The Epigenetic Regulation Of HOX Family Genes In Early Osteogenetic Differentiation Of Human Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are stromal cells that can be derived from several tissues, such as bone marrow and placenta. They can differentiate into several cell lineages including osteoblasts, chondrocytes, adipocytes and myoblasts in vivo and in vitro. It has been reported that the mammalian chromatin undergoes global remodeling during early development. HOX family encoding the class of transcription factors called homeobox, which is spatially and temporally regulated during embryonic development. We induced MSCs differentiated into osteoblasts,and investigated the expression of the genes in HOX family during the osteogenetic process. We found that the genes in 3'side of HOX family were down-regulated in the early stage of MSCs osteogenetic differentiation, whereas acetylation of H3-lys9 was declined and H3-lys9 methyation was raised in their promoter regions. Our data indicated that the 3'side genes in HOX family are repressed in the process of MSCs differentiated into osteoblasts, and the inhibition is closely linking with the chromatin remodeling.