM and N-CAM are cell adhesion molecules (CAMs), and each CAM can bind homophilically as demonstrated by the ability of CAM-coated beads (Covaspheres) to self-aggregate. We have found that the extent of aggregation of Covaspheres coated with either Ng-CAM or N-CAM was strongly inhibited by the intact 1D1 and 3F8 chondroitin sulfate proteoglycans of rat brain, and by the core glycoproteins resulting from chondroitinase treatment of the proteoglycans. Much higher concentrations of rat chondrosarcoma chondroitin sulfate proteoglycan (aggrecan) core proteins had no significant effect in these assays. The 1D1 and 3F8 proteoglycans also inhibited binding of neurons to Ng-CAM when mixtures of these proteins were adsorbed to polystyrene dishes. Direct binding of neurons to the proteoglycan core glycoproteins from brain but not from chondrosarcoma was demonstrated using an assay in which cell-substrate contact was initiated by centrifugation, and neuronal binding to the 1D1 proteoglycans was specifically inhibited by the 1D1 monoclonal antibody. Different forms of the 1D1 proteoglycan have been identified in developing and adult brain. The early postnatal form (neurocan) was found to bind neurons more effectively than the adult proteoglycan, which represents the C-terminal half of the larger neurocan core protein. Our results therefore indicate that certain brain proteoglycans can bind to neurons, and that Ng-CAM and N-CAM may be heterophilic ligands for neurocan and the 3F8 proteoglycan. The ability of these brain proteoglycans to inhibit adhesion of cells to CAMs may be one mechanism to modulate cell adhesion and migration in the nervous system.
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PMID:Functional characterization of chondroitin sulfate proteoglycans of brain: interactions with neurons and neural cell adhesion molecules. 842 2

We have previously suggested that sulfated polysaccharides could be used in a vaginal formulation to inhibit infection by human immunodeficiency virus (HIV-1). This supposition was based on studies in which we developed and employed an in vitro model to simulate the mechanism of HIV-1 transmission during coitus. We found that adhesion of mononuclear cells to epithelia was the initial step in infection and speculated that blocking adhesion would prevent HIV-1 transmission. We observed that certain sulfated polysaccharides prevented adhesion of lymphoma cell lines to epithelial cell lines, which were derived from the genital tract, in concentrations of a few milligrams per milliliter; and we theorized that sulfated polysaccharides could thus be used as active ingredients in a topical "microbicide." In the present in vitro study, evidence is presented that a number of sulfated polysaccharides, including carrageenan, dextran sulfate, heparin, fucoidan, and pentosan polysulfate, are capable of blocking infection by mechanisms other than adhesion at concentrations of a thousand times lower than the dosages that are needed to block cell adhesion. One of these compounds, iota carrageenan, is capable not only of blocking infection of epithelia at concentrations of 1-2 micrograms, but of blocking adhesion to a far greater extent than the other sulfated polysaccharides tested. For this reason, as well as for considerations of safety, stability, and gelling properties, we suggest that iota carrageenan may be the best choice of the sulfated polysaccharides tested for use as a vaginal microbicide. The same in vitro model was employed to decipher the cell surface molecules involved in lymphocyte-to-epithelial adhesion. To accomplish this, we screened for the presence of cell adhesion molecules (CAMs), carbohydrates, proteoglycans, and carbohydrate-binding sites. HIV-1-infected lymphocytic cells expressed a CAM profile typical of activated, infected cells (e.g., HLA-DR+, CD4-, LFA-1+, ICAM-1+, LFA-3+, CD2+) whereas epithelia expressed few CAMs (LFA-3, ICAM-1, VLA-5, CD44, CD26, sLEX). Both cell types expressed heparan sulfate and chondroitin sulfate proteoglycans. A variety of sugars (mannose, fucose, galactose, Nac-galactosamine, Nac-glucosamine) were also present, but these cells expressed few carbohydrate-binding sites; lymphocytes bound beta-galactose. We were unable to block the adhesion with anti-CAM antibodies or with exogenous sugars. When enzymes were used against sulfated cell surface molecules, chondroitinase was found to block the adhesion. Our evidence suggests that this CAM-independent adhesion may be a lectin-glycosaminoglycan interaction.
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PMID:Sulfated polysaccharides inhibit lymphocyte-to-epithelial transmission of human immunodeficiency virus-1. 883 15

