Department of Animal Sciences, Donald Henry Barron Reproductive and Perinatal Biology Research Program, and Genetics Institute, University of Florida, Gainesville, FL, USA.
Department of Animal Science, University of California, Davis, CA, USA.
Biol Reprod. 2021 Jul 2;105(1):52-63. doi: 10.1093/biolre/ioab075.
The WNT signaling system plays an important but paradoxical role in the regulation of pluripotency. In the cow, IWR-1, which inhibits canonical WNT activation and has WNT-independent actions, promotes the derivation of primed pluripotent embryonic stem cells from the blastocyst. Here, we describe a series of experiments to determine whether derivation of embryonic stem cells could be generated by replacing IWR-1 with other inhibitors of WNT signaling. Results confirm the importance of inhibition of canonical WNT signaling for the establishment of pluripotent embryonic stem cells in cattle and indicate that the actions of IWR-1 can be mimicked by the WNT secretion inhibitor IWP2 but not by the tankyrase inhibitor XAV939 or WNT inhibitory protein dickkopf 1. The role of Janus kinase-mediated signaling pathways for the maintenance of pluripotency of embryonic stem cells was also evaluated. Maintenance of pluripotency of embryonic stem cells lines was blocked by a broad inhibitor of Janus kinase, even though the cells did not express phosphorylated signal transducer and activator of transcription 3 (pSTAT3). Further studies with blastocysts indicated that IWR-1 blocks the activation of pSTAT3. A likely explanation is that IWR-1 blocks differentiation of embryonic stem cells into a pSTAT3+ lineage. In conclusion, results presented here indicate the importance of inhibition of WNT signaling for the derivation of pluripotent bovine embryonic stem cells, the role of Janus kinase signaling for maintenance of pluripotency, and the participation of IWR-1 in the inhibition of activation of STAT3.
WNT 信号系统在多能性调控中发挥着重要但矛盾的作用。在奶牛中，抑制经典 WNT 激活且具有 WNT 非依赖性作用的 IWR-1 可促进囊胚中原始多能胚胎干细胞的衍生。在这里，我们描述了一系列实验，以确定是否可以用其他 WNT 信号抑制剂替代 IWR-1 来生成胚胎干细胞。结果证实了抑制经典 WNT 信号对牛多能胚胎干细胞建立的重要性，并表明 IWR-1 的作用可以被 WNT 分泌抑制剂 IWP2 模拟，但不能被 tankyrase 抑制剂 XAV939 或 WNT 抑制蛋白 dickkopf 1 模拟。还评估了 Janus 激酶介导的信号通路对胚胎干细胞多能性维持的作用。尽管细胞不表达磷酸化信号转导和转录激活因子 3(pSTAT3)，但广谱 Janus 激酶抑制剂阻断了胚胎干细胞多能性的维持。对囊胚的进一步研究表明，IWR-1 阻断了 pSTAT3 的激活。一个可能的解释是，IWR-1 阻止了胚胎干细胞分化为 pSTAT3+谱系。总之，这里提出的结果表明，抑制 WNT 信号对衍生多能牛胚胎干细胞的重要性、Janus 激酶信号对多能性维持的作用以及 IWR-1 参与抑制 STAT3 激活的作用。
