Notch信号介导共培养脐带间充质干细胞和造血干细胞的相互作用

Notch pathway gene expression after co-culture of umbilical cord mesenchymal stem cells and hematopoietic stem cells

目的:探讨脐带间充质干细胞(UC-MSC)体外与造血干细胞共培养后Notch信号分子的改变。方法:通过胶原酶消化方法分离UC-MSC,通过流式细胞仪检测以及成脂、成骨和成软骨诱导鉴定UC-MSC具备间充质干细胞的特性。进而,将UC-MSC与脐血CD34+造血干细胞(HSC)体外培养,实时PCR方法检测MSC及CD34+细胞表面Notch配体及受体表达以及表达是否存在变化;在共培养体系中加入Notch信号阻滞剂DAPT(γ-secretase抑制剂),比较Hes-1基因活化状态的改变。结果:体外实验显示:UC-MSC在形态学、细胞表面表型和诱导分化能力上均具备间充质干细胞的特性。UC-MSC及CD34+细胞表面存在Notch信号配体及受体的表达,共培养后Jagged 1、Notch1基因表达明显增加;共培养后CD34+细胞中的Hes-1基因表达明显增加而加入DAPT后Hes-1基因表达未检出明显改变。结论:UC-MSC支持造血中,Notch信号可能发挥重要作用。

AIM： To detect the gene expression of signal molecules involved in the Notch pathway after co-culture of umbilical cord mesenchymal stem cells（UC-MSCs） and CD34＋ hematopoietic stem cells.METHODS： UC-MSCs were isolated by collagenase digestion,and the phenotype was tested by flow cytometry.The differentiation ability of UC-MSCs into adipocytes,osteoblasts and chondroblasts was analyzed using three induction systems,respectively.After UC-MSCs were co-cultured in vitro with CD34＋ cells for 6 d,real-time PCR was applied to investigate the gene expressions of notch ligands（Jagged 1,2 Delta1,3,4）,receptors（Notch1-4） and Hes-1.RESULTS： The isolated UC-MSCs were found with the typical characteristics of MSCs in morphology,phenotype and differentiation ability.After co-culture in vitro of MSCs and CD34＋ cells,real-time PCR assay showed a significant up-regulation of Jagged-1 and Notch1.The expression of Hes-1 in CD34＋ cells also increased,but there was no obvious change after DAPT（50 nmol/L） was added in co-culture medium.CONCLUSION： Notch signaling may play an important role in the process of the expansion of hematopoietic stem cells supported by UC-MSCs.