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Liu Z, Xie W, Li H, Liu X, Lu Y, Lu B, Deng Z, Li Y. Novel perspectives on leptin in osteoarthritis: Focus on aging. Genes Dis 2024; 11:101159. [PMID: 39229323 PMCID: PMC11369483 DOI: 10.1016/j.gendis.2023.101159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 09/10/2023] [Accepted: 09/16/2023] [Indexed: 09/05/2024] Open
Abstract
Osteoarthritis (OA) is a common chronic joint disease characterized by articular cartilage degeneration, subchondral sclerosis, synovitis, and osteophyte formation. OA is associated with disability and impaired quality of life, particularly among the elderly. Leptin, a 16-kD non-glycosylated protein encoded by the obese gene, is produced on a systemic and local basis in adipose tissue and the infrapatellar fat pad located in the knee. The metabolic mechanisms employed by leptin in OA development have been widely studied, with attention being paid to aging as a corroborative risk factor for OA. Hence, in this review, we have attempted to establish a potential link between leptin and OA, by focusing on aging-associated mechanisms and proposing leptin as a potential diagnostic and therapeutic target in aging-related mechanisms of OA that may provide fruitful guidance and emphasis for future research.
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Affiliation(s)
- Zimo Liu
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Xiangya School of Medicine, Central South University, Changsha, Hunan 410083, China
| | - Wenqing Xie
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Hengzhen Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Xu Liu
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yao Lu
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Xiangya School of Medicine, Central South University, Changsha, Hunan 410083, China
| | - Bangbao Lu
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Zhenhan Deng
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Yusheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
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Rahmati M, Nalesso G, Mobasheri A, Mozafari M. Aging and osteoarthritis: Central role of the extracellular matrix. Ageing Res Rev 2017; 40:20-30. [PMID: 28774716 DOI: 10.1016/j.arr.2017.07.004] [Citation(s) in RCA: 311] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/10/2017] [Accepted: 07/24/2017] [Indexed: 12/11/2022]
Abstract
Osteoarthritis (OA), is a major cause of severe joint pain, physical disability and quality of life impairment in the aging population across the developed and developing world. Increased catabolism in the extracellular matrix (ECM) of the articular cartilage is a key factor in the development and progression of OA. The molecular mechanisms leading to an impaired matrix turnover have not been fully clarified, however cellular senescence, increased expression of inflammatory mediators as well as oxidative stress in association with an inherently limited regenerative potential of the tissue, are all important contributors to OA development. All these factors are linked to and tend to be maximized by aging. Nonetheless the role of aging in compromising joint stability and function in OA has not been completely clarified yet. This review will systematically analyze cellular and structural changes taking place in the articular cartilage and bone in the pathogenesis of OA which are linked to aging. A particular emphasis will be placed on age-related changes in the phenotype of the articular chondrocytes.
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Affiliation(s)
- Maryam Rahmati
- Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran; Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Giovanna Nalesso
- Department of Veterinary Pre-Clinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Ali Mobasheri
- The D-BOARD European Consortium for Biomarker Discovery, The APPROACH Innovative Medicines Initiative (IMI) Consortium, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK; Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Arthritis Research UK Pain Centre, Medical Research Council and Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK; Center of Excellence in Genomic Medicine Research (CEGMR), King Fahd Medical Research Center (KFMRC) and Sheik Salem Bin Mahfouz Scientific Chair for Treatment of Osteoarthritis with Stem Cells, King AbdulAziz University, Jeddah, 21589, Saudi Arabia
| | - Masoud Mozafari
- Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran; Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran; Bioengineering Research Group, Nanotechnology and Advanced Materials Department, Materials and Energy Research Center (MERC), P.O. Box 14155-4777, Tehran, Iran.
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Roughley PJ, Mort JS. The role of aggrecan in normal and osteoarthritic cartilage. J Exp Orthop 2014; 1:8. [PMID: 26914753 PMCID: PMC4648834 DOI: 10.1186/s40634-014-0008-7] [Citation(s) in RCA: 211] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 05/22/2014] [Indexed: 01/13/2023] Open
Abstract
Aggrecan is a large proteoglycan bearing numerous chondroitin sulfate and keratan sulfate chains that endow articular cartilage with its ability to withstand compressive loads. It is present in the extracellular matrix in the form of proteoglycan aggregates, in which many aggrecan molecules interact with hyaluronan and a link protein stabilizes each interaction. Aggrecan structure is not constant throughout life, but changes due to both synthetic and degradative events. Changes due to synthesis alter the structure of the chondroitin sulfate and keratan sulfate chains, whereas those due to degradation cause cleavage of all components of the aggregate. These latter changes can be viewed as being detrimental to cartilage function and are enhanced in osteoarthritic cartilage, resulting in aggrecan depletion and predisposing to cartilage erosion. Matrix metalloproteinases and aggrecanases play a major role in aggrecan degradation and their production is upregulated by mediators associated with joint inflammation and overloading. The presence of increased levels of aggrecan fragments in synovial fluid has been used as a marker of ongoing cartilage destruction in osteoarthritis. During the early stages of osteoarthritis it may be possible to retard the destructive process by enhancing the production of aggrecan and inhibiting its degradation. Aggrecan production also plays a central role in cartilage repair techniques involving stem cell or chondrocyte implantation into lesions. Thus aggrecan participates in both the demise and survival of articular cartilage.
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Affiliation(s)
- Peter J Roughley
- Shriners Hospital for Children and McGill University, Montreal, Quebec, Canada.
| | - John S Mort
- Shriners Hospital for Children and McGill University, Montreal, Quebec, Canada.
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Characterization of opticin digestion by proteases involved in osteoarthritis development. Joint Bone Spine 2013; 81:137-41. [PMID: 23845380 DOI: 10.1016/j.jbspin.2013.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 05/23/2013] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Opticin is a class III member of the small leucine-rich repeat proteoglycan (SLRP) family, produced in articular joint tissues. In normal and osteoarthritic (OA) cartilage, opticin is degraded. This study aimed to assess whether human cartilage opticin is degraded by the main proteases involved in OA pathophysiology, and to determine the protease cleavage sites of this SLRP. METHODS We analyzed the proteolytic activity of matrix metalloproteinases (MMPs)-1, -2, -3, -7, -8 and -9, and ADAMTS-4 and -5 on proteoglycan extracts from normal and moderately fibrillated OA human cartilage, and on recombinant human opticin. Opticin degradation was analyzed by Western blotting and cleavage sites were determined by sequence analysis. RESULTS All eight proteases digested opticin from proteoglycan extracts from both normal and OA samples, as well as recombinant human opticin, MMP-2 and MMP-7 are the proteases that degrade recombinant human opticin most efficiently. The opticin cleavage site determined for these MMPs was between the glycosylation and leucine-rich repeat domains. MMP-7 had two additional digestion sites near the N-terminal end of opticin. CONCLUSION Opticin is a substrate for several MMPs and aggrecanases involved during OA cartilage degradation, and seems to be a preferential substrate for MMP-7. The role of opticin in cartilage degeneration could be related to decreased levels of intact opticin, followed by its proteolytic degradation, which in turn may stimulate some of the modifications observed in the OA cartilage, such as neovascularisation and changes in the extracellular matrix.
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Abstract
STUDY DESIGN Histologic analysis of spine development in cartilage-specific knockout mice. OBJECTIVE To evaluate the role hyaluronan produced by hyaluronan synthase-2 (Has2) in spine development. SUMMARY OF BACKGROUND DATA The Has2 gene is responsible for most hyaluronan production throughout the body, including the skeleton. However, it is not possible to study the involvement of hyaluronan in skeletal development using constitutive Has2 knockout mice, as the embryonic mice die early before skeletal development has occurred. This problem can be overcome by the use of cartilage-specific knockout mice. METHODS Mice possessing floxed Has2 genes were crossed with mice expressing Cre recombinase under control of the type II collagen promoter to generate cartilage-specific Has2 knockout mice. Spine development was studied by histology. RESULTS Knockout mice died near birth and displayed severe abnormality in skeletal development. The spine showed defects in vertebral body size and the formation of the intervertebral discs. There was no evidence for the formation of an organized primary center of ossification within the vertebrae, and the appearance and organization of the hypertrophic chondrocytes was abnormal. Although no organized endochondral ossification appeared to be taking place, there was excessive bone formation at the center of the vertebrae. There was also a generalized increased cellularity of the vertebral cartilage and a corresponding decrease in the abundance of extracellular matrix. The nucleus pulposus of the intervertebral discs were less flattened than in the control mice and possessed an increased amount of large vacuolated cells. Remnants of the notochord could also be seen between adjacent discs. CONCLUSION Hyaluronan production by Has2 is essential for normal vertebral and intervertebral disc development within the spine, and the absence of this synthase impairs the organization of both soft and hard tissue elements.
