S1P-mediated homing of HSPCs to BM could be improved by upregulating the S1P level in the BM microenvironment by DOP or THI, which inhibit SPL activity by blockade of the S1P2 receptor on transplanted donor cells (e.g., employing JTE-013) or by inhibiting the LPP and SPP receptors on donor HSPCs (e.g., with XY-14). Similar strategies could be helpful in directing other types of stem cells involved in the regeneration of damaged tissues (e.g., MSCs, EPCs, and VSELs).