Human articular chondrocytes express osteogenic protein-1

Susan Chubinskaya, Charis Merrihew, Gabriella Cs-Szabo, Juergen Mollenhauer, John McCartney, David C. Rueger, Klaus E. Kuettner

Research output: Contribution to journalArticlepeer-review


This study demonstrates for the first time that human articular chondrocytes express osteogenic protein-1 (OP-1). OP-1 was originally purified from bone matrix and was shown to induce cartilage and bone formation. Both OP-1 protein and message were present in human normal and osteoarthritic (OA) cartilages. OP-1 mRNA was upregulated in OA cartilage compared with normal adult tissues. However, the level of mature OP-1 protein in the same OA tissues was downregulated, whereas the pro-OP-1 remained high. Moreover, these two forms of OP-1 were localized in an inverted manner. Mature OP-1 was primarily detected in the superficial layer, whereas the pro- form was mostly in the deep layer of cartilage. The presence of pro- and mature OP-1 in extracts of normal and OA cartilages was confirmed by Western blotting. These findings imply that articular chondrocytes continue to express and synthesize OP-1 throughout adulthood. The observed patterns of the distribution of pro- and mature OP-1 also suggest differences in the processing of this molecule by normal and OA chondrocytes and by the cells in the superficial and deep layers. Distinct distribution of OP-1 and its potential activation in deep zones and regions of cloning in OA cartilages may provide clues to the potential involvement of endogenous OP-1 in repair mechanisms.

Original languageEnglish (US)
Pages (from-to)239-250
Number of pages12
JournalJournal of Histochemistry and Cytochemistry
Issue number2
StatePublished - Feb 2000
Externally publishedYes


  • Comparative RT-PCR
  • Human articular cartilage
  • Immunohistochemistry
  • In situ hybridization
  • Osteogenic protein-1
  • Western blotting

ASJC Scopus subject areas

  • Anatomy
  • Histology


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