Notch1突变对HSC体外分化为T/B淋巴细胞的影响

摘要

Objective : To investigate the effects of Notchl signal transduction level on hempatopoietic stem cells (HSCs) in vitro differentiation into T/B lymphocytes.Methods : The HSCs from fetal liver cells or bone marrow frum mice that carrying a Notchl point mutation within its ligand binding domain were co-cultured with stromal OP9 or OP9-DL1 that can express Deltal.Proportions of B lymphocytes or CD4+ CD8+ cells were analyzed by FACS.Results: Notchl mutation may change conformation of ligand binding domain of Notch1 receptor, that dccrease the abilities of ligand binding and signaling transduction.Differentiation of HSCs from mutant fetal liver or bone marrow to B lymphocytes was not affected, however, differentiation to T lymphocytes was obviously inhibited by Notchl point mutant in hematopoietic stem cells from fctal liver and bone marrow.Comparing to wild-type control, the inhibition are 44％ and 34％ , respectively.Conclusion: Notchl point mutation can reduce the level of signal transduction, which is no effects on B lymphocyte development hut inhibits T lymphocyte devclopment from HSCs.%目的:探讨Notch1信号传递水平对小鼠造血干细胞(HSC)体外分化为T/B淋巴细胞的影响.方法:应用表达Notch1配体Delta1的基质细胞OP9-DL与来源于小鼠胎肝和骨髓的Lin- HSC在体外共培养,检测Notch1基因突变对HSC在体外分化后B淋巴细胞或者CD4+CD8+细胞的比例.结果:Notch1基因点突变后Notch1受体结构发生改变,和特异性抗体以及配体的结合能力降低,导致信号传递能力下降.Notch1突变后,胎肝和骨髓HSC向B淋巴细胞分化过程未受影响,但是向T淋巴细胞的分化过程受到明显抑制,其中Notch1突变对胎肝HSC分化能力的影响高于骨髓HSC,分别被抑制44%和34%.结论:Notch1突变导致Notch1信号水平降低,对HSC向B淋巴细胞分化没有影响,但是能抑制向T淋巴细胞的分化.