Epigenetic stimulation of pluripotency genes in cord blood derived neural stem cells

Epigenetic cues are potent tools for in vitro control of the stem cell fate decisions. Since human iPSc, can be derived from any tissue of the body and are characterized by unlimited self-renewal and potential to differentiation into all cell types of the body, they are considered as a good source for autologous transplantation. In this report we were studying the process of induction of pluripotency in neural stem cells derived from human cord blood using only epigenetic stimulation by small molecules and changing oxygen tension. “Pluripotency” is regulated by the set of genes including the expression of Oct4, Nanog and Sox2. Methylation status of the promoters of “pluripotency” genes as well as the chromatin histon acetylation determine self-renewal and differentiation of stem cells. However the low oxygen environmental condition and small molecules have been used only as additional factors for enhancing induction of pluripotency state. We were testing the influence of lowered (5%) oxygen conditions as well as TSA and RG-108 (histon deacetylase and DNA methyltransferase inhibitors respectively) on the expression of Oct4, Sox 2, Rex1 and Nanog genes in HUCB-NSC (human umbilical cord blood neural stem cells). Cells were cultured from 5 days until one month in serum-free medium supplemented with TSA and/or RG-108 in 5% oxygen. Our results show that low oxygen tensions can activate Oct4 and Nanog genes in HUCB-NSC. Small molecules: TSA and RG-108 enhance this process and additionally induce expression of Sox2 and Rex1. The time of cultivation of the cells in low oxygen conditions and the developmental stage of the cells are the important factors for the induction of the expression of “pluripotency” genes. Our observations confirm that the low oxygen tensions promote maintenance of undifferentiated state of the cells. Sponsored by grant from Polish Ministry of Scientific Research and Higher Education No. NN302 597838.

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