Brainy stem cells

The search is on to identify and locate neural stem cells (NSCs). In the August 16 issue of Nature, Rodney Rietze and colleagues at The Walter and Eliza Hall Institute for Medical Research Australia, report the isolation of a pluripotent stem cell population from mouse brains (Nature 2001, 412:736-739). They performed a series of enrichment steps to purify NSCs from the ependymal and subventricular zones of the lateral ventricular walls. Flow cytometry was used to select a population expressing low amounts of peanut agglutinin (PNAlo) and heat-stable antigen (HSAlo). Although these cells represent just 0.27% of the unsorted population, they contain predominantly NSCs and account for 63.2% of the total NSC activity. The neural stem cells gave rise to neurospheres containing neurons, astrocytes and oligodendrocytes. Rietze et al. demonstrate that this cell population is severely reduced (6-fold) in the querkopf mutant mouse strain which exhibits stem cell deficiency. The isolated NSC could differentiate into neurons in vivo and into non-neural cell types in vitro. Thus, pluripotent stem cells (PNAlo HSAlo netrin+) can be efficiently isolated from the subventricular zone of the forebrain.