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Type II collagen modulates the composition of extracellular matrix synthesized by articular chondrocytes
Author(s) -
Qi WenNing,
Scully Sean P.
Publication year - 2003
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(02)00136-5
Subject(s) - extracellular matrix , chondroitin sulfate , chemistry , keratan sulfate , type ii collagen , cartilage , tenascin , aggrecan , tenascin c , microbiology and biotechnology , proteoglycan , chondrocyte , decorin , extracellular , collagen, type i, alpha 1 , epitope , biochemistry , glycosaminoglycan , fibronectin , immunology , biology , osteoarthritis , pathology , antibody , anatomy , in vitro , medicine , alternative medicine , articular cartilage
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‐generatedepitope 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. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.