基质细胞衍生因子-1和血小板第4因子对体外扩增后脐血CD34+细胞黏附特性和趋化功能的影响

为了研究基质细胞衍生因子-1（SDF—1）和血小板第4因子（PF4）对扩增后脐血CD34^＋细胞归巢相关功能的影响，将纯化的脐血CD34^＋细胞接种入无血清培养液中，加入不同组合的细胞因子FST（FL＋SCF＋TPO）、FST＋SDF—1、FST＋PF4或FST＋SDF—1＋PF4，分别于培养第7、10、14天检测CD34^＋细胞扩增倍数、集落形成能力、细胞的黏附分子表达、总黏附性、趋化功能。结果表明：①加入SDF—1的实验组CD34^＋细胞及造血祖细胞集落扩增倍数高于对照组；②加入SDF—1明显上调扩增的CD34^＋细胞CD49e的表达，加入PF4明显上调扩增的CD34^＋细胞CD49e、CD54的表达，在扩增体系中加入SDF—1或PF4均能够明显提高扩增的CD34^＋细胞的总黏附性；③在扩增体系中加入SDF—1能够明显提高扩增的CD34^＋细胞的自发迁移率，但导致CXCR-4的表达和SDF—1诱导迁移率降低；而PF4能够明显提高扩增的CD34^＋细胞的CXCR-4的表达和SDF—1诱导迁移率；在扩增体系中同时加入SDF—1和PF4能够明显提高扩增的CD34^＋细胞自发迁移率和SDF—1诱导迁移率。结论：体外扩增体系中加入SDF—1和PF4能够上调部分归巢相关黏附分子的表达，保持扩增的CD34^＋细胞的黏附和迁移能力，有利于降低体外扩增对造血干／祖细胞（HSPC）归巢相关功能的不利影响，维持扩增的HSPC的归巢潜能。

Effects of Stromal Cell-derived Factor 1 and Platelet Factor 4 on the Adhesion Characteristics and Chemotactic Function of Ex Vivo Expanded Umbilical Cord Blood CD34 + Cells

To investigate the effects of stromal cell-derived factor 1 (SDF-1) and platelet factor 4 (PF4) on the homing-related function of expanded ex vivo umbilical cord blood CD34~+ cells, purified cord blood CD34~+ cells were cultured in serum-free medium containing a HGF combination of FL+SCF+TPO (FST) with either 100 ng/ml SDF-1 alone, 100 ng/ml PF4 alone, or both of these 2 cytokines. The expansion rate of CD34~+ cells, colony formation, homing-related functions including expression of homing-related adhesion molecules of expanded CD34~+ cell, adhesion activity and chemotactic function of the re-selected expanded CD34~+ cells were evaluated at different time points. The results showed that expansion rate of CD34~+ cells and expansion multiple of CFU in SDF-1 groups were higher than those in control. The expression of CD49e on the expanded CD34~+ cells was remarkable up-regulated, in contrast, expression of CXCR-4 on the expanded CD34~+ cells was remarkable down-regulated in SDF-1 groups. The expression of CD49e, CD54 and CXCR-4 on the expanded CD34~+ cells were remarkably up-regulated in the PF4 groups. In all the SDF-1 group, PF4 group and SDF-1 plus PF4 group, the ability of expanded CD34~+ cells adhering to fibronectin layer were higher than those in the control on day 10. Spontaneous migration rate of expanded CD34~+ cells in SDF-1 groups were higher than those in control, while SDF-1-induced migration rate were lower than those in control on day 10. SDF-1-induced migration rate in PF4 groups were higher than those in control on day 10. Spontaneous and SDF-1-induced migration rate of expanded CD34~+ cells in the SDF-1 plus PF4 groups were higher than those in control on day 10. It is concluded that, SDF-1 and PF4 can up-regulate expression of adhension molecules on expanded CD34~+ cells, and retain the adherent and migration ability of expanded CD34~+ cells, which is helpful for the homing of expanded CD34~+ cells. In short, SDF-1 and PF4 are helpful for the homing-related function of the expanded UCB HSPC.