Figure 1.

Hematopoietic stem and progenitor cells bone marror homing in the context of hematopoietic stem cell transplantation. Upon hematopoietic stem cell transplantation (HSCT), the hematopoietic stem and progenitor cells (HSPC) extravasate through the bone marrow (BM) vascular endothelium enter and repopulate the BM niche. The BM endothelium expresses several adhesion molecules, such as selectins and VCAM-1, which facilitate rolling and firm adhesion of HSPC on the endothelial cells. Subsequently, the HSPC preferentially migrate through the endothelial cell body, designated as transcellular transmigration. VE-cadherin regulates vascular endothelial integrity by stabilizing the endothelial cell-cell junctions. Following inhibition of VE-cadherin, vascular permeability increases and HSPC may also migrate through the endothelial cell junctions in a paracellular manner.