Role of glycosylphosphatidylinositol-specific phospholipase D in the homing of umbilical cord blood, mobilized peripheral blood and bone marrow-derived hematopoietic stem/progenitor cells

Recent studies suggested that glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) correlated with tumor malignancy and prognosis of certain tumors. As hematopoietic stem/progenitor cells (HS/PC) homing was similar to tumor invasion and metastasis in some mechanisms, which arose our intrests in whether GPI-PLD contribution to the homing of HS/PC. In this study, CD34+ cells from umbilical cord blood (UCB), mobilized peripheral blood (MPB), and bone marrow (BM) were assayed for their differences in adhesion, migration, respectively. The expression of GPI-anchored proteins (CD48, CD90) on the cells were analyzed by flow cytometry. Semi-quantitive RT-PCR was used to detect GPI-PLD expression in the three different CD34+ cells. The results showed that GPI-PLD had no effect on the adhesion of CD34+ cells. While, spontaneous and SDF-1 induced migration of UCB and MPB, but not BM CD34+ cells were decreased after 1,10-phenanthroline (an inhibitor of GPI-PLD) pretreatment. Furthermore, we found little difference in GPI-anchored adhesion molecules (CD48, CD90) expression between untreated and pretreated CD34+ cells. GPI-PLD mRNA was low expressed in MPB and undetected in UCB and BM CD34+ cells. Our results suggested that GPI-PLD probably had no contribution to HS/PC homing, which may due to its low or no expression in UCB, BM and MPB CD34+ cells.