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)

Proteoglycans (PGs) have been suggested to work as receptors in lipoprotein uptake mechanisms. An interaction between apolipoprotein E (apoE) and glucosaminoglycans (GAG), polysaccharides linked to proteoglycans, has been proposed in this pathway. At the same time, proteoglycans, apoE as well as lipoprotein receptors have been reported to be constituents of amyloid plaques, one hallmark of Alzheimer's disease. With this study, we are the first to investigate the interaction between beta very low density lipoprotein (beta-VLDL) and a neuronal highly abundant GAG, chondroitin sulphate (CS), comparing hippocampal neurons, expressing high levels of low density lipoprotein receptor related protein (LRP) and U373 astrocytoma cells, highly positive for the low density lipoprotein receptor (LDLR). We were able demonstrate that degradation of chondroitin sulphate proteoglycans (CSPGs) with chondroitinase ABC resulted in reduced (125)I-beta-VLDL uptake. We showed that externally added CSs compete with internalization of beta-VLDL. The effect was found to be dose-dependent, but was influenced neither by cell type, nor receptor type. The position of sulphation of added CSs showed only a slight influence. The data generated suggested an interaction between apolipoproteins and soluble CSs; therefore, 3H-cholesterol linked to apoE was coadministered with CSs to the cells. The results revealed that apoE bound, but no unbound cholesterol, was reduced in cellular internalization, suggesting that CSPGs may be involved in lipoprotein uptake in the intact brain, mediated, at least in part, by apoE.
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PMID:Role of chondroitin sulphate in the uptake of beta-VLDL by brain cells. 1619 Aug 94

Chondroitin sulfate proteoglycans (CSPGs) are up-regulated following spinal cord injury and are partly responsible for failed regeneration. Experimental paradigms in vivo that degrade chondroitin sulfate glycosaminoglycan chains with the bacterial enzyme, chondroitinase, greatly enhance the ability of axons to regenerate through the glial scar. Unfortunately, enthusiasm for this treatment paradigm is diminished by the lack of a minimally invasive and sustained delivery method. To address these deficits, we have engineered a Tet-On adenoviral vector encoding chondroitinase AC and have characterized its enzymatic function in vitro. U373 human astrocytoma cells were transduced with adenovirus and subsequently induced with doxycycline to secrete enzymatically active chondroitinase as detected by western blot and kinetic analyses. Enzymatic activity demonstrated biological relevance in studies where neurite outgrowth into and across CSPG-adsorbed regions pre-treated with conditioned media from chondroitinase secreting astrocytes was significantly increased compared with untreated controls (p < 0.0001). We also measured important parameters of enzyme activity including: pH, temperature, and enzyme stability that are fundamental to harnessing the true therapeutic potential of this approach. The use of resident cells for continuous secretion of CSPG-degrading enzymes at the site of the glial scar promises to be of greater clinical relevance than contemporary methods.
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PMID:Mammalian-produced chondroitinase AC mitigates axon inhibition by chondroitin sulfate proteoglycans. 1739 47