Hypoxia-induced in vivo sickling of transgenic mouse red cells

Abstract

To develop an animal model for sickle cell anemia, we have created transgenic mice that express a severe naturally occurring human sickling hemoglobin, Hb S Antilles. Due to its low solubility and oxygen affinity, Hb S Antilles has a greater propensity to cause red cell sickling than Hb S. To make transgenic animals that express a high level of Hb S Antilles, the erythroid-specific DNAse I hypersensitive site II from the human β-globin cluster was linked independently to the human α 2-globin gene and to the βS Antilles gene. Embryos were injected with both constructs simultaneously and seven transgenic mice were obtained, three of which contained both the human a and the human βS Antilles transgene. After crossing the human transgenes into the mouse β-thalassemic background a transgenic mouse line was derived in which approximately half the β-globin chains in the murine red cells were human βS Antilles. Deoxygenation of the transgenic red cells in vitro resulted in extensive sickling. An increase of in vivo sickling was achieved by placing these transgenic mice in a low oxygen environment. This murine model for red cell sickling should help to advance our understanding of sickle cell disease and may provide a model to test therapeutic interventions.