血小板第4因子对脐血CD34+细胞黏附功能的影响

目的研究血小板第4因子(PF4)对新鲜脐血CD34+细胞及扩增后脐血CD34+细胞黏附功能的影响;PF4对脐血CD34+细胞上的黏附分子CD49d及基质细胞趋化因子(SDF-1)受体CXCR4的作用.方法采用免疫磁珠法(MACS)分选CD34+细胞,结晶紫染色测定细胞总黏附性,免疫荧光标记流式细胞仪测定CD49d及CXCR4的表达.结果①PF4 可使新鲜脐血CD34+细胞总黏附性提高,且与剂量相关.②SDF-1 100 ng/ml可使脐血CD34+细胞总黏附性提高.③脐血CD34+细胞扩增10 d后未加PF4刺激的自发以及经SDF-1诱导的黏附功能开始下降,在扩增脐血CD34+细胞不同时间段加入100ng/ml PF4,脐血CD34+细胞对基质层的黏附能力始终保持较高水平,以0天时脐血CD34+细胞黏附性为100%,扩增14 d时脐血CD34+细胞黏附性PF4组为(262.04±64.81)%,同期对照组为(64.35±8.29)%,经SDF-1诱导下扩增14 d的CD34+细胞的总黏附性PF4组为(138.31±32.39)%,同期对照组为(67.66±12.44)%.④PF4 100 ng/ml作用于CD34+细胞时,CD49d表达增长13.02%,CXCR4表达增长17.33%.结论 PF4可使新鲜及扩增后的脐血CD34+细胞黏附功能增强,并促进CD49d及CXCR4的表达,提示PF4可能有助于脐血干细胞的归巢.

Effect of platelet factor 4 on the adherence of cord blood CD34+ cells

OBJECTIVE: To investigate the effects of platelet factor 4 (PF4) on the adherence, and the expressions of adherent molecules CD(49d) and CXCR4 and the receptor of SDF-1 of fresh and expanded cord blood CD(34)(+) cells. METHODS: CD(34)(+) cells were isolated from cord blood using MACS immune magnetic beads. The adherent ability was assayed by using crystal violet staining and the expression of adherent molecule CD(49d) and CXCR4 by FACS. RESULTS: (1) PF4 could increase the adherent ability of the fresh cord blood CD(34)(+) cells, the effect being positively correlated with the dose of PF4. (2) SDF-1 at concentration of 100 ng/ml increased the adherent ability of the fresh cord blood CD(34)(+) cells. (3) The spontaneous and the SDF-1 induced adherent ability of the cord blood CD(34)(+) cells began to decrease after being cultured for 10 days without PF4, while in the presence of PF4 at 100 ng/ml, the ability of the cord blood CD(34)(+) cell adhering to the stroma layer still remained at higher level. At day 14, the adherent ability was (262.04 +/- 64.81)% and (64.35 +/- 8.29)% in PF4 group and control group, respectively, if it was defined as 100% at day 0. SDF-1 at concentration of 100 ng/ml induced adherent ability was (138.31 +/- 32.39)% and (67.66 +/- 12.44)% in PF4 group and control group, respectively. (4) The expression of CD(49d) and CXCR4 increased 13.02% and 17.33%, respectively, when incubated with PF4. CONCLUSIONS: PF4 could increase the adherent ability and promote the expression of CD(49d) and CXCR4 of the cord blood CD(34)(+) cells, suggesting that PF4 promote the circulating stem cells homing to the marrow in the process of stem cells transplantation.