The complex array of cells in our blood is constantly replenished by a pool of specific stem cells. These haematopoietic stem cells (HSCs) have the capacity to form all types of blood cells.
HSCs first appear in the embryo during development, and originate in the embryonic arteries from so-called haemogenic endothelium. Though the onset of circulation was known to coincide with the development of HSCs and signals derived from blood flow were shown to be important for HSC development, it was not clear when in the generation of HSCs from haemogenic endothelium these signals acted.
To explore this, researchers from the Developmental Haematopoiesis Group at the MRC Molecular Haematology Unit compared embryos with and without a heartbeat and found that circulation promotes the transition of haemogenic endothelium into HSC precursors, which is linked to key metabolic changes required for normal haematopoietic development.
‘The onset of circulation is a major event during embryogenesis. This study uncovers its importance for HSC precursors through the modulation of their metabolism’ says Dr Emanuele Azzoni, previously a post-doctoral researcher in the de Bruijn Group, and now an Assistant Professor at the University of Milano-Bicocca, Italy.
‘This was a collaborative effort which opens up a new avenue of research for our group’ says Professor Marella de Bruijn, Professor of Developmental Haematopoiesis at the MRC Weatherall Institute of Molecular Medicine.
By unravelling the complex combinations of signals cells experience during development, researchers hope to improve methods to produce HSCs in the laboratory in order to facilitate their use in regenerative medicine.
Read the full paper in Cell Reports.