Author(s) : Luc Douay, Hélène Lapillonne, Laurent Garderet, Marie-Catherine Giarratana, Jean-Pierre Cartron , Inserm U832, Faculté de Médecine Pierre et Marie Curie, 27 rue de Chaligny, 75012 Paris, France, Service d’hématologie biologique, hôpital A. Trousseau, 26 av. Netter, 75012 Paris, France, Inserm U665, Paris ; INTS, 6 rue Alexandre Cabanel, 75739 Paris Cedex 15, France.
Summary : We discuss here the potential interest of research into a methodology allowing the massive production ex vivo of mature and functional human red blood cells (RBC) from hematopoietic stem cells (HSC) of diverse origins. These RBC have all the characteristics of native adult RBCs. The protocol comprises three steps. The fist step involves cell proliferation and induction of erythroid differentiation in a liquid medium without serum, with, however, added stem cell factor (SCF), interleukin-3 (IL-3) and erythropoietin (Epo). The second step is based on the reconstitution of the medullar microenvironment, in the presence of Epo, and the third step is performed in the medullar microenvironment alone, with no added growth factor. This protocol permits both a massive expansion of the HSC/progenitors and their complete differentiation into RBCs. We show how this two compartment model of erythropoiesis can be used to study terminal erythropoiesis. On the one hand cell proliferation and erythroid commitment can be analyzed using this model, and on the other hand one can analyse the role of the microenvironment in enucleation, a phenomenon very characteristic of erythropoiesis. We also discuss the interest of this protocol for the study of haemoglobin synthesis, as much as for understanding the physiology of the globin gene switch. In addition this model can be used as a tool to analyse acquired or congenital disorders of erythropoiesis, such as myeloplastic syndromes and dyserythropoieses. The function of genes involved in erythropoiesis can be studied by RNA interference. Models of the deficiency of erythrocyte proteins implicated in various forms of congenital hemolytic anemia can be constructed. This model could also have applications outside haematology, such as for the study of intra-erythrocyte cycles of diverse plasmodial species and their chemoresistance, or for improving the standardization of culture methods of Plasmodium Falciparum. Finally, concerning HSCs derived from embryonic cells, this model should allow us to determine if mature and functional cells can be produced ex vivo from human embryonic cells.
Keywords : hematopoietic stem cell, erythropoiesis, red blood cell
Pictures
Figure 1 Génération de globules rouges matures
énucléés in vivo par injection à la souris NOD/SCID de précurseurs
érythroïdes de J10.
Figure 2 Maturation terminale en globules rouges par
reconstitution in vitro du microenvironnement médullaire.
Figure 3 Cinétique de différenciation des cellules
érythroïdes in vitro sur stroma médullaire.
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