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Stevens AL, Wishnok JS, White FM, Grodzinsky AJ, Tannenbaum SR. Mechanical injury and cytokines cause loss of cartilage integrity and upregulate proteins associated with catabolism, immunity, inflammation, and repair. Mol Cell Proteomics 2009; 8:1475-89. [PMID: 19196708 DOI: 10.1074/mcp.m800181-mcp200] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The objectives of this study were to perform a quantitative comparison of proteins released from cartilage explants in response to treatment with IL-1beta, TNF-alpha, or mechanical compression injury in vitro and to interpret this release in the context of anabolic-catabolic shifts known to occur in cartilage in response to these insults in vitro and their implications in vivo. Bovine calf cartilage explants from 6-12 animals were subjected to injurious compression, TNF-alpha (100 ng/ml), IL-1beta (10 ng/ml), or no treatment and cultured for 5 days in equal volumes of medium. The pooled medium from each of these four conditions was labeled with one of four iTRAQ labels and subjected to nano-2D-LC/MS/MS on a quadrupole time-of-flight instrument. Data were analysed by ProQuant for peptide identification and quantitation. k-means clustering and biological pathways analysis were used to identify proteins that may correlate with known cartilage phenotypic responses to such treatments. IL-1beta and TNF-alpha treatment caused a decrease in the synthesis of collagen subunits (p < 0.05) as well as increased release of aggrecan G2 and G3 domains to the medium (p < 0.05). MMP-1, MMP-3, MMP-9, and MMP-13 were significantly increased by all treatments compared with untreated samples (p < 0.10). Increased release of proteins involved in innate immunity and immune cell recruitment were noted following IL-1beta and TNF-alpha treatment, whereas increased release of intracellular proteins was seen most dramatically with mechanical compression injury. Proteins involved in insulin-like growth factor and TGF-beta superfamily pathway modulation showed changes in pro-anabolic pathways that may represent early repair signals. At the systems level, two principal components were sufficient to describe 97% of the covariance in the data. A strong correlation was noted between the proteins released in response to IL-1beta and TNF-alpha; in contrast, mechanical injury resulted in both similarities and unique differences in the groups of proteins released compared with cytokine treatment.
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Affiliation(s)
- Anna L Stevens
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Monfort J, Tardif G, Roughley P, Reboul P, Boileau C, Bishop PN, Pelletier JP, Martel-Pelletier J. Identification of opticin, a member of the small leucine-rich repeat proteoglycan family, in human articular tissues: a novel target for MMP-13 in osteoarthritis. Osteoarthritis Cartilage 2008; 16:749-55. [PMID: 18164633 DOI: 10.1016/j.joca.2007.11.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 11/17/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE One of the proteoglycan families is the small leucine-rich proteoglycans (SLRPs) that are characterized by their association with collagen fibrils and/or some glycosaminoglycans. Opticin is a glycoprotein and class III member of the SLRP family, which was initially identified in the vitreous humour of the eye. In this study, we first investigated whether opticin is expressed and produced in normal and OA human articular tissues/cells. Further, we investigated the ability of the key metalloprotease involved in cartilage pathology, MMP-13, to cleave human cartilage opticin. METHODS Opticin gene expression was investigated in normal and OA human chondrocytes, synovial fibroblasts, and subchondral bone osteoblasts by reverse transcriptase-polymerase chain reaction (RT-PCR). Opticin protein production was determined in normal and OA synovial membrane and cartilage by immunohistochemistry. Opticin was isolated from human cartilage using guanidinium chloride extraction, and human MMP-13-induced opticin degradation analyzed by Western blotting. Finally, the opticin MMP-13 cleavage site was determined. RESULTS Opticin was expressed in human chondrocytes, synovial fibroblasts and subchondral osteoblasts, and the protein identified in synovial membrane and cartilage. At the protein level, OA cartilage showed a slightly higher level of opticin positive stained chondrocytes than normal cartilage; this did not reach statistical significance. However, in contrast with OA, normal cartilage demonstrated a high level of matrix staining in the superficial zone of the tissue, suggesting that in the OA cartilage matrix, opticin is degraded. Data also showed that cartilage opticin could be cleaved by MMP-13 after only 2h of incubation, indicating a preferential substrate compared to other SLRPs for this enzyme. Microsequencing revealed a major cleavage site at the G(104)/L(105)LAAP and a minor at P(109)/A(110)NHPG upon MMP-13 exposure. CONCLUSION We demonstrated, for the first time, that opticin is expressed and produced in human articular tissues. Our data also showed that opticin in OA cartilage is degraded in a process that could be mediated by MMP-13. As opticin may contribute towards the structural stability of cartilage, its cleavage by MMP-13 may predispose cartilage to degeneration, particularly at the surface.
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Affiliation(s)
- J Monfort
- Department of Rheumatology, Universitat Autonoma de Barcelona, Hospital del Mar, Passeig del Mar, Barcelona 08003, Spain
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Mason RM, Crossman MV, Sweeney C. Hyaluronan and hyaluronan-binding proteins in cartilaginous tissues. CIBA FOUNDATION SYMPOSIUM 2007; 143:107-16; discussion 117-20, 281-5. [PMID: 2680341 DOI: 10.1002/9780470513774.ch7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Recent developments in the biology of hyaluronan in cartilage are reviewed. The homology between the hyaluronan-binding sites of cartilage proteoglycan and link protein is discussed. Previous reports indicate that an increased concentration of extracellular hyaluronan inhibits 35S-proteoglycan synthesis by several types of chondrocyte. We report data showing that this response varies in its reproducibility and sensitivity to low concentrations of hyaluronan in rat chondrosarcoma chondrocytes and pig laryngeal chondrocytes in suspension culture. Two newly recognized hyaluronan-binding proteins have been isolated from extracts of Swarm rat chondrosarcoma. The major protein has a molecular mass of 102 kDa and the less prominent protein a molecular mass of 91 kDa. The latter may be derived from the former. Neither protein cross-reacts with antisera against cartilage proteoglycan HABR (hyaluronan-binding region), link protein, hyaluronectin or type II collagen.
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Affiliation(s)
- R M Mason
- Department of Biochemistry, Charing Cross and Westminster Medical School, London, UK
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Hardingham TE, Beardmore-Gray M, Dunham DG, Ratcliffe A. Cartilage proteoglycans. CIBA FOUNDATION SYMPOSIUM 2007; 124:30-46. [PMID: 3816421 DOI: 10.1002/9780470513385.ch3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The structure of the protein core of the high molecular weight aggregating proteoglycan from pig laryngeal cartilage has been investigated. Mild trypsin digestion of proteoglycan aggregates released a large (Mr approximately equal to 150K) protein-rich fragment that contained the hyaluronate-binding region (Mr 66K). Rotary-shadowing electron microscopy of this preparation showed it to contain 'double globe' structures, similar to those seen with intact proteoglycans. Interaction studies and immunochemical evidence showed that one of the globular domains was the binding region. The second globular domain did not interact with hyaluronate or share any major antigenic determinants with the binding region and its function remains unknown. Further evidence from rotary shadowing also suggested that the protein core contained a third globular domain at the C-terminal end. The complete protein core sequence thus contains long folded globular protein regions, in addition to the extended regions bearing glycosaminoglycan chains. Studies of proteoglycan turnover in explants of pig articular cartilage showed that proteoglycan fragments were continuously released into the medium during culture. These included large non-aggregating proteoglycan fragments, free binding region and also link protein. Proteoglycans retained within the cartilage matrix remained intact and able to aggregate. Only in the presence of interleukin 1 was there evidence of more extensive proteolytic digestion. The results suggest normal turnover to be a conservative mechanism involving the selective cleavage of proteoglycan close to the hyaluronate-binding region. This releases the major glycosaminoglycan-bearing domain and enables it to diffuse out of the matrix. The site of the initial cleavage appears to be in the region of the N-terminal globular domains.
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Monfort J, Tardif G, Reboul P, Mineau F, Roughley P, Pelletier JP, Martel-Pelletier J. Degradation of small leucine-rich repeat proteoglycans by matrix metalloprotease-13: identification of a new biglycan cleavage site. Arthritis Res Ther 2006; 8:R26. [PMID: 16507124 PMCID: PMC1526547 DOI: 10.1186/ar1873] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 11/25/2005] [Accepted: 11/28/2005] [Indexed: 11/10/2022] Open
Abstract
A major and early feature of cartilage degeneration is proteoglycan breakdown. Matrix metalloprotease (MMP)-13 plays an important role in cartilage degradation in osteoarthritis (OA). This MMP, in addition to initiating collagen fibre cleavage, acts on several proteoglycans. One of the proteoglycan families, termed small leucine-rich proteoglycans (SLRPs), was found to be involved in collagen fibril formation/interaction, with some members playing a role in the OA process. We investigated the ability of MMP-13 to cleave members of two classes of SLRPs: biglycan and decorin; and fibromodulin and lumican. SLRPs were isolated from human normal and OA cartilage using guanidinium chloride (4 mol/l) extraction. Digestion products were examined using Western blotting. The identities of the MMP-13 degradation products of biglycan and decorin (using specific substrates) were determined following electrophoresis and microsequencing. We found that the SLRPs studied were cleaved to differing extents by human MMP-13. Although only minimal cleavage of decorin and lumican was observed, cleavage of fibromodulin and biglycan was extensive, suggesting that both molecules are preferential substrates. In contrast to biglycan, decorin and lumican, which yielded a degradation pattern similar for both normal and OA cartilage, fibromodulin had a higher level of degradation with increased cartilage damage. Microsequencing revealed a novel major cleavage site (... G177/V178) for biglycan and a potential cleavage site for decorin upon exposure to MMP-13. We showed, for the first time, that MMP-13 can degrade members from two classes of the SLRP family, and identified the site at which biglycan is cleaved by MMP-13. MMP-13 induced SLRP degradation may represent an early critical event, which may in turn affect the collagen network by exposing the MMP-13 cleavage site in this macromolecule. Awareness of SLRP degradation products, especially those of biglycan and fibromodulin, may assist in early detection of OA cartilage degradation.
