SEARCH FOR A CURE: Can putting a protein into overdrive result in healing of spinal cord injuries?

New spinal neurons converted from glia

The spinal cord typically does not generate new neurons after injury – a key roadblock to recovery. Using genetic engineering, researchers at UT Southwestern and Indiana University have reprogrammed scar-forming cells in mouse spinal cords to create new nerve cells, spurring recovery after spinal cord injury. Now, before you get all excited about this work, please note that this is being done to mice only, so we have years of research left to see if this approach is effective in humans or not.

Working with a mouse model of spinal cord injury, the researchers looked in the animals’ injured spinal cords for a marker normally found in immature neurons. Not only was this marker also present in the spinal cord after injury, but the researchers tracked down the cells that produce it: non-neuronal cells called NG2 glia.

NG2 glia serve as progenitors for cells called oligodendrocytes, which produce the insulating fat layer that surrounds neurons. They are also well-known to form glial scars following injury. The researchers showed that when the spinal cord was injured, these glia transiently adopted molecular and morphological markers of immature neurons.

To determine what causes NG2 glia to change, the researchers focused on SOX2, a stem cell protein induced by injury. They genetically manipulated these cells to inactivate the gene that makes this protein. When spinal cords of mice that had been manipulated were cut, the researchers saw far fewer immature neurons in the days following injury, suggesting that SOX2 plays a key role in helping NG2 glia make these cells. However, even with normal levels of SOX2, these immature neurons never matured into replacements for those affected by the injury.

Taking an opposite tack, the researchers used a different genetic manipulation technique to make NG2 glia overproduce SOX2. Excitingly, in the weeks after spinal cord injury, mice with this manipulation produced tens of thousands of new mature neurons. Further investigation showed that these neurons integrated into the injured area, making the new connections with existing neurons that are necessary to relay signals between the brain and body.

You can read more about this research HERE.