Researchers continue to make progress in understanding how to guide stem cells to a desired outcome:
During development, blood cells emerge in the aorta, a major blood vessel in the embryo. There, blood cells, including hematopoietic stem cells, are generated by budding from a unique population of what scientists call hemogenic endothelial cells. The new report identifies two distinct groups of transcription factors that can directly convert human stem cells into the hemogenic endothelial cells, which subsequently develop into various types of blood cells. The discovery gives scientists the tools to make the cells themselves, investigate how blood cells develop and produce clinically relevant blood products.
The factors identified [were] capable of making the range of human blood cells, including white blood cells, red blood cells and megakaryocytes, commonly used blood products. The method [was] shown to produce blood cells in abundance. For every million stem cells, the researchers were able to produce 30 million blood cells. A critical aspect of the work is the use of modified messenger RNA to direct stem cells toward particular developmental fates. The new approach makes it possible to induce cells without introducing any genetic artifacts. By co-opting nature's method of making cells and avoiding all potential genetic artifacts, cells for therapy can be made safer. "You can do it without a virus, and genome integrity is not affected."
While the new work shows that blood can be made by manipulating genetic mechanisms, the approach is likely to be true as well for making other types of cells with therapeutic potential, including cells of the pancreas and heart.