scholarly journals The degradation of cartilage proteoglycans by tissue proteinases. Proteoglycan heterogeneity and the pathway of proteolytic degradation

1977 ◽  
Vol 167 (3) ◽  
pp. 639-646 ◽  
Author(s):  
P J Roughley
Keyword(s):  
Cathepsin B ◽  
Degradation Products ◽  
Chondroitin Sulphate ◽  
Cathepsin G ◽  
Proteolytic Degradation ◽  
Single Chain ◽  
Structural Variations ◽  
Nasal Cartilage ◽  
Core Proteins ◽  
Average Size

1. CaCl2-extracted proteoglycan from bovine nasal cartilage was degraded by four tissue proteinases till no further decrease in hydroynamic size was obtained. The proteoglycan and its final degradation products were then fractionated by Sepharose 2B chromatography. 2. The average size of the degradation products was least for cathepsin B and lysosomal elastase, and greatest for cathepsin D and cathepsin G. The latter two proteinases also produced degradation products that showed the widest range of sizes. 3. The structure of the degradation products ranged from peptides containing a single glycosaminoglycan chain to those containing twelve or more chains. Of the four proteinases, only cathepsin B produced peptides that contained a single chondroitin sulphate chain. 4. The proteoglycan was very heterogeneous with respect to size and chemical composition. Its behaviour on electrophoresis suggested that at least two genetically distinct core proteins might exist. 5. Irrespective of their structural variations, all proteoglycan molecules were able to interact with hyaluronic acid. In contrast, none of the degradation products were capable of this type of interaction. 6. A pathway for the proteolytic degradation of proteoglycans is postulated in which the sites of initial cleavage may be common to the majority of proteinases, whereas the production of the final clusters is dependent on the specificity of the proteinase. Only those proteinases of broadest specificity can produce single-chain chondroitin sulphate-peptides.

scholarly journals The degradation of cartilage proteoglycans by tissue proteinases. Proteoglycan structure and its susceptibility to proteolysis

1977 ◽  
Vol 167 (3) ◽  
pp. 629-637 ◽  
Author(s):  
P J Roughley ◽  
A J Barrett
Keyword(s):  
Ionic Strength ◽  
Cathepsin D ◽  
Core Protein ◽  
Degradation Products ◽  
Gradient Centrifugation ◽  
Limited Proteolysis ◽  
Extraction Procedure ◽  
Cathepsin G ◽  
Nasal Cartilage ◽  
Cscl Density Gradient

1. Proteoglycan was obtained from bovine nasal cartilage by a procedure involving sequential extraction with a low-ionic-strength KCl solution, then a high-ionic-strength CaCl2 solution. Purification was by CsCl-density-gradient centrifugation. 2. The CaCl2- extracted proteoglycan was subjected to proteolytic degradation by papain, trypsin, cathepsin D, cathepsin B, lysosomal elastase or cathepsin G. Degradation was allowed to proceed until no further decrease in viscosity was detectable. 3. The size and chemical composition of the final degradation products varied with the different proteinases. Cathepsin D and cathepsin G produced glycosaminoglycan-peptides of largest average size, and papain produced the smallest product. 4. The KCl-extracted proteoglycan was intermediate in molecular size and composition between the CaCl2-extracted proteoglycan and the largest final degradation products, and may have been formed by limited proteolysis during the extraction procedure. 5. It is postulated that the glycosaminoglycan chains are arranged in groups along the proteoglycan core protein. Proteolytic cleavage between the groups may be common to the majority of proteinases, whereas clevage within the groups is dependent on the specificity of each individual proteinase.

scholarly journals Fractionation and characterization of proteoglycans isolated from chondrocyte cell cultures

1981 ◽  
Vol 197 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Sven Björnsson ◽  
Dick Heinegȧrd
Keyword(s):  
Cell Culture ◽  
Chondroitin Sulphate ◽  
Calf Serum ◽  
Void Volume ◽  
Cartilage Tissue ◽  
Foetal Calf Serum ◽  
Nasal Cartilage ◽  
Core Proteins ◽  
Minor Portion ◽  
A Minor

