Peri-sinusoidal stromal cells form a unique multispecific niche for hematopoietic stem cells and early B cells

In the bone marrow, CXCL12 and IL7 are essential for B cell differentiation whereas hematopoietic stem cells (HSC) maintenance requires SCF and CXCL12. Previous studies, including ours, indicate that peri-sinusoidal stromal (PSS) cells are heterogeneous and that part of them express and are the main source of IL7. Our single cell qPCR and transcriptomic analysis demonstrate that SCF, CXCL12 and IL7 are co-expressed by a unique peri-sinusoidal stromal cell subset. Overall design: CD45-CD51+BP1+ peri-sinusoidal stromal cells, CD45-CD51+BP1- mesenchymal cells and CD45-CD31+ endothelial cells were sorted and mixed together