Ronald Cole-Turner: Transcending Evolution

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A New Source for New Neurons

The day when stem cell research will give us treatments for common brain disorders such as Parkinson’s or Alzheimer’s just got a little closer. So, by the way, did the day when this research will be used to enhance the capacities of the normal or healthy human brain. The latest advance comes from an international team based mostly in Germany, which has figured out a way to generate new neurons from cells that already exist in the human brain.

The human brain naturally contains specialized cells called pericytes. Usually, they are located at the edge of the capillaries that carry blood to the brain. They play a vital role in maintaining the blood-brain barrier.

Now, thanks to the discovery reported in Cell Stem Cell, pericytes might be about to learn a new trick: forming new neurons. Using stem cell reprogramming techniques, researchers learned that two factors—Sox2 and Mash1—would induce pericytes to change their developmental state and begin to function as newly formed neurons.

According to the article, “these induced neuronal cells acquire the ability of repetitive action potential firing and serve as synaptic targets for other neurons, indicating their capability of integrating into neuronal networks.” In other words, they do what neurons normally do. They process signals from one end of the cell to another. They form synaptic connections with other neurons. And they integrate into larger networks.

Will this become a new strategy for treating diseases or injuries to brain cells? That is the hope, but difficult challenges remain. How can living pericytes in a functioning human brain be targeted and induced to become neurons? If they generate new neurons, will they function properly? Will they integrate themselves into a functioning brain, preferably taking up the cognitive processes that are lost because of disease or injury?

The authors conclude that “much needs to be learned” but that “our data provide strong support for the notion that neuronal reprogramming of cells of pericytic origin within the damaged brain may become a viable approach to replace degenerated neurons.”

According to Benedikt Berninger of the Johannes Gutenberg University in Mainz, a leader in the research team, “The ultimate goal we have in mind is that this may one day enable us to induce such conversion within the brain itself and thus provide a novel strategy for repairing the injured or diseased brain."

That may be the goal, but it's hard to imagine this research will be limited to therapy. In fact, it may turn out to be easier to use it to enhance the cognitive capacity of normal or healthy aging brains than it is to treat disease. Anything that stimulates the growth of new neurons is likely to be very appealing to aging adults.

If human stem cell research is to reach its full promise, many more advances like this will have to occur. With each advance, however, comes growing confidence that the promise of the field may be highly challenging, but it is not hype. 

A version of this post first appeared on Enhancing Theology.

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