Regulation of erythropoiesis in the spleen by Desert Hedgehog (Dhh)

Dhh negatively regulates multiple stages of erythrocyte differentiation. In Dhh-deficient bone marrow, the common myeloid progenitor (CMP) population was increased, but differentiation from CMP to granulocyte/macrophage progenitor was decreased, and the mature granulocyte population was decreased, compared with wild-type (WT). In contrast, differentiation from CMP to megakaryocyte/erythrocyte progenitor was increased, and the megakaryocyte/erythrocyte progenitor population was increased. In Dhh-deficient spleen and bone marrow, BFU-Es and erythroblast populations were increased compared with WT. During recovery of hematopoiesis after irradiation, and under conditions of stress-induced erythropoiesis, erythrocyte differentiation was accelerated in both spleen and bone marrow of Dhh-deficient mice compared with WT. To investigate possible mechanisms for its regulation of erythropoiesis we carried out RNAsequencing on Facs-sorted erythroblast population II (CD71+Ter119+) cells from Dhh-/-, Dhh+/- and WR mice. Overall design: Splenocyte suspensions were prepared from 4 week old Wildtype (WT), Dhh heterozygous (Dhh+/-) and Dhh knockout (Dhh-/-) mice spleen. Cells were stained against Ter119 and CD71 and facs sorted to purify CD71+Ter119+ cells. RNA was extracted from this CD71+Ter119+ cells defined as erythroblast population II.