N-Cadherin-Expressing Bone and Marrow Stromal Progenitor Cells Maintain Reserve Hematopoietic Stem Cells (Cell Reports)

Zhao et al. demonstrate that blood-forming stem cells have a back-up system in stressed condition. Both reserve and active stem cells are maintained in the bone marrow by specific niches. While the latter are chemo-sensitive, the former survive and restore stem cells, and thereby generate the blood system.