胸腺肽类药物对体外诱导ES细胞分化为T细胞的作用

Effects of Thymic Polypeptides on Thymopoiesis of Mouse Embryonic Stem Cells

【目的】研究目前临床常用的增强细胞免疫功能的胸腺肽,胸腺5肽和胸腺素α-1在小鼠胚胎干细胞向T淋巴细胞分化过程中的作用。【方法】借助小鼠胚胎干细胞(ESC)体外自然分化形成的类胚体(EB)中含有三胚层细胞的独特细胞环境,加入多种细胞因子和胸腺多肽,体外诱导小鼠ESC向T淋巴细胞分化。利用流式细胞仪检测在三种不同胸腺多肽的诱导下,不同时间点的小鼠ESC来源的细胞表面CD3分子的表达水平。并在相应时间点通过RT-PCR检测与T淋巴细胞发育密切相关的Notch信号分子的转录水平。【结果】在加入胸腺肽和胸腺素α1诱导的实验组,均有细胞表达CD3分子,CD3+细胞的百分比随诱导时间的增加而增多;而加入胸腺五肽的实验组无CD3+细胞出现。加入胸腺素α1和胸腺肽的实验组,有Notch1及其配体delta-like-1和delta-like-4的转录;而加入胸腺五肽的实验组的细胞无Notch1及其配体转录。【结论】胸腺素α1或胸腺肽可能通过影响Notch1信号途径支持ES细胞向T细胞分化,而胸腺五肽无此作用。

[Objective] To compare the effects of three thymic polypeptides including thymopentin-5 （TP5）, thymosin-alphal Tα-1） and thymopeptides on the thymopoiesis of mouse embryonic stem （ES） cells in vitro. [Method] EBs were obtained from spontaneously differentiated ES cells and were induced into T lymphocytes in vitro by utilizing three different inducing media, which contain TP5, Tα-1, and thymopeptides, respectively. Then the expression of CD3 on these differentiated cells were analyzed by flow cytometry at different time points. At the corresponding time-point, the transcription levels of Notch signal molecules were also detected by RT-PCR. [Results] The results showed that inducing systems containing either Tα-1 or thymopeptides promoted the emergence of CD3＋ cells during the observation period, and the percentage of CD3 ^＋ cells increased with a longer induction period. However, we never found CD^＋ cells in the inducing system containing TP5 throughout the inducing period. And Notch 1 receptor and its ligands, involving Delta-like-1 and Delta-like-4, expressed in inducing systems containing either Tα-1 or thymopeptides. However, neither Notchl nor its ligands were detected in the inducing system containing TP-5 during the observation period. [Conclusion] Tα-1 and thymopeptides may play a role in promoting T cells differentiation from ES cells by Notchl signal pathway, while TP-5 may not.