Immunocytochemical and physiological characterization of a population of cultured human neural precursors

Human neural precursor cells (HNPC) have recently become commercially avail able. In an effort to determine the usefulness of these cells for in vitro studies, we have grown cultured HNPCs (cHNPCs) according to the supplier sp ecifications. Here we report our characterization of cHNPCs under nondiffer entiating and differentiating growth conditions and make a comparison to pr imary HNPCs (pHNPCs) obtained at the same developmental time point from a d ifferent commercial supplier. We found that under nondifferentiating condit ions, cHNPCs expressed nestin, divided rapidly, expressed few markers of di fferentiated cells, and displayed both 4-aminopyridine (4-AP)-sensitive and delayed-rectifier type K+ currents. No inward currents were observed. On c hanging to differentiating culture conditions, a majority of the cells expr essed neuronal markers, did not divide, expressed inward and outward time- and voltage-dependent currents, and responded to the application of the neu rotransmitters acetylcholine and glutamate. The outward current densities w ere indistinguishable from those in undifferentiated cells. The inward curr ents included TTX-sensitive and -resistant Na+ currents, sustained Ca2+ cur rents, and an inwardly rectifying K+ current. Comparison of the properties of differentiated cells from cHNPCs with neurons obtained from primary feta l cultures (pHNPCs) revealed two major differences: the differentiated cHNP Cs did not express embryonic neural cell adhesion molecule (E-NCAM) immunor eactivity but did co-express GFAP immunoreactivity. The co-expression of ne uronal and glial markers was likely due to the growth of cells in serum con taining medium as the pHNPCs that were never exposed to serum did express E -NCAM and did not co-express glial fibrillary acidic protein (GFAP). The re levance of these results is discussed and compared with results from other neuronal progenitor populations and cultured human neuronal cells.