News Note: Cell ‘barcodes’ trace the natural development of blood

in situ blood development
(Credit: Stem Cell Program, Boston Children’s Hospital)

Genetic labels, or “barcodes,” are shedding new light on the natural process of blood development and immune-cell production, finds a study published in Nature this week. It was led by Fernando Camargo, PhD, and first author Alejo Rodriguez Fraticelli, PhD, at Boston Children’s Hospital’s Stem Cell Research Program, the Harvard Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute.

Most of what we know about blood production is through observing what happens when blood stem and progenitor cells are transplanted into an animal. To observe what happens “in the wild,” researchers went in and tagged the blood stem and progenitor cells of mice, using genetic elements called transposons. This allowed them to track how the cells differentiated into five kinds of blood cells (above: megakaryocytes, erythroid cells, granulocytes, monocytes and B-cell progenitors).

Rethinking stem cell transplants

It turns out that, in the natural environment, there’s a different roadmap to blood production than after a stem cell transplant. For example, in situ, blood stem cells primarily gave rise to megakaryocytes, whereas in transplant studies they give rise to all five major blood cell types.

The study’s observations could have implications for optimizing stem cell transplants (also referred to as bone marrow transplants) in the future.

“Moving forward, we need to come up with methods to better predict what types of cells will be the most optimal for therapy, for instance in reprogramming cells, and editing,” said Rodriguez Fraticelli in a press release from the National Heart, Lung, and Blood Institute.

In addition to the NHLBI, the study was supported by the Leukemia and Lymphoma Society, the Howard Hughes Medical Institute and the Life Sciences Research Foundation. For a full list of authors, see the paper in Nature.