In Vitro Differentiation of Mouse ES Cells Towards the CNS Progenitors and Mature Neurons for Cell Transplantation

[[abstract]]The central nervous system (CNS) is a highly complicate network in the brain that can be reformed after recovering from the brain-related injuries or disorders. Embryonic stem cells (ESCs) are pluripotent, being capable of self-renewed and differentiated into any cell type of the body. Previous studies suggested that ESC-derived neural progenitor cells (NPCs) can be transplanted into the brain to rescue degenerated residential neural cells. However, it is still unclear how the transplanted cells to be integrated into the existing neuronal network and function properly. To fill the gaps, this study aimed to first confirm the available neural differentiation protocols to prepare various stages of candidate neural cells for therapeutic transplantation; and, secondly, to investigate how the cell transplant is induced to differentiate and integrate into the existing neuronal cell population using in vitro matured neuronal cell cultures. Starting from the ES cell culture, neurospheres (NBs) were formed after the induction of differentiation from the embryoid bodies (EBs). The NPCs were observed as early as day 7 after the onset of EBs/NBs formation. According to the marker expressions, all the CNS cells including neurons, astrocytes and oligodendrocytes, were identified during the final maturation phase in the culture, demonstrating the reliability of the current protocols for CNS neuron differentiation. Therefore, the wildtype non-EGFP ES cells were introduced into the previously matured non-EGFP ES cell-derived neuronal cell cultures. The results showed that the NPCs formed a better connection with the host cells, compared to the ES cells. Moreover, it appeared that the NPCs at day 4 after EB/NB formation provided a better connection between the introduced neuronal cells and the host cells