Type II collagen modulates the composition of extracellular matrix synthesized by articular chondrocytes

• Published in: Journal of orthopaedic research Vol. 21; no. 2; pp. 282 - 289
• Main Authors: Qi, Wen-ning, Scully, Sean P
• Format: Journal Article
• Language: English
• Published: Hoboken Elsevier Ltd 01.03.2003; Wiley Subscription Services, Inc., A Wiley Company; Blackwell Publishing Ltd
• Subjects: Animals; Articular chondrocytes; Biomarkers; Cartilage, Articular - cytology; Cartilage, Articular - drug effects; Cartilage, Articular - metabolism; Cattle; Cells, Cultured; Chondrocytes - cytology; Chondrocytes - drug effects; Chondrocytes - metabolism; Collagen; Collagen Type II - pharmacology; DNA - biosynthesis; DNA Replication - drug effects; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Epitopes; Extracellular Matrix - drug effects; Extracellular Matrix - metabolism; Immunohistochemistry; Matrix; Proteoglycans - immunology; Proteoglycans - metabolism; Signal Transduction; Signaling; Stifle; Tenascin - immunology; Tenascin - metabolism; TGF-β1; Transforming Growth Factor beta - pharmacology; Transforming Growth Factor beta1; Signaling; TGF-β1; Matrix; Collagen; Articular chondrocytes
• ISSN: 0736-0266; 1554-527X
• DOI: 10.1016/S0736-0266(02)00136-5

The articular cartilage extracellular matrix (ECM) interfaces with chondrocytes and influences many biological processes important to cartilage homeostasis and repair. The alginate bead culture system can be viewed as a model of cartilage repair in which the chondrocyte attempts to recreate the pericellular matrix while maintaining a differentiated phenotype. The purpose of this study was to evaluate the alteration in epitopes of proteoglycan and tenascin synthesized by chondrocytes in the presence of exogenous extracellular type II collagen. We evaluated the effects on four biomarkers associated with the creation of the denovo matrix using ELISA and immunohistochemistry: keratan sulfate epitope (5D4), 3B3(−) neoepitope of chondroitin-6- sulfate, 3B3(+) chondroitinase-generated epitope of chondroitin-6-sulfate, and tenascin-C expression. TGF-β1 stimulated the production of 3B3(+), 5D4, and tenascin-C in a dose-dependent manner and decreased 3B3(−) levels. Following the addition of exogenous type II collagen, 3B3(−) increased and tenascin-C decreased but did not change the direction of TGF-β1 effects. In contrast, 5D4 expression decreased in the presence of collagen II as TGF-β1 increased to 10 ng/ml. Interestingly, the amount of 3B3(+) epitope was not affected by the incorporation of type II collagen. Immunohistochemistry found there was no significant difference in distribution of these biomarkers in the presence and absence of extracellular type II collagen incorporation. These results elucidate the subtle biochemical differences in ECM synthesized by chondrocytes in the presence of type II collagen and further characterize the role played by ECM in the TGF-β1 regulation of the articular cartilage physiology.