How to integrate a fate: explicating the context-dependent molecular mechanisms of WNT signalling in early human embryogenesis

WNT信号通路在胚胎发育、干细胞动力学和癌症中发挥着一系列关键作用(Cleves，2006，《自然》)。虽然发育生物学和癌症生物学是一枚硬币的两面，但WNT信号通路目前是一个紧张的研究领域。然而，尽管已经描述了一些机制，但我们在我们自己物种的发育背景下的理解需要一个复杂的询问。一项跨物种转录分析揭示了WNT信号在人类和猴子植入前胚胎发育中以前未被认识到的作用(Boroviak等人，2015；Stirparo等人，2018，Development Cell and Development)。更令人兴奋的是，来自种植后绒猴胚胎的证据揭示了规范和非规范WNT信号的特征(Bergmann等人，未发表的数据)。此外，我们关于胚胎干细胞中WNT信号的大部分知识都归功于对小鼠胚胎中天真的多能干细胞的研究。目前繁殖人类幼稚ES细胞的培养条件需要WNT抑制，而WNT激活允许小鼠ES细胞长期自我更新。这一根本差异揭示了人类和小鼠着床前发育的急剧差异，因此需要更深入的研究。在这里，我的目标是使用干细胞模型和胚胎剖析规范的WNT信号通路在人类早期胚胎发生中的作用。将使用RT-qPCR、免疫荧光、芯片序列、单细胞RNA测序、合成mRNA过表达、siRNA介导的敲除和CRISPR-Cas9靶向突变来研究这一点。

The WNT signalling pathway plays a range of crucial role in embryonic development, stem cell dynamics and cancer (Clevers, 2006, Nature). Whilst developmental and cancer biology are two sides of the same coin, the WNT signalling pathway currently is a field of intense research. However, whilst some of the mechanisms have been characterised, our understanding in a developmental context in our own species requires a sophisticated interrogation. A cross-species transcriptomic analysis revealed a previously unappreciated role for WNT signalling in human and monkey preimplantation embryonic development (Boroviak et al., 2015; Stirparo et al., 2018, Developmental Cell and Development). More excitingly, evidence from postimplantation marmoset embryos reveals hallmarks of canonical and non-canonical WNT signalling (Bergmann et al, unpublished data). Further to this, the majority of our knowledge surrounding WNT signalling in embryonic stem cells is owed to research in naïve pluripotent stem cells from mouse embryos. Current culturing regeimes to propagate human naïve ES cells require WNT inhibition, in contrast where WNT activation permits long term self-renewal of mouse ES cells. This fundamental difference reveals a sharp divergence in human and mouse preimplantation development and thus, requires a more in-depth investigation.Here, I aim to dissect the roles of the canonical WNT signalling pathway throughout early human embryogenesis using stem cell models and embryos. This will be investigated using RT-qPCR, immunofluorescence, ChIP-seq, single-cell RNA sequencing, synthetic mRNA overexpression, siRNA-mediated knockdown and CRISPR-CAS9 targeted mutagenesis.