scholarly journals Characterization of proteoglycans synthesized by human adult glomerular mesangial cells in culture

1991 ◽  
Vol 277 (1) ◽  
pp. 81-88 ◽  
Author(s):  
G J Thomas ◽  
R M Mason ◽  
M Davies

1. The newly synthesized proteoglycans from human adult glomerular mesangial cells labelled in vitro for 24 h with [35S]sulphate have been characterized using biochemical and immunological techniques. 2. The following proteoglycans were identified (% of total synthesized). (i) A large chondroitin sulphate proteoglycan, CSPG-I, Mr approximately 1 x 10(6) (10.6%). This proteoglycan consisted of a protein core of Mr approximately 4 x 10(5) and glycosaminoglycan chains of Mr 2.5 x 10(4), and was present in both the cell layer and the culture medium. (ii) A major small dermatan sulphate proteoglycan, DSPG-I, Mr 3.5 x 10(5) (46%), which was mainly located in the culture medium. (iii) A second minor small dermatan sulphate, DSPG-II, Mr approximately 2 x 10(5) (9.8%). This molecule was exclusively located in the culture medium. (iv) A large heparan sulphate proteoglycan, HSPG-I, Mr 8 x 10(5) (3.3%). (v) A second large heparan sulphate proteoglycan HSPG-II, Mr approximately 6 x 10(5) (23%). HSPG-I and HSPG-II were extracted from both the culture medium and the cell layer. 3. Western blot analysis of the core proteins released by chondroitin ABC lyase treatment of DSPG-I and DSPG-II identified these dermatan sulphate proteoglycans as biglycan and decorin respectively. Both DSPG-I and DSPG-II had core proteins of Mr 45,000. 4. The cell-layer-associated forms of CSPG-I, HSPG-I and HSPG-II were accessible to limited trypsin treatment, bound to octyl-Sepharose and could be inserted into liposomes, indicating a possible cell membrane location. 5. Pulse-chase experiments indicated that the cell-layer-associated [35S]proteoglycans undergo limited metabolism to inorganic [35S]sulphate, the majority of which is accounted for by the degradation of HSPG-II and to a lesser extent DSPG-I.

1990 ◽  
Vol 265 (1) ◽  
pp. 289-300 ◽  
Author(s):  
A Schmidtchen ◽  
I Carlstedt ◽  
A Malmström ◽  
L Å Fransson

Heparan sulphate and chondroitin/dermatan sulphate proteoglycans of human skin fibroblasts were isolated and separated after metabolic labelling for 48 h with 35SO4(2-) and/or [3H]leucine. The proteoglycans were obtained from the culture medium, from a detergent extract of the cells and from the remaining ‘matrix’, and purified by using density-gradient centrifugation, gel and ion-exchange chromatography. The core proteins of the various proteoglycans were identified by electrophoresis in SDS after enzymic removal of the glycosaminoglycan side chains. Skin fibroblasts produce a number of heparan sulphate proteoglycans, with core proteins of apparent molecular masses 350, 250, 130, 90, 70, 45 and possibly 35 kDa. The major proteoglycan is that with the largest core, and it is principally located in the matrix. A novel proteoglycan with a 250 kDa core is almost entirely secreted or shed into the culture medium. Two exclusively cell-associated proteoglycans with 90 kDa core proteins, one with heparan sulphate and another novel one with chondroitin/dermatan sulphate, were also identified. The heparan sulphate proteoglycan with the 70 kDa core was found both in the cell layer and in the medium. In a previous study [Fransson, Carlstedt, Cöster & Malmström (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 5657-5661] it was suggested that skin fibroblasts produce a proteoglycan form of the transferrin receptor. However, the core protein of the major heparan sulphate proteoglycan now purified does not resemble this receptor, nor does it bind transferrin. The principal secreted proteoglycans are the previously described large chondroitin sulphate proteoglycan (PG-L) and the small dermatan sulphate proteoglycans (PG-S1 and PG-S2).


1990 ◽  
Vol 123 (5) ◽  
pp. 541-549 ◽  
Author(s):  
Yoshimasa Shishiba ◽  
Yasuhiro Takeuchi ◽  
Noriko Yokoi ◽  
Yasunori Ozawa ◽  
Taeko Shimizu