We used flow cytometry to characterize cell adhesion molecule expression of the human haemopoietic cell lines KG1a, K562, HL-60, NALM-6 and CEM. A 51chromium labelling assay was used to study the adhesion of these cell lines to extracellular matrix components and to bone marrow stromal and endothelial cultures. Both adhesion molecule expression and functional binding behaviour varied between cell lines. All five cell lines expressed the integrins alpha4beta1 and alpha5beta1 and all adhered to fibronectin. However, differences in intensity of expression of these integrins failed to correlate with extent of fibronectin adhesion. Inhibition experiments demonstrated that adhesion of KG1a to fibronectin was completely inhibited by divalent cation chelation and partially inhibited by RGDS peptides and chondroitinase ABC, suggesting that both alpha4beta1 and alpha5beta1 as well as CD44 were responsible for this interaction. Adhesion to bone marrow stromal and endothelial layers was superior to that to purified extracellular matrix components and was partially inhibited by divalent cation chelation. RGD peptides and anti-alpha4 monoclonal antibody also partially inhibited KG1a adhesion to bone marrow endothelium. Discordance between cell adhesion molecule expression and adhesive behaviour suggest that current phenotypic descriptions remain incomplete and reinforce the need for complementary functional binding studies.
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PMID:Comparative adhesion of human haemopoietic cell lines to extracellular matrix components, bone marrow stromal and endothelial cultures. 945 Jul 99

Correlations have been noted between the expression of certain alternatively spliced CD44 isoforms and the metastatic propensity of various histologically distinct tumor cell types. The precise mechanism by which particular CD44 isoforms contribute to the metastatic process is, however, unclear. In the present study we demonstrate that CD44R2, a CD44 isoform highly expressed on activated and transformed hemopoietic cells, can recognize and bind a common determinant present on CD44H and CD44R1. Importantly, CD44H lacked this activity. Pretreatment of TIL1 cells expressing CD44H or CD44R1 with chondroitinase ABC inhibited adhesion to CD44R2, suggesting that the unique inserted region present within the CD44R2 molecule, encoded by exon v10, mediates cell adhesion by potentiating the recognition of chondroitin sulfate moieties presented in association with other CD44 molecules. These data help explain the differential involvement of v10-containing CD44 isoforms in tumor metastasis.
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PMID:Alternatively spliced CD44 isoforms containing exon v10 promote cellular adhesion through the recognition of chondroitin sulfate-modified CD44. 1009 37

CD44 is a widely expressed cell adhesion molecule that binds hyaluronan, an extracellular matrix glycosaminoglycan, in a tightly regulated manner. This regulated interaction has been implicated in inflammation and tumor metastasis. CD44 exists in the standard form, CD44H, or as higher molecular mass isoforms due to alternative splicing. Here, we identify serine 180 in human CD44H as the site of chondroitin sulfate addition and show that lack of chondroitin sulfate addition at this site enhances hyaluronan binding by CD44. A CD44H-immunoglobulin fusion protein expressed in HEK293 cells, and CD44H expressed in murine L fibroblast cells were modified by chondroitin sulfate, as determined by reduced sulfate incorporation after chondroitinase ABC treatment. Mutation of serine 180 or glycine 181 in CD44H reduced chondroitin sulfate addition and increased hyaluronan binding, indicating that serine 180 is the site for chondroitin sulfate addition in CD44H and that this negatively regulates hyaluronan binding.
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PMID:Chondroitin sulfate addition to CD44H negatively regulates hyaluronan binding. 1600 44

