The adaptation of bovine embryonic stem cells to the changes of feeder layers.

Although the feeder-free culture system has been established, the microenvironment provided by the feeder cells still possesses a unique advantage in maintaining the long-term stability and the rapid proliferation of pluripotent stem cells (PSCs). The aim of this study is to discover the adaptive ability of PSCs upon changes of feeder layers. In this study, the morphology, pluripotent marker expression, differentiation ability of bovine embryonic stem cells (bESCs) cultured on low-density, or methanol fixed mouse embryonic fibroblasts were examined by immunofluorescent staining, Western blotting, real-time reverse transcription polymerase chain reaction, and RNA-seq. The results showed that the changes of feeder layers did not induce the rapid differentiation of bESCs, while resulting in the differentiation initiation and alteration of pluripotent state of bESCs. More importantly, the expression of endogenous growth factors and extracellular matrix were increased, and the expression of cell adhesion molecules was altered, which indicated that bESCs may compensate some functions of the feeder layers upon its changes. This study shows the PSCs have the self-adaptive ability responded to the feeder layer alteration.