Developmental biology: New theory of blood cell development (AOP)

How the blood system forms in a developing embryo is a topic of intensive research, and is addressed in a paper published online in this week’s Nature. The findings should help researchers who are trying to convert stem cells into therapeutically useful blood stem cells.

Specialized progenitor cells called haemangioblasts generate an intermediate endothelial cell type that then gives rise to blood cells. Nancy Speck and colleagues show that the protein Runx1 is involved as these endothelial cells generate blood cells. Previous theories suggested that blood cells developed from either a specialized progenitor or a type of endothelial cell. The new theory suggests that both were right as blood cells are formed from specialized progenitors and endothelial cells albeit in a sequential and linear manner.