Identification and characterization of neuronal precursors and their progeny from human fetal tissue

We have examined primary human neuronal precursors (HNPs) from 18–22‐week‐old fetuses. We showed that E‐NCAM/MAP2/β‐III tubulin‐immunoreactive neuronal precursors divide in vitro and could be induced to differentiate into mature neurons in 2 weeks. HNPs did not express nestin and differentiated slowly compared to rodent neuronal restricted precursors (NRPs, 5 days). Immunocytochemical and physiological analyses showed that HNPs could generate a heterogeneous population of neurons that expressed neurofilament‐associated protein and various neurotransmitters, neurotransmitter synthesizing enzymes, voltage‐gated ion channels, and ligand‐gated neurotransmitter receptors and could fire action potentials. Undifferentiated and differentiated HNPs did not coexpress glial markers. Only a subset of cells that expressed GFP under the control of the Tα1 tubulin promoter was E‐NCAM/β‐III tubulin‐immunoreactive, indicating nonexclusive overlap between these two HNP cell populations. Overall, HNPs resemble NRPs isolated from rodent tissue and appear to be a neuronal precursor population. J. Neurosci. Res. 66:356–368, 2001. © 2001 Wiley‐Liss, Inc.