scholarly journals AN N-terminal peptide from link protein stimulates proteoglycan biosynthesis in human articular cartilage in vitro

1998 ◽  
Vol 41 (1) ◽  
pp. 157-162 ◽  
Author(s):  
Louise A. McKenna ◽  
Hongxiang Liu ◽  
Paul A. Sansom ◽  
Michael F. Dean
Keyword(s):  
Articular Cartilage ◽  
Human Articular Cartilage ◽  
Link Protein

scholarly journals The action of human articular-cartilage metalloproteinase on proteoglycan and link protein. Similarities between products of degradation in situ and in vitro

1986 ◽  
Vol 237 (1) ◽  
pp. 117-122 ◽  
Author(s):  
I K Campbell ◽  
P J Roughley ◽  
J S Mort
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Interleukin 1 ◽  
Human Articular Cartilage ◽  
Link Protein ◽  
Protein Components ◽  
Stimulation Of ◽  
Hyaluronic Acid Binding

Interleukin 1 stimulation of human articular cartilage in organ culture produced the concomitant release of proteoglycan fragments and latent metalloproteinase. The released fragments ranged in size from that of almost intact proteoglycan subunits to the product of limiting digestion generated by the activated metalloproteinase. None of the fragments possessed the ability to interact with hyaluronic acid. Analysis of proteoglycan aggregate digested with the activated metalloproteinase showed that isolated hyaluronic acid-binding regions were produced from the proteoglycan subunits, and that the two higher-Mr link-protein components (Mr 48,000 and 44,000) were converted into the lowest-Mr component (Mr 41,000). Link protein extracted from cartilage under stimulation with interleukin 1 showed a similar conversion. These results suggest that interleukin 1 stimulates the release of latent metalloproteinase from chondrocytes and that a proportion of the enzyme is activated in situ in the cartilage matrix. The mode of action of the activated enzyme is compatible with a role in the changes in proteoglycan structure seen in aging.

scholarly journals Link protein as a monitor in situ of endogenous proteolysis in adult human articular cartilage

1991 ◽  
Vol 278 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Q Nguyen ◽  
J Liu ◽  
P J Roughley ◽  
J S Mort
Keyword(s):  
Articular Cartilage ◽  
Degradation Products ◽  
Proteolytic Processing ◽  
Cathepsin G ◽  
Human Articular Cartilage ◽  
Link Protein ◽  
Adult Human ◽  
Protein Components

The link protein components of proteoglycan aggregates in adult human articular cartilage show heterogeneity due to proteolysis. Cleavages near the N-terminus of the intact link proteins, before residues 17, 19 and 24, generate three proteins of slightly diminished size (LP3). Cleavages within the N-terminal disulphide-bonded loop, before residues 66 and 73 of the intact link proteins, generate proteins that yield smaller degradation products upon reduction (LP fragments). In vitro, modified link protein components of a similar size to LP3 can be generated by a variety of proteinases, but of the physiologically relevant enzymes only stromelysin, cathepsin B and cathepsin G have the ability to yield modified link proteins with N-termini identical with those observed in situ. None of the proteolytic agents tested was able to produce LP fragments with N-termini identical with those observed in situ, and the majority of proteinases were not able to cleave within the disulphide-bonded loops. Cathepsin L and hydroxyl radicals can cleave within the N-terminal disulphide-bonded loop, and have the potential of initially opening the loop to allow further proteolytic processing by other agents to generate the native cleavage sites.

scholarly journals Biosynthesis of proteoglycan in vitro by cartilage from human osteochondrophytic spurs

1982 ◽  
Vol 206 (2) ◽  
pp. 329-341 ◽  
Author(s):  
Charles J. Malemud ◽  
Victor M. Goldberg ◽  
Roland W. Moskowitz ◽  
Lee L. Getzy ◽  
Robert S. Papay ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Deae Cellulose ◽  
Culture Conditions ◽  
Human Articular Cartilage ◽  
Guanidinium Chloride ◽  
Tissue Slices ◽  
Keratan Sulphate ◽  
Defined Culture

