人诱导多能干细胞与人胚胎干细胞分化过程中Oct4/Nanog基因表达的比较

目的：比较通过慢病毒方法获得的人诱导多能性干细胞（iPSCs）与人胚胎干细胞（hESCs）分化过程中全能性基因Oct4、Nanog的表达变化。方法：收集分化不同时间点的拟胚体（EBs）,检测三胚层分化基因以及全能性基因Oct4/Nanog的表达,并通过畸胎瘤组织切片的荧光染色分析Oct4的表达。结果：iPSCs获得的EB中内外三胚层分化基因表达的出现明显晚于hESCs来源的EB。不同于hESCs,iPSCs悬浮培养获得的EBs在体外培养18天未见内源性Oct4、Nanog基因表达的下调。未分化的iPSCs注射严重联合免疫缺陷（SCID）小鼠培养10周后获得的畸胎瘤中仍存在Oct4阳性的细胞,但iPS-#2中明显少于iPS-#5。结论：通过慢病毒方法获得的iPSCs虽然具有向三胚层分化的能力,但在分化过程中仍维持较高水平的全能性基因Oct4、Nanog的表达。

Comparison of Human Induced Pluripotent Stem Cells and Oct4/Nanog Gene Expression in Human Embryonic Stem Cell Differentiation

Objective： To compare the expression of pluripotency gene Oct4/Nanog in the differentiated human induced pluripo-tent stem cells（iPSCs） and embryonic stem cells（ESCs）.Methods： The RNA of embryoid bodies（EBs） derived from undifferentiated human iPSCs and hESCs at different time of differentiation were collected.The gene expression related to three-layer differentiation and pluripotency gene Oct4/Nanog was detected by RT-PCR.The Oct4 positive cells in the teratoma derived from both human iPSCs and hESCs were detected by immunofluorescence staining.Results： The expression of endoderm and ectroderm related gene in the EBs derived from iPSCs was later than that derived from hESCs.The expression of Oct4 and Nanog was still existence in D18 EBs derived from undifferentiated human iPSCs.The Oct4 positive cells were detected in iPSCs derivded-teratoma.Conclusion： Although the iPSCs can differentiate into three-layer cells,the higher expression of pluriotency gene Oct4/Nanog was maintained in the differentiated iPSCs generated by lentivirus infection than hES.