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Affiliation(s)
- Jordi Monfort
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
| | - Ginette Tardif
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
| | - Pascal Reboul
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
| | - François Mineau
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
| | - Peter Roughley
- Genetics Unit, Shriner's Hospital for Children, 1529 Cedar Avenue, Montreal, Quebec H3G 1A6, Canada
| | - Jean-Pierre Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
| | - Johanne Martel-Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke Street East, Montreal, Quebec H2L 4M1, Canada
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Embry JJ, Knudson W. G1 domain of aggrecan cointernalizes with hyaluronan via a CD44-mediated mechanism in bovine articular chondrocytes. ACTA ACUST UNITED AC 2004; 48:3431-41. [PMID: 14673994 DOI: 10.1002/art.11323] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To determine whether aggrecan fragments bound to hyaluronan (HA) can be retained and internalized by articular chondrocytes and whether these events are dependent on HA and its receptor, CD44. An additional objective was to determine whether partial degradation of aggrecan is a prerequisite for internalization. METHODS Binding and internalization of a variety of fluorescein isothiocyanate (FITC)- or biotin-labeled HA/proteoglycan probes were investigated on normal bovine articular cartilage chondrocytes, bovine articular chondrocytes transfected with a dominant-negative construct of CD44, or COS-7 cells transfected with wild-type CD44. The probes were defined as being internalized by the presence of label associated with the cells following extensive trypsinization of the cell surface. RESULTS Biotinylated aggrecan fragments bound to FITC-HA were cointernalized in bovine articular chondrocytes or COS-7 cells transfected with CD44. Intracellular vesicles containing FITC-HA colocalized with a fluorescent probe for lysosomes. The internalization of the aggrecan fragments was dependent on the presence of HA as well as the presence of functional CD44. Intact aggrecan/FITC-HA complexes bound to the cell surface but were not internalized. However, following brief trypsin digestion of the aggrecan/HA complex, the remaining proteoglycan fragments were bound and internalized. CONCLUSION Partially degraded aggrecan fragments (e.g., aggrecan G1 domains bound to HA) can be internalized by articular chondrocytes via a mechanism involving HA/CD44-mediated endocytosis. Further, the presence of an intact aggrecan monomer bound to HA inhibits the internalization of HA as well as HA-bound fragments.
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Affiliation(s)
- Jennifer J Embry
- Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA
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Chockalingam PS, Zeng W, Morris EA, Flannery CR. Release of hyaluronan and hyaladherins (aggrecan G1 domain and link proteins) from articular cartilage exposed to ADAMTS-4 (aggrecanase 1) or ADAMTS-5 (aggrecanase 2). ACTA ACUST UNITED AC 2004; 50:2839-48. [PMID: 15457452 DOI: 10.1002/art.20496] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To determine whether aggrecanase (ADAMTS) activities in articular cartilage can directly lead to the release of hyaluronan (HA) and hyaladherins (aggrecan G1 domain and link proteins), as may occur ex vivo during stimulation of cartilage explants with interleukin-1 (IL-1) or retinoic acid or in vivo in synovial joints during aging and joint pathology. METHODS Bovine articular cartilage discs (live or freeze-killed) were cultured in the presence of IL-1 or were incubated in digestion buffer containing recombinant human ADAMTS-4 (rHuADAMTS-4; aggrecanase 1) or rHuADAMTS-5 (aggrecanase 2). Culture media, digestion supernatants, and tissue extracts were assayed for sulfated glycosaminoglycan (sGAG) content and analyzed by Western blotting to detect aggrecanase-generated G1 domain (using neoepitope monoclonal antibody AGG-C1/anti-NITEGE(373)) and link proteins (using monoclonal antibody 8-A-4), as well as by quantitative enzyme-linked immunosorbent assays to detect aggrecanase-generated G1 domain (G1-NITEGE(373)) and HA. RESULTS IL-1 treatment of live cartilage explants induced a time-dependent release of sGAG, aggrecanase-generated G1 domain (G1-NITEGE(373)), and HA into the culture media. Exposure of live or freeze-killed articular cartilage discs to rHuADAMTS-4 or rHuADAMTS-5 resulted in a dose- and time-dependent release of sGAG and hyaluronan from the tissue, accompanied by a concomitant release of functionally intact hyaladherins (aggrecan G1-NITEGE(373) and link proteins). CONCLUSION Coincident with aggrecanolysis, aggrecanase activities in articular cartilage may actuate the release of HA and associated hyaladherins, thereby further compromising the integrity of the cartilage matrix during degenerative joint diseases such as osteoarthritis.
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Yang BL, Yang BB, Erwin M, Ang LC, Finkelstein J, Yee AJM. Versican G3 domain enhances cellular adhesion and proliferation of bovine intervertebral disc cells cultured in vitro. Life Sci 2003; 73:3399-413. [PMID: 14572881 DOI: 10.1016/j.lfs.2003.06.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The functional role of versican in influencing intervertebral disc cell adhesion and proliferation was analyzed in bovine intervertebral disc. We have previously demonstrated the C-terminal globular G3 (or selectin-like) domain of versican to influence mesenchymal chondrogenesis and fibroblast proliferation in vitro. For this study, a versican G3 expression construct was generated to examine the role of the G3 domain of versican. Nucleus pulposus and annulus fibrosus cells were isolated from adult bovine caudal discs using sequential enzymatic digestion and versican expression characterized by RT-PCR. In cell proliferation assays, we observed that there was greater cellular proliferation in the presence of versican G3 for both disc cell types. The higher proliferation rate of annulus fibrosus cells when compared to nucleus pulposus cells seeded in monolayer supports heterogeneity of intervertebral disc cell populations. The presence of versican G3 construct enhanced the adhesion of isolated nucleus pulposus and annulus fibrosus cells approximately 4 to 6 fold, respectively. Cellular adhesion was greater in the presence of versican G3 in a dose dependent manner. G3 product was purified using affinity columns, and the purified G3 also enhanced cell adhesion.
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Affiliation(s)
- Bing L Yang
- Sunnybrook and Women's College Health Sciences Centre, and University of Toronto, Toronto, Ontario, Canada
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Sztrolovics R, Grover J, Cs-Szabo G, Shi SL, Zhang Y, Mort JS, Roughley PJ. The characterization of versican and its message in human articular cartilage and intervertebral disc. J Orthop Res 2002; 20:257-66. [PMID: 11918305 DOI: 10.1016/s0736-0266(01)00110-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Splicing variation of the versican message and size heterogeneity of the versican core protein were analyzed in human articular cartilage and intervertebral disc. Splicing variation of the message was studied by PCR analysis to detect the presence or absence of exons 7 and 8, which encode large chondroitin sulfate attachment regions. At all ages in normal cartilage from the third trimester fetus to the mature adult, the presence of the versican isoform possessing exon 8 but not exon 7 (V1) could be readily detected. The message isoforms possessing neither exon 7 nor 8 (V3) or both exons 7 and 8 (V0) were only detectable in the fetus, and the isoform possessing only exon 7 (V2) was never detected. In osteoarthritic cartilage and in adult intervertebral disc the versican message pattern was the same as that observed in the normal adult with only the isoform possessing exon 8 being detected. Core protein heterogeneity was studied by immunoblotting following enzymic removal of the glycosaminoglycan chains from the proteoglycan, using an antibody recognizing the globular G1 region of versican. All articular cartilage extracts from the fetus to the mature adult contained multiple core protein sizes of greater than 200 kDa. The adult cartilage extracts tended to have an increased proportion of the smaller sized core proteins and osteoarthritic cartilage possessed similar core protein sizes to the normal adult. In contrast, intervertebral disc at all post-natal ages showed a greater range of size heterogeneity with a prominent component of about 50 kDa. The abundance of this component increased if the samples were treated with keratanase prior to analysis, suggesting that the G1 region of versican in disc can be substituted with keratan sulfate. The increased presence of versican in the disc relative to articular cartilage may suggest a more pronounced functional role for this proteoglycan, particularly in the nucleus pulposus.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Alternative Splicing
- Cartilage, Articular/embryology
- Cartilage, Articular/metabolism
- Child
- Child, Preschool
- Chondroitin Sulfate Proteoglycans/biosynthesis
- Chondroitin Sulfate Proteoglycans/genetics
- Fetus
- Humans
- Infant
- Infant, Newborn
- Intervertebral Disc/embryology
- Intervertebral Disc/metabolism
- Knee Joint/anatomy & histology
- Knee Joint/embryology
- Knee Joint/pathology
- Lectins, C-Type
- Middle Aged
- Osteoarthritis, Knee/metabolism
- Osteoarthritis, Knee/pathology
- Osteoarthritis, Knee/surgery
- Proteoglycans/biosynthesis
- Proteoglycans/genetics
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Versicans
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15
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Abstract
The structure of the extracellular matrix of articular cartilage varies considerably with age. These changes are attributable to variations in molecular abundance and structure, and they can affect all the matrix components, but none more so than the proteoglycans. Some of these changes are attributable to variations in synthesis whereas others are attributable to variations in degradation, some of the changes occur during juvenile development whereas others occur throughout life, and some of the changes are beneficial to cartilage function whereas others are detrimental. These variations result in a cartilage that not only changes in its phenotype with age, but also in one whose functional properties are changing continuously throughout life. In a similar manner, the cartilage formed during repair also may show considerable variation in structure and function, depending on whether tissue is being replaced or regenerated and whether mature or immature cells are being used. Because all cartilage is not ceated equal, different repair techniques may not be equally efficacious.
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Affiliation(s)
- P J Roughley
- Shriners Hospital for Children and Department of Surgery, McGill University, Montreal, Quebec, Canada
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16
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Abstract
Aggrecan in cartilage forms aggregates with hyaluronan and link protein, embedded in a collagen network. It accounts for the compressive stiffness and resilience of the hyaline cartilage. Many forms of inflammatory arthritis were shown to be accompanied with aggrecan degradation and loss from the cartilage. The loss of this major component of cartilage renders the tissue more vulnerable when exposed to abrasive forces. Therefore, aggrecan degradation may significantly contribute to cartilage destruction in arthritis. Furthermore, fragments of degraded aggrecan are released during joint inflammation. Thus, molecules of an avascular, immune-privileged tissue (hyaline cartilage) may become accessible to the cells of the immune system. Similarly, there is a "leakage" of aggrecan fragments from cartilage during aging and after joint injury, which may also lead to autosensibilisation. Autoimmune reactivity to aggrecan can be detected in human joint diseases, as well as in animal models of arthritis. The epitopes involved in these processes are currently being identified. Recent data from work with mice suggest a strong immune response focused to the N-terminal G1 domain of aggrecan that leads to arthritis and spondylitis.
