New human neurons from adult cells right there in the brain

"This work aims at converting cells that are present throughout the brain but themselves are not nerve cells into neurons," said Benedikt Berninger, now at the Johannes Gutenberg University Mainz. "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."

The cells that made the leap from one identity to another are known as pericytes. Those cells, found in close association with the blood vessels, are important for keeping the blood-brain barrier intact and have been shown to participate in wound healing in other parts of the body.

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This is a direct observation of neuronal reprogramming of PDGFR-sorted pericyte-derived cells from the adult human brain by continuous live imaging in culture. Note the change in morphology of a cell coexpressing Sox2 and Mash1 (blue arrow) during reprogramming. Postimaging immunocytochemistry for III-tubulin (white) confirms the neuronal identity of the reprogrammed cell at the end of live imaging. Credit: Cell Stem Cell, a Cell Press Journal, Karow et al.

"Now, we reason, if we could target these cells and entice them to make nerve cells, we could take advantage of this injury response," Berninger says.

Further testing showed that those newly converted neurons could produce electrical signals and reach out to other neurons, providing evidence that the converted cells could integrate into neural networks.

"While much needs to be learnt about adapting a direct neuronal reprogramming strategy to meaningful repair in vivo, 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," the researchers write.

More information: Karow et al.: "Reprogramming of pericyte-derived cells of the adult human brain into induced neuronal cells." DOI: 10.1016/j.stem.2012.07.007

Journal reference: Cell Stem Cell

Provided by Cell Press