If you follow medical news at all, you probably hear a lot about stem cells. Usually it's embryonic or induced pluripotent stem cells that get most of the attention. Those avenues of research are certainly very promising, but they aren't the entire stem cell picture. What you may or may not know is that the human body is naturally full of stem cells.
These adult stem cells are partially specialized depending on where they are, and they don't have the plasticity of their more popular kin. Still, adult stem cells are what make normal replenishing of tissue possible. Understanding how they work and how they malfunction sometimes is vitally important.
In a Eureka Alert press release, scientists from The Scripps Research Institute have been studying blood stem cells. As you may have guessed, these cells are responsible for replenishing the blood, including red blood cells and immune cells.
They are generally dormant in the bone marrow except for creating a natural resupply of progenitor cells every two months. Injuries and infections can also ramp up their activity, but that's not necessarily a good thing. Overactivity means more dividing, and an increased risk of mutations in the genome. This could lead to blood cancer or simply a malfunction of the stem cells.
The scientists were specifically investigating an enzyme for its role in dampening stem cell activity. Called ItpkB, it's an enzyme that adds phosphate to other signaling molecules and has been implicated in the regulation of other cell types. To test this they created a strain of mice that lacked the gene for the enzyme. The mice quickly developed over active blood stem cells that eventually wore themselves out, leading to death by severe anemia.
Further supporting the hypothesis was the fact that administering the approved cancer drug rapamycin seemed to stabilize the modified mice. Likely because the cancer drug also has a dampening effect on rapidly dividing cells, like a tumor would be behaving.
It remains to be seen whether this enzyme has the exact same function in humans, but that will be the next stage of research. The hope is that better understanding this enzyme could help doctors regulates blood stem cell activity. Whether it's overactive in the case of blood cancer, or underactive in the case of anemia.
