Many specialized cells, such as in the skin, gut or even blood, have a lifespan of only a few days. Therefore , regular replenishment of these cells is indispensable. They arise through so-called “adult” stem cells that divide continuously. Additionally , there is a group of very special stem cells in the bone tissue marrow that were first discovered in 2008 by a research group led by Andreas Trumpp, who is a division mind at the DKFZ and director of HI-STEM. These tissues remain in a kind of dormancy most of the time and only become active within an emergency such as bacterial or viral infections, heavy loss of blood, or in the wake of chemotherapy. Once their function is done, the body sends its most potent stem cells returning to sleep. The scientists assume that this protects them through dangerous mutations that may lead to leukemia.
The mechanisms that activate these special come cells or make them go back to sleep after their function is done have remained elusive until now. The scientists have identified retinoic acid, a vitamin A metabolite, as being a crucial factor in this process. If this substance is absent, energetic stem cells are unable to return to a dormant state plus mature into specialized blood cells instead. This means that they may be lost as a reservoir. This was shown in studies along with specially bred mice whose dormant stem cells are usually green fluorescent. “If we feed these mice on the vitamin A deficient diet for some time, this leads to a lack of the stem cells, ” said Nina Cabezas-Wallscheid, who may be the first author of the publication. “Thus, we can prove initially that vitamin A has a direct impact on blood originate cells. ”
This finding not only improves our understanding of the development of blood cells, it also sheds brand new light on prior studies that demonstrate that supplement A deficiency impairs the immune system. “This shows how very important it is to have a sufficient intake of vitamin A from the balanced diet, ” Cabezas-Wallscheid emphasized. The body cannot generate its own vitamin A.
The scientists also provide hopes for new prospects in cancer treatment. There is proof that cancer cells, like healthy stem cells, furthermore rest in a state of dormancy. When dormant, their own metabolism is almost completely shut down — and this makes them resists chemotherapy. “Once we understand in detail how vitamin The or retinoic acid, respectively, sends normal and cancerous stem cells into dormancy, we can try to turn the particular tables, ” explained Trumpp. “If we could make malignancy cells temporarily enter an active state, we could thus get them to vulnerable to modern therapies. ”
In addition , within collaboration with colleagues from the European Bioinformatics Institute within Cambridge, the team performed genome-wide analyses of one cells and discovered that the transition from dormant in order to active stem cells and then on to progenitor cells is really a continuous one and follows a different path for each person cell. So far, scientists had assumed that specific cellular types develop step by step in a defined pattern. This searching for revolutionizes the previous concept of how cell differentiation in the body happens.
Materials provided by German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) . Note: Content may be edited for design and length.