Differentiation propensity of human embryonic stem cell lines: assays and molecular mechanisms.

Human pluripotent stem cells (hPSCs) hold a great promise for many biomedical applications due to their ability to give rise to any cell type of the adult human body. However, not every hPSC line will differentiate towards a targeted lineage with high efficiency and this variability can significantly hinder hPSC-based applications. The first aim of this PhD thesis was to evaluate distinct short-term differentiation assays (spontaneous embryoid body differentiation and directed differentiation in a monolayer and a micropatterned culture) for their suitability to accurately assess and compare differentiation propensities between individual human embryonic stem cell lines. The second aim was to gain new insight into molecular mechanisms which may cause differentiation bias. The two aims were addressed in three separate studies presented in the thesis. Taken together this thesis demonstrates that differences in the activity of signalling pathways influence the efficacy of early lineage specification already at the very onset of differentiation and highlights which technical aspects should be taken into account to study the differentiation propensity and which to improve the efficiency of hPSC differentiation protocols.