Phenotypic maintenance of articular chondrocytes in vitro requires BMP activity

A. O. Oshin, E. Caporali, C. R. Byron, A. A. Stewart, M. C. Stewart

Research output: Contribution to journalArticlepeer-review


Articular chondrocytes are phenotypically unique cells that are responsible for the maintenance of articular cartilage. The articular chondrocyte phenotype Is influenced by a range of soluble factors. In particular, members of the bone morphogenetic protein (BMP) family support the articular chondrocyte phenotype and stimulate synthesis of cartilaginous matrix. This study was catried out to determine the importance of BMPs in supporting the differentiated phenotype of articular chondrocytes in vitro. Exogenous BMP-2 supported expression of collagen type II and aggrecan in monolayer chondrocyte cultures, slowing the dedifferentlotion process that occurs under these conditions. In contrast, BMP-2 had little effect on expression of these genes in three-dimensional aggregate cultures. Endogenous BMP-2 expression was lost in monoloyer cultures, coIncident with the down-regulation of collagen type II and aggrecan mRNAs, whereas BMP-2 mRNA levels were stable in aggregate cultures. Antagonism of endogenous BMP activity in aggregate cultures by Noggin or a soluble form of the BMP receptor resulted In reduced expression of collagen type II and aggrecan mRNAs, reduced collagen type II protein and sulfated glycosaminoglycan (GAG) deposition into the aggregate motrices and reduced secretion of GAGs into the culture media. These results Indicate that endogenous BMPs are required for maintenance of the differentiated articular chondrocyte phenotype in vitro. These findings are of importance to cell-based strategies designed to repair articular cartilage. Articular chondrocytes require conditions that will support endogenous expression of BMPs to maintain the specialized phenotype of these cells.

Original languageEnglish (US)
Pages (from-to)185-191
Number of pages7
JournalVeterinary and Comparative Orthopaedics and Traumatology
Issue number3
StatePublished - 2007


  • Articulor chondrocyte
  • BMPs
  • Cartilage
  • Phenotype

ASJC Scopus subject areas

  • Animal Science and Zoology
  • General Veterinary


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