scholarly journals Quantitative analysis of type X-collagen biosynthesis by embryonic-chick sternal cartilage

1986 ◽  
Vol 233 (2) ◽  
pp. 357-367 ◽  
Author(s):  
S A Jimenez ◽  
R Yankowski ◽  
A M Reginato

We have performed a quantitative analysis of the various collagens biosynthesized by organ cultures of whole embryonic-chick sternum and its separate anatomical regions corresponding to the zones of permanent hyaline and presumptive-calcification cartilages. Our studies demonstrated that embryonic-chick sternum devotes a large portion of its biosynthetic commitment towards production of Type X collagen, which represented approx. 18% of the total newly synthesized collagen. Comparison of the collagens biosynthesized by the permanent hyaline cartilage and by the cartilage from the presumptive-calcification zone demonstrated that Type X-collagen production was strictly confined to the presumptive-calcification region. Sequential extraction of the newly synthesized Type X collagen demonstrated the existence of two separate populations. One population (approx. 20%) was composed of easily extractable molecules that were solubilized with 1.0 m-NaCl/50 mM-Tris/HCI buffer, pH 7.4. The second population was composed of molecules that were not extractable even after repeated pepsin digestion, but became completely solubilized after treatment with 20 mM-dithiothreitol/0.15 M-NaCl buffer at neutral pH. These results suggest that most of the Type X collagen normally exists in the tissue as part of a pepsin-resistant molecular aggregate that may be stabilized by disulphide bonds. Quantitative analysis of the proportion of Type X collagen relative to the other collagens synthesized in the cultures indicated that this collagen was a major biosynthetic product of the presumptive-calcification cartilage, since it represented about 35% of the total collagen synthesized by this tissue. In contrast, the permanent hyaline cartilage did not display any detectable synthesis of Type X collagen. When compared on a per-cell basis, the chondrocytes from the presumptive-calcification zone synthesized approx. 33% more Type X collagen than the amount of Type II collagen synthesized by the chondrocytes from the permanent-hyaline-cartilage zone. Subsequently, it was demonstrated that Type X collagen is a structural component of chick sternum matrix, since quantitative amounts could be extracted from the region of presumptive calcification of 17-day-old chick-embryo sterna and from the calcified portion of adult-chick sterna. The strict topographic distribution in the expression of Type X collagen biosynthesis to the zone of presumptive calcification suggests that this collagen may play an important role in initiation or progression of tissue calcification.

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 191-196 ◽  
Author(s):  
T.F. Linsenmayer ◽  
Q.A. Chen ◽  
E. Gibney ◽  
M.K. Gordon ◽  
J.K. Marchant ◽  
...  

To examine the regulation of collagen types IX and X during the hypertrophic phase of endochondral cartilage development, we have employed in situ hybridization and immunofluorescence histochemistry on selected stages of embryonic chick tibiotarsi. The data show that mRNA for type X collagen appears at or about the time that we detect the first appearance of the protein. This result is incompatible with translational regulation, which would require accumulation of the mRNA to occur at an appreciably earlier time. Data on later-stage embryos demonstrate that once hypertrophic chondrocytes initiate synthesis of type X collagen, they sustain high levels of its mRNA during the remainder of the hypertrophic program. This suggests that these cells maintain their integrity until close to the time that they are removed at the advancing marrow cavity. Type X collagen protein in the hypertrophic matrix also extends to the marrow cavity. Type IX collagen is found throughout the hypertrophic matrix, as well as throughout the younger cartilaginous matrices. But the mRNA for this molecule is largely or completely absent from the oldest hypertrophic cells. These data are consistent with a model that we have previously proposed in which newly synthesized type X collagen within the hypertrophic zone can become associated with type II/IX collagen fibrils synthesized and deposited earlier in development (Schmid and Linsenmayer, 1990; Chen et al. 1990).


