Spontaneous neural differentiation of stem cells in culture of human olfactory epithelium.

We studied differentiation of stem cells in dissociated cultures of olfactory epithelium. Staining with anti-nestin antibodies revealed stem cells in the primary monolayer culture of the olfactory epithelium from adult human. Proliferation of these cells during culturing in serum-containing medium in the presence of nerve growth factors FGF2 and NGF led to the formation of neurospheres freely floating in the medium or attached to the substrate. Further long-term culturing and cloning of dissociated cells from these neurospheres in media not containing nerve growth factors led to spontaneous neural differentiation of the olfactory epithelium stem cells. The cells with phenotypic signs of differentiated neurons were stained with antibodies against beta-tubulin and neurospecific enolase. Differentiated neurons formed diffuse and spatially organized neuronal networks. We hypothesized that factors triggering neural differentiation of olfactory epithelium stem cells are produced byastrocytes present in these cultures.