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 ◽  
...  

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.

1983 ◽  
Vol 209 (2) ◽  
pp. 387-400 ◽  
Author(s):  
M T Bayliss ◽  
M Venn ◽  
A Maroudas ◽  
S Y Ali

Full-depth plugs of adult human articular cartilage were cut into serial slices from the articular surface and analysed for their glycosaminoglycan content. The amount of chondroitin sulphate was highest in the mid-zone, whereas keratan sulphate increased progressively through the depth. Proteoglycans were isolated from each layer by extraction with 4M-guanidinium chloride followed by centrifugation in 0.4M-guanidinium chloride/CsCl at a starting density of 1.5 g/ml. The efficiency with which proteoglycans were extracted depended on slice thickness, and extraction was complete only when cartilage from each zone was sectioned at 20 microns or less. When thick sections (250 microns) were extracted, hyaluronic acid was retained in the tissue. Most of the proteoglycans, extracted from each layer under optimum conditions, could interact with hyaluronic acid to form aggregates, although the extent of aggregation was less in the deeper layers. Two pools of proteoglycan were identified in all layers by gel chromatography (Kav. 0.33 and 0.58). The smaller of these was rich in keratan sulphate and protein, and gradually increased in proportion through the cartilage depth. Chondroitin sulphate chain size was constant in all regions. The changes in composition and structure observed were consistent with the current model for hyaline-cartilage proteoglycans and were similar to those observed with increasing age in human articular cartilage.


1978 ◽  
Vol 176 (3) ◽  
pp. 683-693 ◽  
Author(s):  
M T Bayliss ◽  
S Y Ali

1. Analysis of the purified proteoglycans extracted from normal human articular cartilage with 4M-guanidinium chloride showed that there was an age-related increase in their content of protein and keratan sulphate. 2. The hydrodynamic size of the dissociated proteoglycans also decreased with advancing age, but there was little change in the proportion that could aggregate. 3. Results suggested that some extracts of aged-human cartilage had an increased content of hyaluronic acid compared with specimens from younger patients. 4. Dissociated proteoglycans, from cartilage of all age groups, bind to hyaluronic acid and form aggregates in direct proportion to the hyaluronic acid concentration. 5. Electrophoretic heterogeneity of the dissociated proteoglycans was demonstrated on polyacrylamide/agarose gels. The number of proteoglycan species observed was also dependent on the age of the patient.


1986 ◽  
Vol 237 (1) ◽  
pp. 117-122 ◽  
Author(s):  
I K Campbell ◽  
P J Roughley ◽  
J S Mort

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.


1978 ◽  
Vol 169 (1) ◽  
pp. 123-132 ◽  
Author(s):  
M T Bayliss ◽  
S Y Ali

Proteoglycans were extracted from normal human articular cartilage of various ages with 4M-guanidinium chloride and were purified and characterized by using preformed linear CsCl density gradients. With advancing age, there was a decrease in high-density proteoglycans of low protein/uronic acid weight ratio and an increase in the proportion of lower-density proteoglycans, richer in keratan sulphate and protein. Proteoglycans of each age were also shown to disaggregate in 4M-guanidinium chloride and at low pH and to reaggregate in the presence of hyaluronic acid and/or low-density fractions. Osteoarthrotic-cartilage extracts had an increased content of higher-density proteoglycans compared with normal cartilage of the same age, and results also suggested that these were not mechanical or enzymic degradation products, but were possibly proteoglycans of an immature nature.


1985 ◽  
Vol 232 (1) ◽  
pp. 111-117 ◽  
Author(s):  
M T Bayliss ◽  
P J Roughley

Proteoglycan was extracted from adult human articular cartilage from both the knee and the hip, and A1 preparations were prepared by CsCl-density-gradient centrifugation at starting densities of 1.69 and 1.5 g/ml. Irrespective of whether the cartilage was diced to 1 mm cubes or sectioned to 20 micron slices there was always a lower proportion of both protein and proteoglycan aggregate in the A1 preparation prepared at 1.69 g/ml. Furthermore, the addition of exogenous hyaluronic acid to the extracts before centrifugation did not improve the yield of aggregate at 1.69 g/ml. These results were not affected by the presence of proteinase inhibitors in the extraction medium. It appears that adult human articular cartilage contains a high proportion of low-density proteoglycan subunits and hyaluronic acid-binding proteins that make most of the re-formed proteoglycan aggregates of a lower density than is usually encountered with younger human and mammalian hyaline cartilages.


2019 ◽  
Vol 5 (1) ◽  
pp. 171-174 ◽  
Author(s):  
Gözde Dursun ◽  
Bernd Markert ◽  
Marcus Stoffel

AbstractCell-free based approaches are introduced as a promising treatment method for articular cartilage. The success of this method requires cell colonisation from resident tissue into cell-free implants. The objective of our study is to promote the cell colonisation into cell-free collagen I based implants by mechanical stimulation. Therefore, a new in vitro cellular model consisting chondrocyte-seeded matrix and cell-free implants was developed in a polydimethylsiloxan (PDMS) mold. These constructs were cultured under dynamic and static culture conditions. For the dynamic culture, we have developed an in-house bioreactor system where both the load and the deformation applied to the specimen are recorded. Cyclic compression, with a strain of 5% and frequency of 0.1 Hz, was applied to constructs without any break. At the end of three days of dynamic and static cultivation, the cell-free implants were seperated from cell-seeded matrix and cultured in a petri dish three days long. Afterwards, they were analysed using fluoresence dyes. The microscopic assessment indicated that there was a cell migration into the cell-free implants which were cultured dynamically.


1974 ◽  
Vol 139 (3) ◽  
pp. 565-581 ◽  
Author(s):  
Timothy E. Hardingham ◽  
Helen Muir

1. Dissociation of purified proteoglycan aggregates was shown to release an interacting component of buoyant density higher than that of the glycoprotein-link fraction of Hascall & Sajdera (1969). 2. This component, which produced an increase in hydrodynamic size of proteoglycans on gel chromatography, was isolated by ECTEOLA-cellulose ion-exchange chromatography and identified as hyaluronic acid. 3. The effect of pH of extraction showed that the proportion of proteoglycan aggregates isolated from cartilage was greatest at pH4.5. 4. The proportion of proteoglycans able to interact with hyaluronic acid decreased when extracted above or below pH4.5, whereas the amount of hyaluronic acid extracted appeared constant from pH3.0 to 8.5. 5. Sequential extraction of cartilage with 0.15m-NaCl at neutral pH followed by 4m-guanidinium chloride at pH4.5 was shown to yield predominantly non-aggregated and aggregated proteoglycans respectively. 6. Most of the hyaluronic acid in cartilage, representing about 0.7% of the total uronic acid, was associated with proteoglycan aggregates. 7. The non-aggregated proteoglycans were unable to interact with hyaluronic acid and were of smaller size, lower protein content and lower keratan sulphate content than the disaggregated proteoglycans. Together with differences in amino acid composition this suggested that each type of proteoglycan contained different protein cores.


2020 ◽  
Vol 2 (4) ◽  
pp. 100124
Author(s):  
Jessica Feldt ◽  
Jessica Welss ◽  
Verena Schropp ◽  
Kolja Gelse ◽  
Michael Tsokos ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document