采用单细胞RNA测序技术研究卵裂球表达谱与植入前胚胎质量评估的分子机理

The molecular mechanism of human embryonic development has not yet been fully revealed, and most of the previous researches focused on embryos regarding morphology and karyotype. The advent of single-cell deep-sequencing technology aids in effective analysis of gene structure and expression in a single blastomere. Our project has investigated 43 embryos from 9 donors, including 2 donors of high-fragmentation embryos and 2 donors of underdeveloped embryos. Our present protocol showed very high reproducibility, reflected by correlation coefficients of > 0.95 with the results in the published literatures of normal embryos, and > 0.98 within blastomeres from the same embryo. We defined 10 gene sets of coordinated expression in normal embryos, which may be critical in the early embryonic development. Our results of medium-to-low grading embryos showed that in severely fragmented embryos there were three gene sets perturbed, and in underdeveloped embryos there were five gene sets disturbed. Our initial analysis concluded that genes responsible for chromosomal disassembly/assembly and for protein synthesis are critical in normal division and development of embryos. We propose thus to expand the size of cohort in order to define developmental markers for normal embryos and reveal pathological mechanism of abnormal embryos by means of functional genomics and big data analysis, so as to provide molecular evidence for improving preimplantation embryo assessment.

人类胚胎发育的分子机理尚未完全阐明，既往研究主要集中在胚胎的形态和染色体核型等。新出现的单细胞测序技术能有效分析单个卵裂球的基因结构及其表达。本课题组前期实验采用单细胞RNA测序技术分析来源于9个供体的43个胚胎，包括2个高度碎片化供体和2个发育迟缓供体。正常胚胎基因表达谱与既往文献报道的相关性超过0.95，而同一胚胎各卵裂球之间相关性超过0.98，显示了实验方案的可靠性。初步分析显示，正常胚胎存在10个共表达基因群，可能对胚胎早期发育起重要作用。而高度碎片化胚胎中3个基因群被扰动，发育迟缓胚胎中2个基因群被扰动。预实验结果提示：负责染色体解构和重构的基因群和负责蛋白质合成的基因群是影响胚胎正常发育的关键因素。本研究拟扩大样本数，从功能基因组角度结合大数据分析，鉴定胚胎特定发育时期的分子标记，并探索不良发育胚胎的分子病理机制，为完善植入前胚胎质量评估体系提供分子层面的科学依据。

本项目通过单细胞组学技术研究胚胎发育极早期异常的分子机制。为此我们按照严格规范建立起极早期发育胚胎队列，包含碎片化、发育迟缓和单原核胚胎三种常见发育异常。单细胞基因组学和单细胞转录组学被用于检测发育异常的可能机制。我们由此鉴定出一系列相关基因，并发现若干与胚胎早期发育关系密切的功能模块，为临床诊断和机理研究提供一定的理论依据。