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Affiliation(s)
- Edit I Buzás
- University of Medicine, The Institute of Anatomy, Histology and Embryology, Debrecen, Hungary
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17
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Caterson B, Flannery CR, Hughes CE, Little CB. Mechanisms involved in cartilage proteoglycan catabolism. Matrix Biol 2000; 19:333-44. [PMID: 10963994 DOI: 10.1016/s0945-053x(00)00078-0] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The increased catabolism of the cartilage proteoglycan aggrecan is a principal pathological process which leads to the degeneration of articular cartilage in arthritic joint diseases. The consequent loss of sulphated glycosaminoglycans, which are intrinsic components of the aggrecan molecule, compromises both the functional and structural integrity of the cartilage matrix and ultimately renders the tissue incapable of resisting the compressive loads applied during joint articulation. Over time, this process leads to irreversible cartilage erosion. In situ degradation of aggrecan is a proteolytic process involving cleavage at specific peptide bonds located within the core protein. The most well characterised enzymatic activities contributing to this process are engendered by zinc-dependent metalloproteinases. In vitro aggrecanolysis by matrix metalloproteinases (MMPs) has been widely studied; however, it is now well recognised that the principal proteinases responsible for aggrecan degradation in situ in articular cartilage are the aggrecanases, two recently identified isoforms of which are members of the 'A Disintegrin And Metalloproteinase with Thrombospondin motifs' (ADAMTS) gene family. In this review we have described: (i) the development of monoclonal antibody technologies to identify catabolic neoepitopes on aggrecan degradation products; (ii) the use of such neoepitope antibodies in studies designed to characterise and identify the enzymes responsible for cartilage aggrecan metabolism; (iii) the biochemical properties of soluble cartilage aggrecanase(s) and their differential expression in situ; and (iv) model culture systems for studying cartilage aggrecan catabolism. These studies have clearly established that 'aggrecanase(s)' is primarily responsible for the catabolism and loss of aggrecan from articular cartilage in the early stages of arthritic joint diseases that precede overt collagen catabolism and disruption of the tissue integrity. At later stages, when collagen catabolism is occurring, there is evidence for MMP-mediated degradation of the small proportion of aggrecan remaining in the tissue, but this occurs independently of continued aggrecanase activity. Furthermore, the catabolism of link proteins by MMPs is also initiated when overt collagen degradation is evident.
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Affiliation(s)
- B Caterson
- Connective Tissue Biology Laboratories, Cardiff School of Biosciences, Cardiff University, Museum Avenue, CF10 3US, Wales, Cardiff, UK.
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18
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Liu H, McKenna LA, Dean MF. The macromolecular characteristics of cartilage proteoglycans do not change when synthesis is up-regulated by link protein peptide. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1428:191-200. [PMID: 10434036 DOI: 10.1016/s0304-4165(99)00074-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previous studies have shown that a synthetic, unglycosylated analogue of the N-terminal peptide from link protein can function as a growth factor and up-regulate proteoglycan biosynthesis in explant cultures of normal human articular cartilage from a wide age range of subjects (McKenna et al., Arthritis Rheum. 41 (1998) 157-162). The present work further shows that link peptide increased proteoglycan synthesis by cartilage cultured in both the presence and absence of serum, suggesting that the mechanism of up-regulation may be different from that of insulin-like growth factors. The proteoglycans synthesised during stimulation with link peptide were of normal hydrodynamic size and the ratio of core protein to glycosaminoglycan side chains and the proportions of the large proteoglycan aggrecan to the small proteoglycans, decorin and biglycan, remained constant. Aggrecan molecules were equally capable of forming aggregates as those from control tissues and the relative proportions of decorin and biglycan were unchanged showing that both were co-ordinately up-regulated. These results confirmed that this novel peptide is a potent stimulator of proteoglycan synthesis by articular cartilage and showed that the newly synthesised proteoglycans were of normal composition.
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Affiliation(s)
- H Liu
- Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
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19
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Sztrolovics R, White RJ, Poole AR, Mort JS, Roughley PJ. Resistance of small leucine-rich repeat proteoglycans to proteolytic degradation during interleukin-1-stimulated cartilage catabolism. Biochem J 1999; 339 ( Pt 3):571-7. [PMID: 10215595 PMCID: PMC1220192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A bovine nasal-cartilage culture system has been utilized to analyse the catabolic events occurring in response to interleukin-1beta 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.
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Affiliation(s)
- R Sztrolovics
- Joint Diseases Laboratory, Shriners Hospital for Children, 1529 Cedar Avenue, Montreal, Quebec, Canada H3G 1A6
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20
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Cao L, Yang BB. Chondrocyte apoptosis induced by aggrecan G1 domain as a result of decreased cell adhesion. Exp Cell Res 1999; 246:527-37. [PMID: 9925769 DOI: 10.1006/excr.1998.4335] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major feature of cartilage deterioration during joint injury and disease is aggrecan degradation and the loss of proteoglycan. Most of the degraded fragments are released into the circulatory system except the G1 domain which accumulates locally in the synovial fluid and cartilage because of its hyaluronan-binding ability. In this study, our objective was to investigate the effects of G1 accumulation on chondrocyte function. We chose to mimic the accumulation of G1 domain by developing a method to express G1 in chondrocytes. We transiently and stably expressed aggrecan G1 domain in the cells and tested the effects of G1 in cell adhesion and apoptosis. Overexpression of the G1 construct induced apoptosis in adherent chondrocytes but not in chondrocytes maintained in suspension cultures. Higher levels of G1 expression caused greater reduction in cell-substratum interaction and induced more cell death. The effect was dose dependent. To corroborate our findings, the role of G1 in reducing adhesion and inducing apoptosis was further investigated in fibroblasts. We found that low adherent cultures also had high levels of apoptosis. Our results suggest that G1 induced apoptosis by destabilizing cell-substratum interaction.
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Affiliation(s)
- L Cao
- Sunnybrook Health Science Centre, Department of Laboratory Medicine and Pathobiology, University of Toronto, 2075 Bayview Avenue, Toronto, M4N 3M5, Canada
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21
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Lee ER, Lamplugh L, Leblond CP, Mordier S, Magny MC, Mort JS. Immunolocalization of the cleavage of the aggrecan core protein at the Asn341-Phe342 bond, as an indicator of the location of the metalloproteinases active in the lysis of the rat growth plate. Anat Rec (Hoboken) 1998; 252:117-32. [PMID: 9737748 DOI: 10.1002/(sici)1097-0185(199809)252:1<117::aid-ar10>3.0.co;2-r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In view of the extensive lysis of hyaline cartilage known to take place during endochondral bone formation, the current study was designed to test the hypothesis that metalloproteinases are the agents that mediate this lysis. Since these enzymes have been shown in vitro to cleave the core protein of the major proteoglycan of cartilage, aggrecan, at the Asn341-Phe342 bond, an immunohistochemical method has been developed to find out whether or not there are sites in the growth plate of the rat tibia where cleavage of this bond takes place. The cleavage of aggrecan by metalloproteinases is followed by the retention of the fragment known as G1, for it includes the G1 domain. Since the G1 fragment terminates in the amino acid residues ...FVDIPEN, we prepared an antiserum against FVDIPEN, confirmed its specificity, then applied it to the growth plate of 21-day-old rat tibia in the hope of localizing the G1 fragments. The antiserum specificity was shown by its recognition of the ...FVDIPEN sequence at the C-terminus of peptides and of G1 fragments produced by aggrecan cleavage. When the antiserum was applied to Western blots of guanidinium chloride extracts prepared from epiphyseal growth plate, it recognized two species (56 and 52 kDa), which differed only in the degree of glycosylation. These fragments were comparable in size to the G1 fragments generated by the action of recombinant metalloproteinase in vitro, thus confirming antiserum specificity for these fragments. Applying the antiserum to cryosections of 21-day-old rat tibiae revealed immunostaining at two intensities within the growth plate matrix: a strong staining was observed in a 1-5 microm-wide layer designated "peripheral" matrix, which borders the epiphyseal and metaphyseal marrow spaces as well as the perichondrium, while a weak staining was found in the rest of the plate, designated "central" matrix. The abundance of G1 fragments terminating in ...FVDIPEN in the peripheral matrix indicates that this is where the growth plate is lysed to achieve longitudinal and latitudinal bone growth. The site where metalloproteinases exert their main lytic activity is a thin layer of matrix separating central from peripheral matrix.
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Affiliation(s)
- E R Lee
- Electron Microscopy Unit, Shriners Hospital for Children, Montreal, Quebec, Canada.
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22
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Guerassimov A, Zhang Y, Banerjee S, Cartman A, Leroux JY, Rosenberg LC, Esdaile J, Fitzcharles MA, Poole AR. Cellular immunity to the G1 domain of cartilage proteoglycan aggrecan is enhanced in patients with rheumatoid arthritis but only after removal of keratan sulfate. ARTHRITIS AND RHEUMATISM 1998; 41:1019-25. [PMID: 9627011 DOI: 10.1002/1529-0131(199806)41:6<1019::aid-art8>3.0.co;2-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To determine whether patients with rheumatoid arthritis (RA) express cellular immunity to the purified G1 globular domain of cartilage proteoglycan (PG) aggrecan and whether it is influenced by the removal of keratan sulfate (KS) chains from the molecule. METHODS The G1 globular domain of PG was purified from mature bovine articular cartilage, digested with keratanase, and used in proliferation assays with peripheral blood lymphocytes (PBL) isolated from 43 patients with RA, 11 patients with nonarticular rheumatism (NAR), including soft tissue rheumatism and mechanical back pain, and 13 healthy age- and sex-matched control subjects. RESULTS Removal of KS chains from the G1 globular domain resulted in significantly increased prevalence and values of cellular immune responses to G1 in RA patients compared with the control and NAR groups. In the majority of RA patients, KS chains on G1 significantly inhibited its immune recognition by PBL. There was no significant effect of KS removal on the immunity to G1 in patients with NAR and in the healthy control group. CONCLUSION These results reveal that immune reactivity to the G1 globular domain of the cartilage PG aggrecan is enhanced in patients with RA but only when KS chains are removed. Thus, KS chains inhibit immune responses to this domain of aggrecan. Since immunity to the G1 globular domain of aggrecan induces an erosive polyarthritis in BALB/c mice after removal of KS chains, immunity to the G1 globular domain, cleaved by proteases to remove KS chains, may play a role in the pathogenesis of RA.
