A new study conducted by scientists at the German Cancer Research Center (DKFZ) describes how brain stem cells “make the decision” to transform into new nerve cells. As stem cells can turn into any kind of cell in our body, the tissues of our body (like muscles, bones or even the brain) can heal after an injury. This quality makes stem cells a key potential tool to develop regenerative medicine.
For the study, published in the journal Nature, DKFZ researcher Ana Martin-Villalba and colleagues tracked stem cells along the path to neurons, analysing in each step what genes were switched on and which of them were really turned into proteins.
Originally, the team the team of researchers expected to observe that, in order to become a neuron, stem cells would switch off their stem cells genes. However, what they found resulted to be much more complicate. They found in those new neurons that stem cell genes were not switch off as they previously thought; they were only in a ‘stand by’ mode by preventing them from making the protein product that keeps the cell multipotent.
“To go into this standby mode and thus start the journey to become a neuron, stem cells switch off their inner signal to proliferate (called TOR) and stop to divide,” says Ana Martin-Villalba. Very surprisingly, the researchers also found that stem cells always buy a return ticket. Just as flights can travel back and forth between countries, switching on or off TOR allows cells to travel from stem cell to neuron or back. “Thus, the decisions of a stem cell to become a neuron, remains reversible for some time,” says Avni Baser, the scientist leading this project.
Unless something goes wrong in the process, the course of stem cells to become neurons is normally in one direction only. According to the researchers, on those cases when something goes wrong, if stem cells cannot properly control their TOR signal, they return to their previous state, which in the long run can cause brain cancer rather than healing the brain. Indeed, in many cancers the levels of the TOR signal is artificially high. For future developments of stem cell therapy, understanding and controlling TOR activity in stem cell will thus be very important.
Source: Sience Daily