Genetic enhancement of matrix synthesis by articular chondrocytes: Comparison of different growth factor genes in the presence and absence of interleukin-1

P. Smith, F. D. Shuler, H. I. Georgescu, S. C. Ghivizzani, B. Johnstone, C. Niyibizi, P. D. Robbins, C. H. Evans

Research output: Contribution to journalArticlepeer-review

164 Scopus citations


Objective. To determine whether articular chondrocytes express growth factor genes delivered by adenoviral vectors and whether expression of these genes influences matrix synthesis in the presence and absence of interleukin- 1 (IL-1). Methods. Monolayer cultures of rabbit articular chondrocytes were infected with recombinant adenovirus carrying genes encoding the following growth factors: insulin-like growth factor 1 (IGF-1), transforming growth factor β1 (TGFβ1), and bone morphogenetic protein 2 (BMP-2). As a control, cells were transduced with the lac Z gene. Cultures were also treated with each growth factor supplied as a protein. Levels of gene expression were noted, and the synthesis of proteoglycan, collagen, and noncollagenous proteins was measured by radiolabeling. Collagen was typed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. The effects of growth factor gene transfer on proteoglycan synthesis in the presence of IL-1 were also measured. Results. The expression of all transgenes was high following adenoviral transduction. Proteoglycan synthesis was stimulated ~8- fold by the BMP-2 gene and 2-3-fold by the IGF-1 gene. The effects of BMP-2 and IGF-1 genes were additive upon cotransduction. Synthesis of collagen and noncollagenous proteins, in contrast, was most strongly stimulated by the IGF-1 gene. In each case, collagen typing confirmed the synthesis of type II collagen. IL-1 suppressed proteoglycan synthesis by 50-60%. IGF-1 and TGFβ genes restored proteoglycan synthesis to control levels in the presence of IL-1. The BMP-2 gene, in contrast, elevated proteoglycan synthesis beyond control levels in the presence of IL-1. Conclusion. Transfer of growth factor genes to articular chondrocytes can greatly increase matrix synthesis in vitro, even in the presence of the inflammatory cytokine IL-1. This result encourages the further development of gene therapy for the repair of damaged cartilage.

Original languageEnglish (US)
Pages (from-to)1156-1164
Number of pages9
JournalArthritis and rheumatism
Issue number5
StatePublished - May 2000

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Rheumatology
  • Immunology
  • Pharmacology (medical)


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