BCL11A-deficient human erythropoiesis is impaired in vitro and after xenotransplantation into mice

Genetic depletion of the transcriptional repressor BCL11A in red blood cell precursors alleviates β-hemoglobinopathies by inducing the fetal γ-globin genes. However, additional erythroid genes are regulated by BCL11A and the effects of its deficiency on erythropoiesis are insufficiently described. We discovered that Cas9 disruption of the BCL11A intron 2 erythroid enhancer in CD34+ hematopoietic stem and progenitor cells using a clinically approved strategy caused impaired expansion and apoptosis of erythroid precursors in vitro and reduced repopulation of the erythroid compartment after xenotransplantation into immunodeficient mice. Mutant colony-forming unit erythroid cells, proerythroblasts, and basophilic erythroblasts exhibited dysregulation of 94 genes (more than twofold change, false discovery rate < 0.05), 25 of which are likely direct targets of BCL11A. Differentially expressed genes were associated with a range of biological pathways that affect cell expansion and survival. Our findings reveal that BCL11A regulates additional aspects of erythropoiesis beyond γ-globin gene repression, with unknown clinical consequences.