Brain cells can repair themselves

How old blood cells become young brain cells

BONN. Researchers at the University Hospital Bonn and the German Center for Neurodegenerative Diseases (DZNE) have succeeded in reprogramming blood cells directly into neural stem cells and at the same time rejuvenating them (Nat Commun 2018; online October 2). The stem cells can be used, for example, to research neurological diseases and to grow replacements for defective brain tissue in the future, the University of Bonn announced.

Leukocytes from adult donors served as the starting material. The researchers smuggled two transcription factors into the cells, i.e. proteins that selectively control the activity of certain genes. This enabled them to reprogram the blood cells into neural stem cells. From these, in turn, they could then grow nerve and glial cells.

The transcription factors introduced are not stable and are later lost again.

Rejuvenation included

Interestingly, this transformation was accompanied by a rejuvenation. In cells, some genes are given a chemical label as they age, which means that they are turned up or down. Old cells therefore have a characteristic gene activity pattern that differs from that of young cells.

"During our reprogramming, the age-related labeling was almost completely reversed," one of the authors, Professor Oliver Brüstle, is quoted in the communication. "The stem cells therefore hardly differed in their gene activity and their function from those of a newborn." These "youthful-fit" cells are presumably particularly suitable for tissue replacement therapies.

It is not new that leukocytes can be used to grow brain cells. However, as is well known, induced pluripotent stem cells (iPS cells) are first produced from the blood, which can develop into a wide variety of tissue types. In a second step, they are converted into neural stem cells.

According to the University of Bonn, this process could take four months or more. In a sense, the new method is a shortcut, without the intermediate step via the iPS cells. You therefore only need a good two weeks. (eb)