1989 ◽  
Vol 109 (3) ◽  
pp. 1363-1369 ◽  
Author(s):  
B Swoboda ◽  
R Holmdahl ◽  
H Stöss ◽  
K von der Mark

Collagen type XI is a component of hyaline cartilage consisting of alpha 1(XI), alpha 2(XI), and alpha 3(XI) chains; with 5-10% of the total collagen content, it is a minor but significant component next to type II collagen, but its function and precise localization in cartilaginous tissues is still unclear. Owing to the homology of the alpha 3(XI) and alpha 1(II) collagen chains, attempts to prepare specific antibodies to native type XI collagen have been unsuccessful in the past. In this study, we report on the preparation and use for immunohistochemistry of a polyclonal antibody specific for alpha 2(XI) denatured collagen chains. The antibody was prepared by immunization with the isolated alpha 2(XI) chain and reacts neither with native type XI collagen nor type I, II, V, or IX by ELISA or immunoblotting, nor with alpha 1(XI) or alpha 3(XI), but with alpha 2(XI) chains. Using this antibody, it was possible to specifically localize alpha 2(XI) in cartilage by pretreating tissue sections with 6 M urea. In double immunofluorescence staining experiments, the distribution of alpha 2(XI) as indicative for type XI collagen in fetal bovine and human cartilage was compared with that of type II collagen, using a monoclonal antibody to alpha 1(II). Type XI collagen was found throughout the matrix of hyaline cartilage. However, owing to cross-reactivity of the monoclonal anti-alpha 1(II) with alpha 3(XI), both antibodies produced the same staining pattern. Cellular heterogeneity was, however, detected in monolayer cultures of human chondrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)


1989 ◽  
Vol 109 (5) ◽  
pp. 2547-2554 ◽  
Author(s):  
A R Poole ◽  
I Pidoux

Immunofluorescence and immunoelectron microscopy were used in conjunction with a monoclonal antibody to investigate the localization of type X collagen in the proximal tibial growth plate of 7-d-old chicks. This molecule was detected throughout the hypertrophic zone first appearing when chondrocytes exhibited hypertrophy: it was absent from the proliferative zone. Type X collagen was primarily associated with type II collagen fibrils as demonstrated by immunogold staining. Type X collagen was not concentrated in the focal calcification sites nor was it associated with matrix vesicles. These observations suggest that type X collagen may play a role other than that directly related to the nucleation of calcification.


Biochemistry ◽  
1981 ◽  
Vol 20 (12) ◽  
pp. 3523-3527 ◽  
Author(s):  
Larry M. Paglia ◽  
Manfred Wiestner ◽  
Michael Duchene ◽  
Lucille A. Ouellette ◽  
Dietrich Hoerlein ◽  
...  

2020 ◽  
Vol 65 (3) ◽  
pp. 155-162
Author(s):  
E. V. Gladkova

The complete laboratory and clinical instrumental examination was conducted, it included serum COMP test, circadian excretion of type II collagen C-terminal telopeptides Urine CartiLaps (СТХ II) and Т2 relaxometry in 29 patients of both sexes of the main group with early (0-I) X-ray osteoarthrosis stages, 30 subjects of comparison group with no X-ray osteoarthrosis evidences aged 44.7±5.9 years and 25 healthy subjects aged 26.3±2.6 years of the control group. The increase (р<0,05) of COMP and Urine CartiLaps levels as well as the increase of Т2 relaxation signal was found at early osteoarthrosis evidences. It was proven that there was (р<0.01) a connection (R=0.8) between COMP and Urine CTX II levels as well as (р<0.05) results of Т2 relaxometry (R=0.8). It was proven that collagen anisotropy and formation of chondromalacia areas as Т2 relaxometry showed in patients with early OA evidences were connected with accumulation of serum COMP and increase of type II collagen circadian renal excretion. The combination of laboratory and radiological methods of articular hyaline cartilage assessment may be used for finding early osteoarthrosis stages.


