Olfactory horizontal basal cells demonstrate a conserved multipotent progenitor phenotype.

Stem cells of adult regenerative organs share a common goal but few established conserved mechanisms. Within the neural stem cell niche of the mouse olfactory epithelium, we identified a combination of extracellular matrix (ECM) receptors that regulate adhesion and mitosis in non-neural stem cells [intercellular adhesion molecule-1 (ICAM-1), beta1, beta4, and alpha-1, -3, and -6 integrins] and on horizontal basal cells (HBCs), candidate olfactory neuro-epithelial progenitors. Using ECM receptors as our guide, we recreated a defined microenvironment in vitro that mimics olfactory basal lamina and, when supplemented with epidermal growth factor, transforming growth factor alpha, and leukemia inhibitory factor, allows us to preferentially expand multiple clonal adherent colony phenotypes from individual ICAM-1+ and ICAM-1+/beta1 integrin+-selected HBCs.

Neurotrophins and their receptors in the primary olfactory neuraxis.

The primary olfactory pathway is an elegant and simple system in which to study neurogenesis and neuronal plasticity because of the simple fact that olfactory receptor neurons (ORNs) are continually generated throughout the adult lifetimes of vertebrates. Thus, neuronal birth, differentiation, survival, axon pathfinding, target recognition, synapse formation, and cell death are developmental events that can be examined in the mature olfactory epithelium (OE). Neurotrophins (nerve growth factor, brain-derived neurotrophic factor, and neurotrophin 3, and 4/5) are a family of bioactive peptides that exert their effects by interacting with high- and low-affinity receptors on the surfaces of responsive cells, and have been implicated in several stages of neuronal development throughout the central and peripheral nervous system (CNS and PNS).