How effective are some of the new stem cell activators, such as SR-1 and UM171? Is it known how these molecules work?

Answer

Adding StemRegenin 1 (SR1) or UM171 to HSPC cultures improves the expansion of primitive hematopoietic cells, as compared to cytokine-only cultures without these small molecules.  SR1 inhibits the aryl hydrocarbon receptor (AhR), which has a role in regulating HSC activity, but beyond that, little is known. For UM171 the target molecule and pathways inside the cell have not yet been identified, although we do know the mechanism is different from AhR antagonists, as there is a synergistic effect leading to higher expansion of HSCs when SR1 and UM171 are combined in culture. For more information on the combined effects of SR1, UM171 and cytokines in stimulating HSC expansion, check out our small molecules for ex vivo HSC expansion technical bulletin.