The synthesis of type X collagen by bovine and human growth-plate chondrocytes

1991 ◽  
Vol 99 (3) ◽  
pp. 641-649 ◽  
Author(s):  
A. Marriott ◽  
S. Ayad ◽  
M.E. Grant

Chondrocytes were isolated from bovine growth-plate cartilage and cultured within type I collagen gels. A major collagen with chains of Mr 59,000, decreasing to 47,000 on pepsinization, was synthesized and identified as type X collagen. This collagen was cleaved at two sites by mammalian collagenase, resulting in a major triple-helical fragment with chains of Mr 32,000. The species of Mr 59,000, 47,000 and 32,000 were not detected by SDS-polyacrylamide gel electrophoresis before reduction, indicating the presence of disulphide bonds within the triple helix. In contrast, similar biosynthetic studies with human growth-plate cartilage in organ culture, indicated that human type X collagen does not contain disulphide bonds. A polyclonal antiserum was raised to bovine type X collagen and used in immunolocalization studies to provide direct evidence for the association of type X collagen with the hypertrophic chondrocytes in both bovine and human growth plates during development.

1996 ◽  
Vol 109 (5) ◽  
pp. 1119-1131
Author(s):  
R.J. Wardale ◽  
V.C. Duance

Collagen expression in growth plate cartilage derived from broiler chickens with tibial dyschondroplasia was studied and compared with samples from unaffected birds. Normal growth plate contains 12% collagen (dry weight) and dyschondroplastic growth plate 19% collagen compared with articular cartilage, which contains 55%. Dyschondroplastic growth plate collagens were more resistant to extraction by pepsin treatment than were those from unaffected growth plate. Normal and dyschondroplastic growth plate cartilages contain similar amounts of type I collagen (5% of the total collagen) but dyschondroplastic growth plate cartilage contains slightly less type II and type XI collagens, and significantly more type X collagen (25% as compared to 11%) than in normal growth plate. The levels of the mature collagen cross-link, hydroxylysyl-pyridinoline, are very low in normal growth plate but are six times higher in dyschondroplastic lesions. Immunolocalisation studies show that there is little change to the normal patterns of collagen organisation in dyschondroplastic growth plate. Investigation of metalloproteinase activity showed there to be a reduction in MMP-2 levels in dyschondroplastic growth plate compared to normal growth plate. In vitro studies on articular, normal growth plate and dyschondroplastic growth plate chondrocytes cultured in alginate or on plastic revealed differences between the cell types. When plated on plastic, articular chondrocytes rapidly assume a fibroblastic morphology. In contrast, normal growth plate chondrocytes retain their polygonal morphology whereas chondrocytes derived from dyschondroplastic cartilage initially exhibit both fibroblastic and polygonal phenotypes but gradually change to totally fibroblastic. These morphological changes are reflected by the collagen synthesis in vitro. Chondrocytes derived from normal articular cartilage synthesised collagen types I, II and X when cultured in alginate but type X synthesis was lost when cultured on plastic. Chondrocytes derived from normal growth plate cartilage synthesised predominantly type X collagen when cultured in either system. Chondrocytes derived from dyschondroplastic growth plate exhibited a similar phenotype to normal growth plate chondrocytes when cultured in alginate beads, but showed signs of dedifferentiation with reduced type X collagen and increased type I collagen when plated on plastic. These results suggest that the chondrocytes in dyschondroplastic growth plate cartilage are at a different stage of maturity than normal resulting in a cartilage that is failing to turn over at a normal rate.


2005 ◽  
Vol 25 (1) ◽  
pp. 312-323 ◽  
Author(s):  
Wei Wang ◽  
Jinping Xu ◽  
Bin Du ◽  
Thorsten Kirsch

ABSTRACT Mineralization of growth plate cartilage is a critical event during endochondral bone formation, which allows replacement of cartilage by bone. Ankylosis protein (Ank), which transports intracellular inorganic pyrophosphate (PPi) to the extracellular milieu, is expressed by hypertrophic and, especially highly, by terminally differentiated mineralizing growth plate chondrocytes. Blocking Ank transport activity or ank expression in terminally differentiated mineralizing growth plate chondrocytes led to increases of intra- and extracellular PPi concentrations, decreases of alkaline phosphatase (APase) expression and activity, and inhibition of mineralization, whereas treatment of these cells with the APase inhibitor levamisole led to an increase of extracellular PPi concentration and inhibition of mineralization. Ank-overexpressing hypertrophic nonmineralizing growth plate chondrocytes showed decreased intra- and extracellular PPi levels; increased mineralization-related gene expression of APase, type I collagen, and osteocalcin; increased APase activity; and mineralization. Treatment of Ank-expressing growth plate chondrocytes with a phosphate transport blocker (phosphonoformic acid [PFA]) inhibited uptake of inorganic phosphate (Pi) and gene expression of the type III Na+/Pi cotransporters Pit-1 and Pit-2. Furthermore, PFA or levamisole treatment of Ank-overexpressing hypertrophic chondrocytes inhibited APase expression and activity and subsequent mineralization. In conclusion, increased Ank activity results in elevated intracellular PPi transport to the extracellular milieu, initial hydrolysis of PPi to Pi, Pi-mediated upregulation of APase gene expression and activity, further hydrolysis and removal of the mineralization inhibitor PPi, and subsequent mineralization.