Abstract We previously demonstrated that proteoglycan accumulated in the affected skin of circumscribed pretibial myxedema of Graves' disease. As an underlying mechanism responsible for the accumulation, we sought to determine whether excess thyroid hormone was partially responsible for the increase in proteoglycan synthesis. Human skin fibroblasts were cultured in Ham's F-10 medium containing 1% Nutridoma with graded doses of T3 (0.184 × 10−9 to 46 × 10−9 mol/l) and were labelled with [35S]sulphate and [3H]glucosamine. Proteoglycans were purified by Sephadex G-50, Q-Sepharose chromatography with NaCl-gradient and Sepharose CL-6B chromatography. 35S and 3H incorporated into dermatan sulphate proteoglycan and heparan sulphate proteoglycan and 3H incorporated into hyaluronan were measured. 35S and 3H incorporation into dermatan sulphate proteoglycan was minimum at a T3 concentration of 0.184 × 10−9 mol/l, and increased with increasing doses of T3 up to 46 × 10−9 mol/l. 35S and 3H incorporation into heparan sulphate proteoglycan also increased with increasingdoses of T3. 3H incorporation into hyaluronan was not influenced at all by T3. The increased incorporation of 35S into proteoglycan in high-T3 culture reflects the increased synthesis of proteoglycan because 1. the extent of sulphation of disaccharides examined by thin-layer chromatography was not altered by T3; 2. the specific activity of [35S]sulphate was not influenced by T3, and 3. T3 did not decrease the degradation rate of cell-associated proteoglycan.


1989 ◽  
Vol 264 (2) ◽  
pp. 457-465 ◽  
Author(s):  
L P W J van den Heuvel ◽  
J van den Born ◽  
T J A M van de Velden ◽  
J H Veerkamp ◽  
L A H Monnens ◽  
...  

Heparan sulphate proteoglycan was solubilized from human glomerular basement membranes by guanidine extraction and purified by ion-exchange chromatography and gel filtration. The yield of proteoglycan was approx. 2 mg/g of basement membrane. The glycoconjugate had an apparent molecular mass of 200-400 kDa and consisted of about 75% protein and 25% heparan sulphate. The amino acid composition was characterized by a high content of glycine, proline, alanine and glutamic acid. Hydrolysis with trifluoromethanesulphonic acid yielded core proteins of 160 and 110 kDa (and minor bands of 90 and 60 kDa). Alkaline NaBH4 treatment of the proteoglycan released heparan sulphate chains with an average molecular mass of 18 kDa. HNO2 oxidation of these chains yielded oligosaccharides of about 5 kDa, whereas heparitinase digestion resulted in a more complete degradation. The data suggest a clustering of N-sulphate groups in the peripheral regions of the glycosaminoglycan chains. A polyclonal antiserum raised against the intact proteoglycan showed reactivity against the core protein. It stained all basement membranes in an intense linear fashion in immunohistochemical studies on frozen kidney sections from man and various mammalian species.


1996 ◽  
Vol 134 (3) ◽  
pp. 326-330 ◽  
Author(s):  
Vibeke B Thøgersen ◽  
Lene Heickendorff ◽  
Thomas Ledet

Thogersen VB, Heickendorff L, Ledet T. Effect of insulin and growth hormone on the synthesis of radiolabelled proteoglycans from cultured human arterial smooth-muscle cells. Eur J Endocrinol 1996;134:326–30. ISSN 0804–4643 The present study focuses on the pathogenesis of increased frequency of large-vessel disease in diabetes. The diabetic arterial wall displays characteristic alterations of the extracellular matrix secreted by arterial smooth-muscle cells. The effects of insulin and growth hormone on the synthesis of sulphate-labelled proteoglycans and heparan sulphate proteoglycan were studied. Proteoglycans and heparan sulphate proteoglycan were obtained from the medium and the cell layer of cultured human arterial smooth-muscle cells grown in 5% human serum. Heparan sulphate proteoglycan was quantified using ethanol precipitation combined with specific enzyme degradation. Addition of insulin (0.01, 0.05 and 0.10 mU/ml) induced a significant accumulation of 35S-labelled proteoglycans in the cell layer (2p < 0.005 and 2p < 0.001). The relative amount of cell-associated heparan sulphate proteoglycan increased during insulin stimulation (2p < 0.05). Growth hormone stimulation (5.0 and 10.0 ng/ml) caused a significant decrease in the ratio between heparan sulphate proteoglycan and proteoglycan in the cell layer (2p < 0.02 and 2p < 0.01). whereas the distribution of proteoglycans between the cell layer and the medium was unaltered. Vibeke Bech Thogersen, Research Laboratory for Biochemical Pathology, Department of Pathology, Aarhus University Hospital, Kommunehospitalet, Nørrebrogade 44, DK-8000, Aarhus C, Denmark


1989 ◽  
Vol 261 (1) ◽  
pp. 145-153 ◽  
Author(s):  
A Lindblom ◽  
I Carlstedt ◽  
L Å Fransson