Dermatopontin, an extracellular matrix component initially purified from bovine dermis, promoted cell adhesion of the human epidermal keratinocyte cell line (HaCaT cells). HaCaT cells spread on dermatopontin and formed actin fibers. Adhesion of HaCaT cells to dermatopontin was inhibited by both EDTA and heparin and was mediated in part by alpha3beta1 integrin. A synthetic peptide (DP-4, PHGQVVVAVRS; bovine dermatopontin residues 33-43) specifically inhibited adhesion of cells to dermatopontin, and when the DP-4 peptide was coated on the well, it promoted cell adhesion in a dose-dependent manner. An active core sequence of the DP-4 peptide was localized to an eight-amino acid sequence (GQVVVAVR). These results indicate that dermatopontin is a novel epidermal cell adhesion molecule and suggest that the DP-4 sequence is critical for the cell adhesive activity of dermatopontin. Adhesion of cells to DP-4 was strongly inhibited by heparin. When HaCaT cells were treated with heparitinase I, the cells failed to adhere to DP-4 but chondroitinase ABC treatment did not influence the adhesion activity. DP-4 specifically interacted with biotinylated heparin, and this interaction was inhibited by unlabeled heparin. DP-4 peptide significantly promoted the adhesion of cells overexpressing syndecans, and syndecan bound to a DP-4 peptide affinity column. These results suggest that HaCaT cells adhere to dermatopontin through alpha3beta1 integrin and a heparan sulfate proteoglycan-type receptor, which is likely a syndecan. We conclude that dermatopontin plays a role as a multifunctional adhesion molecule for epidermal cells.
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PMID:Dermatopontin promotes epidermal keratinocyte adhesion via alpha3beta1 integrin and a proteoglycan receptor. 1992 97

The present study was designed to investigate whether chondroitin sulfate (CS)-E, a CS structural isomer variant, alter the differentiation of macrophage cell line RAW264 cells to osteoclast-like cells. CS-B, CS-E, low molecular weight CS-E, synthetic chondroitin polysulfate (CPS) and heparin significantly inhibited the formation of tartrate-resistant acid phosphatase-positive multinuclear cells and pit formation on calcium phosphate (CaP)-coated plates. CS-E pre-coated on the CaP plate also inhibited pit formation. Digestion of CS on the cell surface by chondroitinase showed no effect on the osteoclastic differentiation of RAW264 cells whereas inhibitory effect on the differentiation of osteoblastic cell line MC3T3-E1. On the other hand, exogenously added fluorescein-labeled CS-E directory bound to fibronectin and RAW264 cells. These results suggest that CS-E structure on the surface of osteoblasts or bone matrix binds to cell adhesion molecule such as integrin on the pre-osteoclastic cells and inhibits the differentiation into osteoclasts. CS-E may have a potential in treating bone defect if combined with CaP materials.
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PMID:Effect of chondroitin sulfate-E on the osteoclastic differentiation of RAW264 cells. 2061 Aug 74

Extracellular matrix (ECM) molecules, their receptors at the cell surface, and cell adhesion molecules (CAMs) involved in cell-cell or cell-ECM interactions are implicated in processes related to major diseases of the central nervous system including Alzheimer's disease (AD), epilepsy, schizophrenia, addiction, multiple sclerosis, Parkinson's disease, and cancer. There are multiple strategies for targeting the ECM molecules and their metabolizing enzymes and receptors with antibodies, peptides, glycosaminoglycans, and other natural and synthetic compounds. ECM-targeting treatments include chondroitinase ABC, heparin/heparan sulfate-mimicking oligosaccharides, ECM cross-linking antibodies, and drugs stimulating expression of ECM molecules. The amount or activity of ECM-degrading enzymes like matrix metalloproteinases can be modulated indirectly via the regulation of endogenous inhibitors like TIMPs and RECK or at the transcriptional and translational levels using, e.g., histone deacetylase inhibitors, synthetic inhibitors like Periostat, microRNA-interfering drugs like AC1MMYR2, and natural compounds like flavonoids, epigallocatechin-3-gallate, anacardic acid, and erythropoietin. Among drugs targeting the major ECM receptors, integrins, are the anticancer peptide cilengitide and anti-integrin antibodies, which have a potential for treatment of stroke, multiple sclerosis, and AD. The latter can be also potentially treated with modulators of CAMs, such as peptide mimetics derived from L1-CAM and NCAM1.
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PMID:Targeting of ECM molecules and their metabolizing enzymes and receptors for the treatment of CNS diseases. 2541 Mar 65


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