In vivo and in vitro characteristics of human neuronal cells derived from the teratocarcinoma cell line NT2

The human teratocarcinoma cell line NTera 2 (NT2) is a committed neuronal precursor line, capable of generating large populations of neuron-like cells (NT2N cells) after retinoic acid (RA) treatment. The NT2N cells are post-mitotic, terminally differentiated and express morphological and molecular neuronal markers. Because of these attributes, I was interested in determining the potential for of these cells for therapeutic purposes and as models of neuronal differentiation and development. In order to assess their value in these regards, I demonstrated the viability and molecular changes of NT2N cells after implantation into murine central nervous system (CNS). Additionally, I determined which neurotransmitters the NT2N cells express. In order to examine the ability of the NT2N cells to survive in a CNS environment, I implanted NT2N cells into adult and neonatal nude mouse CNS. The NT2N cells can survive in this environment for more than a year, with no evidence of tumor formation. Grafted NT2N cells extend neurites with markers of axons and dendrites and express markers of neuronal maturation which were not observed in vitro. Finally, NT2N cells express synaptophysin, and immature synaptic profiles were observed. Thus, I showed that implanted NT2N cells maintain their neuronal phenotype, survive for extended periods, and are non-toxic to the host brain. These attributes indicate that the NT2N cells are a promising cell type for future therapeutic cell transplantation in cases of human neuronal degeneration and loss. The differentiation of the NT2N cells from neuroepithelial precursors to neuron-like cells makes them a valuable tool for studying late developmental events. However, a better understanding of the particular type of neuron which the NT2N cells most resemble is essential. As one criteria by which neurons are classified is their neurotransmitter phenotype, I sought to determine which neurotransmitters the NT2N cells express. I found that the NT2N cells express both cholinergic and GABAergic properties. These properties develop during the course of differentiation, and are maintained well beyond the cessation of RA treatment. In addition, the untreated NT2 cells express glutamic acid decarboxylase, the biosynthetic enzyme for GABA, although it is not enzymatically active at this stage