Genome-wide demethylation by 5-aza-2'-deoxycytidine alters the cell fate of stem/progenitor cells.

DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) is able to cause DNA demethylation in the genome and induce the expression of silenced genes. Whether DNA demethylation can affect the gene expression of stem/progenitor cells has not been understood. Mouse utricle epithelia-derived progenitor cells (MUCs), which possess stem cell features as previously described, exhibit a potential DNA methylation status in the genome. In this study, MUCs were treated with 5-aza-CdR to determine whether DNMT inhibitor is able to induce the differentiation of MUCs. With 5-aza-CdR treatment for 72 hr, MUCs expressed epithelial genes including Cdh1, Krt8, Krt18, and Dsp. Further, hair cell genes Myo7a and Myo6 increased their expressions in response to 5-aza-CdR treatment. The decrease in the global methylated DNA values after 5-aza-CdR treatment indicated a significant DNA demethylation in the genome of MUCs, which may contribute to remarkably increased expression of epithelial genes and hair cell genes. The progenitor MUCs then turned into an epithelial-like hair cell fate with the expression of both epithelial and hair cell genes. This study suggests that stem cell differentiation can be stimulated by DNA demethylation, which may open avenues for studying stem cell fate induction using epigenetic approaches.