Mutualism in the Marrow

Cross-talk between hematopoietic stem cells (HSCs) and the HSC niche is likely important in hematopoiesis but not well demonstrated. Now in Cell Stem Cell, Chen et al. (2019) describe how specialized endothelial cells regulate hematopoietic stem cell maintenance and how hematopoietic stem/progenitor cells facilitate vascular regeneration in return.