Chondrocyte cultures were established from foetal bovine tracheal cartilage and maintained in Ham's F12 medium with or without 10% (v/v) foetal calf serum. The proteoglycans were isolated and characterized. (1) The proteoglycans from cultures both with and without serum distributed in associative or dissociative CsCl gradients like proteoglycans from cartilage tissue. (2) The amino acid composition, protein contents and glucosamine/galactosamine ratios were grossly identical with those of the tissue derived proteoglycans. (3) Sedimentation coefficients (s0) for the monomers were 21.0S and 22.7S from cultures without and with serum respectively. The s0 values obtained for aggregates were 72.3S and 93.2S respectively. The limiting viscosity numbers [η] were 248ml/g and 298ml/g respectively. These data corresponded well to those obtained for the tissue-derived proteoglycans. (4) The sizes of the core proteins and chondroitin sulphate chains respectively were the same for both types of cell-culture proteoglycans and similar to those of the tissue proteoglycans. Both the keratan sulphate-rich region and the hyaluronic acid-binding region were identified. The latter, however, was not resistant to limit digestion with trypsin, in contrast with the fragment derived from the bovine nasal cartilage. (5) About 70% of the cell-culture proteoglycans chromatographed in the void volume on a Sepharose 2B column, whereas reduced and alkylated samples (monomers) chromatographed completely included in the column. The two link proteins present in A1 preparations of cartilage proteoglycans were also present in A1 preparations of cell-culture proteoglycans. (6) A minor portion (10%) of the 35S-labelled proteoglycans in the cultures was associated with the cells. Reduced and alkylated samples were larger compared with the monomers in the medium, and chromatographed partly (25%) excluded on the Sepharose 2B column. A larger proportion (50%) of the non-reduced samples chromatographed in the void volume of the column.

scholarly journals Resistance of small leucine-rich repeat proteoglycans to proteolytic degradation during interleukin-1-stimulated cartilage catabolism

1999 ◽  
Vol 339 (3) ◽  
pp. 571-577 ◽  
Author(s):  
Robert SZTROLOVICS ◽  
Robert J. WHITE ◽  
A. Robin POOLE ◽  
John S. MORT ◽  
Peter J. ROUGHLEY
Keyword(s):  
Degradation Product ◽  
Culture Media ◽  
Degradation Products ◽  
Interleukin 1 ◽  
Culture Period ◽  
Proteolytic Degradation ◽  
Early Event ◽  
Globular Domain ◽  
Leucine Rich Repeat ◽  
Nasal Cartilage

A bovine nasal-cartilage culture system has been utilized to analyse the catabolic events occurring in response to interleukin-1β over a 14-day period. An early event following the start of interleukin-1 treatment was the release of glycosaminoglycan into the culture medium. This release was accompanied by the appearance in the tissue, and shortly thereafter also in the culture media, of a globular domain (G1)-containing aggrecan degradation product generated by the action of aggrecanase. Link protein was also released from the cartilage with a similar timeframe to that of the G1 fragment, although there was no evidence of its proteolytic degradation. By comparison with aggrecan, the small leucine-rich repeat proteoglycans decorin, biglycan and lumican showed a resistance to both proteolytic cleavage and release throughout the culture period. In contrast, fibromodulin exhibited a marked decrease in size after day 4, presumably due to proteolytic modification, but the major degradation product was retained throughout the culture period. Also in contrast with the early changes in the components of the proteoglycan aggregate, type II collagen did not display signs of extensive degradation until much later in the culture period. Collagen degradation products compatible with collagenase action first appeared in the medium by day 10 and increased thereafter. These data demonstrate that the leucine-rich repeat proteoglycans are resistant to proteolytic action during interleukin-1-stimulated cartilage catabolism, compared with aggrecan. This resistance and continued interaction with the surface of the collagen fibrils may help to stabilize the collagen fibrillar network and protect it from extensive proteolytic attack during the early phases of cartilage degeneration.

scholarly journals Identification of Novel Cathepsin B Inhibitors with Implications in Alzheimer’s Disease: Computational Refining and Biochemical Evaluation

