Intimacy of the niche: perivascular remodeling cuddles incoming HSCs

Abstract

Stem cells reside in "niches," which provide signaling cues necessary for self-renewal. In a recent issue of Cell, Tamplin et al. (2015) perform live imaging of hematopoietic stem and progenitor cells (HSPCs) and find dynamic remodeling of endothelial cells is triggered upon arrival of HSPCs at the caudal hematopoietic tissue.

Figure 1. Remodeling of the Endothelial Niche Cells in the CHT

HSPCs (green) arrive to the CHT via circulation, extravasate, and lodge at the outer wall of the endothelium. A small group of endothelial cells (red), different from those that make initial contact, undergo “endothelial cuddling,” remodeling their membranes around a single HSPC. Stromal cells (blue) are located adjacent to the HSPC. Previous work has shown that perivascular stromal cells are necessary for HSPC maintenance in mouse bone marrow (Ding et al., 2012).