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Affiliation(s)
- A Guerassimov
- Shriners Hospital for Children, Montreal, Quebec, Canada
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23
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24
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Maroudas A, Bayliss MT, Uchitel-Kaushansky N, Schneiderman R, Gilav E. Aggrecan turnover in human articular cartilage: use of aspartic acid racemization as a marker of molecular age. Arch Biochem Biophys 1998; 350:61-71. [PMID: 9466821 DOI: 10.1006/abbi.1997.0492] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aggrecan is a key component of the cartilage matrix. During aging, many changes occur in its composition and structure; in particular, there is an increase in the proportion of lower molecular weight monomers and of the "free" binding region. An important question has been whether these changes represent alterations in biosynthesis or whether they are due to the accumulation with age of the partially degraded fragments of the originally synthesized large monomer. In the present work we have used an independent tool, viz., the extent of racemization of aspartic acid to study the molecular "age" of different buoyant density fractions of the aggrecan of human articular cartilage, as well as of isolated free binding region and link protein. By measuring the D/LAsp ratio of the different aggrecan species, we were able to establish directly the relative residence times of these molecules in the cartilage matrix and, in combination with compositional and structural analyses, to define their "history" and calculate some of the kinetics constants characterizing their turnover. The value of the turnover constant for the large monomer in fraction A1D1 is 0.206 per year, which corresponds to a half-life of 3.4 years, while the turnover constant for the free binding region is 0.027 per year, which corresponds to a half-life of 25 years. It is thus clear that the rate of formation and turnover of the large monomer is much more rapid than the final degradation of the free binding region fragments, which explains the accumulation of the latter in cartilage during aging.
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Affiliation(s)
- A Maroudas
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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25
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Buckwalter JA. Do intervertebral discs deserve their bad reputation? THE IOWA ORTHOPAEDIC JOURNAL 1998; 18:1-11. [PMID: 9807702 PMCID: PMC2378178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- J A Buckwalter
- Department of Orthopaedics, University of Iowa College of Medicine, Iowa City 52242, USA.
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26
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Lark MW, Bayne EK, Flanagan J, Harper CF, Hoerrner LA, Hutchinson NI, Singer II, Donatelli SA, Weidner JR, Williams HR, Mumford RA, Lohmander LS. Aggrecan degradation in human cartilage. Evidence for both matrix metalloproteinase and aggrecanase activity in normal, osteoarthritic, and rheumatoid joints. J Clin Invest 1997; 100:93-106. [PMID: 9202061 PMCID: PMC508169 DOI: 10.1172/jci119526] [Citation(s) in RCA: 344] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To examine the activity of matrix metalloproteinases (MMPs) and aggrecanase in control and diseased human articular cartilage, metabolic fragments of aggrecan were detected with monospecific antipeptide antibodies. The distribution and quantity of MMP-generated aggrecan G1 fragments terminating in VDIPEN341 were compared with the distribution of aggrecanase-generated G1 fragments terminating in NITEGE373. Both types of G1 fragments were isolated from osteoarthritic cartilage. The sizes were consistent with a single enzymatic cleavage in the interglobular domain region, with no further proteolytic processing of these fragments. Both neoepitopes were also detected by immunohistochemistry in articular cartilage from patients undergoing joint replacement for osteoarthritis (OA), rheumatoid arthritis (RA), and in cartilage from adults with no known joint disease. In control specimens, the staining intensity for both G1 fragments increased with age, with little staining in cartilage from 22-wk-old fetal samples. There was also an increase with age in the extracted amount of MMP-generated neoepitope in relation to both aggrecan and collagen content, confirming the immunohistochemical results. After the age of 20-30 yr this relationship remained at a steady state. The staining for the MMP-generated epitope was most marked in control cartilage exhibiting histological signs of damage, whereas intense staining for the aggrecanase-generated fragment was often noted in adult cartilage lacking overt histological damage. Intense staining for both neoepitopes appeared in the more severely fibrillated, superficial region of the tissue. Intense immunostaining for both VDIPEN- and NITEGE- neoepitopes was also detected in joint cartilage from patients with OA or RA. Cartilage in these specimens was significantly more degraded and high levels of staining for both epitopes was always seen in areas with extensive cartilage damage. The levels of extracted VDIPEN neoepitope relative to collagen or aggrecan in both OA and RA samples were similar to those seen in age-matched control specimens. Immunostaining for both types of aggrecan fragments was seen surrounding the cells but also further removed in the interterritorial matrix. In some regions of the tissue, both neoepitopes were found while in others only one was detected. Thus, generation and/or turnover of these specific catabolic aggrecan fragments is not necessarily coordinated. Our results are consistent with the presence in both normal and arthritic joint cartilage of proteolytic activity against aggrecan based on both classical MMPs and "aggrecanase."
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Aggrecans
- Aging
- Amino Acid Sequence
- Arthritis, Rheumatoid/metabolism
- Arthritis, Rheumatoid/pathology
- Arthritis, Rheumatoid/surgery
- Cartilage, Articular/growth & development
- Cartilage, Articular/metabolism
- Cartilage, Articular/pathology
- Child
- Child, Preschool
- Chondroitin Sulfate Proteoglycans/metabolism
- Endopeptidases/metabolism
- Epitopes/analysis
- Extracellular Matrix Proteins
- Female
- Fetus
- Gestational Age
- Humans
- Infant, Newborn
- Knee Joint
- Knee Prosthesis
- Lectins, C-Type
- Male
- Middle Aged
- Osteoarthritis/metabolism
- Osteoarthritis/pathology
- Osteoarthritis/surgery
- Peptide Fragments/analysis
- Proteoglycans/metabolism
- Reference Values
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Affiliation(s)
- M W Lark
- Department of Inflammation Research, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
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27
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Olszewski J, McDonnell J, Stevens K, Visco D, Moore V. A matrix metalloproteinase-generated aggrecan neoepitope as a marker of skeletal maturation and aging in cartilage. ARTHRITIS AND RHEUMATISM 1996; 39:1234-7. [PMID: 8670336 DOI: 10.1002/art.1780390724] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To quantify the matrix metalloproteinase-induced neoepitope F(M/V)DIPEN (Phe-[Met/Val]-Asp-Ile-Pro-Glu-Asn341) in guinea pig and rabbit cartilage during aging. METHODS Cartilage was taken from the stifle joint, nasal septum, and xiphoid process in guinea pigs and rabbits at selected ages. The cartilage was then extracted and evaluated for F(M/V)DIPEN levels by radioimmunoassay. RESULTS In the 3 tissues studied, there were major increases in F(M/V)DIPEN levels during skeletal maturation and aging in both the guinea pig and rabbit cartilage. Except for spontaneous osteoarthritis that develops in guinea pigs with aging, increases in the neoepitope were not correlated with arthritis pathology. CONCLUSION Increases in the level of F(M/V)DIPEN in cartilage occur as a result of skeletal maturation and aging. This physiologic accumulation of F(M/V)DIPEN in cartilage should be considered when using the neoepitope as a disease marker in arthritis.
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Affiliation(s)
- J Olszewski
- Merck Research Laboratories, Rahway New Jersey 07065-0900, USA
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28
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Leroux JY, Guerassimov A, Cartman A, Delaunay N, Webber C, Rosenberg LC, Banerjee S, Poole AR. Immunity to the G1 globular domain of the cartilage proteoglycan aggrecan can induce inflammatory erosive polyarthritis and spondylitis in BALB/c mice but immunity to G1 is inhibited by covalently bound keratan sulfate in vitro and in vivo. J Clin Invest 1996; 97:621-32. [PMID: 8609216 PMCID: PMC507097 DOI: 10.1172/jci118458] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Earlier work from this laboratory showed that the human proteoglycan aggrecan from fetal cartilages can induce a CD4+ T cell-dependent inflammatory polyarthritis in BALB/c mice when injected after removal of chondroitin sulfate chains. Adult keratan sulfate (KS)-rich aggrecan does not possess this property. We found that two CD4+ T cell hybridomas (TH5 and TH14) isolated from arthritic mice recognize bovine calf aggrecan and the purified G1 domain of this molecule, which also contains a portion of the interglobular domain to which KS is bound. These hybridoma responses to G1 are enhanced by partial removal of KS by the endoglycosidase keratanase or by cyanogen bromide cleavage of core protein. KS removal results in increased cellular uptake by antigen-present cells in vitro. After removal of KS by keratanase, G1 alone can induce a severe erosive polyarthritis and spondylitis in BALB/c mice identifying it as an arthritogenic domain of aggrecan. The presence of KS prevents induction of arthritis presumably as a result of an impaired immune response as observed in vitro. These observations not only identify the arthritogenic properties of G1 but they also point to the importance of glycosylation and proteolysis in determining the arthritogenicity of aggrecan and fragments thereof.
