Single brain stem cell 'can replace itself, generate new ones'

A new study has shown that a lone brain stem cell is capable of replacing itself and giving rise to specialised neurons and glia (important types of brain cells).

The study conducted by researchers from Johns Hopkins University School of Medicine on adult mice revealed that a stem cell can also take a wholly unexpected path ie generate two new brain stem cells.

"Now we know they don’t just maintain their numbers, or go down in number, but that stem cells can amplify," said Hongjun Song, PhD, professor of neurology and neuroscience and director of the Stem Cell Program in the Institute for Cell Engineering at Hopkins.

"If we can somehow cash in on this newly discovered property of stem cells in the brain, and find ways to intervene so they divide more, then we might actually increase their numbers instead of losing them over time, which is what normally happens, perhaps due to aging or diseases," he added.

It is known that a green fluorescent protein-labeled neural stem cell clone contains the 'mother stem cell' with neuronal and astroglial progeny within the mouse brain.

Using mice genetically modified with special genes that colour-code cells for easy labeling and tracking, the researchers injected a very small amount of a chemical into about 50 mouse brains to induce extremely limited cell labeling.

Next, they developed computer programmes and devised a new imaging technique that allowed them to examine stained slices of the mouse brain and, ultimately, follow single, randomly chosen radial glia-like stem cells over time.

"We discovered that single cells in an intact animal nervous system absolutely do exhibit stem-cell properties; they are capable of both replicating themselves and producing different types of differentiated neural progeny," said Guo-li Ming, associate professor of neurology and neurosciencel at Hopkins.

The team followed the fates of all the marked radial glia-like stem cells for at least a month or two, and discovered a year later that even over the long term, the 'mother' cell was still generating itself as well as different kinds of progeny.

The study appears in the journal Cell.