Transendothelial migration of CD133+ hematopoietic progenitor cells isolated from human umbilical cord blood

Abstract

Transmigration of hematopoietic progenitor cells across the vascular endothelium and subsequent maturation in the tissue helps to maintain the pool of resident mast cells. We determined the potential of CD133+ cells isolated from umbilical cord blood to migrate across an endothelial cell monolayer. CD133+ cells possess mRNA for several adhesion molecules that are critical in the process of neutrophil transmigration. Stem cell factor & its receptor CD117 are required for homing & differentiation of mast cells in the tissue. We detected the presence of CD34, CD117, CD29, & CD18 on the surface of CD133+ cells using flow cytometry. Tryptase stimulation leads to increased endothelial cell platelet activating factor (PAF) production that may facilitate the interaction between the endothelium & the PAF receptor (PTAFR) on circulating CD133+ cells. Treatment with the PTAFR antagonist CV3988 significantly reduced the percentage of transmigrating CD133+ cells across a tryptase stimulated endothelial monolayer. This suggests that CD133+ cell migration depends on the PAF/PTAFR interaction in a manner similar to that involved in neutrophil transmigration. Following transmigration there is the potential for a subset of these cells, in the presence of SCF & IL‐6, to mature into tissue mast cells.This work was supported by AHA Heartland Affiliate Grant # 0610118Z.