Proteoglycan biosynthesis by human osteochondrophytic spurs (osteophytes) obtained from osteoarthritic femoral heads at the time of surgical joint replacement was studied under defined culture conditions in vitro. Osteophytes were primarily present in two anatomic locations, marginal and epi-articular. Minced tissue slices were incubated in the presence of [35S]sulphate or [14C]glucosamine. Osteophytes incorporated both labelled precursors into proteoglycan, which was subsequently characterized by CsCl-isopycnic-density-gradient ultracentrifugation and chromatography on Sepharose CL-2B. The material extracted with 0.5m-guanidinium chloride showed 78.1% of [35S]sulphate in the A1 fraction after centrifugation. Only 23.0% of the [35S]sulphate in this A1 fraction was eluted in the void volume of Sepharose CL-2B under associative conditions. About 60–80% of the [35S]sulphate in the tissue 4m-guanidinium chloride extract was associated with monomeric proteoglycan (fraction D1). The average partition coefficient (Kav.) of the proteoglycan monomer on Sepharose CL-2B was 0.28–0.33. Approx. 12.4% of this monomer formed stable aggregates with high-molecular-weight hyaluronic acid in vitro. Sepharose CL-2B chromatography of fractions with lower buoyant densities (fractions D2–D4) demonstrated elution profiles on Sepharose CL-2B substantially different than that of fraction D1, indicative of the polydisperse nature of the newly synthesized proteoglycan. Analysis of the composition and chain size of the glycosaminoglycans showed the following: (1) preferential elution of both [35S]sulphate and [14C]glucosamine in the 0.5m-LiCl fraction on DEAE-cellulose; (2) the predominant sulphated glycosaminoglycan was chondroitin 6-sulphate (60–70%), with 9–11% keratan sulphate in the monomer proteoglycan; (3) Kav. values of 0.38 on Sephadex G-200 and 0.48 on Sepharose CL-6B were obtained with papain-digested and NaBH4-treated D1 monomer respectively. A comparison of the synthetic with endogenous glycosaminoglycans indicated similar types. These studies indicated that human osteophytes synthesized in vitro sulphated proteoglycans with some characteristics similar to those of mature human articular cartilage, notably in the size of their proteoglycan monomer and predominance of chondroitin 6-sulphate. They differed from articular cartilage primarily in the lack of substantial quantities of keratan sulphate and aggregation properties associated with monomer interaction with hyaluronic acid.

scholarly journals Recombinant human gelsolin promotes the migration of human articular cartilage chondrocytes by regulating gene expression in vitro

2020 ◽  
Vol 2 (4) ◽  
pp. 100124
Author(s):  
Jessica Feldt ◽  
Jessica Welss ◽  
Verena Schropp ◽  
Kolja Gelse ◽  
Michael Tsokos ◽  
...  
Keyword(s):  
Gene Expression ◽  
Articular Cartilage ◽  
Human Articular Cartilage

scholarly journals Characterization of proteins from human synovium and mononuclear leucocytes that induce resorption of cartilage proteoglycan in vitro

1983 ◽  
Vol 209 (2) ◽  
pp. 337-344 ◽  
Author(s):  
J Saklatvala ◽  
S J Sarsfield ◽  
L M C Pilsworth
Keyword(s):  
Articular Cartilage ◽  
Synovial Tissue ◽  
Gel Filtration ◽  
Human Articular Cartilage ◽  
Nasal Cartilage ◽  
Cartilage Proteoglycan ◽  
Mononuclear Leucocytes ◽  
Culture Supernatants

Both human synovial tissue in culture and lectin-stimulated mononuclear leucocytes produced a protein that induced proteoglycan resorption in explants of bovine nasal cartilage and human articular cartilage. On gel filtration the protein had Mr 16000-20000 and on isoelectric focusing its pI was 5.2-5.3. The protein corresponded to catabolin, which has previously been identified as a product of cultured porcine synovial tissue and mononuclear leucocytes. The action of partially purified human catabolin was not inhibited by cortisol, although the activity of the leucocyte supernatants from which it had been isolated was inhibited. For this reason it is not possible to be sure that the active factor detected in the bioassay of the crude leucocyte culture supernatants is in fact catabolin.

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