Downregulation of Odd-Skipped Related 2, a Novel Regulator of Epithelial-Mesenchymal Transition, Enables Efficient Somatic Cell Reprogramming
Downregulation of Odd-Skipped Related 2, a Novel Regulator of Epithelial-Mesenchymal Transition, Enables Efficient Somatic Cell Reprogramming
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DOI：
10.1093/stmcls/sxac012
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发表时间：
2022-02-25
期刊：
影响因子：
5.2
通讯作者：
Hisatake，Koji
中科院分区：
文献类型：
--
作者：
Nishimura，Ken;Hisatake，Koji
体细胞重编程通过一系列事件进行，以产生诱导多能干细胞 (iPSC)。小鼠胚胎成纤维细胞重编程的早期特征是细胞快速增殖和形态变化，并伴有间充质相关基因的下调。然而，它们的下调与重编程的功能相关性仍然不明确。在这项研究中，我们筛选了在重编程后立即下调的转录调节因子，大概是通过重编程因子的直接靶向。为了测试这些转录调节因子在连续表达时是否会影响重编程，我们生成了一种表达载体，其中包含人巨细胞病毒上游开放阅读框 2 (uORF2)，它可以减少翻译，从而最大限度地减少表达蛋白的有害影响。使用该表达载体筛选转录调节因子表明，（奇数跳跃相关 2 [Osr2]）的下调对于有效重编程至关重要。使用基于细胞的上皮-间质转化 (EMT) 模型，我们证明 Osr2 是一种新型 EMT 调节因子，通过诱导转化生长因子-β (TGF-β) 信号传导发挥作用。在重编程过程中，Osr2 下调不仅会减弱 TGF-β 信号传导，还可以激活 Wnt 信号传导，从而促进间充质-上皮转化 (MET) 获得多能性。我们的结果阐明了Osr2下调在体细胞重编程早期消除间充质表型中的功能意义。
Somatic cell reprogramming proceeds through a series of events to generate induced pluripotent stem cells (iPSCs). The early stage of reprogramming of mouse embryonic fibroblasts is characterized by rapid cell proliferation and morphological changes, which are accompanied by downregulation of mesenchyme-associated genes. However, the functional relevance of their downregulation to reprogramming remains poorly defined. In this study, we have screened transcriptional regulators that are downregulated immediately upon reprogramming, presumably through direct targeting by reprogramming factors. To test if these transcriptional regulators impact reprogramming when expressed continuously, we generated an expression vector that harbors human cytomegalovirus upstream open reading frame 2 (uORF2), which reduces translation to minimize the detrimental effect of an expressed protein. Screening of transcriptional regulators with this expression vector revealed that downregulation of (odd-skipped related 2 [Osr2]) is crucial for efficient reprogramming. Using a cell-based model for epithelial-mesenchymal transition (EMT), we show thatOsr2is a novel EMT regulator that acts through induction of transforming growth factor-β (TGF-β) signaling. During reprogramming,Osr2downregulation not only diminishes TGF-β signaling but also allows activation of Wnt signaling, thus promoting mesenchymal-epithelial transition (MET) toward acquisition of pluripotency. Our results illuminate the functional significance ofOsr2downregulation in erasing the mesenchymal phenotype at an early stage of somatic cell reprogramming.