A team of North Carolina State University researchers has discovered more about how a gene connected to the production of new brain cells in adults does its job. Their findings could pave the way to new therapies for brain injury or disease.
Most areas of the brain do not generate new brain cells, or neurons, after we are born. One exception is the olfactory bulb, the brain's scent processor, which continually produces new neurons. Dr. Troy Ghashghaei, assistant professor of neurobiology, had previously found a gene known as Foxj1connected to the production of an area inside the olfactory bulb where stem cells could form. Ghashghaei and his team discovered that Foxj1 was an "off switch" that told neuronal stem cells to stop reproducing and triggered the development of a stem cell "niche" in the olfactory bulbs.
However, further experiments with newly developed genetically modified mice unexpectedly revealed that a fraction of Foxj1-expressing cells actually functioned as stem cells. But they only did so until the mouse reached the age equivalent of a human toddler, not throughout adulthood. In addition, the number of neurons generated by these cells was much lower than expected, which led to more questions about its function.
"Essentially, the experiments we did weren't giving us the numbers of neurons from Foxj1-expressing stem cells that we expected. We could have gotten disappointed with what may have been perceived as a road-block in our findings" says Ghashghaei. "If the gene was one that stem cells had to express in order to produce neurons, then we should have seen a greater number of neurons produced from the Foxj1-expressing stem cells. Instead, only about three percent of the olfactory neurons came from the Foxj1 stem cells. More importantly, we could not identify these unique neurons as belonging to known types of neurons in the olfactory system."
These findings and subsequent experimentation helped the team disc
|Contact: Tracey Peake|
North Carolina State University