Proteoglycans, metabolically labelled with [3H]leucine and 35SO4(2-), were isolated from the spent media and from guanidinium chloride extracts of cultured human umbilical-vein endothelial cells by using isopycnic density-gradient centrifugation, gel filtration and ion-exchange h.p.l.c. The major proteoglycan species were subjected to SDS/polyacrylamide-gel electrophoresis before and after enzymic degradation of the polysaccharide chains. The cell extract contained mainly a heparan sulphate proteoglycan that has a buoyant density of 1.31 g/ml and a protein core with apparent molecular mass 300 kDa. The latter was heterogeneous and migrated as one major and one minor band. After reduction, the apparent molecular mass of the major band increased to approx. 350 kDa, indicating the presence of intrachain disulphide bonds. The proteoglycan binds to octyl-Sepharose and its polysaccharide chains are extensively degraded by heparan sulphate lyase. The proteoglycans of the medium contained 90% of all the incorporated 35SO4(2-). Here the predominant heparan sulphate proteoglycan was similar to that of the cell extract, but was more heterogeneous and contained an additional core protein with apparent molecular mass 210 kDa. Furthermore, two different chondroitin sulphate proteoglycans were found: one 200 kDa species with a high buoyant density (approx. 1.45 g/ml) and one 100 kDa species with low buoyant density (approx. 1.3 g/ml). Both these proteoglycans have a core protein of molecular mass approx. 47 kDa.


1984 ◽  
Vol 99 (3) ◽  
pp. 852-860 ◽  
Author(s):  
J G Heathcote ◽  
R W Orkin

Rabbit lens epithelial cells synthesize and secrete a variety of [35S]sulphate-labeled glycoconjugates in vitro. Associated with the cell layer, and with the medium, was a high molecular weight glycoconjugate(s) that contained heparan sulphate which was apparently covalently linked to sulphated glycoprotein. This component(s) was eluted in the void volume of a Sepharose CL-2B column and could not be fractionated by detergent treatment or extraction with lipid solvents. The cell layer also contained glycosaminoglycans (72% heparan sulphate, 28% chondroitin sulphate), as well as a small proportion of a low molecular weight sulphated glycoprotein. The major 35S-labeled species secreted into the medium were sulphated glycoproteins with approximate molecular weights of 120,000 and 35,000 together with a heparan sulphate proteoglycan. This proteoglycan could be precipitated from the culture medium with 30% saturated (NH4)2SO4 and eluted from Sepharose CL-4B columns at approximately the same position (Kav = 0.15) as heparan sulphate proteoglycans described in the basement membrane of the EHS "sarcoma" (Hassell, J. R., P. G. Robey, H. J. Barrach, J. Wilczek, S. I. Rennard, and G. R. Martin, 1980, Proc. Natl. Acad. Sci. USA, 77:4494-4498) and of the mouse mammary epithelium (David, G., and M. Bernfield, 1981, J. Cell Biol., 91:281-286). Its presence in the culture medium was unanticipated but may be explained by the inability of these cultures to deposit a basement membrane when grown on a plastic surface. The relationship of this heparan sulphate proteoglycan to the lens epithelial basement membrane is the subject of the following paper.


1995 ◽  
Vol 307 (3) ◽  
pp. 759-768 ◽  
Author(s):  
N F van Det ◽  
J van den Born ◽  
J T Tamsma ◽  
N A M Verhagen ◽  
L P W J van den Heuvel ◽  
...  

