Epigenetic control of functional maintenance and differentiation capacity of USSC

点击翻译按钮获取中文摘要

Recent evidence suggests that expression of Dlk1 distinguishes between two types of cord bloodderived stem cells, namely Dlk1+ USSC that have the potential to differentiate to the osteogenic lineage and Dlk1- CB-MSC, which have mainly adipogenic differentiation potential. Dlk1 is part of the imprinted dlk1-dio3 locus, which was recently associated with incomplete epigenetic reprogramming and impaired differentiation potential in murine induced pluripotent stem (iPS) cells. In the first part of the project, we aim to dissect the epigenetic basis for the regulation of Dlk1 in the context of the extended dlk1-dio3 locus. High-density tiling arrays covering the complete locus in sense and antisense direction will be used for comparative analysis of DNA methylation and histone modifications in cord blood-derived somatic stem and iPS cells. Analysis of other components of the Dlk1-Dio3 locus such as miRNAs, snoRNAs, and large non-coding RNAs will add to a comprehensive picture of the regulation of DLK1 in stem cells. In the second part of the project we will explore the potential for epigenetic reprogramming of USSC using epigenetic modifiers. In this context, we have already shown that Dlk1+ USSC can be reproducibly converted to Dlk1- cells that adopt a sphere-like phenotype (spheUSSC) and can be differentiated to adipocytes with high efficiency. Importantly, spheUSSC can be propagated to large cell numbers without further treatment with epigenetic modifiers. We will further characterize the differentiation potential of spheUSSC, their suitability for induction of pluripotency by exogenous factors and their potential for “trophic activity”. Finally, we will further elucidate the potential for directed epigenetic reprogramming of USSC using novel combinations of epigenetic drugs.