1992 ◽  
Vol 119 (4) ◽  
pp. 989-995 ◽  
Author(s):  
R Quarto ◽  
G Campanile ◽  
R Cancedda ◽  
B Dozin

Chondrocytes from chicken embryo tibia can be maintained in culture as adherent cells in Coon's modified Ham's F-12 medium supplemented with 10% FCS. In this condition, they dedifferentiate, losing type II collagen expression in favor of type I collagen synthesis. Their differentiation to hypertrophy can be obtained by transferring them to suspension culture. Differentiation is evidenced by the shift from type I to type II and type IX collagen synthesis and the following predominant expression of type X collagen, all markers of specific stages of the differentiation process. To identify the factors required for differentiation, we developed a serum-free culture system where only the addition of triiodothyronine (T3; 10(-11) M), insulin (60 ng/ml), and dexamethasone (10(-9) M) to the F-12 medium was sufficient to obtain hypertrophic chondrocytes. In this hormonal context, chondrocytes display the same changes in the pattern of protein synthesis as described above. For proper and complete cell maturation, T3 and insulin concentrations cannot be modified. Insulin cannot be substituted by insulin-like growth factor-I, but dexamethasone concentration can be decreased to 10(-12) M without chondrogenesis being impaired. In the latter case, the expression of type X collagen and its mRNA are inversely proportional to dexamethasone concentration. When ascorbic acid is added to the hormone-supplemented medium, differentiating chondrocytes organize their matrix leading to a cartilage-like structure with hypertrophic chondrocytes embedded in lacunae. However, this structure does not present detectable calcification, at variance with control cultures maintained in FCS. Accordingly, in the presence of the hormone mixture, the differentiating chondrocytes have low levels of alkaline phosphatase activity. This report indicates that T3 and insulin are primary factors involved in the onset and progression of chondrogenesis, while dexamethasone supports cell viability and modulates some differentiated functions.


Author(s):  
B.M. Vertel

Normal cartilage function is dependent upon the unique structural properties of the extensive extracellular matrix (ECM). In final assembled form, the ECM of hyaline cartilage is composed of abundant amounts of proteoglycan (PG) and type II collagen. Additional collagens and glycoproteins may be important structural components as well. Through their concentration of negative charges, PGs confer upon the cartilage ECM the ability to retain high levels of hydration and thereby resist compression. Type II collagen fibers contribute to the tensile strength of cartilage.In the cartilage ECM, PG monomers associate with hyaluronic acid and link protein to form large aggregates. In turn, PG aggregates are associated with the fibrous meshwork of type II collagen. Interactions with other ECM molecules may occur as well. The cartilage matrix constituents are themselves large and complex. For example, the PG monomer is 1-5 x 106 daltons in size and contains a core protein of Mr >300K (comprising only 8-10% of the complete monomer).


1977 ◽  
Vol 161 (2) ◽  
pp. 239-245 ◽  
Author(s):  
K B M Reid ◽  
R B Sim ◽  
A P Faiers

1. A fragment of subcomponent C1q, which contained all the collagen-like features present in the intact molecule, was isolated by pepsin digestion as described by Reid [Biochem. J. (1976) 155, 5-17]. 2. The pepsin-derived fragment of subcomponent C1q did not bind to antibody-coated erythrocytes under conditions where complete binding of sub-component C1q took place. 3. The peptic fragment blocked the reconstitution of C1 haemolytic activity by competing with intact subcomponent C1q in the utilization of a mixture of the other two subcomponents, C1r and C1s. 4. Reduction and alkylation of the interchain disulphide bonds in the pepsin fragment did not markedly affect its inhibitory effect, whereas heating at 56 degrees C for 30min completely abolished the effect. 5. Lathyritic rat skin collagen and CNBr-derived peptides of pig type II collagen showed no ability to mimic the inhibitory effect of the pepsin fragment when tested over the same concentration range as used for the peptic fragment. 6. The peptic fragment was unable to block efficiently the reconstitution of C1 haemolytic activity unless it was added to the mixture of subcomponents C1r and C1s before the attempt to reconstitute C1 haemolytic activity, in solution, or on the surface of antibody-coated erythrocytes. 7. Evidence was obtained that suggested that subcomponent C1q bound the subcomponent C1r-C1s complex more efficiently when the subcomponent C1q was bound to antibody than when it was free in solution.


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