VGLL1 regulates extraembryonic lineage specification in human [RNA-Seq]. VGLL1 regulates extraembryonic lineage specification in human [RNA-Seq]

Placenta abnormality is one of the key reasons for early pregnancy loss but the regulatory mechanisms underlying placenta formation are largely unknown. Here, we applied a human naïve pluripotent stem cell (PSC) derived TE model to explore the driven regulatory machinery. We demonstrate that VGLL1 (vestigial like family member 1) is crucial for TE self-renewal and TE-specific gene expression, thus suppressing VGLL1 leads to severely impaired cell proliferation and skewed TE induction. VGLL1 exerts its function through interacting with TEAD4 (TEA domain transcription factor 4) and colocalize at target gene promoters and enhancers. Further investigation uncovers the enrichment of H3K27ac active histone marks at genomic regions occupied by VGLL1-TEAD4 complex, indicates a close association between them. Overall, our data reveals the critical function model of VGLL1-TEAD4 in human TE derivation, highlighting a potential interspecies difference between human and mouse TE induction. Overall design: Human naïve PSC were plated at a density of 100000 cells per well onextracellular matrix (ECM; Geltrex™)-coated 6-well plates and cultured with TE medium. Cells were collected for sequencing on day 5. For human TSC cells, cells cultured in TS-1 medium for five or six days were plated on Collagen IV coated 6-well plates and cultured with TSC medium. Cells cultured in TSC medium became morphologically stable after 2-3 passages.

胎盘异常是早期妊娠丢失的核心诱因之一，但胎盘形成的调控机制在很大程度上仍未被阐明。本研究采用源自人类原始多能干细胞（naïve pluripotent stem cell, PSC）的滋养外胚层（trophectoderm, TE）模型，探究其驱动性调控机制。研究证实，VGLL1（vestigial like family member 1）对滋养外胚层的自我更新及谱系特异性基因表达至关重要；抑制VGLL1会严重损害细胞增殖，并使滋养外胚层诱导过程出现显著偏差。VGLL1通过与TEAD4（TEA domain transcription factor 4）相互作用发挥功能，并共同定位于靶基因的启动子与增强子区域。进一步研究发现，H3K27ac活性组蛋白修饰在VGLL1-TEAD4复合物结合的基因组区域富集，提示二者存在紧密关联。综上，本研究数据揭示了VGLL1-TEAD4在人类滋养外胚层衍生过程中的关键功能模型，同时凸显了人类与小鼠滋养外胚层诱导过程中潜在的种间差异。

实验整体设计：将人类原始多能干细胞以每孔1×10^5个细胞的密度接种于包被细胞外基质（extracellular matrix, ECM；Geltrex™）的6孔板中，使用滋养外胚层培养基进行培养。于第5天收集细胞用于测序。对于人类滋养层干细胞（trophoblast stem cell, TSC），将在TS-1培养基中培养5至6天的细胞接种于包被IV型胶原蛋白的6孔板中，使用TSC培养基进行培养。经2-3次传代后，在TSC培养基中培养的细胞将获得稳定的形态学特征。