Interaction of transferrin with rat alveolar macrophages

1995 ◽  
Vol 73 (1-2) ◽  
pp. 73-79
Author(s):  
Maria Janicka ◽  
Erwin Regoeczi ◽  
Maria Bolyos ◽  
Wei-Li Hu
Keyword(s):  
Alveolar Macrophages ◽  
Transferrin Receptor ◽  
Binding Sites ◽  
Heparan Sulphate ◽  
Bovine Lactoferrin ◽  
Heparan Sulphate Proteoglycan ◽  
High Affinity ◽  
Sulphate Proteoglycan ◽  
Order Of Magnitude ◽  
Affinity Interaction

Binding of rat transferrin to isolated alveolar macrophages was investigated in the 0.125 nM to 2 μM range. Computer analysis of the data revealed two classes of binding sites, a small number (<1000 exposed/cell) having high affinity (dissociation constant (Kd), 3.4 nM) and a large number (approximately 4 × 106/cell) having low affinity (Kd48 μM). Measurements with a monoclonal antibody to the rat transferrin (rTf) receptor yielded values in the same range as the high-affinity sites derived from studies of ligand binding. Binding to the low-affinity sites at pH 5.8 was nearly one order of magnitude stronger than that at pH 7.3. Bovine lactoferrin (12 μM), cationized bovine serum albumin (14 μM), L-arginine (50 mM), and L-lysine (50 mM) did not compete against rTf binding to the low-affinity sites. Removal of an average of 2.6 × 108sialyl residues from each cell did not affect binding. Heparan sulphate proteoglycan purified from alveolar macrophages bound strongly to immobilized rTf, thus raising the possibility that the low-affinity interaction of transferrin with these cells may be mediated, at least in part, by this glycosaminoglycan.Key words: heparan sulphate proteoglycan, macrophage, transferrin, transferrin receptor.

Thyroid hormone excess stimulates the synthesis of proteoglycan in human skin fibroblasts in culture

1990 ◽  
Vol 123 (5) ◽  
pp. 541-549 ◽  
Author(s):  
Yoshimasa Shishiba ◽  
Yasuhiro Takeuchi ◽  
Noriko Yokoi ◽  
Yasunori Ozawa ◽  
Taeko Shimizu
Keyword(s):  
Thyroid Hormone ◽  
Human Skin ◽  
Specific Activity ◽  
Heparan Sulphate ◽  
Skin Fibroblasts ◽  
Proteoglycan Synthesis ◽  
Heparan Sulphate Proteoglycan ◽  
Human Skin Fibroblasts ◽  
Dermatan Sulphate ◽  
Sulphate Proteoglycan

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.

Differential deposition of basement membrane components during formation of the caudal neural tube in the mouse embryo

Development ◽  
1987 ◽  
Vol 99 (4) ◽  
pp. 509-519
Author(s):  
K.S. O'Shea
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Heparan Sulphate ◽  
Heparan Sulphate Proteoglycan ◽  
Sulphate Proteoglycan ◽  
Secondary Neurulation ◽  
Type Iv ◽  
Posterior Neuropore ◽  
Membrane Components ◽  
Basement Membrane Components

The distribution of basement membrane and extracellular matrix components laminin, fibronectin, type IV collagen and heparan sulphate proteoglycan was examined during posterior neuropore closure and secondary neurulation in the mouse embryo. During posterior neuropore closure, these components were densely deposited in basement membranes of neuroepithelium, blood vessels, gut and notochord; although deposition was sparse in the midline of the regressing primitive streak. During secondary neurulation, mesenchymal cells formed an initial aggregate near the dorsal surface, which canalized and merged with the anterior neuroepithelium. With aggregation, fibronectin and heparan sulphate proteoglycan were first detected at the base of a 3- to 4-layer zone of radially organized cells. With formation of a lumen within the aggregate, laminin and type IV collagen were also deposited in the forming basement membrane. During both posterior neuropore closure and secondary neurulation, fibronectin and heparan sulphate proteoglycan were associated with the most caudal portion of the neuroepithelium, the region where newly formed epithelium merges with the consolidated neuroepithelium. In regions of neural crest migration, the deposition of basement membrane components was altered, lacking laminin and type IV collagen, with increased deposition of fibronectin and heparan sulphate proteoglycan.

scholarly journals Biosynthesis of sulphated macromolecules by rabbit lens epithelium. II. Relationship to basement membrane formation.

