Background—Preeclampsia (PE) is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human-specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in PE. Our study aims at investigating whether disturbed imprinting contributes to PE.Methods—We first aimed at confirming that PE is a disease of the placenta by generating and analysing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from normal and PE patients. Next, we identified differentially expressed genes (DEGs) in PE placenta, and intersected them with the list of human imprinted genes. We employed bioinformatics/statistical analyses to confirm association between imprinting and PE, and to predict biological processes affected in PE. Validation included epigenetic and cellular assays. Regarding human-specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque and mouse preimplantation embryogenesis.Results—We found disturbed placental imprinting in PE and revealed potential candidates, including GATA3 and DLX5, with poorly explored imprinted status and no prior association with PE. Due to loss of imprinting DLX5 was upregulated in 69% of PE placentas. Levels of DLX5 correlated with classical PE marker. DLX5 is expressed in human, but not in murine trophoblast. The DLX5^high phenotype resulted in reduced proliferation, increased metabolism and ER stress-response activation in trophoblasts in vitro. The transcriptional profile of such cells mimics the transcriptome of PE placentas. Pan-mammalian comparative analysis identified DLX5 as a part of the human-specific regulatory network of trophoblast differentiation.Conclusions—Our analysis provides evidence of a true association between disturbed imprinting, gene expression and PE. Due to disturbed imprinting, the upregulated DLX5 affects trophoblast proliferation. Our in vitro model might fill a vital niche in PE research. Human-specific regulatory circuitry of DLX5 might help to explain certain aspects of PE.

背景— 先兆子痫 (PE) 是一种复杂且常见的与胎盘病理相关的人类特异性妊娠综合征。人类特异性提供了智力和方法上​​的挑战，缺乏强大的模型系统。鉴于印记基因在人类胎盘中的作用以及印记基因对印记变化丧失的脆弱性，有广泛的推测，但没有强有力的证据表明印记基因与 PE 有关。我们的研究旨在调查受干扰的印记是否会导致 PE。方法— 我们首先旨在通过在充分表征的患者材料上生成和分析全基因组分子数据来确认 PE 是一种胎盘疾病。我们对来自正常和 PE 患者的多个胎盘样本进行了高通量转录组分析。接下来，我们鉴定了 PE 胎盘中的差异表达基因 (DEG)，并将它们与人类印迹基因列表相交。我们采用生物信息学/统计分析来确认印记和 PE 之间的关联，并预测 PE 影响的生物过程。验证包括表观遗传和细胞分析。关于人类特异性，我们建立了体外侵袭-分化滋养层模型。我们的比较系统发育分析涉及人类、猕猴和小鼠植入前胚胎发生的单细胞转录组数据。结果——我们发现 PE 中的胎盘印记受到干扰，并揭示了潜在的候选者，包括GATA3和DLX5，它们的印记状态探索很少，并且与 PE 没有先前的关联。由于印迹丢失，DLX5在 69% 的 PE 胎盘中上调。DLX5 水平与经典 PE 标志物相关。DLX5 在人中表达，但不在鼠滋养层中表达。DLX5^高表型导致体外滋养层细胞增殖减少、代谢增加和 ER 应激反应激活. 这种细胞的转录谱模拟了 PE 胎盘的转录组。泛哺乳动物比较分析确定DLX5是人类特异性滋养层分化调节网络的一部分。结论——我们的分析提供了干扰印记、基因表达和 PE 之间真正关联的证据。由于受干扰的印记，上调的DLX5影响滋养层增殖。我们的体外模型可能会填补 PE 研究中的一个重要领域。DLX5的人类特异性调节电路可能有助于解释 PE 的某些方面。