The skin’s stem cells (‘adult stem cells’) are essential for healing wounds, mending hair, and otherwise replenishing the cells that get lost through injury or degeneration—activity which happens under the watchful eye of two proteins whose role has recently been recognized thanks to researchers from Barcelona.
Stem cells are a fascinating area of medical research because of their potential to develop into various other cell types. In this case it was found that two proteins, called Dnmt3a and Dnmt3b, are key for the self-renewal and maintenance of the body’s skin stem cell reserves. This is because the proteins are the trigger for the cells’ genetic programme. No proteins, no activation, and the stem cell ends up collapsing and fading away.
The protein pair works by triggering genetic “superenhancers”, a type of messenger that can boost gene transcription and speed up the transcription process up to 200-fold. By triggering a single region, the two proteins can initiate the roughly 1,000 genes required to activate a skin stem cell’s self-renewal.
This particular finding was surprising since Dnmt3a and Dnmt3b, prior to this bit of research, was primarily associated with repressing genes, not speeding up their copying. It was actually impossible to take a close look of how these proteins behave in a cell since it relied on recent advances in sequencing technology.
In addition to improving understanding of skin stem cell longevity, the discovery may also have implications for cancer research. Gene enhances are highly mutated within cancer cells and the cells themselves show alterations in “methylation”, the process that the proteins use to trigger superenhancers.
Dnmt3a and Dnmt3b are also known to show up in altered forms when seen in lung or colon cancers or in leukemia. These observations do not suggest any specific relationship between these proteins and cancer, but it may be worth investigating whether the pair could have a role in tumor development now that they have been linked to self-renewal.
“Two proteins safeguard skin stem cells,” IRB Barcelona web site, July 28, 2016; https://www.irbbarcelona.org/en/news/two-proteins-safeguard-skin-stem-cells, last accessed July 29, 2016.