Nitric Oxide Regulates Stem Cell Division in the Adult Brain

Strategy Seen for Repairing Brain Damage Caused by Neurodegenerative Disease and Stroke

Cold Spring Harbor, NY, July 28 – Most neurons in the mammalian brain are produced during embryonic development. However, several regions of the adult brain continue to spawn large numbers of neurons through the proliferation of neural stem cells. Moreover, it is becoming clear that these new neurons are integrated into existing brain circuitry.

Now, researchers at Cold Spring Harbor Laboratory have discovered that a molecule called nitric oxide (NO) is a pivotal, natural regulator of the birth of new neurons in the adult brain. The study, published in this week’s issue of the Proceedings of the National Academy of Sciences, shows that blocking nitric oxide production stimulates neural stem cell proliferation and hence dramatically increases the number of neurons that are generated in the brains of adult rats.

RMS
Image of neurons in the rostral migratory stream of the rat brain. Red cells express nitric oxide synthase, whereas green cells are actively proliferating neurons.

Importantly, the new neurons that arise as a consequence of blocking nitric oxide production display properties of normal neurons, and they appear to contribute directly to the architecture of the adult brain. The study suggests that modulating nitric oxide levels might be an effective strategy for replacing neurons that are lost from the brain due to stroke or chronic neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's disease.

The principle investigator on the study is Dr. Grigori Enikolopov (Associate Professor, Cold Spring Harbor Laboratory), who was joined by colleagues including the co-first authors of the study, Drs. Michael A. Packer and Yuri Stasiv, also of Cold Spring Harbor Laboratory.