Red blood cells are the most common cells in the human body, and are necessary in order to transport oxygen and carbon dioxide. Millions of people worldwide suffer from anaemia -- a condition in which the patient has an insufficient amount of red blood cells.

Patients with chronic anaemia are among the most problematic cases. They receive regular blood transfusions from different donors, which can eventually lead to the patient developing a reaction to the new blood. They simply become allergic to the donor's blood. Finding a feasible way to make blood from an individual's own skin cells would bring relief to this group of patients.

Eight days. That's how long it takes for skin cells to reprogram into red blood cells. Researchers have successfully identified the four genetic keys that unlock the genetic code of skin cells and reprogram them to start producing red blood cells instead.

"We have performed this experiment on mice, and the preliminary results indicate that it is also possible to reprogram skin cells from humans into red blood cells. One possible application for this technique is to make personalized red blood cells for blood transfusions, but this is still far from becoming a clinical reality", says senior author.

With the help of a retrovirus, they introduced different combinations of over 60 genes into the skin cells' genome, until one day they had successfully converted the skin cells into red blood cells. The study is published in the scientific journal Cell Reports.

Researchers show that Gata1, Tal1,Lmo2, and c-Myc (GTLM) can rapidly convert murine and human fibroblasts directly to iEPs (erythroid progenitors). The transcriptional signature of murine iEPs resembled mainly that of primitive erythroid progenitors in the yolk sac, whereas addition of Klf1 or Myb to the GTLM cocktail resulted in iEPs with a more adult-type globin expression pattern. 

"This is the first time anyone has ever succeeded in transforming skin cells into red blood cells, which is incredibly exciting", says lead author of the study.

The study shows that out of 20,000 genes, only four are necessary to reprogram skin cells to start producing red blood cells. Also, all four are necessary in order for it to work.

"It's a bit like a treasure chest where you have to turn four separate keys simultaneously in order for the chest to open", explains the researcher.

The discovery is significant from several aspects. Partly from a biological point of view -- understanding how red blood cells are produced and which genetic instructions they require - but also from a therapeutic point of view, as it creates an opportunity to produce red blood cells from the skin cells of a patient. There is currently a lack of blood donors for, for instance, patients with anaemic diseases. However, further studies on how the generated blood performs in living organisms are needed.

http://www.lu.se/article/roda-blodkroppars-genetiska-kod-upptackt