Comparative epigenetic influence of autologous versus fetal bovine serum on mesenchymal stem cells through in vitro osteogenic and adipogenic differentiation.

Mesenchymal stem cells (MSCs) derived from bone marrow (BM) represents a useful source of adult stem cells for cell therapy and tissue engineering. MSCs are present at a low frequency in the BM; therefore expansion is necessary before performing clinical studies. Fetal bovine serum (FBS) as a nutritional supplement for in vitro culture of MSCs is a suitable additive for human cell culture, but not regarding subsequent use of these cells for clinical treatment of human patients due to the risk of viral and prion transmission as well as xenogeneic immune responses after transplantation. Recently, autologous serum (AS) has been as a supplement to replace FBS in culture medium. We compared the effect of FBS versus AS on the histone modification pattern of MSCs through in vitro osteogenesis and adipogenesis. Differentiation of stem cells under various serum conditions to a committed state involves global changes in epigenetic patterns that are critically determined by chromatin modifications. Chromatin immunoprecipitation (ChIP) coupled with real-time PCR showed significant changes in the acetylation and methylation patterns in lysine 9 (Lys9) of histone H3 on the regulatory regions of stemness (Nanog, Sox2, Rex1), osteogenic (Runx2, Oc, Sp7) and adipogenic (Ppar-γ, Lpl, adiponectin) marker genes in undifferentiated MSCs, FBS and AS. All epigenetic changes occurred in a serum dependent manner which resulted in higher expression level of stemness genes in undifferentiated MSCs compared to differentiated MSCs and increased expression levels of osteogenic genes in AS compared to FBS. Adipogenic genes showed greater expression in FBS compared to AS. These findings have demonstrated the epigenetic influence of serum culture conditions on differentiation potential of MSCs, which suggest that AS is possibly more efficient serum for osteogenic differentiation of MSCs in cell therapy purposes.