EZH2, the moderator in the discussion between methyltransferases at histone H3?

In vivo administration of G9a inhibitor A366 decreases osteogenic potential of bone marrow-derived mesenchymal stem cells

Epigenetic mechanisms such as histone methylation are considered as one of the most important mediators that control stem cell behaviors such as proliferation, senescence and differentiation. G9a, a histone methyltransferase, has recently generated intense attention as potential target for controlling many diseases such as cancers. The aim of the present study was to evaluate the effect of in vivo administration of A366, a G9a inhibitor, on proliferative and differentiation potential of bone marrow-derived mesenchymal stem cells (BM-MSCs). We inhibited G9a using intraperitoneally administration of A366, and we evaluated BM-MSC proliferation and differentiation behaviors in vitro. Colony formation assay of BM-MSCs at primary culture showed that in vivo administration of A366 reduced the colony forming capacity of BM-MSCs. Moreover, PDT of BM-MSC isolated from A366-treated rats was higher than control, especially in the early passages. BM-MSC isolated from A366-treated rats showed higher adipogenic potential compared to the control at the early passages as determined by gene expression and Oil Red staining. Whereas, osteogenic potential of BM-MSC isolated from A366-treated rats was lower than control, especially at early passages. Our results suggest that the epigenetic modifier such as A366, which seems to be a therapeutic approach for controlling diseases such as cancer, might also influence the proliferation and differentiation capacity of MSCs both in vitro and in vivo. Moreover, epigenetic modifying chemicals seem to be a strategy to manipulate MSC expansion capacity and differentiation propensity, as well as to efficiently involvement of MSCs in tissue homeostasis, cell-based therapy and tissue engineering.