A rewired myeloid niche in spleen establishes stress erythropoiesis

However, during emergencies, the erythropoietic function can shift to the spleen. It remains unclear how the spleen, which typically performs erythrocyte recycling, can rapidly switch to become a site for erythropoiesis in stress states.

We utilized single-cell sequencing and spatial transcriptomic sequencing to compare changes in myeloid and erythroid cells in the bone marrow and spleen, thereby elucidating the key components of the extramedullary erythropoietic niche. We discovered that inflammation can rewire pre-existing macrophages in the spleen, establishing a novel myeloid microenvironment essential for extramedullary erythropoiesis.