Wnt信号通路与自身免疫调节因子共同参与胚胎干细胞向胸腺上皮祖细胞的分化

Wnt signaling pathway is involved in differentiation of embryonic stem cells into thymic epithelial progenitor cells together with autoimmune regulators

背景:自身免疫调节因子(autoimmune regulator gene,Aire)及Wnt信号通路在小鼠胚胎干细胞多能性的维持及分化中都发挥着重要作用,但Wnt信号与Aire是否参与了小鼠胚胎干细胞向胸腺上皮祖细胞的分化尚未可知。目的:探讨Wnt信号通路和自身免疫调节因子与胚胎干细胞分化的关系。方法:采用两步分化方法定向诱导小鼠胚胎干细胞分化为内胚层再分化为胸腺上皮祖细胞,然后用Aire shRNA慢病毒感染小鼠胚胎干细胞,嘌呤霉素筛选单克隆稳定株,再采用两步分化方法进行诱导分化,分别于定向诱导分化第0,3,10天,采用细胞免疫荧光、流式细胞术、Western blot、Real-Time qPCR检测相关基因及蛋白的表达变化。结果与结论:①定向诱导分化第0天,免疫荧光染色显示SSEA1、OCT4表达呈阳性;②定向诱导分化第3天,免疫荧光染色显示SOX17、FOXA2表达呈双阳性;③定向诱导分化第10天,流式细胞术结果显示EPCAM1、K5、K8表达呈阳性;④与未分化的小鼠胚胎干细胞相比,诱导分化的胸腺上皮祖细胞中Wnt7a、β-catenin、Gsk-3β蛋白表达升高,Aire蛋白表达降低;⑤与未分化的小鼠胚胎干细胞相比,诱导分化的胸腺上皮祖细胞中Wnt7a、β-catenin、Gsk-3β及Aire mRNA表达升高;⑥与正常培养的小鼠胚胎干细胞及其最终分化的胸腺上皮祖细胞相比,敲低Aire基因的小鼠胚胎干细胞及其最终分化的胸腺上皮祖细胞中Wnt7a、β-catenin、Gsk-3β蛋白表达水平降低。综上所述,Wnt信号通路和Aire共同参与了小鼠胚胎干细胞定向诱导分化为小鼠胸腺上皮祖细胞的过程。

BACKGROUND:Autoimmune regulator gene(Aire)and Wnt signaling pathway play an important role in the maintenance and differentiation of mouse embryonic stem cell pluripotency.However,whether the Wnt signal and Aire are involved in the differentiation of embryonic stem cells to thymic epithelial progenitor cells remains poorly understood.OBJECTIVE:To investigate the relationship of the Wnt signaling pathway and Aire with the differentiation of embryonic stem cells.METHODS:A two-step differentiation method was used to induce mouse embryonic stem cells to differentiate into endoderm and then into thymic epithelial progenitor cells.Mouse embryonic stem cells were infected with Aire shRNA lentivirus,and monoclonal stable strains were screened by puromycin.Mouse embryonic stem cells were collected on days 0,3 and 10 of the directed induction of differentiation after the induced differentiation by the two-step differentiation method.Cellular immunofluorescence,flow cytometry,western blot assay,and real-time qPCR were used to detect the expression changes of related genes and proteins.RESULTS AND CONCLUSION:(1)Immunofluorescence staining showed positive expression of SSEA1 and OCT4 on day 0 of targeted induction of differentiation.(2)Immunofluorescence staining showed double-positive expression of SOX17 and FOXA2 on day 3 of targeted induction of differentiation.(3)Flow cytometry results showed positive expression of EPCAM1,K5 and K8 on day 10 of targeted induction of differentiation.(4)Compared with undifferentiated mouse embryonic stem cells,the expressions of Wnt7a,β-catenin,and Gsk-3βproteins were elevated,and the expression level of Aire protein was decreased in induced differentiated thymic epithelial progenitor cells.(5)Compared with undifferentiated mouse embryonic stem cells,the expressions of Wnt7a,β-catenin,Gsk-3βand Aire mRNA were elevated in thymic epithelial progenitor cells.(6)Compared with normal cultured mouse embryonic stem cells and their ultimately differentiated thymic epithelial progenitor cells,the expression levels of Wnt7a,β-catenin and Gsk-3βproteins were reduced in mouse embryonic stem cells with knockdown of Aire genes and their final differentiated thymic epithelial progenitor cells.In conclusion,the Wnt signaling pathway and Aire are jointly involved in the process of targeted induction of differentiation of mouse embryonic stem cells into mouse thymic epithelial progenitor cells.