Biological properties of neural progenitor cells isolated from the hippocampus of adult cynomolgus monkeys.

Background: The existence of neurogenesis in the hippocampus of adult nonhuman primates has been confirmed in recent years, however, the biological properties of adult neural stem cells or neural progenitor cells (NPCs) from this region remain to be extensively explored. The present work was to investigate on the expansion of NSCs/NPCs from the hippocampus of adult cynomolgus monkeys and the examination of their characteristics in vitro.

Methods: NPCs isolated from the hippocampus of adult cynomolgus monkeys were expanded in vitro in serum-free media containing growth factors, and were then allowed to differentiate by removing mitotic factors. The expansion capacity of NPCs and their differentiation potential were assayed by immunohistochemical and immunocytochemical analysis.

Results: During primary culture, NPCs underwent cell division, proliferation and aggregation to form neurospheres that were growing in suspension. Without mitotic stimulation, most neurospheres adhered to the culture dish and started to differentiate. Eventually, nearly 12% of the differentiated cells expressed neuron specific marker-beta III-tubulin (Tuj1) and 84% expressed astrocyte specific marker-fibrillary acidic protein (GFAP). In addition, the expression of a neural stem cell marker, nestin, was found both in NPCs and in the subgranular zone of adult monkey hippocampus, where NPCs were originally derived.

Conclusions: NPCs from the hippocampus of adult cynomolgus monkeys can be expanded to some extent in vitro and are capable of differentiating into neurons and astrocytes. Further experiments to promote the in vitro proliferation capacity of NPCs will be required before adult NPCs can be used as a useful cell model for studying adult neurogenesis and cell replacement therapy using adult stem cells.