Cell
Volume 15, Issue 4, December 1978, Pages 1313-1321
Journal home page for Cell

Article
Independent regulation of collagen types by chondrocytes during the loss of differentiated function in culture

https://doi.org/10.1016/0092-8674(78)90056-9Get rights and content

Abstract

Collagen phenotypes were determined for rabbit articular chondrocytes in cartilage slices and first through fifth monolayer cultures. During the first 24 hr of slice culture, chondrocytes exhibited the following collagen phenotype: 96% type II, 3% X2Y and 1% type III. In primary monolayer culture, no other types of collagen were added to this differentiated chondrocyte phenotype; however, the synthesis per cell of each of the expressed collagens was stimulated. By the fifth day of primary culture, X2Y synthesis increased 10 fold, and by the eighth day, a further 4 fold. In contrast, the synthesis of collagen types II and III showed no change by the fifth day, but increased 7 fold by the eighth day. These results suggest independent regulation of X2Y in this situation. In a separate experiment, first through fifth cultures were studied. The synthesis per cell of type II collagen declined steadily and essentially ceased by the fifth culture, indicating the loss of differentiated function by these chondrocyte progeny. The loss of type II synthesis was not quantitatively replaced by the synthesis of type I trimer and type I collagen which was first detected in the third culture. While these qualitative changes in phenotype occurred, the stimulated rate of type III collagen synthesis did not change and that of X2Y declined only slightly. Thus the termination of type II synthesis did not significantly alter the synthesis of the other collagens produced by differentiated chondrocytes. The final “de-differentiated” phenotype was 41% type I, 25% X2Y, 20% type I trimer, 13% type III and 1% type II.

References (42)

  • M. Pacifici et al.

    Transformation of chondroblasts by Rous sarcoma virus and synthesis of the sulfated proteoglycan matrix

    Cell

    (1977)
  • J.R. Schiltz et al.

    The synthesis of collagen and glycosaminoglycans by dedifferentiated chondroblasts in culture

    Cell Differentiation

    (1973)
  • A. Sibatani

    Precipitation and counting of minute quantities of labeled nucleic acids as cetryltrimethylammonium salt

    Ann. Biochem.

    (1970)
  • M. Solursh et al.

    Depression by hualuronic acid of glycosaminoglycan synthesis by cultured chick embryo chondrocytes

    Dev. Biol.

    (1974)
  • B.C. Sykes et al.

    Molecular weight heterogeneity of the a-chain subunits of collagen

    Biochem. Biophys. Res. Commun.

    (1971)
  • P.D. Benya et al.

    The stability of the collagen phenotype during stimulated collagen, glycosaminoglycan and DNA synthesis by articular cartilage organ cultures

    Arch. Biochem. Biophys.

    (1979)
  • P.D. Benya et al.

    The progeny of rabbit articular chondrocytes synthesize collagen types I and III and type I trimer, but not type II. Verification by cyanogen bromide peptide analysis

    Biochemistry

    (1977)
  • R.E. Burgeson et al.

    Fetal membrane collagens: identification of two new collagen alpha chains

  • H.G. Coon et al.

    Differentiation in vitro: effects of Sephadex fractions of chick embryo extract

    Science

    (1966)
  • K. Deshmukh et al.

    Characterization of collagen and its precursors synthesized by rabbit-articular cartilage cells in various culture systems

    Eur. J. Biochem.

    (1976)
  • S. Gay et al.

    Simultaneous synthesis of types I and III collagen by fibroblasts in culture

  • Cited by (0)

    View full text