alphaIIb integrin, a novel marker for hemopoietic progenitor cells
Published: 1 May 2005
Catherine Corbel*,1, Pierre Vaigot and Josselyne Salaün
Laboratoire d'Embryologie Cellulaire et Moleculaire, CNRS UMR 7128, Nogent-sur-Marne, France and 1Institut Cochin, INSERM U567, Paris, France
Integrin alphaIIbbeta3 (abbreviated as alphaIIb), also known as GPIIb-IIIa or CD41/CD61, is a cell adhesion molecule expressed on cells belonging to the megakaryocytic lineage. Aiming to identify new markers of hemopoietic progenitor cells (HPC), we undertook a developmental study of this molecule since it remains controversial if this integrin is expressed by various progenitors. We reported the expression pattern of two integrins, in both of which the beta3 chain is present, respectively associated with alphaV and alpha IIb in the chick embryo. While at E3.5, the earliest time at which these integrins can be detected, alphaVbeta3 becomes expressed by endothelial cells in the aorta (and only in the aorta), alphaIIbbeta3 becomes detected in the well-defined intra-aortic clusters made up of HPC. The latter were found to be multilineage progenitors when sorted for alphaIIb expression and analyzed by means of clonogenic assays. In mice also, alphaIIb is expressed in the intra-embryonic site of HPC generation, the intra-arterial clusters in the embryo proper, as well as in sites where HPC migrate. Finally we provided the first evidence in two species that multipotent HPC expressing alphaIIb are able to differentiate not only into cells of the erythroid and myeloid lineages but also into lymphocytes. These cell populations actually coexpress alphaIIb and c-Kit. These data establish alphaIIb as a novel marker for HPC, which appears at very early stages in the embryo. Capitalizing on this finding, other investigators confirmed it and suggested that alphaIIb plays a role in regulating hematopoietic development.
integrin, embryo, fetal liver, bone marrow, hemopoiesis