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Affiliation(s)
- J Y Leroux
- Joint Diseases Laboratory, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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29
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Perides G, Asher RA, Lark MW, Lane WS, Robinson RA, Bignami A. Glial hyaluronate-binding protein: a product of metalloproteinase digestion of versican? Biochem J 1995; 312 ( Pt 2):377-84. [PMID: 8526845 PMCID: PMC1136273 DOI: 10.1042/bj3120377] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glial hyaluronate-binding protein (GHAP) is a 60 kDa glycoprotein with an amino acid sequence identical to that of the hyaluronate-binding region of versican, a large fibroblast aggregating proteoglycan found in the brain. Both GHAP and versican were identified by immunoblot in bovine brain extracts prepared only minutes after death. Human recombinant collagenase, stromelysin, mouse gelatinase and gelatinases isolated from human brain by affinity chromatography digest versican and give rise to a polypeptide with electrophoretic mobility identical to GHAP. Immunoblot analysis, peptide mapping and C-terminal amino acid sequencing indicate that the polypeptide generated by digestion with human brain gelatinases is identical to GHAP. We suggest that GHAP is a naturally occurring versican degradation product.
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Affiliation(s)
- G Perides
- Harvard Medical School, Department of Pathology, Boston, MA 02132, USA
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30
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Hughes CE, Caterson B, Fosang AJ, Roughley PJ, Mort JS. Monoclonal antibodies that specifically recognize neoepitope sequences generated by 'aggrecanase' and matrix metalloproteinase cleavage of aggrecan: application to catabolism in situ and in vitro. Biochem J 1995; 305 ( Pt 3):799-804. [PMID: 7531436 PMCID: PMC1136329 DOI: 10.1042/bj3050799] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Monoclonal antibodies have been prepared that react specifically with the neoepitopes present on proteoglycan degradation products generated from the proteolytic cleavage of aggrecan in the interglobular domain. Antibody BC-3 recognizes the new N-terminus (ARGSV...) on aggrecan degradation products produced by the action of the as yet uncharacterized proteolytic activity, 'aggrecanase', and antibody BC-4 recognizes the new C-terminus (...DIPEN) generated by the proteolytic action of matrix metalloproteinases. Specificity for these neoepitope sequences was determined in competitive e.l.i.s.a. using synthetic peptide antigens as inhibitors. Antibody BC-3 was used in the detection of aggrecan degradation products in the culture medium obtained from two different in vitro culture systems: bovine cartilage explants treated with either retinoic acid or interleukin-1, and secondly, rat chondrosarcoma cells treated with retinoic acid. Both interleukin-1 and retinoic acid treatment caused an increase in aggrecan catabolism resulting in an increased release to the medium of specific aggrecan degradation products containing the BC-3 neoepitope generated by the action of 'aggrecanase'. However, several additional aggrecan catabolites were present that were not immunoreactive with antibody BC-3. In addition, under control conditions, in the bovine cartilage cultures the BC-3 epitope was found on some of these aggrecan catabolites. In contrast, no immune-reactive material was found in the aggrecan degradation products present in control media of rat chondrosarcoma cells cultured in the absence of retinoic acid. Collectively, these results demonstrate that 'aggrecanase' activity is not a constitutive event in all cartilage culture systems and also suggest that proteolytic agents other than 'aggrecanase' are involved in aggrecan catabolism in normal turnover compared with pathological conditions. Antibody BC-4 was used to demonstrate the identity of the G1 domain of aggrecan following proteolytic cleavage of a purified G1-G2 preparation with collagenase, gelatinase A or stromelysin. The G2 product of this cleavage did not react with antibody BC-3, indicating that, under the experimental conditions used, none of these enzymes exhibited 'aggrecanase' activity. It is expected that both of these antibodies will play a pivotal role in detailed studies elucidating molecular mechanisms of aggrecan degradation and they will be particularly useful for the sensitive monitoring of aggrecan degradation products in tissue extracts and body fluids.
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Affiliation(s)
- C E Hughes
- Division of Orthopaedics, University of North Carolina at Chapel Hill
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31
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Vilim V, Fosang AJ. Proteoglycans isolated from dissociative extracts of differently aged human articular cartilage: characterization of naturally occurring hyaluronan-binding fragments of aggrecan. Biochem J 1994; 304 ( Pt 3):887-94. [PMID: 7818495 PMCID: PMC1137416 DOI: 10.1042/bj3040887] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Proteoglycans extracted with 4 M guanidinium chloride from young (mean 20 years) or old (mean 79 years) macroscopically normal human articular cartilage were separated by density gradient centrifugation and Q-Sepharose chromatography and characterized by gradient gel SDS/PAGE and immunodetection before and after removal of glycosaminoglycan chains. The extracts contained two large populations of aggrecan, a population of small N-terminal aggrecan fragments, as well as decorin, biglycan and fibromodulin. The distribution of all these species in density gradient fractions has been determined. The large aggrecan populations comprised four different chondroitin sulphate-bearing core proteins while the population of smaller fragments comprised eight different components. The two smallest fragments (35 and 42 kDa), identified as the first globular domain of aggrecan (N-terminal) (G1) and containing no glycosaminoglycan, were detected only in extracts of old cartilage. A 55 and a 70 kDa fragment of G1 were present in both keratan sulphate-containing and non-keratan sulphate-containing forms. Four other fragments, each containing keratan sulphate epitopes, were identified and these contained either G1 epitopes (one 95 kDa species), or G1 and G2 epitopes (three species). These results have suggested that proteolytic processing at the N-terminus is more extensive than has previously been recognized and raises the possibility that more than one proteinase may be involved in aggrecan degradation in vivo. With the exception of the two smallest G1 fragments, the repertoire of proteoglycan fragments found in young and old human articular cartilage is essentially the same, although the relative abudnance of various species differed. The older tissue contains a larger proportion of C-terminally truncated aggrecan fragments and a significantly decreased content of decorin and biglycan.
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Affiliation(s)
- V Vilim
- Institute of Rheumatology, Praha, Czech Republic
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32
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Kahn A, Taitz AD, Pottenger LA, Alberton GM. Effect of link protein and free hyaluronic acid binding region on spacing of proteoglycans in aggregates. J Orthop Res 1994; 12:612-20. [PMID: 7523636 DOI: 10.1002/jor.1100120503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Aging of articular cartilage results in accumulation of aggrecan fragments of various sizes that retain their ability to aggregate even though they may have relatively few glycosaminoglycan chains. Residual binding of partially degraded aggrecan may prevent binding of newly synthesized aggrecan subunits that have greater numbers of glycosaminoglycan chains. This study was undertaken to determine the effects of various relative molar ratios of intact aggrecan, link proteins, and hyaluronic acid binding region fragments on the structure of reconstituted aggregates. High molar ratios of link proteins relative to aggrecan decreased the spacing between adjacent aggrecan subunits; low molar ratios of hyaluronic acid binding region relative to aggrecan (4:1 or less) had no significant effect on spacing, and high molar ratios resulted in an increase in the spacing and a decrease in the percentage of aggrecan subunits found in aggregates. These data suggest that the density of aggrecan subunits on the aggregate is determined primarily by steric hindrance of the glycosaminoglycan chains of the aggrecan subunits and that, to a limited extent, partial degradation of aggrecan in an aggregate allows attachment of more aggrecan subunits.
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Affiliation(s)
- A Kahn
- Department of Orthopaedic Surgery, Baylor College of Medicine, Houston, Texas
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33
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Abstract
Hyaline cartilage contains five well-characterized proteoglycans in its extracellular matrix, and it is likely that others exist. The largest in size and most abundant by weight is aggrecan, a proteoglycan that possesses over 100 chondroitin sulfate and keratan sulfate chains. Aggrecan is also characterized by its ability to interact with hyaluronic acid to form large proteoglycan aggregates. Both the high anionic charge on the individual aggrecan molecules endowed by the sulfated glycosaminoglycan chains and the localization within the matrix endowed by aggregate formation are essential for aggrecan function. The molecule provides cartilage with its osmotic properties, which give articular cartilage its ability to resist compressive loads. The other proteoglycans are characterized by their ability to interact with collagen. They are much smaller than aggrecan in size but may be present in similar molar amounts. Decorin, biglycan, and fibromodulin are closely related in protein structure but differ in glycosaminoglycan composition and function. Decorin and biglycan possess one and two dermatan sulfate chains, respectively, whereas fibromodulin bears several keratan sulfate chains. Decorin and fibromodulin both interact with the type II collagen fibrils in the matrix and may play a role in fibrillogenesis and interfibril interactions. Biglycan is preferentially localized in the pericellular matrix, where it may interact with type VI collagen. Finally, type IX collagen can also be considered as a proteoglycan, as its alpha 2(IX) chain may bear a glycosaminoglycan chain. It may serve as a bridge between the collagen fibrils or with the interspersed aggrecan network.
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Affiliation(s)
- P J Roughley
- Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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34
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Buckwalter JA, Roughley PJ, Rosenberg LC. Age-related changes in cartilage proteoglycans: quantitative electron microscopic studies. Microsc Res Tech 1994; 28:398-408. [PMID: 7919527 DOI: 10.1002/jemt.1070280506] [Citation(s) in RCA: 144] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Biochemical and biophysical studies have shown that the composition and sedimentation velocity of cartilage proteoglycans change with age, but these investigations cannot demonstrate the alterations in molecular structure responsible for these changes. Development of quantitative electron microscopic methods has made it possible to define the age-related structural changes in aggregating proteoglycans and to correlate the alterations in their structure with changes in tissue composition and morphology. Electron microscopic measurement of human and animal hyaline cartilage proteoglycans has shown that with increasing age the length of the chondroitin sulfate-rich region of aggregating proteoglycan monomers (aggrecan molecules) decreases, the variability in aggrecan length increases, the density of aggrecan keratan sulfate chains increases, the number of monomers per aggregate decreases, and the proportion of monomers that aggregate declines. Proteoglycans from the nucleus pulposus of the intervertebral disc show similar but more dramatic age-related alterations. At birth, nucleus pulposus aggrecan molecules are smaller and more variable in length than those found in articular cartilage. Within the first year of human life, the populations of aggregates and large aggrecan molecules analogous to those found in articular cartilage decline until few if any of these molecules remain in the central disc tissues of skeletally mature individuals. The mechanisms of the age-related changes in cartilage proteoglycans have not been fully explained, but measurement of proteoglycans synthesized by chondrocytes of different ages suggests that alterations in synthesis produce at least some of the age-related changes in aggrecan molecules. Degradation of aggrecan chondroitin sulfate-rich regions in the matrix probably also contributes to the structural changes seen by electron microscopy. Age-related changes in proteoglycan aggregation may be due to alterations in link protein function or inhibition of aggregation of newly synthesized aggrecan molecules by accumulation of degraded aggrecan molecules.
