Early dynamic fate changes in haemogenic endothelium characterized at the single-cell level

• Published in: Nature communications Vol. 4; no. 1; p. 2924
• Main Authors: Swiers, Gemma, Baumann, Claudia, O'Rourke, John, Giannoulatou, Eleni, Taylor, Stephen, Joshi, Anagha, Moignard, Victoria, Pina, Cristina, Bee, Thomas, Kokkaliaris, Konstantinos D, Yoshimoto, Momoko, Yoder, Mervin C, Frampton, Jon, Schroeder, Timm, Enver, Tariq, Göttgens, Berthold, de Bruijn, Marella F T R
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 11.12.2013
• Subjects: Animals; Core Binding Factor Alpha 2 Subunit - genetics; Embryo, Mammalian - cytology; Enhancer Elements, Genetic; Female; Gene Expression Regulation, Developmental; Green Fluorescent Proteins - genetics; Hemangioblasts - cytology; Hemangioblasts - physiology; Male; Mice; Mice, Transgenic; Pregnancy; Single-Cell Analysis - methods
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms3924

Haematopoietic stem cells (HSCs) are the founding cells of the adult haematopoietic system, born during ontogeny from a specialized subset of endothelium, the haemogenic endothelium (HE) via an endothelial-to-haematopoietic transition (EHT). Although recently imaged in real time, the underlying mechanism of EHT is still poorly understood. We have generated a Runx1 +23 enhancer-reporter transgenic mouse (23GFP) for the prospective isolation of HE throughout embryonic development. Here we perform functional analysis of over 1,800 and transcriptional analysis of 268 single 23GFP(+) HE cells to explore the onset of EHT at the single-cell level. We show that initiation of the haematopoietic programme occurs in cells still embedded in the endothelial layer, and is accompanied by a previously unrecognized early loss of endothelial potential before HSCs emerge. Our data therefore provide important insights on the timeline of early haematopoietic commitment.