2007 年 26 巻 4 号 p. 171-183
Bone marrow stroma cells (MSCs) have been shown to differentiate into multiple lineages and have great potential for regenerative therapy. We have obtained hMSCs from 6 human adults. They were all positive for CD13, CD44, and CD90 and weakly positive for CD49, while negative for CD45, suggesting that they were different from hematopoetic stem cells. hMSCs were induced to become neuronal cells and maintained as long as three weeks in the serum free medium supplemented with N2. An increase in the amount of mRNA was observed for the NeuroD1, neurofilament M and H, MAP2, neuron-specific enolase, tryptophan hydroxylase, Nurr1, and neuron specific Na+ channel genes, and the existence of voltage-gated Na+ channels that were sensitive to tetrodotoxin was confirmed electro physiologically. These results suggested that hMSCs differentiated into serotonergic neural cells. However, the expression of genes specific for stroma cells, the Big-h3 and vimentin-genes, was observed equally during the induction process, indicating that the expression pattern was not the completely same as in genuine neural cells. hMSCs cultured with serial passages showed aging phenomena at the cellular level under the various conditions examined in this study. Trials to isolate cellular clones proliferating indefinitely have not succeeded.
