Bach Factors Operate Erythro-Myeloid Differentiation by Responding to Infection

Hematopoietic cell differentiation should be tightly regulated in accordance with environmental changes to keep homeostasis. Infection is one of the conditions that induce myelopoiesis to exclude pathogens and repress erythropoiesis, which might be beneficial for the restriction of nutritional iron for pathogens. While several transcription factors (TFs), including C/EBP family and Gata1, play central roles in erythro-myeloid differentiation, the precise mechanism which controls the differentiation for the adaptation to infection remains obscure. In this study, it was revealed that Bach factors induce erythropoiesis and repress myelopoiesis in the erythro-myeloid bifurcation step, and their expressions per se were suppressed by infectious stimuli. Hence, they work as balancers of the erythro-myeloid differentiation between steady state and infectious state. These findings give us new insight into the machinery which regulates the fate of hematopoietic cells by responding to surrounding environments. To investigate the transcriptomic phenotype of Bach1–/–Bach2–/– (double knock out; DKO) mice in common myeloid progenitor level, gene expression profiling by array using primary common myeloid progenitors from WT or DKO mice was performed.