Scheme depicting the effect of HIF1α on HSPC trafficking during transplantation. Ex vivo treatment of HSPCs with PGE₂ or hypoxia-inducible factor prolyl-hydroxylase inhibitor (DMOG) stabilizes HIF1α protein. Stabilized HIF1α translocates to the nucleus with the oxygen-independent subunit HIF1β to transactivate CXCR4 expression and enhance the homing and engraftment of HSPC to the niche.