title: Membrane-associated and secreted proteoglycans from a continuous cell line derived from fibrotic schistosomal granulomas.
abstract: Proteoglycans were isolated from a continuous murine cell line (GRX) established from fibrotic granulomas induced in mouse liver by schistosomal infection, representative of liver connective tissue cells. The proteoglycans were labelled with 35SO4, extracted by guanidine-HCl + Triton X-100 in the presence of proteinase inhibitors, and purified by anion-exchange, gel-filtration and affinity-column chromatography. The major fractions of cell-associated and secreted proteoglycans are heparan sulfate proteoglycans. Gel-filtration chromatography on Sephacryl S-400 revealed Kav values of 0.20 and 0.30 for the cell-associated and secreted heparan sulfate proteoglycans, respectively. About 50% of the cell-associated heparan sulfate proteoglycans contained hydrophobic regions, as evidenced by their ability to bind to octyl-Sepharose, while only about 20% of secreted proteoglycans bound to this resin. In addition, no proteoglycan was competitively displaced from the cell surface by heparin. Taken together with other reports on proteoglycan synthesis by a variety of cell types in culture, these observations suggest that cell-surface heparan sulfate proteoglycans possibly contain a hydrophobic domain that functions as a membrane anchor in their attachment to cells. Addition of beta-D-xyloside to the cultures greatly enhanced the release of 35S-dermatan sulfate to the medium. Interestingly, dermatan sulfate is the major glycosaminoglycan found in the schistosoma-induced granuloma, from which the GRX cell line is derived. These studies provide the first biochemical description of the proteoglycans produced by a liver connective tissue cell line derived from schistosomal granulomas.
authors.affiliation: Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: L C
authors.initials: LC
authors.lastname: Silva
authors.forename: R
authors.initials: R
authors.lastname: Borojevic
authors.forename: P A
authors.initials: PA
authors.lastname: Mourão
mesh_terms: D000818:Animals; D002460:Cell Line; D002853:Chromatography, Liquid; D005958:Glucosephosphates / Q000737:chemistry; D006025:Glycosaminoglycans / Q000378:metabolism; D006099:Granuloma / Q000150:complications / Q000378:metabolism*; D006493:Heparin / Q000737:chemistry; D008106:Liver Cirrhosis, Experimental / Q000209:etiology / Q000378:metabolism*; D051379:Mice; D011509:Proteoglycans / Q000302:isolation & purification / Q000378:metabolism*; D012552:Schistosomiasis / Q000150:complications / Q000378:metabolism*; D013464:Sulfuric Acids / Q000378:metabolism; D014357:Trypsin / Q000737:chemistry
chemical_list: D005958:Glucosephosphates; D006025:Glycosaminoglycans; D011509:Proteoglycans; D013464:Sulfuric Acids; D006493:Heparin; D014357:Trypsin; C033158:sulfuric acid