Introduction

Recent studies have revealed that microRNAs (miRNAs, miRs) are important for self-renewal, differentiation, and cellular reprogramming of somatic cells into induced pluripotent stem cells (iPSC); however, their functional roles and target genes that are regulated by human PSC–specific miRs including hsa-miR-302 clusters remain largely unknown. Analysis of their target gene will give us the opportunity to understand the functional roles of such miRs.

Methods

We analyzed the expression profiles of miRs in 4 somatic cell lines, 8 human iPSC lines derived from 4 different cell types, 3 human ESC lines, and embryoid bodies differentiated from the human ESCs to identify human PSC–specific miRs. We also analyzed the simultaneous expression profiles of miRs and mRNAs to identify candidate targets of human PSC–specific miRs. Then, we constructed a vector for overexpressing one of the target gene to dissect the functions of human PSC–specific miR in maintenance of self-renew and differentiation.

Results

We focused on hsa-miR-302 cluster as a human PSC–specific miR and identified 22 candidate targets of hsa-miR-302 cluster that were moderately expressed in undifferentiated human PSCs and up-regulated in differentiated cells. Deleted in azoospermia-associated protein 2 (DAZAP2), one such target, was directly repressed by hsa-miR-302a, -302b, -302c and -302d, but not by hsa-miR-367. Overexpression of DAZAP2 caused a decrease in cell proliferation of undifferentiated human iPSCs, although morphology and undifferentiated marker gene expression was not affected. In addition, neural differentiation was suppressed in DAZAP2-overexpressing human iPSCs.

Conclusion

Our study revealed that hsa-miR-302 cluster controls the cell proliferation of human PSCs and the neural differentiation of human PSCs by repression of DAZAP2, thereby highlighting an additional function of human PSC–specific miRs in maintaining pluripotency.

中文翻译：

---

hsa-miR-302 簇通过抑制 DAZAP2 控制人多能干细胞的外胚层分化。

介绍

最近的研究表明，microRNAs (miRNAs, miRs) 对于体细胞的自我更新、分化和细胞重编程为诱导多能干细胞 (iPSC) 很重要；然而，它们的功能作用和受人类 PSC 特异性 miR （包括 hsa-miR-302 簇）调节的靶基因在很大程度上仍然未知。对其靶基因的分析将使我们有机会了解此类 miR 的功能作用。

方法

我们分析了 miR 在 4 种体细胞系、8 种源自 4 种不同细胞类型的人类 iPSC 系、3 种人类 ESC 系和从人类 ESC 分化的胚状体中的表达谱，以鉴定人类 PSC 特异性 miR。我们还分析了 miRs 和 mRNAs 的同时表达谱，以确定人类 PSC 特异性 miRs 的候选靶标。然后，我们构建了一个用于过表达其中一个靶基因的载体，以剖析人类 PSC 特异性 miR 在维持自我更新和分化中的功能。

结果

我们专注于作为人类 PSC 特异性 miR 的 hsa-miR-302 簇，并确定了 hsa-miR-302 簇的 22 个候选靶标，这些靶标在未分化的人类 PSC 中适度表达并在分化细胞中上调。在无精子症相关蛋白 2 ( DAZAP2 ) 中缺失，这样的靶点之一直接被 hsa-miR-302a、-302b、-302c 和 -302d 抑制，但不受 hsa-miR-367 抑制。DAZAP2的过表达导致未分化的人类 iPSCs 的细胞增殖减少，尽管形态和未分化的标记基因表达不受影响。此外，在过表达 DAZAP2的人类 iPSC 中，神经分化受到抑制。

结论

我们的研究表明，hsa-miR-302 簇通过抑制DAZAP2来控制人 PSC 的细胞增殖和人 PSC 的神经分化，从而突出人 PSC 特异性 miR 在维持多能性方面的额外功能。