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Affiliation(s)
- J A Buckwalter
- Orthopaedics Department, University of Iowa, Iowa City 52242
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35
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Abstract
Rheumatoid arthritis is characterized by chronic inflammation associated with considerable damage to the musculoskeletal system, particularly in and around diarthrodial joints. By using newly developed immunoassays and chemically based assays for cartilage-, bone-, and synovium-derived molecules, which are products of synthesis and/or degradation, it is now possible to detect the release of these molecules and their degradation products into body fluids such as serum, synovial fluid, and urine. This release is influenced significantly by the inflammatory process and reflects the damage caused to these tissues by chronic inflammation. Some new markers for skeletal metabolism are reviewed and examples are given of how they determine the damaging effects of this chronic inflammatory disease on these tissues before changes are observed radiologically. Some of these markers have both prognostic value and potential for rapidly interpreting the effects of therapy.
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Affiliation(s)
- A R Poole
- Joint Diseases Laboratory, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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36
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Bignami A, LeBlanc A, Perides G. A role for extracellular matrix degradation and matrix metalloproteinases in senile dementia? Acta Neuropathol 1994; 87:308-12. [PMID: 8009963 DOI: 10.1007/bf00296747] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In brain as in cartilage, the extracellular matrix contains aggregates formed by hyaluronic acid (HA) and proteoglycans. In osteoarthritic cartilage, release of the proteoglycans from the aggregates by cleavage of the HA-binding region results in the accumulation of the HA-binding region and in the fragmentation of the released proteoglycans. Stromelysin, a matrix neutral metalloproteinase, is one of the enzymes responsible for the cleavage of the HA-binding region. We suggest that a similar process also occurs in senile dementia. The brain proteoglycan contains sequences identical to those of aggrecan, which are recognized and cleaved by stromelysin, and is, in fact, susceptible to stromelysin digestion. Monoclonal antibodies reacting with glial HA-binding protein, but not with the parent protein, stained several senile plaques as defined by their reactivity with antibodies to the amyloid-beta protein in double-labeling experiments.
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Affiliation(s)
- A Bignami
- Research and Development Service (151), Department of Veterans Affairs Medical Center, West Roxbury, MA 02132
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37
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Buckwalter JA, Woo SL, Goldberg VM, Hadley EC, Booth F, Oegema TR, Eyre DR. Soft-tissue aging and musculoskeletal function. J Bone Joint Surg Am 1993; 75:1533-48. [PMID: 8408143 DOI: 10.2106/00004623-199310000-00015] [Citation(s) in RCA: 157] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J A Buckwalter
- Department of Orthopaedics, University of Iowa Hospitals, Iowa City 52242
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38
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Hua Q, Knudson CB, Knudson W. Internalization of hyaluronan by chondrocytes occurs via receptor-mediated endocytosis. J Cell Sci 1993; 106 ( Pt 1):365-75. [PMID: 7505784 DOI: 10.1242/jcs.106.1.365] [Citation(s) in RCA: 197] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several studies have suggested that chondrocytes must have the capacity to internalize and degrade extracellular hyaluronan. In the present study we show direct evidence that hyaluronan is, in fact, endocytosed by chondrocytes and that the endocytosis is mediated via cell surface CD44/hyaluronan receptors. Cultures of bovine articular chondrocytes as well as rat chondrosarcoma chondrocytes were incubated with either fluorescein- or 3H-labeled hyaluronan. Intense binding and accumulation of labeled hyaluronan was visualized by fluorescence microscopy or bright-field/dark-field microscopy following autoradiography. Cell surface hyaluronan was removed with either trypsin or Streptomyces hyaluronidase in order to distinguish and quantify intracellular endocytosed hyaluronan. Labeled hyaluronan was visualized within small discrete intracellular vesicles distributed throughout the cytoplasm. Binding and endocytosis of fluorescein- or 3H-labeled hyaluronan was totally blocked by the addition of excess unlabeled hyaluronan or hyaluronan hexasaccharides, competitive inhibitors of hyaluronan/hyaluronan receptor interactions. Binding and endocytosis was also blocked by the addition of anti-CD44 monoclonal antibodies. Characterization of endocytosed 3H-labeled hyaluronan demonstrated that a significant portion of the hyaluronan was degraded by both the bovine articular and rat chondrosarcoma chondrocytes. Interestingly, a higher proportion of bound hyaluronan was internalized by the bovine chondrocytes. Therefore, hyaluronan receptor-mediated endocytosis and degradation of hyaluronan may provide a critical link to the maintenance and homeostasis of cartilage tissue.
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Affiliation(s)
- Q Hua
- Department of Biochemistry, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612
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39
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Vilím V, Fosang AJ. Characterization of proteoglycans isolated from associative extracts of human articular cartilage. Biochem J 1993; 293 ( Pt 1):165-72. [PMID: 8328959 PMCID: PMC1134335 DOI: 10.1042/bj2930165] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Approx. 10% of the total proteoglycan content of normal young human articular cartilage was extracted under associative conditions with Dulbecco's PBS. Proteoglycans isolated from the extract by Q-Sepharose chromatography were separated by gel chromatography and characterized by gradient gel SDS/PAGE and immunoblotting. Three species of small proteoglycans, two main populations of aggrecan and a population of its smaller fragments were identified. The major populations of aggrecan contained chondroitin sulphate chains, all or part of the N-terminal G1 and G2 domains and, therefore, intact keratan sulphate domains. The larger population was estimated by gradient SDS/PAGE to have a molecular mass of approx. 600 kDa or greater. The second population had an apparent molecular mass of approx. 300-600 kDa. Core proteins derived from these populations of proteoglycans separated on SDS/PAGE into several clusters of bands in the range from 120 to approx. 360 kDa. The extract further contained smaller fragments which lacked chondroitin sulphate but reacted with antibodies against keratan sulphate, and against epitopes present in the G2 domain of aggrecan. The presence of the G2 domain in a broad range of populations of decreasing size indicated extensive cleavage of the aggrecan core protein within its chondroitin sulphate domain. These findings suggest that fragmentation of aggrecan probably occurs in vivo in normal articular cartilage of young individuals. Associative extracts also contained decorin, biglycan and fibromodulin. These were resolved from aggrecan by gel chromatography and identified by immunodetection.
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Affiliation(s)
- V Vilím
- Institute of Rheumatology, Praha, Czech Republic
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40
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Poole AR, Rizkalla G, Ionescu M, Reiner A, Brooks E, Rorabeck C, Bourne R, Bogoch E. Osteoarthritis in the human knee: a dynamic process of cartilage matrix degradation, synthesis and reorganization. AGENTS AND ACTIONS. SUPPLEMENTS 1993; 39:3-13. [PMID: 8456642 DOI: 10.1007/978-3-0348-7442-7_1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The matrix of articular cartilage undergoes degenerative changes in osteoarthritis which involve a number of matrix molecules. The structural and mechanical integrity is organized around the composite collagen II, IX, XI fibrillar organization. The small proteoglycan decorin that binds to these fibrils may influence their structure and mechanical properties. Aggrecan interacts indirectly via hyaluronic acid and possibly directly through unknown mechanisms. When collagen is cleaved at the articular surface in early osteoarthritis, decorin and aggrecan are lost. Increases in decorin and aggrecan content occur deeper in the cartilage. This is accompanied by evidence for increased formation of collagen fibrils and increased degradation and synthesis of aggrecan and type II collagen. The net contents of these proteoglycan per tissue do not, however, change until advanced degeneration occurs. These degradative processes are likely catalyzed by metalloproteinases and cysteine proteases. Cartilage exhibits significant capacity for remodelling which may be enhanced by therapeutic management of this process.
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Affiliation(s)
- A R Poole
- Shriners Hospital for Crippled Children, Department of Surgery, McGill University, Montreal Quebec, Canada
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41
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Rizkalla G, Reiner A, Bogoch E, Poole AR. Studies of the articular cartilage proteoglycan aggrecan in health and osteoarthritis. Evidence for molecular heterogeneity and extensive molecular changes in disease. J Clin Invest 1992; 90:2268-77. [PMID: 1281828 PMCID: PMC443378 DOI: 10.1172/jci116113] [Citation(s) in RCA: 204] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Changes in the structure of the proteoglycan aggrecan (PG) of articular cartilage were determined immunochemically by RIA and gel chromatography and related to cartilage degeneration documented histologically by the Mankin grading system. Monoclonal antibodies to glycosaminoglycan epitopes were used. In all cartilages, three chondroitin sulfate (CS)-rich populations of large size were observed in addition to a smaller keratan sulfate (KS)-rich population. In grades 7-13 OA cartilages (phase II), molecules were significantly larger than the equivalent molecules of grades 2-6 (phase I). CS chain lengths remained unchanged. In most OA cartilages, a CS epitope 846 was elevated in content, this being most marked in phase II (mean: fivefold). Loss of uronic acid, KS, and hyaluronic acid were only pronounced in phase II OA because of variations in normal contents. Aggregation of PG was unchanged (50-60%) or reduced in OA cartilages, but molecules bearing epitope 846 exhibited almost complete aggregation in normal cartilages. This study provides evidence for the capacity of OA cartilage to synthesize new aggrecan molecules to replace those damaged and lost by disease-related changes. It also defines two phases of PG change in OA: an early predominantly degenerate phase I followed by a net reparative phase II accompanied by net loss of these molecules.
