Effects of interleukin-6 and interleukin-1ß on expression of growth differentiation factor-5 and Wnt signaling pathway genes in equine chondrocytes

• Localización: American Journal of Veterinary Research, ISSN-e 1943-5681, ISSN 0002-9645, Nº. 3-75, 2014, págs. 132-140
• Idioma: inglés
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• Resumen

  • Objective�To determine the effects of interleukin (IL)-6 and IL-1ß stimulation on expression of growth differentiation factor (GDF)-5 and Wnt signaling pathway genes in equine chondrocytes.

    Sample�Macroscopically normal articular cartilage samples from 6 horses and osteochondral fragments (OCFs) from 3 horses.

    Procedures�Chondrocyte pellets were prepared and cultured without stimulation or following stimulation with IL-6 or IL-1ß for 1, 2, 12, and 48 hours; expression of GDF-5 was determined with a quantitative real-time PCR assay. Expression of genes in various signaling pathways was determined with microarrays for pellets stimulated for 1 and 2 hours. Immunohistochemical analysis was used to detect GDF-5, glycogen synthase kinase 3ß (GSK-3ß), and ß-catenin proteins in macroscopically normal cartilage samples and OCFs.

    Results�Chondrocytes stimulated with IL-6 had significantly higher GDF-5 expression within 2 hours versus unstimulated chondrocytes. Microarray analysis of Wnt signaling pathway genes indicated expression of GSK-3ß and coiled-coil domain containing 88C increased after 1 hour and expression of ß-catenin decreased after 2 hours of IL-6 stimulation. Results of immunohistochemical detection of proteins were similar to microarray analysis results. Chondrocytes in macroscopically normal articular cartilage and OCFs had immunostaining for GDF-5.

    Conclusion and Clinical Relevance�Results indicated IL-6 stimulation decreased chondrocyte expression of the canonical Wnt signaling pathway transactivator ß-catenin, induced expression of inhibitors of the Wnt pathway, and increased expression of GDF-5. This suggested IL-6 may inhibit the Wnt signaling pathway with subsequent upregulation of GDF-5 expression. Anabolic extracellular matrix metabolism in OCFs may be attributable to GDF-5 expression. This information could be useful for development of cartilage repair methods.