How embryonic stem cells become fine-tuned brains

Research by Michael Greenberg, Harvard Medical School professor of neurology at Children’s Hospital, begins to explain how the embryonic brain’s stem cells decide whether to mature into nerve or glial cells as development proceeds. Greenberg and colleagues reported that neurogenin, a protein known to nudge stem cells toward turning into neurons, does so by actively inhibiting the cells’ ability to become astrocytes, a type of glial cell. The study gives researchers trying to develop future therapeutic stem cells a handle on controlling their maturation with more precision. Despite stem cells’ much-vaunted potential to repair damaged tissue or repopulate whole organs, scientists working toward these goals currently are grappling with the nagging problem that neural stem cells cultured in the laboratory much prefer to turn into glial cells.