Ex vivo expansion of hematopoietic progenitor cells is associated with downregulation of α4 integrin- and CXCR4-mediated engraftment in NOD/SCID β2-microglobulin-null mice
Ex vivo expansion of hematopoietic progenitor cells is associated with downregulation of α4 integrin- and CXCR4-mediated engraftment in NOD/SCID β2-microglobulin-null mice
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DOI：
10.3324/haematol.13206
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发表时间：
2009-02-01
期刊：
影响因子：
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通讯作者：
Gothot, Andre
中科院分区：
文献类型：
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作者：
Foguenne, Jacques;Di Stefano, Ivano;Gothot, Andre
研究背景多项研究表明，体外扩增诱导造血干细胞植入缺陷。我们研究了α 4整合素、α 5整合素和CXCR 4在未操作和经马槟榔碱处理的人脐带血CD 34（+）细胞植入中的作用。在移植前，通过将细胞与特异性中和抗体孵育来评估α 4和α 5整联蛋白和CXCR 4的功能。α 4整合素的活化状态进一步测试的粘附和迁移assays.ResultsNeutralization的α 4整合素或CXCR 4废除移植后6周的未培养的CD 34（+）细胞的植入，而α 5整合素中和没有显着的效果。然而，在短期离体培养后，阻断α 4整联蛋白或CXCR 4不影响再填充活性，而α 5整联蛋白的中和抑制植入。利用可溶性血管细胞粘附分子-1结合试验，我们观察到α 4整合素在新鲜的CD 34（+）细胞中的亲和力较低，对刺激敏感，而在培养的CD 34（+）细胞中，亲和力较高，对进一步活化不敏感。此外，基质细胞衍生因子-1刺激迁移跨越血管细胞粘附分子-1在新鲜的CD 34（+）细胞，但不是在培养的CD 34（+）cells.ConclusionsOur数据表明，离体培养hernatopoietic祖细胞与下调α 4整合素和CXCR 4介导的植入。进一步的研究表明，这是由α 4整合素亲和力的超生理增加引起的，这损害了响应于基质细胞衍生因子-1的跨血管细胞粘附分子-1的定向迁移。这些变化可能是苦参碱刺激的CD 34（+）细胞植入缺陷的基础。
BackgroundSeveral studies indicate that ex vivo cytokine-supported expansion induces defective hematopoietic stem cell engraftment. We investigated the role of alpha 4 integrin, alpha 5 integrin and CXCR4 in engraftment of unmanipulated and cytokine-treated human cord blood CD34(+) cells.Design and MethodsUncultured or expanded CD34(+) cells were infused in NOD/SCID-beta(2)microglobulin-null mice. The function of alpha 4, and alpha 5 integrins and CXCR4 was assessed by incubating cells with specific neutralizing antibodies, prior to transplant. The activation state of alpha 4 integrin was further tested by adhesion and migration assays.ResultsNeutralization of either alpha 4 integrin or CXCR4 abolished engraftment of uncultured CD34(+) cells at 6 weeks post-transplant, while alpha 5 integrin neutralization had no significant effect. However, after short-term ex vivo culture, blocking alpha 4 integrin or CXCR4 did not affect repopulating activity whereas neutralization of alpha 5 integrin inhibited engraftment. Using soluble vascular cell adhesion molecule-1 binding assays, we observed that a4 integrin affinity in fresh CD34(+) cells was low and susceptible to stimulation while in cultured CD34(+) cells, it was high and insensitive to Further activation. In addition, stromal cell-derived factor-1 stimulated migration across vascular cell adhesion molecule-1 in fresh CD34(+) cells but not in cultured CD34(+) cells.ConclusionsOur data show that ex vivo culture of hernatopoietic progenitor cells is associated with downregulation of both alpha 4 integrin- and CXCR4-mediated engraftment. Further investigations suggest that this is caused by supraphysiological increase of alpha 4 integrin affinity, which impairs directional migration across vascular cell adhesion molecule-1 in response to stromal cell-derived factor-1. Such changes may underlie the engraftment defect of cytokine-stimulated CD34(+) cells.