Many new innovative therapies that scientists come up with rely on stem cells, especially when immune therapy and regenerative medicine are considered. However, these promising research fields are limited by the difficulty of creating stem cells.
Although scientists around the globe have tried many different techniques to make creating stem cells easier, it remained a very complex and difficult process. At least until now, since team of scientists from the RIKEN Center for Integrative Medical Science (IMS) and other institutions in Japan and Europe have found a relatively simple way to keep immune cells in a multipotent stem cell-like state.
They found that by simply blocking a transcription factor that leads to differentiation they can keep immune cells in a state where they can continue to proliferate and can later differentiate into various cell types, which is exactly what scientists need for their stem cell researches. And, compared to previous attempts, it is a rather simple way to produce stem cells.
In the past scientists needed to find a way to take target cells and “dedifferentiate” them into multipotent cells, which inevitably was a painstaking process. However, now scientists found a better and simpler way, when they decided to see if they can create a process in which somatic stem cells could be maintained in a stem cell-like state. In this state they could proliferate, but would not undergo differentiation.
As very often is the case, mouse models were used in this research. Team of scientists took mouse hematopoetic progenitor cells—cells that give rise to white blood cells. They modified them to overexpress a protein called Id3, which inhibits the expression of E-proteins. These proteins are involved in differentiation in somatic cells.
Then scientists placed the cells into culture conditions containing certain cytokines and soon saw that their efforts were successful – cells continued to divide as stem cells instead of undergoing differentiation into B-cells. In a culture without these cytokines the cells differentiated into various immune cells.
Team wanted to test whether these cells would keep these characteristics in living animals. They transplanted them into mice models. Mice had depleted white blood cells and experiment showed that the new cells could expand and differentiate into various types of white blood cells. Of course, there had to be experiments with human stem cells to test potential of the method for future therapeutic application.
Therefore, team attempted a similar experiment using human blood stem cells taken from umbilical cords. As before, researchers transfected the cells with a vector encoding human Id3. Results were as promising as with mice cells – human cells could be maintained in their stem cell-like state where they can continue to proliferate and then prompted to differentiate by changing the conditions.
Tomokatsu Ikawa, the first and corresponding author of the study, said: “With this work we have succeeded in showing that the cells can be kept in a state of undifferentiation where they will proliferate extensively. This is both a useful tool for giving us a better understanding of the genetic and epigenetic program controlling the self-renewal of stem cells, and on a practical side, it could allow us to inexpensively produce large numbers of immune cells, which could then be used for regenerative medicine or immune therapy.”
It is hard to overestimate researches like that. It makes creation of stem cells much easier, which in turn will most likely spawn many new researches and new therapies for harsh conditions in immune therapy and regenerative medicine. We will have to wait and see how this particular study develops, but even as is it is a major breakthrough for stem cell research.