Haematopoietic Stem Cell Development
In the AGM production of HSCs, it is believed that haemogenic endothelial cells play a key role. Haemogenic endothelial cells are specific endothelial cells that concurrently express both haematopoietic and endothelial markers. These haemogenic endothelial cells then become activated, releasing their binding with adjacent endothelial cells, and entering circulation in a process referred to as ‘budding’. This occurs at E9.5 in the developing mouse embryo. From here the haemogenic endothelial cells develop into HSCs. However, the precise signalling pathway involved in haemogenic endothelial cell activation is unknown, but several signalling molecules have been implicated including nitric oxide (NO), Notch 1, and Runx1.
Signaling pathways involved in AGM haemogenic endothelial cell activation include:
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