Scientists at the Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, have identified a new type of stem cells in the brain which might have a high potential for repairing following brain injury or disease.

A major goal of regenerative research is to repair the brain efficiently following injury, for example due to stroke, Alzheimer’s disease or head trauma, disease or ageing.

The brain is known to be poor at repairing itself, however, it may become possible to improve this process without surgery. This could be realised by targeting stem cells located in patients’ brains. Stem cells have the unique capacity to produce all the cells in the brain. Those cells are usually kept inactive in a way of ‘cellular sleep’ known as a quiescence.

Quiescent cells do not vegetate or generate new cells. Thus, to target stem cells for any regenerative therapy they must first be awoken from quiescence. In a published study about PhD student Leo Otsuki and his supervisor Professor Andrea Brand, the discovery of a new quiescent stem cell residing in the brain has been reported, the G2 quiescent stem cell. The special characteristic about this stem cell is that it shows a higher regenerative potential than quiescent stem cells identified in the past. Moreover, the G2 quiescent stem cells are an attractive target for therapies where they can help regenerate brain diseases much faster than other quiescent cells.

“The brain is not good at repairing itself, but these newly-discovered stem cells suggest there may be a way to improve its ability”, says Professor Brand. “These stem cells are in a dormant state, but once awake, they have the ability to generate key brain cells”.

By studying the fruit of fly, the authors identified a gene known as tribbles that selectively regulates G2 quiescent stem cells. The DNA of fruit flies has many similarities with that of humans, making them a useful model to understand human biology, and 60% of human genes associated with disease are also found in Drosophila. The tribbles gene has counterparts in the mammalian genome that are expressed in stem cells in the brain.

The researchers believe, drugs that target tribbles might be one form to help awaken G2 quiescent stem cells. Student Leo Otsuki mentions, they have found a gene that directs these cells to become quiescent in the first place. This is a useful information for identifying potential drug-like molecules, that block this exact gene and awaken the stem cells as a consequence. “We believe there may be similar quiescent stem cells in other organs, and this discovery could help improve or develop new regenerative medicines”.

References

• News Medical Life Science. Sally Robertson (April, 2018). Waking up stem cells in the brain could improve its ability to repair injury. Available at: https://www.news-medical.net/news/20180406/Waking-up-e2809csleepinge2809d-stem-cells-in-the-brain-could-improve-its-ability-to-repair-injury.aspx 
• Innovation Stem Cell Center. (April, 12th, 2018). Waking up sleeping stem cells may mean new treatments for Alzheimers. Available at: http://www.innovationsstemcellcenter.com/about-us/blog/waking-up-sleeping-stem-cells-may-mean-new-treatments-for-alzheimer-s-disease.html