Dedifferentiated chondrocytes reexpress the differentiated collagen phenotype when cultured in agarose gels.
The differentiated phenotype of rabbit articular chondrocytes consists primarily of type II collagen and cartilage-specific proteoglycan. During serial monolayer culture this phenotype is lost and replaced by a complex collagen phenotype consisting predominately of type I collagen and a low level of proteoglycan synthesis. Such dedifferentiated chondrocytes reexpress the differentiated phenotype during suspension culture in firm gels of 0.5% low Tm agarose. Approximately 80% of the cells survive this transition from the flattened morphology of anchorage-dependent culture to the spherical morphology of anchorage-independent culture and then deposit characteristic proteoglycan matrix domains. The rates of proteoglycan and collagen synthesis return to those of primary chondrocytes. Using SDS-polyacrylamide gel electrophoresis of intact collagen chains and two-dimensional cyanogen bromide peptide mapping, we demonstrated a complete return to the differentiated collagen phenotype. These results emphasize the primary role of cell shape in the modulation of the chondrocyte phenotype and demonstrate a reversible system for the study of gene expression.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D003094:Collagen / Q000032:analysis / Q000096:biosynthesis*; D004247:DNA / Q000096:biosynthesis; D005782:Gels; D010455:Peptides / Q000032:analysis; D014176:Protein Biosynthesis; D011509:Proteoglycans / Q000096:biosynthesis; D011817:Rabbits; D012685:Sepharose
D005782:Gels; D010455:Peptides; D011509:Proteoglycans; D003094:Collagen; D004247:DNA; D012685:Sepharose; D002118:Calcium