1984 ◽  
Vol 99 (3) ◽  
pp. 861-869 ◽  
Author(s):  
J G Heathcote ◽  
R R Bruns ◽  
R W Orkin
Keyword(s):  
Basement Membrane ◽  
Type I Collagen ◽  
Heparan Sulphate ◽  
Significant Proportion ◽  
Type I ◽  
Heparan Sulphate Proteoglycan ◽  
Membrane Formation ◽  
Sulphate Proteoglycan ◽  
Type Iv ◽  
Rabbit Lens

Rabbit lens epithelial cells display a similar "cobblestone" morphology and produce the same complement of sulphated macromolecules (also see Heathcote, J.G., and R.W. Orkin, 1984, J. Cell Biol., 99:852-860) whether grown on plastic or glass, dried films of gelatin or type IV collagen with laminin, or on gels of type I collagen. There was no evidence of basement membrane formation by these cells when they were grown on plastic, glass, or dried films. In contrast, cultures that had been grown on gels deposited a discrete basement membrane that followed the contours of the basal surfaces of the cells and in addition, they secreted amorphous basement membrane-like material that diffused into the interstices of the gel and associated with the collagen fibrils of the gel. A significant proportion (approximately 70%) of the heparan sulphate proteoglycan fraction that was secreted into the culture medium (fraction MI) when the cells were grown on plastic became associated with the cell-gel layer in the gel cultures. Further, when basement membrane was isolated by detergent extraction, greater than 90% of the 35S-labeled material present was in this heparan sulphate proteoglycan.

scholarly journals Chondroitin sulphate proteoglycan in the substratum adhesion sites of Balb/c 3T3 cells. Fractionation on various ion-exchange and affinity columns

1986 ◽  
Vol 235 (2) ◽  
pp. 469-479 ◽  
Author(s):  
B C Wightman ◽  
E A Weltman ◽  
L A Culp
Keyword(s):  
Extracellular Matrix ◽  
Affinity Chromatography ◽  
Chondroitin Sulphate ◽  
Heparan Sulphate ◽  
Heparan Sulphate Proteoglycan ◽  
3T3 Cells ◽  
Platelet Factor ◽  
Sulphate Proteoglycan ◽  
Adhesion Sites ◽  
Chondroitin Sulphate Proteoglycan

Proteoglycans on the cell surface play critical roles in the adhesion of fibroblasts to a fibronectin-containing extracellular matrix, including the model mouse cell line Balb/c 3T3. In order to evaluate the biochemistry of these processes, long-term [35S]sulphate-labelled proteoglycans were extracted quantitatively from the adhesion sites of 3T3 cells, after their EGTA-mediated detachment from the substratum, by using an extractant containing 1% octyl glucoside, 1 M-NaCl and 0.5 M-guanidinium chloride (GdnHCl) in buffer with many proteinase inhibitors. Greater than 90% of the material was identified as a large chondroitin sulphate proteoglycan (Kav. = 0.4 on a Sepharose CL2B column), and the remainder was identified as a smaller heparan sulphate proteoglycan; only small amounts of free chains of glycosaminoglycan were observed in these sites. These extracts were fractionated on DEAE-Sepharose columns under two different sets of elution conditions: with acetate buffer (termed DEAE-I) or with acetate buffer supplemented with 8 M-urea (termed DEAE-II). Under DEAE-I conditions about one-half of the material was eluted as a single peak and the remainder required 4 M-GdnHCl in order to recover it from the column; in contrast, greater than 90% of the material was eluted as a single peak from DEAE-II columns. Comparison of the elution of [35S]sulphate-labelled proteoglycan with that of 3H-labelled proteins from these two columns, as well as mixing experiments, indicated that the GdnHCl-sensitive proteoglycans were trapped at the top of columns, partially as a consequence of their association with proteins in these adhesion-site extracts. Affinity chromatography of these proteoglycans on columns of either immobilized platelet factor 4 or immobilized plasma fibronectin revealed that most of the chondroitin sulphate proteoglycan and the heparan sulphate proteoglycan bound to platelet factor 4 but that only the heparan sulphate proteoglycan bound to fibronectin, providing a ready means of separating the two proteoglycan classes. Affinity chromatography on octyl-Sepharose columns to test for hydrophobic domains in their core proteins demonstrated that a high proportion of the heparan sulphate proteoglycan but none of the chondroitin sulphate proteoglycan bound to the hydrophobic matrix. These results are discussed in light of the possible functional importance of the chondroitin sulphate proteoglycan in the detachment of cells from extracellular matrix and in light of previous affinity fractionations of proteoglycans from the substratum-adhesion sites of simian-virus-40-transformed 3T3 cells.

