Involvement of VLA-5 and VLA-6 in facilitating endothelium-oriented transmigration of hematopoietic stem/progenitor cells

摘要

目的:研究VLA-5及VLA-6是否参与内皮细胞促进的造血干/祖细胞定向移行.方法:对纯化人CD34+细胞进行体外移行及阻断实验,观察其穿移覆盖人脐静脉内皮细胞(HUVECs)滤膜的能力.应用四色荧光活化流式细胞术(FACS)检测CD34+细胞其粘附分子及趋化因子受体CXCR-4的表达谱.结果:基质由来因子(SDF)-1α介导的动员外周血(mPB)及骨髓(BM)来源的CD34+细胞穿透覆盖HUVECs滤膜百分率分别为(56.6±20.1)%及(15.6±1.8)%,显著高于其穿移未覆盖HUVECs滤膜的比率.预先对CD34+细胞进行抗VLA-5和/或VLA-6中和抗体处理可消除这一促进效应.此外,BM来源的CD34+细胞其穿移覆盖及未覆盖HUVECs滤膜的能力均显著低于mPB CD34+细胞,两者间穿移能力的差异与其VLA-5及VLA-6(而非VLA-4及趋化因子受体CXCR-4)抗原表达水平相关.结论:VLA-5和VLA-6参与HUVECs促进HS/PCs穿移能力.%Objective:To investigate whether VLA-5 and VLA-6 are involved in facilitating en-dothelium-oriented transmigration of hematopoietic stem/progenitor cells. Methods:Purified hu-man CD34+ cells were subject to ex vivo transmigration assay and blocking experiments throughtranswell filter inserts coated with human umbilical vein endothelial cells (HUVECs). Four-colorfluorescence-activated cell sorting (FACS) analysis was applied to detect the expression profilesof adhesion molecules and chemokine receptor CXCR-4 on CD34bright cells. Results:Stromal cell-derived factor (SDF)-1-induced transmigrations of both mobilized peripheral blood (mPB)-(56.6±20. 1)% and bone marrow (BM)- (15. 6±1. 8)% derived CD34+ cells were significantlyfacilitated through HUVECs-coated transwell filter insters compared with noncoated ones, whichwere efficiently blocked by preincubation of CD34+ cells with neutralizing antibodies to VLA-5,or VLA-6, or both of them; meanwhile the proportions of migrating CD34+ cells through bothHUVECs-coated and noncoated transwell filter inserts in BM were significantly lower than thosein mPB; the different percentages of migrating CD34+ cells between in mPB and BM were corre-lated with their variable expressions of VLA-5 and VLA-6, but not for VLA-4 or chemokine re-ceptor CXCR-4. Conclusion:Facilitating HS/PCs transmigrations through HUVECs are involvedin both VLA-5 and VLA-6.