1997 ◽  
Vol 139 (2) ◽  
pp. 541-552 ◽  
Author(s):  
Rosa Serra ◽  
Mahlon Johnson ◽  
Ellen H. Filvaroff ◽  
James LaBorde ◽  
Daniel M. Sheehan ◽  
...  

Members of the TGF-β superfamily are important regulators of skeletal development. TGF-βs signal through heteromeric type I and type II receptor serine/threonine kinases. When over-expressed, a cytoplasmically truncated type II receptor can compete with the endogenous receptors for complex formation, thereby acting as a dominant-negative mutant (DNIIR). To determine the role of TGF-βs in the development and maintenance of the skeleton, we have generated transgenic mice (MT-DNIIR-4 and -27) that express the DNIIR in skeletal tissue. DNIIR mRNA expression was localized to the periosteum/perichondrium, syno-vium, and articular cartilage. Lower levels of DNIIR mRNA were detected in growth plate cartilage. Transgenic mice frequently showed bifurcation of the xiphoid process and sternum. They also developed progressive skeletal degeneration, resulting by 4 to 8 mo of age in kyphoscoliosis and stiff and torqued joints. The histology of affected joints strongly resembled human osteo-arthritis. The articular surface was replaced by bone or hypertrophic cartilage as judged by the expression of type X collagen, a marker of hypertrophic cartilage normally absent from articular cartilage. The synovium was hyperplastic, and cartilaginous metaplasia was observed in the joint space. We then tested the hypothesis that TGF-β is required for normal differentiation of cartilage in vivo. By 4 and 8 wk of age, the level of type X collagen was increased in growth plate cartilage of transgenic mice relative to wild-type controls. Less proteoglycan staining was detected in the growth plate and articular cartilage matrix of transgenic mice. Mice that express DNIIR in skeletal tissue also demonstrated increased Indian hedgehog (IHH) expression. IHH is a secreted protein that is expressed in chondrocytes that are committed to becoming hypertrophic. It is thought to be involved in a feedback loop that signals through the periosteum/ perichondrium to inhibit cartilage differentiation. The data suggest that TGF-β may be critical for multifaceted maintenance of synovial joints. Loss of responsiveness to TGF-β promotes chondrocyte terminal differentiation and results in development of degenerative joint disease resembling osteoarthritis in humans.


1994 ◽  
Vol 107 (1) ◽  
pp. 47-59 ◽  
Author(s):  
R.J. Wardale ◽  
V.C. Duance

The articular and growth plate cartilages of osteochondrotic pigs were examined and compared with those from clinically normal animals. Both types of osteochondrotic cartilage showed considerable localised thickening apparently due to a lack of ossification. Histological examination of cartilage lesions demonstrated a breakdown in the normal pattern of chondrocyte maturation. Articular cartilage lesions lacked mature clones of chondrocytes in the calcifying region. Growth plate cartilage showed an accumulation of disorganised hypertrophic chondrocytes rather than the well-defined columns seen in normal tissue. The overall percentages of collagen in osteochondrotic lesions from both articular and growth plate cartilage were significantly reduced compared with levels in unaffected cartilage. There were substantial increases in the proportion of type I collagen in lesions from both osteochondrotic articular and growth plate cartilages and a reduction in the proportion of type II collagen. Type X collagen was detected in osteochondrotic but not normal articular cartilage. The proportion of type X collagen was unchanged in osteochondrotic growth plate cartilage. The levels of the collagen cross-links, hydroxylysylpyridinoline, hydroxylysyl-ketonorleucine and dehydrohydroxylysinonorleucine were radically reduced in samples from osteochondrotic growth-plate cartilage lesions when compared with normal tissue. Less dramatic changes were observed in articular cartilage although there was a significant decrease in the level of hydroxylysylketonorleucine in osteochondrotic lesions. Immunofluorescence examination of osteochondrotic lesions showed a considerable disruption of the organisation of the collagenous components within both articular and growth-plate cartilages. Normal patterns of staining of types I and VI collagen seen at the articular surface in unaffected tissue were replaced by a disorganised, uneven stain in osteochondrotic articular cartilage lesions. Incomplete removal of cartilage at the ossification front of osteochondrotic growth plate was demonstrated by immunofluorescence staining of type IX collagen. Type X collagen was produced in the matrix of the calcifying region of osteochondrotic articular cartilage by small groups of hypertrophic chondrocytes, but was not detected in normal articular cartilage. The distribution of type X collagen was unchanged in osteochondrotic growth plate cartilage.