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1946
Author(s):  
Nitin Chitranshi ◽  
Ashutosh Kumar ◽  
Samran Sheriff ◽  
Veer Gupta ◽  
Angela Godinez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Hydrogen Bond ◽  
Virtual Screening ◽  
Cathepsin B ◽  
Amyloid Β ◽  
Proteolytic Degradation ◽  
Hydrogen Bond Acceptor ◽  
Starting Point ◽  
The Brain

Amyloid precursor protein (APP), upon proteolytic degradation, forms aggregates of amyloid β (Aβ) and plaques in the brain, which are pathological hallmarks of Alzheimer’s disease (AD). Cathepsin B is a cysteine protease enzyme that catalyzes the proteolytic degradation of APP in the brain. Thus, cathepsin B inhibition is a crucial therapeutic aspect for the discovery of new anti-Alzheimer’s drugs. In this study, we have employed mixed-feature ligand-based virtual screening (LBVS) by integrating pharmacophore mapping, docking, and molecular dynamics to detect small, potent molecules that act as cathepsin B inhibitors. The LBVS model was generated by using hydrophobic (HY), hydrogen bond acceptor (HBA), and hydrogen bond donor (HBD) features, using a dataset of 24 known cathepsin B inhibitors of both natural and synthetic origins. A validated eight-feature pharmacophore hypothesis (Hypo III) was utilized to screen the Maybridge chemical database. The docking score, MM-PBSA, and MM-GBSA methodology was applied to prioritize the lead compounds as virtual screening hits. These compounds share a common amide scaffold, and showed important interactions with Gln23, Cys29, His110, His111, Glu122, His199, and Trp221. The identified inhibitors were further evaluated for cathepsin-B-inhibitory activity. Our study suggests that pyridine, acetamide, and benzohydrazide compounds could be used as a starting point for the development of novel therapeutics.

Down-regulation of activated factor XIII by polymorphonuclear granulocyte proteases within fibrin clot

2007 ◽  
Vol 98 (08) ◽  
pp. 359-367 ◽  
Author(s):  
Zsuzsa Bagoly ◽  
Gizella Haramura ◽  
László Muszbek
Keyword(s):  
Factor Xiii ◽  
Proteolytic Enzymes ◽  
Fibrin Clot ◽  
Cathepsin G ◽  
Proteolytic Degradation ◽  
Clotting Factors ◽  
Down Regulation ◽  
Elastase Inhibitor ◽  
Partial Protection ◽  
Fibrin Clots

SummaryActivated clotting factors are down-regulated by two major mechanisms which involve protease inhibitors or proteolytic degradation. To date, no down-regulating mechanism for activated factor XIII (FXIIIa) has been demonstrated. As the hemostatic plug contains polymorphonuclear granulocytes (PMNs) rich in proteolytic enzymes, we tested if these proteases are released in fibrin clots, and become involved in the down-regulation of FXIIIa.The supernatant of stimulated granulocytes proteolytically degraded and inactivated FXIIIa. In the fibrin clot formed from fibrinogen solution elastase, cathepsin G and matrix metalloprotease-9 (MMP-9) were released from granulocytes without any external stimulus. PMN proteases released in fibrin clot exerted a fibrinolytic effect and almost completely de-graded both FXIII subunits.The elastase inhibitor, ONO 5046, partially inhibited the proteolytic degradation of FXIII in PMNsupplemented fibrin clots. Cathepsin G and MMP-9 inhibitors provided less protection; in these cases intermediate split products accumulated.The proteolytic degradation of FXIII by PMNs was also significant when the clot was made from whole plasma. The main plasma protease inhibitor, α1-antitrypsin, provided only partial protection. In the fibrin clot which contained α1-antitrypsin FXIIIa was degraded by PMN proteases significantly faster than cross-linked fibrin.The results suggest that the degradation of FXIII subunits by the concerted action of PMN proteases released within the clot represents a novel mechanism for the down-regulation of FXIIIa.

