Document Detail


Blood stem cells emerge from aortic endothelium by a novel type of cell transition.
MedLine Citation:
PMID:  20154732     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The ontogeny of haematopoietic stem cells (HSCs) during embryonic development is still highly debated, especially their possible lineage relationship to vascular endothelial cells. The first anatomical site from which cells with long-term HSC potential have been isolated is the aorta-gonad-mesonephros (AGM), more specifically the vicinity of the dorsal aortic floor. But although some authors have presented evidence that HSCs may arise directly from the aortic floor into the dorsal aortic lumen, others support the notion that HSCs first emerge within the underlying mesenchyme. Here we show by non-invasive, high-resolution imaging of live zebrafish embryos, that HSCs emerge directly from the aortic floor, through a stereotyped process that does not involve cell division but a strong bending then egress of single endothelial cells from the aortic ventral wall into the sub-aortic space, and their concomitant transformation into haematopoietic cells. The process is polarized not only in the dorso-ventral but also in the rostro-caudal versus medio-lateral direction, and depends on Runx1 expression: in Runx1-deficient embryos, the exit events are initially similar, but much rarer, and abort into violent death of the exiting cell. These results demonstrate that the aortic floor is haemogenic and that HSCs emerge from it into the sub-aortic space, not by asymmetric cell division but through a new type of cell behaviour, which we call an endothelial haematopoietic transition.
Authors:
Karima Kissa; Philippe Herbomel
Publication Detail:
Type:  Journal Article     Date:  2010-02-14
Journal Detail:
Title:  Nature     Volume:  464     ISSN:  1476-4687     ISO Abbreviation:  Nature     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-05     Completed Date:  2010-04-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  England    
Other Details:
Languages:  eng     Pagination:  112-5     Citation Subset:  IM    
Affiliation:
Institut Pasteur, Unit? Macrophages et D?veloppement de l'Immunit? and CNRS: URA2578, 25 rue du Dr Roux, F-75724 Paris CEDEX 15, France.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Genetically Modified
Aorta / cytology*,  embryology
Cell Death
Cell Differentiation*
Cell Lineage*
Cell Movement*
Core Binding Factor Alpha 2 Subunit / deficiency,  genetics,  metabolism
Endothelial Cells / cytology
Endothelium, Vascular / cytology*,  embryology
Hematopoietic Stem Cells / cytology*
Zebrafish / blood*,  embryology
Zebrafish Proteins / deficiency,  genetics,  metabolism
Chemical
Reg. No./Substance:
0/Core Binding Factor Alpha 2 Subunit; 0/Zebrafish Proteins; 0/runx1 protein, zebrafish

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