FIG. 3.
Cellular and molecular architecture of the HSC niche. Sinusoid niche with interacting Lepr+ stromal cells as well as arteriole niche with NG2+Nestinhigh pericytes were proposed as the preferential localization of HSCs in the bone marrow. Macrophages and megakaryocytes were shown to be in proximity to HSCs in the bone marrow. Endothelial and stromal cells produce the indispensable factors for HSC maintenance: SDF-1 and SCF. Megakaryocytes are a source of CXCL4 and TGF-β. SCF, stem cell factor; TGF-β, transforming growth factor beta. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars