Summary
Chondrocytes were cultured in gelified agarose. Aggrecans, accumulated during culture, were liberated by agarase digestion of the artificial agarose matrix and studied by electron microscopy. The culture system and the specific method used to liberate the extracellular macromolecules enabled us to study the whole population of de novo synthesized, native aggrecan aggregates. The average length of the aggrecans was 188 nm. Aggrecans were observed as free molecules or attached on hyaluronan chains. In these aggregates no free binding sites on the hyaluronan chain were observed, and the average distance between the aggrecans was 27 nm. Consequently, the length of the hyaluronan chain defines the molecular size of the aggregate. Mature human articular cartilage cells were found to synthesize a relatively small proportion of very large aggrecan aggregates with over 100 aggrecans attached to a single hyaluronan chain. However, the average aggrecan aggregate carried about 12 aggrecans.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bayliss, M. T. Proteoglycan structure in normal and osteoarthritic human cartilage. In: Kuettner K. E.; Schleyerbach, R.; Hascall, V. C., eds. Articular cartilage biochemistry. New York: Raven Press; 1986:295–308.
Benya, P. D.; Shaffer, J. D. Dedifferentiated chondrocytes reexpress the differentiated collagen phenotype when cultured in agarose gels. Cell 30:215–224; 1982.
Brandt, K. D.; Muir, H. Characterisation of protein-polysaccharides of articular cartilage from mature and immature pigs. Biochem. J. 114:871–876; 1969.
Buckwalter, J. A.; Rosenberg, L. C. Electron microscopic studies of cartilage proteoglycans. J. Biol. Chem. 257:9830–9839; 1982.
Buckwalter, J. A.; Rosenberg, L. C.; Tang, L. H. The effect of link protein on proteoglycan aggregate structure. J. Biol. Chem. 259:5361–5363; 1984.
Buckwalter, J. A.; Kuettner, K. E.; Thonar, E. J-M. Age-related changes in articular cartilage proteoglycans: electron microscopic studies. J. Orthop. Res. 3:251–257; 1985.
Buckwalter, J. A.; Roughley, P. J. Age related changes in human articular cartilage proteoglycans. In: Transactions 33th Annual Meeting of the Orthopedic Research Society. 12:125; 1987.
Delbruck, A.; Dressow, B.; Gurr, E., et al. In vitro culture of human chondrocytes from adult subjects. Connect. Tiss. Res. 15:155–172; 1985.
Faltz, L. L.; Reddi, A. H.; Hascall, G. K., et al. Characteristics of proteoglycans extracted from the swarm rat chondrosarcoma with associative solvents. J. Biol. Chem. 250:1375–1380; 1972.
Front, P.; Dauguet, C.; Mitrovic, D. R. Effect of cytochrome C concentration on the ultrastructural appearance of bovine nasal cartilage proteoglycans. Stain Technol. 64:113–119; 1989.
Kimura, J. H.; Osdoby, P.; Caplan, A. I., et al. Electron microscopic and biochemical studies of proteoglycan polydispersity in chick limb bud chondrocyte cultures. J. Biol. Chem. 253:4721–4729; 1978.
Kleinschmidt, A. K.; Zahn, R. K. Uber desoxyribonucleinsaure-molekulen in protein-mischfilmen. Z. Naturforsch. 146:770–779; 1959.
Manicourt, D. H.; Pita, J. C.; Pezon, C. F., et al. Characterization of the proteoglycans recovered under nondissociative conditions from normal articular cartilage of rabbits and dogs. J. Biol. Chem. 261:5426–5439; 1986.
Rosenberg, L.; Hellman, W.; Kleinschmidt, A. K. Macromolecular models of proteinpolysaccharides from bovine nasal cartilage based on electron microscopic studies. J. Biol. Chem. 245:4123–4130; 1970.
Rosenberg, L.; Hellmann, W.; Kleinschmidt, A. K. Electron microscopic studies of proteoglycan aggregates from bovine articular cartilage. J. Biol. Chem. 250:1877–1883; 1975.
Thyberg, J.; Lohmander, S.; Heinegard, D. Electron-microscopic studies on isolated molecules. Biochem. J. 151:157–166; 1975.
Verbruggen, G.; Veys, E. M.; Wieme, N., et al. The synthesis and immobilisation of cartilage-specific proteoglycan by human chondrocytes in different concentrations of agarose. Clin. Exp. Rheumatol. 8:371–378; 1990.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cornelissen, M., Verbruggen, G., Malfait, A.M. et al. The study of representative populations of native aggrecan aggregates synthesized by human chondrocytes in vitro. Journal of Tissue Culture Methods 15, 139–145 (1993). https://doi.org/10.1007/BF02388267
Issue Date:
DOI: https://doi.org/10.1007/BF02388267