DataSheet1_Mosaic results after preimplantation genetic testing for aneuploidy may be accompanied by changes in global gene expression.DOCX

Aneuploidy in preimplantation embryos is a major cause of human reproductive failure. Unlike uniformly aneuploid embryos, embryos diagnosed as diploid-aneuploid mosaics after preimplantation genetic testing for aneuploidy (PGT-A) can develop into healthy infants. However, the reason why these embryos achieve full reproductive competence needs further research. Current RNA sequencing techniques allow for the investigation of the human preimplantation transcriptome, providing new insights into the molecular mechanisms of embryo development. In this prospective study, using euploid embryo gene expression as a control, we compared the transcriptome profiles of inner cell mass and trophectoderm samples from blastocysts with different levels of chromosomal mosaicism. A total of 25 samples were analyzed from 14 blastocysts with previous PGT-A diagnosis, including five low-level mosaic embryos and four high-level mosaic embryos. Global gene expression profiles visualized in cluster heatmaps were correlated with the original PGT-A diagnosis. In addition, gene expression distance based on the number of differentially expressed genes increased with the mosaic level, compared to euploid controls. Pathways involving apoptosis, mitosis, protein degradation, metabolism, and mitochondrial energy production were among the most deregulated within mosaic embryos. Retrospective analysis of the duration of blastomere cell cycles in mosaic embryos revealed several mitotic delays compared to euploid controls, providing additional evidence of the mosaic status. Overall, these findings suggest that embryos with mosaic results are not simply a misdiagnosis by-product, but may also have a genuine molecular identity that is compatible with their reproductive potential.

非整倍体在胚胎植入前是导致人类生殖失败的主要原因。与均匀的非整倍体胚胎不同，经过植入前非整倍体遗传学检测（PGT-A）被诊断为二倍体-非整倍体嵌合体的胚胎，仍有可能发育成健康的婴儿。然而，这些胚胎如何实现完全的生殖能力尚需进一步研究。当前的RNA测序技术允许对人类胚胎植入前转录组进行研究，为胚胎发育的分子机制提供了新的见解。在本项前瞻性研究中，以二倍体胚胎基因表达作为对照，我们比较了来自不同染色体嵌合水平囊胚的内细胞团和外胚层样本的转录组特征。共分析了14个先前PGT-A诊断的囊胚的25个样本，包括5个低级别嵌合胚胎和4个高级别嵌合胚胎。在聚类热图中可视化的全局基因表达谱与原始的PGT-A诊断相关联。此外，基于差异表达基因数量的基因表达距离与二倍体对照相比，随着嵌合水平的增加而增加。涉及细胞凋亡、有丝分裂、蛋白质降解、代谢和线粒体能量产生的通路在嵌合胚胎中最易失调。对嵌合胚胎中滋养层细胞周期持续时间的回顾性分析揭示了与二倍体对照相比的几个有丝分裂延迟，这为嵌合状态提供了额外的证据。总体而言，这些发现表明，嵌合结果并非仅仅是误诊的副产品，这些胚胎可能拥有与其生殖潜力相匹配的真实分子身份。