1988 ◽  
Vol 8 (2) ◽  
pp. 163-171 ◽  
Author(s):  
J. Terrig Thomas ◽  
Michael E. Grant

Chick embryo sternal chondrocytes from the caudal and cephalic regions were cultured within type I collagen gels and type I collagen/proteoglycan aggregate composite gels in normal serum. Caudal region chondrocytes were also cultured within type I collagen gels in the presence of fibronectindepleted serum. There was a marked stimulation of type X collagen synthesis by the caudal region chondrocytes after 9 days in the presence of fibronectin-depleted serum and after 14 days in the presence of proteoglycan aggregate. These results provide evidence for the ability of chondrocytes from a zone of permanent cartilage to synthesise type X collagen and for the involvement of extracellular matrix components in the control of type X collagen gene expression.


1993 ◽  
Vol 105 (4) ◽  
pp. 975-984 ◽  
Author(s):  
R.J. Wardale ◽  
V.C. Duance

The collagens of growth plate and articular cartilage from 5–6 month old commercial pigs were characterised. Growth plate cartilage was found to contain less total collagen than articular cartilage as a proportion of the dry weight. Collagen types I, II, VI, IX and XI are present in both growth plate and articular cartilage whereas type X is found exclusively in growth plate cartilage. Types III and V collagen could not be detected in either cartilage. Type I collagen makes up at least 10% of the collagenous component of both cartilages. There are significant differences in the ratios of the quantifiable collagen types between growth plate and articular cartilage. Collagen types I, II, and XI were less readily extracted from growth plate than from articular cartilage following pepsin treatment, although growth plate cartilage contains less of the mature collagen cross-links, hydroxylysyl-pyridinoline and lysyl-pyridinoline. Both cartilages contain significant amounts of the divalent reducible collagen cross-links, hydroxylysyl-ketonorleucine and dehydro-hydroxylysinonorleucine. Immunofluorescent localisation indicated that type I collagen is located predominantly at the surface of articular cartilage but is distributed throughout the matrix in growth plate. Types II and XI are located in the matrix of both cartilages whereas type IX is predominantly pericellular in the calcifying region of articular cartilage and the hypertrophic region of the growth plate. Collagen type VI is located primarily as a diffuse area at the articular surface.


10.4081/1687 ◽  
2010 ◽  
Vol 46 (3) ◽  
pp. 249 ◽  
Author(s):  
K Huch ◽  
V Mordstein ◽  
J Stöve ◽  
AG Nerlich ◽  
H Arnholdt ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomomi Nakamura ◽  
Motozo Yamashita ◽  
Kuniko Ikegami ◽  
Mio Suzuki ◽  
Manabu Yanagita ◽  
...  

AbstractAutophagy is a lysosomal protein degradation system in which the cell self-digests its intracellular protein components and organelles. Defects in autophagy contribute to the pathogenesis of age-related chronic diseases, such as myocardial infarction and rheumatoid arthritis, through defects in the extracellular matrix (ECM). However, little is known about autophagy in periodontal diseases characterised by the breakdown of periodontal tissue. Tooth-supportive periodontal ligament (PDL) tissue contains PDL cells that produce various ECM proteins such as collagen to maintain homeostasis in periodontal tissue. In this study, we aimed to clarify the physiological role of autophagy in periodontal tissue. We found that autophagy regulated type I collagen synthesis by elimination of misfolded proteins in human PDL (HPDL) cells. Inhibition of autophagy by E-64d and pepstatin A (PSA) or siATG5 treatment suppressed collagen production in HPDL cells at mRNA and protein levels. Immunoelectron microscopy revealed collagen fragments in autolysosomes. Accumulation of misfolded collagen in HPDL cells was confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. E-64d and PSA treatment suppressed and rapamycin treatment accelerated the hard tissue-forming ability of HPDL cells. Our findings suggest that autophagy is a crucial regulatory process that facilitates type I collagen synthesis and partly regulates osteoblastic differentiation of PDL cells.


Author(s):  
Joshua M. Abzug ◽  
Hongying Tian ◽  
Masatake Matsuoka ◽  
Danielle A. Hogarth ◽  
Casey M. Codd ◽  
...  

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