Mouse ES cells maintained in different pluripotency-promoting conditions differ in their neural differentiation propensity.

Prior to differentiation, embryonic stem (ES) cells in culture are maintained in a so-called "undifferentiated" state, allowing derivation of multiple downstream cell lineages when induced in a directed manner, which in turn grants these cells their "pluripotent" state. The current work is based on a simple observation that the initial culture condition for maintaining mouse ES cells in an "undifferentiated" state does impact on the differentiation propensity of these cells, in this case to a neuronal fate. We point out the importance in judging the "pluripotency" of a given stem cell culture, as this clearly demonstrated that the "undifferentiated" state of these cells is not necessarily a "pluripotent" state, even for a widely used mouse ES cell line. We partly attribute this difference in the initial value of ES cells to the naïve-to-primed status of pluripotency, which in turn may affect early events of the differentiation in vitro.