Comparison of neuron-like cells derived from bone marrow stem cells to those differentiated from adult brain neural stem cells.

Bone marrow-derived stem/progenitor cells have been shown by independent investigators to give rise to neural-like cells (neurons and glia) both in vitro and in vivo. The objective of the present study was to determine whether nestin-enriched cells derived from bone marrow can differentiate into cells with the same morphological and functional characteristics as neurons derived from adult brain neurogenic zones. Cell culture methods were used for generation of adult bone marrow and brain stem/progenitor cells and for studying their differentiation into neural-like cells. The proportion of cells expressing neuronal markers was greater in cultures derived from adult hippocampal neural stem cells than in the bone marrow-derived cells, but the electrophysiological and functional characteristics of the cells were similar. Action potentials with electrical characteristics corresponding to those exhibited by adult neural stem cell-derived neurons were recorded from approximately 2.5% of patched neuron-like cells differentiated from bone marrow cells. The active uptake of tritium-labeled neurotransmitters gamma-aminobutyric acid ([(3)H]GABA) and dopamine ([(3)H]DA) was measured in both sets of cultures. [(3)H]GABA uptake, but not [(3)H]DA, was significantly increased in differentiated neurons in both neural stem cell cultures and bone marrow-derived cultures. [(3)H]GABA uptake was greater in differentiated neurons derived from brain neural stem cells. In summary, both the nestin-expressing bone marrow and the adult brain neural stem/progenitors developed into cells with morphological, immunocytochemical, and functional characteristics of neurons. Even though a smaller proportion of neuron-like cells was generated from bone marrow-derived progenitors than from brain-derived neural stem cells, these cells may be useful in the cellular therapy of neurodegenerative diseases and traumatic brain and spinal cord injury.