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Affiliation(s)
- G Rizkalla
- Joint Diseases Laboratory, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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42
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Malemud CJ, Papay RS. Synthesis of low buoyant density proteoglycans by human chondrocytes in culture. MATRIX (STUTTGART, GERMANY) 1992; 12:427-38. [PMID: 1287411 DOI: 10.1016/s0934-8832(11)80087-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human chondrocyte strains were derived from explant outgrowth of nonarthritic or osteoarthritic human cartilage. Chondrocytes radiolabeled with [35SO4] or [35S]-methionine were used to measure the biosynthesis of proteoglycans recovered from the most buoyant fraction (A4) of a CsCl density gradient centrifugation performed under associative conditions. The proteoglycans isolated from the A4 fraction (rho < 1.47 g/ml) were hydrodynamically small and contained both large and small glycosaminoglycan chains. When assessed by SDS/PAGE using 3-16% gradient gels, two subpopulations of small proteoglycans (smPG) were identified. The larger of the two species (smPG-I) migrated slower than the 200 kDa marker protein; when reassessed on 3-5% acrylamide gels, its apparent molecular mass was larger than the 480 kDa and 440 kDa alpha and beta heavy chains of dynein. We estimated the apparent molecular size of this smPG to be approximately 520 kDa. The smaller smPG (smPG-II) had an apparent average molecular mass of 180 kDa (range 170-210 kDa) after 3-16% SDS/PAGE. Three monoclonal antibodies, 1C6, 5D4, and S103L, reactive with the hyaluronic acid binding region of the aggregating proteoglycan core protein, keratan sulfate, and a core protein domain in the chondroitin sulfate attachment region, respectively, reacted with a single protein (apparent molecular mass, 180 kDa) that was similar in size to smPG-II.
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Affiliation(s)
- C J Malemud
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
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43
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Perides G, Rahemtulla F, Lane W, Asher R, Bignami A. Isolation of a large aggregating proteoglycan from human brain. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)35919-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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44
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Bignami A, Asher R, Perides G, Rahemtulla F. The extracellular matrix of cerebral gray matter: Golgi's pericellular net and Nissl's nervösen grau revisited. Int J Dev Neurosci 1992; 10:291-9. [PMID: 1414442 DOI: 10.1016/0736-5748(92)90018-u] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Glial hyaluronate-binding protein (GHAP) and a large aggregating chondroitin sulfate proteoglycan (Ag-Pg) similar to a fibroblast proteoglycan (versican) were localized in bovine, dog and cat central nervous system (CNS) gray matter by indirect immunofluorescence. The distribution of the two hyaluronate-binding proteins was identical with that of hyaluronate, an extracellular glycosaminoglycan. All substances formed a finely reticulated mesh in the neuropil with a condensation of the stain around large neurons. It is concluded that in gray matter, as in white matter, the extracellular matrix (ECM) contains hyaluronate-protein aggregates. We suggest that the hyaluronate-protein aggregates correspond to the pericellular network first described by Golgi.
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Affiliation(s)
- A Bignami
- Department of Pathology, Harvard Medical School, Boston, MA
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45
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Loulakis P, Shrikhande A, Davis G, Maniglia CA. N-terminal sequence of proteoglycan fragments isolated from medium of interleukin-1-treated articular-cartilage cultures. Putative site(s) of enzymic cleavage. Biochem J 1992; 284 ( Pt 2):589-93. [PMID: 1599440 PMCID: PMC1132679 DOI: 10.1042/bj2840589] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Bovine articular cartilage was cultured both in the presence and in the absence of human recombinant interleukin-1 alpha (IL-1) (100 units/ml). Addition of this cytokine stimulated matrix degradation approx. 3-fold. This increased degradation permitted characterization of the large chondroitin sulphate proteoglycan (aggrecan) fragments accumulating in the media. When compared with controls, the proteoglycans isolated from the medium of cultures treated with IL-1 exhibited a decrease in the Kav. (control 0.25; IL-1-treated 0.37), determined by Sepharose CL-2B chromatography. This decrease in proteoglycan size was accompanied by a decreased ability of these monomers to associate with hyaluronic acid. Thus only 20% of the proteoglycans isolated from the medium of IL-1-treated cultures, compared with 39% for control cultures, had the capacity to form high-M(r) aggregates with hyaluronic acid. SDS/PAGE analysis of the proteoglycans from the media of IL-1-treated cultures demonstrated several large proteoglycan protein-core bands (M(r) 144,000-380,000). The protein-core bands with M(r) 144,000-266,000 exhibited a significantly decreased reactivity with monoclonal antibody 1-C-6 (specific for domains G1 and G2). The N-terminal amino acid sequence of four of these protein-core bands (M(r) 144,000, 173,000, 214,000 and 266,000) yielded sequences LGQRPPV-Y-PQLF(E), AGEGP(S)GILEL-GAP(S)-AP(D)M, GLG-VEL-LPGE and (A)RGSVIL-AKPDFEV-P-A. A comparison of these N-terminal amino acid sequences with the published proteoglycan sequence for bovine nasal cartilage [Oldberg, Antonsson & Heinegård (1987) Biochem. J. 243, 255-259], rat chondrosarcoma [Doege, Sasaki, Horigan, Hassell & Yamada (1987) J. Biol. Chem. 262, 17757-17769] and human articular cartilage [Doege, Sasaki, Kimura & Yamada (1991) J. Biol. Chem. 266, 894-902] permitted assignment of their relative positions on the core protein. Furthermore, on the basis of this similarity to published sequence, putative sites of enzymic cleavage were constructed. These theoretical cleavage sites revealed a glutamic acid residue in the P1 position and an uncharged polar or non-polar residue in the P1' position.
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Affiliation(s)
- P Loulakis
- Institute for Arthritis and Autoimmunity, Miles Inc., West Haven, CT 06516
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46
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Identification of a stromelysin cleavage site within the interglobular domain of human aggrecan. Evidence for proteolysis at this site in vivo in human articular cartilage. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48387-1] [Citation(s) in RCA: 188] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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47
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48
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Nguyen Q, Liu J, Roughley PJ, Mort JS. Link protein as a monitor in situ of endogenous proteolysis in adult human articular cartilage. Biochem J 1991; 278 ( Pt 1):143-7. [PMID: 1883326 PMCID: PMC1151460 DOI: 10.1042/bj2780143] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
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.
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Affiliation(s)
- Q Nguyen
- Joint Diseases Laboratory, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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Liu J, Roughley PJ, Mort JS. Identification of human intervertebral disc stromelysin and its involvement in matrix degradation. J Orthop Res 1991; 9:568-75. [PMID: 1646316 DOI: 10.1002/jor.1100090413] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Human intervertebral disc when maintained in organ culture released a latent casein-degrading metalloproteinase into the medium in a manner analogous to cultures of human cartilage. This enzyme was demonstrated to be immunologically identical to prostromelysin. It was also found that the amount of procollagenase secreted by both cartilage and disc cells was considerably less than that of prostromelysin. Tissue extraction confirmed that the low level of procollagenase observed was not due to retention of the enzyme within the tissue. Human intervertebral disc link proteins were found to possess the same N-termini as those of their counterparts in human articular cartilage, where it appears that stromelysin is responsible for generating molecular heterogeneity. These results suggest that intervertebral disc cells are capable of secreting prostromelysin, which can become activated within the extracellular matrix and hence contribute to the age-related and degenerative changes in the disc.
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Affiliation(s)
- J Liu
- Joint Diseases Laboratory, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada
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Vilim V, Krajickova J. Proteoglycans of human articular cartilage. Identification of several populations of large and small proteoglycans and of hyaluronic acid-binding proteins in successive cartilage extracts. Biochem J 1991; 273 ( Pt 3):579-85. [PMID: 1705114 PMCID: PMC1149802 DOI: 10.1042/bj2730579] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two specimens of human articulage were successively extracted with solutions of phosphate-buffered saline (PBS), 7 M-urea and 4 M-guanidine hydrochloride (Gdn-HCl). Proteoglycans from individual extracts were fractionated by DEAE-Sephacel chromatography and gel chromatography on Sephacryl S-400. The presence of three populations of large proteoglycans was demonstrated in all three extracts by composite agarose/polyacrylamide-gel electrophoresis (CAPAGE). The population corresponding to the fastest CAPAGE band of aggregating proteoglycans was shown to be extremely polydisperse, having Mr (as estimated by SDS/PAGE) decreasing continuously from more than 300,000 to the size corresponding to 'free' hyaluronic acid-binding region (HABR) (about 70,000). A rather polydisperse set of HABR-containing fragments which spanned a broad range of sizes, and also differed in their keratan sulphate contents, was isolated from both 7 M-urea and 4 M-Gdn-HCl extracts. PBS and 7 M-urea extracts, but not the Gdn-HCl extract, further contained small proteoglycans, identified as fast-migrating bands on CAPAGE electrophoretograms. One of those small species was recognized with an antibody against the small proteoglycan PG II; the other two remain to be positively identified. However, the glycosaminoglycan of the small species which was present exclusively in the PBS extract was identified as keratan sulphate; this species may thus belong to the family of small keratan sulphate-containing proteolygans.
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Affiliation(s)
- V Vilim
- Research Institute of Rheumatology, Praha, Czechoslovakia
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