CHANGES IN PROTEOGLYCAN AND SULFATED PROTEIN SYNTHESIS DURING MEGAKARYOCYTE MATURATION IN VIVO

1987 ◽  
Author(s):  
B P Schick ◽  
C J Walsh ◽  
T Jenkins-West
Keyword(s):  
Protein Synthesis ◽  
The Core ◽  
Small Peak ◽  
Core Proteins ◽  
Time Period ◽  
Sds Page ◽  
Isoelectric Points ◽  
Average Size ◽  
Triton X

We investigated changes in sulfated proteoglycan (PG) and sulfated protein synthesis during megakaryocyte (MK) maturation in vivo by characterizing the (35S)-labeled molecules in MKs and platelets (PLTs) obtained daily from 3 hr to 5 days after injection of guinea pigs with (35S)sulfate. Radioactivity in macromolecules was maximal in MKs 3 hr and in PLTs 3 days after the injection. The cells were solubilized in 8M urea/50mM Tris/0.2% Triton X-100/0.1M NaCl, and PGs and sulfoproteins were separated by DEAE-Sephacel chromatography. PGs (65% of cell 35s) were eluted as two fractions, one (PG-1, 87%) with 4M Gdn HC1 and another (PG-2, 13%) with 4M Gdn HCl/2% TX-100. The Kav of PLT PG-1 on Sepharose CL-6B shifted gradually from 0.18 to 0.10 from 1-5 days after (35S) injection, and the smaller and larger PG-1 species were resolved on SDS-PAGE by fluorography. The size of PG-1 molecules was a function of glycosaminoglycan (GAG) chain length. The appearance of the different size PG-1 molecules in PLTs was accounted for by their disappearance from MKs over the same time period. Thus the size of the PG-1 synthesized by MKs decreased with MK maturation. The (35S)-PG-2 appeared in PLTs only 2-3 days after (35S) injection, had Kav 0.07 on CL-6B, but had GAGs of the same average size as those of PG-1. The hydrophobic character of PG-2 suggests that it might be the membrane PG. PG-1 and PG-2 were separated by SDS-PAGE and identified by fluorography. The core proteins of PG-1 and PG-2 were obtained by chondroitinase digestion and identified by SDS-PAGE and fluorography. The GAGs of PG-1 and PG-2 were almost entirely chondroitin-6-sulfate. The average size of PG-1 was 200,000 and its GAGs about 45,000.The sulfated proteins (20-25% of total cell 35S) eluted in the wash-through of the DEAE-Sephacel column and with 0.23M NaCl. Their isoelectric points were 4.0-6.5. They eluted as a small peak near the V0 and a major broad peak from Kav 0.3-0.6 on CL-6B columns, and could be identified as at least 8 distinct bands on SDS-PAGE by fluorography. Digestion with NaOH/NaBH4, Pronase or papain released small (35S)-labeled fragments, and the (35S) appeared to be associated with oligosaccharides. The sulfoproteins appeared in PLTs primarily 2-4 days after (35S) injection, and different proteins were labeled at different time points.

Observations on the morphology of the proteinpolysaccharide complex of bovine nasal cartilage and its relationship to collagen

1966 ◽  
Vol 165 (1001) ◽  
pp. 440-449 ◽  
Keyword(s):  
Nitric Acid ◽  
Aqueous Extract ◽  
Chondroitin Sulphate ◽  
Carbohydrate Chain ◽  
Average Particle Size ◽  
Heavy Fraction ◽  
Bismuth Nitrate ◽  
Average Particle ◽  
Nasal Cartilage ◽  
Intact Cartilage

