Differential expression of KDR/VEGFR-2 and CD34 during mesoderm development of the early human embryo.
Recent findings on vertebrate embryos have provided compelling evidence for the existence of hemangioblasts, i.e. common precursors for endothelial and hematopoietic cells, characterized by expression of the VEGFR2/Flk1 receptor. We describe here a population of KDR+ CD34- mesoderm cells that emerges in early-somitic human embryos, by the beginning of the 4th week of gestation. In the developing blood vessels, KDR-expressing CD34- cells gradually coexpress increasing levels of CD34 antigen. Remarkably, as development proceeds, a KDR+ CD34- contingent persists in the paraaortic splanchnopleura until just prior to the emergence of aorta-associated hematopoietic cell clusters. These observations suggest that KDR+ CD34- mesodermal cells might represent the putative hemangioblastic precursor of human hematopoietic and endothelial lineages.
Cortés
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F
Institut d'Embryologie Cellulaire et Moléculaire, CNRS UPR 9064, 49bis, avenue de la Belle Gabrielle, 94736, Nogent-sur-Marne Cedex, France.
Debacker
C
C
Péault
B
B
Labastie
M C
MC
D018952:Antigens, CD34 / Q000032:analysis / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000033:anatomy & histology* / Q000378:metabolism*; D006801:Humans; D008648:Mesoderm / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis / Q000378:metabolism*; D017978:Receptors, Growth Factor / Q000032:analysis / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor; D013997:Time Factors
D018952:Antigens, CD34; D017978:Receptors, Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor