Age-related skeletal degeneration in patients with osteoporosis is characterized by decreased bone mass and occurs concomitant with an increase in bone marrow adipocytes. Using microarray expression profiling with high temporal resolution, we identified gene regulatory events in early stages of osteogenic and adipogenic lineage commitment of human mesenchymal stromal cells (hMSCs). Data analysis revealed three distinct phases when cells adopt a committed expression phenotype: initiation of differentiation (0-3 hr, phase I), lineage acquisition (6-24 hr, phase II), and early lineage progression (48-96 hr, phase III). Upstream regulator analysis identified 34 transcription factors (TFs) in phase I with a role in hMSC differentiation. Interestingly, expression levels of identified TFs did not always change and indicate additional post-transcriptional regulatory mechanisms. Functional analysis revealed that forced expression of IRF2 enhances osteogenic differentiation. Thus, IRF2 and other early-responder TFs may control osteogenic cell fate of MSCs and should be considered in mechanistic models that clarify bone-anabolic changes during clinical progression of osteoporosis. In this article, van Leeuwen and colleagues determine high temporal gene expression changes in human mesenchymal stromal cells upon induction of adipocyte and osteoblast differentiation. They identify three early differentiation phases within the first 4 days. Furthermore, novel transcription factors were identified that may control cell fate of hMSCs and should be considered in mechanistic models that clarify bone-anabolic changes.

Additional Metadata
Keywords Adipocyte, Bioinformatics, Bone, Gene expression profiling, Human MSC differentiation, Interferon, Osteoblast, Regenerative medicine, Transcription factor
Persistent URL dx.doi.org/10.1016/j.stemcr.2017.02.018, hdl.handle.net/1765/99027
Journal Stem Cell Reports
Note Supplemental Information includes four figures and one table can be found with this article online at http://dx.doi.org/10.1016/j.stemcr.2017.02.018.
Grant This work was funded by the European Commission 7th Framework Programme; grant id fp7/311815 - Biopolymers from syngas fermentation (SYNPOL), This work was funded by the European Commission 7th Framework Programme; grant id h2020/642691 - Epigenetic regulation of endocrine therapy resistance in breast cancer: A systems medicine approach to predict treatment outcome (EpiPredict)
Citation
van de Peppel, J, Strini, T, Tilburg, J, Westerhoff, H.V, van Wijnen, A.J, & van Leeuwen, J.P.T.M. (2017). Identification of Three Early Phases of Cell-Fate Determination during Osteogenic and Adipogenic Differentiation by Transcription Factor Dynamics. Stem Cell Reports, 8(4), 947–960. doi:10.1016/j.stemcr.2017.02.018