The investigation has been carried out by electron microscope examination of intact cartilage and of various fractions of an aqueous extract of that tissue. The materials were stained, either with an 0·5 % solution of bismuth nitrate in 0·1 m nitric acid in water at a pH of 1·2, or with a similar solution of bismuth nitrate in 0·1 m nitric acid in 90 % acetone. It is considered that in both circumstances the bismuth was bound exclusively to the sulphate group of chondroitin sulphate and keratosulphate. The protein and chondroitin sulphate moieties of the proteinpolysaccharide complex were isolated after alkaline treatment. The former contains 15 % keratosulphate and it is only this part which stains. Both the protein and the chondroitin sulphate were visualized as discrete groups of particles in which the average particle diameter was 23 Å. It is suggested that each group represents a network of keratosulphate or chondroitin sulphate A ( CSA ) chains respectively, cross-linked by bismuth ions. And that each individual particle represents a segment of a carbohydrate chain which has assumed a coiled configuration owing to the neutralization of its net charge by bismuth. The light fraction of the aqueous extract of cartilage contains the proteinpolysaccharide complex alone. After precipitation with aqueous bismuth nitrate its appearance was essentially similar to that of its CSA and protein fractions, except that the average particle size was 47 Å. After precipitation by bismuth nitrate in acetone, on the other hand, it was seen as single rows of particles, the length of the rows varying from 1100 Å to 1500 Å, and the particles having an average diameter of 30 Å. Each row is interpreted as a proteinpolysaccharide macro-molecule, and it is considered that each particle represents an individual carbohydrate chain, whereas the intervals between the particles represent the unstained protein moiety. The indi­viduality of the macromolecules in these circumstances is ascribed to the low dielectric constant of acetone. The relationship of the proteinpolysaccharide complex to collagen was studied in the heavy fraction of the aqueous extract of cartilage and in intact cartilage. It was observed that the heavy fraction consists of proteinpolysaccharide and collagen and that a pro­portion of the complex is bound to collagen. In each collagen period, proteinpolysaccharide macromolecules were attached transversely round the circumference of the fibre over the a and b 1 bands. A similar relationship was noted in intact cartilage.

scholarly journals Immunochemical analysis of cartilage proteoglycans. Cross-reactivity of molecules isolated from different species

1981 ◽  
Vol 199 (1) ◽  
pp. 81-87 ◽  
Author(s):  
J Wieslander ◽  
D Heinegård
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Chondroitin Sulphate ◽  
Limb Bud ◽  
Binding Region ◽  
Human Cartilage ◽  
Nasal Cartilage ◽  
Cartilage Proteoglycans ◽  
Rabbit Articular Cartilage ◽  
Hyaluronic Acid Binding

Antibodies directed against whole bovine nasal-cartilage proteoglycan and against the hyaluronic acid-binding region and chondroitin sulphate peptides from the same molecule were used in immunodiffusion and immunoelectromigration experiments. Proteoglycans from bovine nasal and tracheal cartilage showed immunological identity, with all three antisera. Proteoglycans from pig hip articular cartilage, dog hip articular cartilage, human tarsal articular cartilage and rat chondrosarcoma reacted with all the antisera and showed immunological identity with the corresponding structures isolated from bovine nasal-cartilage proteoglycans. In contrast, proteoglycans from rabbit articular cartilage, rabbit nasal cartilage and cultured chick limb buds did not react with the antibodies directed against the hyaluronic acid-binding region, though reacting with antibodies raised against whole proteoglycan monomer and against chondroitin sulphate peptides. All the proteoglycans gave two precipitation lines with the anti-(chondroitin sulphate peptide) antibodies. Similarly, the proteoglycans reacting with the anti-(hyaluronic acid-binding region) antibodies gave two precipitation lines. The results indicate the presence of at least two populations of aggregating proteoglycan monomers in cartilage. The relative affinity of the antibodies for cartilage proteoglycans and proteoglycan substructures from various species was determined by radioimmunoassay. The affinity of the anti-(hyaluronic acid-binding region) antibodies for the proteoglycans decreased in the order bovine, dog, human and pig cartilage. Rat sternal-cartilage and rabbit articular-cartilage proteoglycans reacted weakly, whereas chick limb-bud and chick sternal-cartilage proteoglycans did not react. In contrast, the affinity of antibodies to chondroitin sulphate peptides for proteoglycans increased in the order bovine cartilage, chick limb bud and chick sternal cartilage, dog cartilage, rat chondrosarcoma, human cartilage, pig cartilage, rat sternal cartilage and rabbit cartilage.

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