Localization of epidermal growth factor receptors and putative neuroblastsin human subependymal zone

Studies in rodents and monkeys suggest that neuronal precursor cells contin ue to exist and differentiate well into adulthood in these species. These r esults challenge the long held assumption that neurogenesis does not occur in the postnatal human brain. We examined the rostral subependymal zone (SE Z) of postnatal human brain for expression of cell phenotypic markers that have been associated with neuronal precursors and neuroblasts in rodent bra in. We found epidermal growth factor receptor (EGF-R) mRNA and protein to b e expressed in infant, teen, young adult, and adult human SEZ. Some SEZ cel ls expressed the polysialic acid form of neural cell adhesion molecule (PSA -NCAM), characteristic of migrating neuroblasts, as well as class III P-tub ulin and Hu protein, characteristic of neuroblasts and early neurons. These neuroblast-like cells were negative for glial fibrillary acidic protein (G FAP), 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase), and vimentin, s uggesting that they were not differentiating as glia. Our results show that neuroblast-like cells exist in the human SEZ and support the theory that S EZ of postnatal human brain has neurogenic potential. Published 2000 Wiiey- Liss. Inc.(+).