Mesenchymal stem cells （MSCs） of nonembryonic origins possess the proliferation and multi-lineage differentiation potentials. It has been established that epigenetic mechanisms could be critical for determining the fate of stem cells, and MSCs derived from different origins exhibited different expression profiles individually to a certain extent. In this study, ChiP-on-chip was used to generate genome-wide histone H3-Lys9 acetylation and dimethylation profiles at gene promoters in human bone marrow MSCs. We showed that modifications of histone H3-Lys9 at gene promoters correlated well with mRNA expression in human bone marrow MSCs. Functional analysis revealed that many key cellular pathways in human bone marrow MSC self-renewal, such as the canonical signaling pathways, cell cycle pathways and cytokine related pathways may be regulated by H3-Lys9 modifications. These data suggest that gene activation and silencing affected by H3-Lys9 acetylation and dimethylation, respectively, may be essential to the maintenance of human bone marrow MSC self-renewal and multi-potency.
Jiang TanHui HuangWei HuangLin LiJianhua GuoBaiqu HuangJun Lu
The human pituitary tumor transforming gene （hPTTG） serves as a marker for malignancy grading in several cancers, hPTTG is involved in multiple cellular pathways including cell transformation, apoptosis, DNA repair, genomic instability, mitotic control and angiogenesis induction. However, the molecular mechanisms underlying hPTTG regulation have not been fully explored. In this study, we found that overexpression of histone acetyltransferase （HAT） p300 upregulated hPTTG at the levels of promoter activity, mRNA and protein expression. Moreover, the HAT activity of p300 was critical for its regulatory function. Chromatin immunoprecipitation （CHIP） analysis revealed that overexpression of p300 elevated the level of histone H3 acetylation on the hPTTG promoter. Additionally, the NF-Y sites at the hPTTG promoter exhibited a synergistic effect on upregulation of hPTTG through interacting with p300. We also found that treatment of 293T cells with the histone deacetylase （HDAC） inhibitor Tfichostatin A （TSA） increased hPTTG promoter activity. Meanwhile, we provided evidence that HDAC3 decreased hPTTG promoter activity. These data implicate an important role of the histone acetylafion modification in the regulation of hPTTG.
