Functional analysis of embryonic stem cell-derived glial cells after integration into hippocampal slice cultures

Embryonic stem (ES) cell-derived neural progenitor cells (ESNPs) generated in vitro are multipotent progenitors which can differentiate into oligodendrocytes, astrocytes, and neurons. Given the exciting prospects for ES cell-based treatments of neurological disorders, several studies investigated the migration, integration, and differentiation of grafted ESNPs into neurons and glial cells. However, little is known about the functional properties of transplanted ESNPs on the single cell level. In this study, we combined electrophysiology, single cell reverse transcription polymerase chain reaction (RT-PCR) and immunochemistry to determine the developmental time course of molecular and functional properties of ES cell-derived glial precursors (ESGPs) after deposition onto hippocampal slice cultures. Based on functional criteria, donor cells possessed three different phenotypes. During an observation period of 3 weeks after engraftment, the proportion of donor cells with a passive current pattern (type 3) continuously increased. The majority of these cells expressed astroglial markers. Type 3 host cells underwent similar developmental changes. In contrast, donor and host cells expressing time- and voltage-dependent currents (types 1, 2) displayed different developmental profiles. Importantly, type 2 donor and host cells also differed in the expression of inwardly rectifying K(+) channels. This suggests that despite several similarities in overall current phenotypes and timing of maturation, many donor cells integrated into host tissue but did not acquire the full set of ion channels present in their native counterparts. These findings emphasize the need to carefully characterize ES cell-derived progeny aimed for neural repair and cell-mediated gene transfer strategies.