Revealing the Invisible: Scientists Uncover the Secret Ingredient to Making Blood-Forming Stem Cells

They are among the most versatile types of stem cell types in the body. They live inside bone marrow and in the blood of the umbilical cord. They can be used to treat deadly cancers such as leukemia (Leukemia Fact Sheet) as well as many blood disorders. But no one really understood the details of how they were made.

How are blood stem cells made? Australian scientists have uncovered a missing ingredient.

How are blood stem cells made? Australian scientists have uncovered a missing ingredient.

That is, until scientists at the Australian Regenerative Medicine Institute devised an ingenious way to view the formation of these hematopoetic stem cells (HSC’s) in unprecedented detail. And in so doing, found the missing ingredient that may make it possible to grow fully functioning versions of these cells in the lab—opening the door to treating a wide range of blood and immune disorders. Attempts to grow these in the past have resulted in immature versions more like those found in a fetus than those in an adult.

One of the study’s senior authors, Dr. Peter Currie, even goes so far as to say this discovery represents a ‘Holy Grail’ for the field. As he explained in today’s news release:

“HSCs are one of the best therapeutic tools at our disposal because they can make any blood cell in the body. Potentially we could use these cells in may more ways than current transplantation strategies to treat serious blood disorders and diseases, but only if we can figure out how they are generated in the first place.”

Fortunately, this new study—published today in the journal Nature—brings researchers closer to that goal.

Using high-resolution microscopic imaging techniques, Currie and his team filmed the development of a zebra fish embryo—with a particular focus on HSCs. When they played back the video, the team saw something that no one had noticed before. In order for HSCs to develop properly, they needed a little support from another cell type known as endotomes. As Currie explained:

“Endotome cells act like a comfy sofa for pre-HSCs to snuggle into, helping them progress to become fully fledged [HSCs]. Not only did we identify some of the cells and signals required for HSC formation, we also pinpointed the genes required for endotome formation in the first place.”

It appears that this unique relationship between endotomes and HSCs is key to HSC formation, a process that had for so long evaded researchers. But armed with this newfound knowledge, the team could one day produce different types of blood cells ‘on demand’—and potentially treat many types of blood disorders. This has been such a tough nut to crack with such great potential CIRM convened an international panel of experts to produce a whitepaper on the issue.

The team’s immediate next steps, according to Currie, are to pinpoint the molecular switches themselves (within endotomes and HSCs) that trigger the production of these stem cells. And while these results are preliminary, he is cautiously optimistic about the potential power to treat a variety of illnesses:

“Potentially, it’s imaginable that you could even correct genetic defects in cells and then transplant them back into the body.”