scholarly journals A study of the interaction in vitro between type I collagen and a small dermatan sulphate proteoglycan

1988 ◽  
Vol 251 (3) ◽  
pp. 643-648 ◽  
Author(s):  
N Uldbjerg ◽  
C C Danielsen
Keyword(s):  
Steady State ◽  
Binding Sites ◽  
Type I Collagen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Side Chains ◽  
Type I ◽  
Dermatan Sulphate ◽  
Collagen Fibrillogenesis ◽  
High Affinity ◽  
Sulphate Proteoglycan

The interaction between a small dermatan sulphate proteoglycan isolated from human uterine cervix and collagen type I from human and rat skin was investigated by collagen-fibrillogenesis experiments. Collagen fibrillogenesis was initiated by elevation of temperature and pH after addition of proteoglycan, chondroitinase-digested proteoglycan or isolated side chains, and monitored by turbidimetry. Collagen-associated and unbound proteoglycan was determined by enzyme-linked immunosorbent assay after aggregation was complete. (1) The binding of proteoglycan to collagen could be explained by the presence of two mutually non-interacting binding sites, with Ka1 = 1.3 x 10(8) M-1 and Ka2 = 1.3 x 10(6) M-1. The number of binding sites per tropocollagen molecule was n1 = 0.11 and n2 = 1.1. The 0.1 high-affinity binding site per tropocollagen molecule indicates that the strong interaction between proteoglycan and collagen results from a concerted action of tropocollagen molecules in fibrils. Digestion of the proteoglycan with chondroitinase ABC did not affect these binding characteristics. (2) Proteoglycan did not affect the rate of fibrillogenesis, but increased the steady-state A400 by up to 90%. This increase was directly proportional to the saturation of the high-affinity type of binding sites. Neither isolated core protein nor isolated side chains induced a similar high increase in steady-state A400. (3) Electron micrographs showed that the fibril diameter was affected only to a minor extent, if at all, by the proteoglycan, whereas bundles of laterally aligned fibrils were common in the presence of proteoglycan. (4) Results obtained with human and rat collagen were similar.

scholarly journals Expression of a Xenopus counterpart of mammalian syndecan 2 during embryogenesis

1995 ◽  
Vol 309 (1) ◽  
pp. 69-76 ◽  
Author(s):  
N D Rosenblum ◽  
B B Botelho ◽  
M Bernfield
Keyword(s):  
Amino Acid ◽  
Northern Blot Analysis ◽  
Transmembrane Domain ◽  
Heparan Sulphate ◽  
Attachment Site ◽  
Heparan Sulphate Proteoglycan ◽  
Cell Stage ◽  
Reading Frame ◽  
Sulphate Proteoglycan ◽  
Polyclonal Antisera

We have identified a Xenopus cDNA, XS-2, by screening a Xenopus embryonic stage-22-24 cDNA library with a DNA probe encoding the transmembrane and cytoplasmic domains of mouse syndecan 1. The 1.4 kb cDNA consists of an open reading frame of 642 nucleotides encoding a protein of 191 amino acids. The predicted protein of 20869 Da contains a 25-amino acid putative transmembrane domain and a 32-amino acid putative cytoplasmic domain, both of which are highly similar to the corresponding regions of rat syndecan 2 (92% identity) and to a lesser degree those of rat syndecans 1, 3 and 4 (62, 64 and 78% respectively). The putative N-terminal ectodomain contains a possible attachment site for heparan sulphate, identical with the comparable glycosaminoglycan-attachment sequence of rat syndecan 2. Polyclonal antisera raised against recombinant ectodomain of XS-2, expressed as a fusion protein, recognized a heparan sulphate proteoglycan in XTC cell-culture medium. This proteoglycan bound to DEAE-Sephacel and was eluted with 1 M NaCl; digestion with heparitinase but not chondroitinase ABC resulted in the identification of a 46 kDa protein by these antisera. Northern-blot analysis indicated that XS-2 identifies two Xenopus mRNA species approx. 4 and 2 kb in size in embryos ranging in maturation from the 64-cell stage to stage 54. These results demonstrate that a heparan sulphate proteoglycan, similar to syndecan 2, is expressed during Xenopus embryogenesis.

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