P225 - Transcription factor reporters suitable for monitoring patient dependent chondrogenic capacity in osteoarthritis
- P. Kraan Van Der (Nijmegen, NL)
- P. Kraan Van Der (Nijmegen, NL)
- M. Neefjes (Nijmegen, NL)
- B. Housmans (Maastricht, NL)
- T. Welting (Maastricht, NL)
- A. Van Caam (Nijmegen, NL)
Abstract
Purpose
Recent developments have demonstrated that intrinsic cartilage repair is possible in certain osteoarthritis (OA) patients. Literature suggests an influence of joint microenvironment on intrinsic cartilage repair via affecting chondrogenic capacity of stem cells. A method able to discriminate between patients with permissive or non-permissive articular joint microenvironments would be of great use to predict the outcome of cartilage repair therapies. Therefore, our goal is to develop a rapid bioassay that will be able to discriminate between these joint conditions.
Methods and Materials
To construct our bioassay, sixteen transcription factor binding sequences were cloned in the pNL1.2 vector. Transcription factor reporter constructs were stably integrated into SW1353 cells using virus transduction. Cells were stimulated for 6 hours with OA-synovium conditioned medium (OAs-cm; n=32) and luciferase activity was measured. These results were correlated (Pearson) with the ability of these OAs-cm to inhibit sGAG formation during chondrogenesis. This was tested by chondrogenic differentiation of human fetal bone-marrow derived MSCs in an established three-dimensional pellet culture model. Pellets were cultured for 14 days in chondrogenic medium and were exposed to OAs-cm after 10 days of differentiation. Cartilage formation was determined at day 14 by measuring sGAG content.
Results
Large heterogeneity was observed in the response of the transcription factor reporters between the OAs-cm from individual patients. Furthermore, individual OAs-cm reduced sGAG content of differentiating MSCs by a range between 3% and 65%. Significant correlations were found between the fold change of the reporter activity and the percentage of inhibition on chondrogenesis for seven out of the sixteen tested transcription factor reporters (AP1, CRE, ISRE, NFAT5, NFκB, SIE and SRE; Figure 1).
Conclusion
This set of seven transcription factor reporters appears to be able to predict repair capacity of stem cells in an OA microenvironment and could be of use for a personalized treatment strategy.