gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2017)

24.10. - 27.10.2017, Berlin

Chondral versus endochondral chondrocyte differentiation: differential expression of TGF-beta superfamily members and role of Smad1/5/9-signalling

Meeting Abstract

  • presenting/speaker Jennifer Fischer - Orthopädische Universitätsklinik Heidelberg, Experimentelle Orthopädie, Heidelberg, Germany
  • Verena Dexheimer - Orthopädische Universitätsklinik Heidelberg, Experimentelle Orthopädie, Heidelberg, Germany
  • Jessica Gabler - Orthopädische Universitätsklinik Heidelberg, Experimentelle Orthopädie, Heidelberg, Germany
  • Bomans Katharina - Orthopädische Universitätsklinik Heidelberg, Heidelberg, Germany
  • Georg Omlor - Orthopädische Universitätsklinik Heidelberg, Abteilung für Orthopädie und Unfallchirurgie, Heidelberg, Germany
  • Tanja Sims - Orthopädische Universitätsklinik Heidelberg, Experimentelle Orthopädie, Heidelberg, Germany
  • Wiltrud Richter - Orthopädische Universitätsklinik Heidelberg, Experimentelle Orthopädie, Heidelberg, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2017). Berlin, 24.-27.10.2017. Düsseldorf: German Medical Science GMS Publishing House; 2017. DocGR20-438

doi: 10.3205/17dkou549, urn:nbn:de:0183-17dkou5496

Veröffentlicht: 23. Oktober 2017

© 2017 Fischer et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: Proteins of the TGF-beta superfamily are potent inducers of cartilage and bone and the crosstalk of TGF-beta- and BMP-signalling pathways appears crucial during chondrogenesis. Aim of this study was to assess the regulation of TGF-beta superfamily members and of Smad2/3- versus Smad1/5/9-signalling during endochondral in vitro chondrogenesis of human mesenchymal stromal cells (MSC)in comparison to chondral redifferentiation of human articular chondrocytes (AC) in order to identify new means capable of adjusting chondrocyte development of MSC towards a less hypertrophic phenotype.

Methods: Human MSC and AC were subjected to in vitro chondrogenesis for up to six weeks. Gene expression of both cell types was analysed by genome-wide micro array analysis and by qPCR. To further dissect the role of TGF-beta superfamily members and Smad2/3- versus Smad1/5/9-signalling, cells were treated with agonists (BMP4/7, TGF-beta) or the BMP receptor antagonist dorsomorphin. Chondrogenic and hypertrophic marker expression was analysed on gene and protein level by qPCR, western blot analysis, ELISA and enzyme activity assays.

Results and Conclusion: While MSC increased BMP4 and BMP7 and reduced TGFBR2 and TGFBR3-expression during chondrogenesis, an opposite regulation was observed during AC-redifferentiation. Antagonists CHRD and CHL2 rose significantly only in AC-cultures. AC showed higher initial BMP4, pSmad1/5/9 and SOX9 protein levels, a faster (re-)differentiation but a similar decline of pSmad2/3- and pSmad1/5/9-signalling versus MSC-cultures. BMP-4/7-stimulation of MSC-pellets enhanced SOX9 and accelerated ALP-induction but did not shift differentiation towards osteogenesis. Inhibition of BMP signalling by dorsomorphin significantly reduced SOX9, raised RUNX2, maintained collagen-type-II and collagen-type-X lower and kept ALP-activity at Levels reached at initiation of treatment.

Conclusively, ALK1,2,3,6-signalling was essential for MSC-chondrogenesis and its prochondrogenic rather than prohypertrophic role may explain why inhibition of canonical BMP-signalling could not uncouple cartilage matrix production from hypertrophy as this was achieved with pulsed PTHrP application.