Proteoglycans metabolically labelled with [35S]sulphate and [3H]glucosamine or [3H]leucine were isolated from the incubation medium and cell layer of human adult mesangial cells and glomerular visceral epithelial cells using sequential DEAE chromatography purification steps followed by gel-filtration chromatography. The proteoglycan composition of each peak was analysed by treatment with HNO2, chondroitinase ABC or chondroitinase AC followed by chromatography on Sephadex G-50 columns. Heparan sulphate proteoglycan (HSPG) and dermatan sulphate proteoglycan were detected in both the culture medium and cell layer of mesangial cells. Culture medium of glomerular visceral epithelial cells contained HSPG and a second proteoglycan with the properties of a hybrid molecule containing HS and chondroitin sulphate (CS). The cell layer contained HSPG and CSPG. Detailed analysis of the hybrid molecule revealed that it had an apparent molecular mass of 400 kDa. SDS/PAGE of hybrid molecules, after treatment with heparitinase and chondroitinase ABC, revealed a core protein of 80 kDa. Using 1.8% polyacrylamide/0.6% agarose-gel electrophoresis, we deduced that the HS and CS were independently attached to one core protein. Because glomerular-basement-membrane HSPG is thought to be derived from mesangial cells and glomerular visceral epithelial cells and this molecule is involved in several kidney diseases, we investigated its synthesis in more detail. Anti-(rat glomerular-basement-membrane HSPG) monoclonal antibodies (JM403) and anti-(human glomerular-basement-membrane HSPG) polyclonal antibodies (both antibodies known to react with the large basement-membrane HSPG, perlecan) reacted strongly with HSPG obtained from both mesangial cells and glomerular visceral epithelial cells. However, the hybrid molecule did not react with these antibodies, suggesting that the HS side chain and the core protein were different from glomerular-basement-membrane HSPG. To quantify HS we performed an inhibition ELISA using mouse antibodies specific for glomerular-basement-membrane HS glycosaminoglycan side chains. Glomerular visceral epithelial cells produced significantly higher levels of HS (between 197.56 and 269.40 micrograms/72 h per 10(6) cells) than mesangial cells (between 29.8 and 45.5 micrograms/72 h per 10(6) cells) (three different cell lines; n = 3; P < 0.001). HS production by these cells was inhibited by cycloheximide, revealing that it was synthesized de novo. Expression of perlecan mRNA, demonstrated using reverse transcriptase PCR, was different in the two cell types. We conclude that glomerular visceral epithelial cells and mesangial cells have characteristic patterns of proteoglycan production. Glomerular visceral epithelial cells produced a hybrid proteoglycan containing CS and HS independently attached to its core protein.(ABSTRACT TRUNCATED AT 250 WORDS)


1981 ◽  
Vol 197 (1) ◽  
pp. 217-225 ◽  
Author(s):  
I Carlstedt ◽  
L Cöster ◽  
A Malmström

35SO42(-)- and [3H]leucine-labelled proteoglycans were isolated from the medium and cell layer of human skin fibroblast cultures. Measures were taken to avoid proteolytic modifications during isolation by adding guanidinium chloride and proteolysis inhibitors immediately after harvest. The proteoglycans were purified and fractionated by density-gradient centrifugation, followed by gel and ion-exchange chromatography. Our procedure permitted the isolation of two major proteoglycan fractions from the medium, one large, containing glucuronic acid-rich dermatan sulphate chains, and one small, containing iduronic acid-rich ones. The protein core of the latter proteoglycan had an apparent molecular weight of 47000 as determined by polyacrylamide-gel electrophoresis, whereas the protein core of the former was considerably larger. The major dermatan sulphate proteoglycan of the cell layer was similar to the large proteoglycan of the medium. Only small amounts of the iduronic acid-rich dermatan sulphate proteoglycan could be isolated from the cell layer. Instead most of the iduronic acid-rich glycans appeared as free chains. The heparan sulphate proteoglycans found in the cell culture were largely confined to the cell layer. This proteoglycan was of rather low buoyant density and seemed to contain a high proportion of protein. The major part of the heparan sulphate proteoglycan from the medium had a higher buoyant density and contained a smaller amount of protein.


1999 ◽  
Vol 344 (3) ◽  
pp. 723-730 ◽  
Author(s):  
Youmie PARK ◽  
Guyong YU ◽  
Nur Sibel GUNAY ◽  
Robert J. LINHARDT

A heparan sulphate proteoglycan was purified from adult bovine brain tissues and its structure was characterized. The major heparan sulphate proteoglycan from whole bovine brain had a molecular mass of > 200 kDa on denaturing SDS/PAGE and a core protein size of 66 kDa following the removal of glycosaminoglycan chains. Fractionation on DEAE-Sephacel showed that this proteoglycan consisted of three major forms having high, intermediate and low overall charge. All core proteins were identical in size and reacted with heparan sulphate proteoglycan-stub antibody and an antibody made to a synthetic peptide based on rat glypican. The three forms of proteoglycans had identical peptide maps and their amino acid compositional analysis did not match any of the known glypicans. The internal sequence of a major peptide showed only 37.5% sequence similarity with human glypican 5. The glycosaminoglycan chain sizes of the three forms of this proteoglycan, determined after β-elimination by PAGE, were identical. The disaccharide compositional analysis on the heparan sulphate chains from the three forms of the proteoglycan, determined by treatment with a mixture of heparin lyases followed by high-resolution capillary electrophoresis, showed that they differed primarily by degree of sulphation. The most highly sulphated proteoglycan isolated had a disaccharide composition similar to heparan sulphate glycosaminoglycans found in brain tissue. Based on their sensitivity to low pH nitrous acid treatment, the N-sulphate groups in these proteoglycans were found to be primarily in the smaller glycosaminoglycan chains. The heparan sulphate proteoglycans were also heavily glycosylated with O-linked glycans and no glycosylphosphatidylinositol anchor could be detected.


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