Ex vivo expansion of human cord blood Lin-CD34-cells using indian hedgehog stromal cells

造血干细胞（HSC）的移植通常基于静脉注射，这是一个复杂的过程，需要通过血液循环，通过骨髓血管系统识别和外渗，并迁移到支持性微环境。然而，包括CB Lin-CD 34-干细胞在内的一些HSC很少在骨髓中植入。在TPO、FL和SCF存在下，我们将CB Lin-CD 34-细胞与人基质细胞共培养。结果，共培养的CB Lin-CD 34-细胞显著表达具有显著增殖潜力的趋化因子受体CXCR 4，尽管CB Lin-CD 34-细胞在无基质游离培养的情况下经历凋亡（总细胞，92±10 vs. 1542±161（x10^3）; CD 34+细胞，0±0 vs. 156±16（x10^3）; CFU-C，192±46 vs. 120320±34762 ; CFU-Mix，8±5 vs. 6513±3791，来自五十万CB Lin-CD 34-细胞）。此外，这些细胞获得了对BM的归巢活性，并在NOD/SCID/IL 2 R_链缺失小鼠中移植24周，尽管在没有人基质细胞的情况下培养的Lin-CD_（34）-细胞几乎不能移植。因此，基质与CB Lin-CD 34-细胞的相互作用赋予了植入BM龛的能力和对造血生长因子的反应性。这些发现可能为骨髓移植和利用CB Lin-CD 34-组分体外生产血细胞提供新的策略。

Transplantation of hematopoietic stem cells (HSCs) is usually based on intravenous injection, a complex process that requires circulation through blood, recognition and extravasation through bone marrow vasculature, and migration to a supportive microenvironment. However, some of HSCs including CB Lin-CD34- stem cells rarely engraft in bone marrow. We cocultured CB Lin-CD34- cells with human stromal cells in the presence of TPO, FL and SCF. As a result, cocultured CB Lin-CD34- cells remarkably expressed chemokine receptor CXCR4 with remarkable proliferative potential although CB Lin-CD34- cells undergo apoptosis without stromal free culture (Total cells, 92±10 vs. 1542±161(x10^3) ; CD34+ cells, 0±0 vs. 156±16 (x10^3) ; CFU-C, 192±46 vs. 120320±34762 ; CFU-Mix, 8±5 vs. 6513±3791 from five hundred thousand CB Lin-CD34- cells). Moreover, these cells acquired homing activity to BM and engrafted in NOD/SCID/IL2R _chain null mice for 24 weeks although Lin-CD34- cells cultured without human stromal cells hardly engrafted. Therefore, stromal interaction with CB Lin-CD34- cells confers the ability of engraftment to BM niche and responsiveness to hematopoietic growth factors. These findings may provide novel strategy of BM transplantation and utilization of CB Lin-CD34- fraction for ex vivo production of blood cells.