Scientists have revealed new discoveries about the role of endothelial cell-selective adhesion molecule (ESAM) in blood cell development.
ESAM is a surface marker for hematopoietic stem cells and vascular endothelial cells. The team, from Osaka University in Japan, have shown in tests on rodents that ESAM also plays a particularly important role in definitive haematopoesis in the developing foetus.
Their findings appeared in December in the journal Stem Cell Reports. In previous research, the team had confirmed the functional importance of ESAM in stress-induced haematopoiesis in adults. However, it was unclear how ESAM affects blood cell development during gestation.
So in this study, they tested mice in which ESAM had been deactivated. This led to death from anaemia in half of the foetuses mid-way through gestation.
ESAM-negative hematopoietic stem cells showed a downregulation of adult-type globin genes. In addition, ESAM-negative foetal livers had a reduced ability to synthesise adult-type haemoglobins.
These observations “revealed the critical involvement of ESAM” in the health of endothelial cells. “Thus, we showed that ESAM had important roles in developing definitive haematopoiesis,” they write.
Researcher Dr Tomoaki Udea said: “Properties of haematopoietic stem cells and haematopoiesis mechanisms are not well understood because it is difficult to study haematopoiesis, especially in human foetal life.
“We’d like to continue our research so that our achievements will elucidate the mechanisms of haematopoiesis and lead to the identification of the cause of congenital disorders of the hematopoietic system, especially the cause of genetic anaemia, and the development of treatment methods.”
Ueda T, Yokota T, Okuzaki D, Uno Y, Mashimo T, Kubota Y, Sudo T, Ishibashi T, Shingai Y, Doi Y, Ozawa T, Nakai R, Tanimura A, Ichii M, Ezoe S, Shibayama H, Oritani K, Kanakura Y (2019) “Endothelial cell-selective adhesion molecule contributes to the development of definitive hematopoiesis in the fetal liver”, Stem Cell Reports, doi: 10.1016/j.stemcr.2019.11.002