Saturday, 10 December 2011
Origins of blood stem cells unlocked
Scientists have discovered a molecular marker for the immediate precursors of hematopoietic (blood) stem cells (HSCs) in the developing embryo, which provides much-needed insights for making these cells from engineered precursors.
Because HSCs, found in the bone marrow of adult mammals, generate all of the blood cell types of the body, unlocking the secrets of their origin may help researchers to better manipulate embryonic stem cells to generate new blood cells for therapy.
Nancy Speck, PhD, professor of Cell and Developmental Biology at the Perelman School of Medicine at the University of Pennsylvania led the team.
“The ultimate goal for stem-cell therapies is to take precursor stem cells and push them down a particular lineage to replace diseased or dead cells in human adults or children,” said Speck.
Previous studies indicated that HSCs originated from a small population of cells lining blood vessels, called endothelial cells. But, it was unclear precisely which endothelial cells transitioned to blood stem cells during early development.
“Understanding the developmental origins of hematopoietic stem cells is important for learning how to produce them in the lab from embryonic or induced pluripotent stem cells,” added Speck.
The team used a special marker to follow the development of HSCs.
The marker, called Ly6a, is expressed in the endothelial cells that lead to HSCs, and it is not expressed in endothelial cells that make the first wave of blood cells.
The work was published this week in Cell Stem Cell.