Hierarchical organization and regulation of the hematopoietic stem cell osteoblastic niche

Hematopoietic stem cells (HSCs) are characterized with long-term self-renewal and multi-lineage differentiation. HSCs preferentially reside in osteoblastic niche that is hierarchically organized so as to exactly regulate HSCs properties and maintain organism hematopoietic homeostasis. Hematopoietic stem cell–mesenchymal stem cell pairings share stem cell niches in adult bone marrow under immune–humoral–neural regulation. Here, we review the hierarchical HSC osteoblastic niche in terms of its localization, composition, function, and multi-layer regulation systems.