Fig. (3).

Role of histone acetylation in hMSCs differentiation into osteoblasts. (A) Differentiation of hMSCs into osteoblasts produces a genome-wide reduction of the levels of acetylated H3K9 and H3K27, together with an increase in the histone acetylation at the promoters of osteogenic genes. (B) Sclerostin, the product of the SOST gene, binds to the LPR5/6 receptors inhibiting the activation of the wnt pathway and therefore, osteogenic differentiation. HDAC SIRT1 would activate osteogenesis by deacetylating SOST promoter and thus, inhibiting its expression. (C) Activation of OCN is mediated by an active (acetylated) RUNX2 protein and by the acetylation of histones at its promoter, mediated by the HAT p300.