After 20 years of trying , two teams of scientists have succeeded with two different recipes to transform stem cells into primordial blood cells (hematopoietic) capable of producing most tissues. This work offers hope to people with leukemia and other blood disorders who need bone marrow transplants, but for whom a match cannot be found. Thanks to this advance, these patients could receive lab-grown versions of their own healthy cells.
“We are tantalizingly close to generating reliable human blood stem cells in the laboratory. This work is the culmination of more than 20 years of struggle, ” explains George Daley, leader of the work and director of a research laboratory in the Stem Cell Program of the Children’s Hospital Boston (USA), as well as Dean of Harvard Medical School.
The first team, from Children’s Hospital Boston , combined two previous approaches: exposing human pluripotent stem cells to chemical signals that directed them to differentiate into specialized cells and tissues during normal embryonic development (hemogenic endothelial tissue) and then adding genetic regulatory factors to them. (transcriptional) to incite the hemogenic endothelium into a blood-forming state.
With 5 key transcription factors, they managed to create blood stem cells. The process concluded with the transplantation of genetically modified hemogenic endothelial cells to a group of rodents. After several weeks, the mice had several types of human blood cells (such as red blood cells) and T and B lymphocytes (cells responsible for the defense of the immune system) in their bone marrow and circulatory system.
The second research team, from Weill Cornell Medicine in New York (USA) used adult mouse endothelial cells. They altered the levels of transcription factors to drive their transition to blood stem cells, which formed in a layer of fetal endothelial cells to confirm their properties.
The objective of both investigations is to generate a technique to create blood stem cells in a simple and safe way. This will make it possible to manufacture an unlimited supply of blood stem cells drawn from universal donor cells. “This could increase the blood supply for patients who need transfusions,” the authors clarify.
“Now we can show the function of human blood in ‘humanized mice’. It is a great step to investigate genetic blood diseases, ” says George Daley.
The study has been published in the journal Nature.
