Early in embryogenesis, arterial endothelial cells develop into hematopoietic (blood) stem and progenitor cells (HSPCs), which later differentiate into the body’s blood cells. But how endothelial cells become HSPCs is not well known.

In a study published online on March 2 in Science Advances, Meelad Dawlaty, Ph.D., and colleagues show that this transformation from endothelial cells to HSPCs is controlled by Tet enzymes, which promote the expression of blood genes in endothelial cells. The researchers also show that loss of Tet enzymes in mouse embryos reduces the number of HSPCs and leads to embryonic death by mid-gestation. The findings have implications for efforts to derive blood cells from stem cells and may offer insight into blood disorders and cancers driven by mutations or dysregulation of Tet genes.

Dr. Dawlaty is an associate professor of genetics and of developmental and molecular biology and a member of the Ruth L. and David S. Gottesman Institute for Stem Cell Biology and Regenerative Medicine at Einstein.