The Journal of Neuroscience June 17, 2009, 29(24): 7649–7657
The prospect of replenishing damaged cells in the brain using transplanted stem cells is perhaps most hopeful in the case of replacing oligodendrocytes in demyelinating diseases such as multiple sclerosis (MS). Wu et al. report what might be a landmark step in this direction: the discovery of a previously unrecognized population of cells in the adult subventricular zone (SVZ) that can differentiate into neurons, astrocytes, and oligodendrocytes, depending on culturing conditions. These cells, distinguishable from other SVZ cells by their expression of _4 tubulin (T4), were scattered throughout the SVZ in humans, and their numbers were significantly elevated near lesions in MS patients. T4-expressing cells exhibited several features of stem cells in addition to multipotency: low basal proliferation rate, contact inhibition via homophilic adhesion, and resistance to dissociation. Most importantly, when injected into the brain of myelin-deficient rats, T4 cells produced mature oligodendrocytes that migrated far from the injection site and produced widespread remyelination.